[feat]: complete RHI api

6 files changed, 1271 insertions, 2918 deletions

diff --git a/src/platform/vulkan/vulkan_context.cpp b/src/platform/vulkan/vulkan_context.cpp
deleted file mode 100644
index ece7700..0000000
--- a/src/platform/vulkan/vulkan_context.cpp
+++ /dev/null
@@ -1,789 +0,0 @@
-#include "vulkan_context.h"
-#include "core/log.h"
-
-#include <vulkan/vulkan.h>
-
-#include <glm/glm.hpp>
-#include <glm/gtc/type_ptr.hpp>
-#include "stb_image_write.h"
-
-#include <vector>
-#include <cstring>
-#include <cstdlib>
-#include <fstream>
-
-namespace Donut
-{
-    // Logs and returns false from the enclosing function on any non-success result.
-    #define VK_CHECK(expr)                                                     \
-        do {                                                                   \
-            VkResult _r = (expr);                                              \
-            if (_r != VK_SUCCESS) {                                            \
-                DONUT_ERROR("Vulkan: {} failed ({})", #expr, (int)_r);         \
-                return false;                                                  \
-            }                                                                  \
-        } while (0)
-
-    struct VulkanContext::Impl
-    {
-        VkInstance       instance       = VK_NULL_HANDLE;
-        VkPhysicalDevice physical       = VK_NULL_HANDLE;
-        VkDevice         device         = VK_NULL_HANDLE;
-        VkQueue          graphics_queue  = VK_NULL_HANDLE;
-        uint32_t         graphics_family = 0;
-        VkPhysicalDeviceMemoryProperties mem_props{};
-
-        auto find_memory_type(uint32_t type_filter, VkMemoryPropertyFlags flags) const -> uint32_t
-        {
-            for (uint32_t i = 0; i < mem_props.memoryTypeCount; ++i)
-                if ((type_filter & (1u << i)) &&
-                    (mem_props.memoryTypes[i].propertyFlags & flags) == flags)
-                    return i;
-            return UINT32_MAX;
-        }
-
-        bool create_buffer(VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags props,
-                          VkBuffer& buf, VkDeviceMemory& mem) const
-        {
-            VkBufferCreateInfo bci{ VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
-            bci.size = size; bci.usage = usage; bci.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
-            if (vkCreateBuffer(device, &bci, nullptr, &buf) != VK_SUCCESS) return false;
-            VkMemoryRequirements req{}; vkGetBufferMemoryRequirements(device, buf, &req);
-            VkMemoryAllocateInfo ai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-            ai.allocationSize = req.size;
-            ai.memoryTypeIndex = find_memory_type(req.memoryTypeBits, props);
-            if (vkAllocateMemory(device, &ai, nullptr, &mem) != VK_SUCCESS) return false;
-            vkBindBufferMemory(device, buf, mem, 0);
-            return true;
-        }
-    };
-
-    VulkanContext::VulkanContext()  { m_impl = new Impl(); }
-    VulkanContext::~VulkanContext() { shutdown(); delete m_impl; m_impl = nullptr; }
-
-    auto VulkanContext::init() -> bool
-    {
-        Impl& v = *m_impl;
-
-#ifdef __APPLE__
-        // The Homebrew Vulkan loader does not auto-discover MoltenVK or the
-        // validation layers; point it at both unless already configured.
-        if (!getenv("VK_ICD_FILENAMES"))
-            setenv("VK_ICD_FILENAMES", "/opt/homebrew/etc/vulkan/icd.d/MoltenVK_icd.json", 0);
-        if (!getenv("VK_LAYER_PATH"))
-            setenv("VK_LAYER_PATH", "/opt/homebrew/share/vulkan/explicit_layer.d", 0);
-#endif
-
-        // Instance
-        VkApplicationInfo app{ VK_STRUCTURE_TYPE_APPLICATION_INFO };
-        app.pApplicationName = "Donut";
-        app.apiVersion       = VK_API_VERSION_1_2;
-
-        // MoltenVK is a portability driver: without the portability-enumeration
-        // extension + flag, vkEnumeratePhysicalDevices returns zero devices.
-        std::vector<const char*> exts = {
-            VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME,
-            VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME,
-        };
-
-        // Enable validation layers when they are installed (optional).
-        std::vector<const char*> layers;
-        uint32_t layer_count = 0;
-        vkEnumerateInstanceLayerProperties(&layer_count, nullptr);
-        std::vector<VkLayerProperties> avail(layer_count);
-        vkEnumerateInstanceLayerProperties(&layer_count, avail.data());
-        for (const auto& l : avail)
-            if (std::strcmp(l.layerName, "VK_LAYER_KHRONOS_validation") == 0)
-                layers.push_back("VK_LAYER_KHRONOS_validation");
-
-        VkInstanceCreateInfo ici{ VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO };
-        ici.flags                   = VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR;
-        ici.pApplicationInfo        = &app;
-        ici.enabledExtensionCount   = (uint32_t)exts.size();
-        ici.ppEnabledExtensionNames = exts.data();
-        ici.enabledLayerCount       = (uint32_t)layers.size();
-        ici.ppEnabledLayerNames     = layers.data();
-        VK_CHECK(vkCreateInstance(&ici, nullptr, &v.instance));
-
-        // Physical device
-        uint32_t device_count = 0;
-        vkEnumeratePhysicalDevices(v.instance, &device_count, nullptr);
-        if (device_count == 0) { DONUT_ERROR("Vulkan: no physical devices"); return false; }
-        std::vector<VkPhysicalDevice> devices(device_count);
-        vkEnumeratePhysicalDevices(v.instance, &device_count, devices.data());
-        v.physical = devices[0];
-
-        VkPhysicalDeviceProperties props{};
-        vkGetPhysicalDeviceProperties(v.physical, &props);
-        vkGetPhysicalDeviceMemoryProperties(v.physical, &v.mem_props);
-
-        // Graphics queue family
-        uint32_t q_count = 0;
-        vkGetPhysicalDeviceQueueFamilyProperties(v.physical, &q_count, nullptr);
-        std::vector<VkQueueFamilyProperties> qfams(q_count);
-        vkGetPhysicalDeviceQueueFamilyProperties(v.physical, &q_count, qfams.data());
-        bool found = false;
-        for (uint32_t i = 0; i < q_count; ++i)
-            if (qfams[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) { v.graphics_family = i; found = true; break; }
-        if (!found) { DONUT_ERROR("Vulkan: no graphics queue family"); return false; }
-
-        // Logical device
-        // MoltenVK requires VK_KHR_portability_subset to be enabled if present.
-        std::vector<const char*> dev_exts;
-        uint32_t dev_ext_count = 0;
-        vkEnumerateDeviceExtensionProperties(v.physical, nullptr, &dev_ext_count, nullptr);
-        std::vector<VkExtensionProperties> dev_ext_props(dev_ext_count);
-        vkEnumerateDeviceExtensionProperties(v.physical, nullptr, &dev_ext_count, dev_ext_props.data());
-        for (const auto& e : dev_ext_props)
-            if (std::strcmp(e.extensionName, "VK_KHR_portability_subset") == 0)
-                dev_exts.push_back("VK_KHR_portability_subset");
-
-        float priority = 1.0f;
-        VkDeviceQueueCreateInfo qci{ VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO };
-        qci.queueFamilyIndex = v.graphics_family;
-        qci.queueCount       = 1;
-        qci.pQueuePriorities = &priority;
-
-        VkDeviceCreateInfo dci{ VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO };
-        dci.queueCreateInfoCount    = 1;
-        dci.pQueueCreateInfos       = &qci;
-        dci.enabledExtensionCount   = (uint32_t)dev_exts.size();
-        dci.ppEnabledExtensionNames = dev_exts.data();
-        VK_CHECK(vkCreateDevice(v.physical, &dci, nullptr, &v.device));
-        vkGetDeviceQueue(v.device, v.graphics_family, 0, &v.graphics_queue);
-
-        DONUT_INFO("Vulkan device: {} (API {}.{}.{}, validation {})",
-                   props.deviceName,
-                   VK_API_VERSION_MAJOR(props.apiVersion),
-                   VK_API_VERSION_MINOR(props.apiVersion),
-                   VK_API_VERSION_PATCH(props.apiVersion),
-                   layers.empty() ? "off" : "on");
-        return true;
-    }
-
-    auto VulkanContext::self_test_clear() -> bool
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) return false;
-
-        const uint32_t W = 64, H = 64;
-        const VkFormat fmt = VK_FORMAT_R8G8B8A8_UNORM;
-
-        // Offscreen colour image
-        VkImage image = VK_NULL_HANDLE; VkDeviceMemory image_mem = VK_NULL_HANDLE;
-        VkImageCreateInfo ici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        ici.imageType   = VK_IMAGE_TYPE_2D;
-        ici.format      = fmt;
-        ici.extent      = { W, H, 1 };
-        ici.mipLevels   = 1;
-        ici.arrayLayers = 1;
-        ici.samples     = VK_SAMPLE_COUNT_1_BIT;
-        ici.tiling      = VK_IMAGE_TILING_OPTIMAL;
-        ici.usage       = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
-        ici.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
-        VK_CHECK(vkCreateImage(v.device, &ici, nullptr, &image));
-
-        VkMemoryRequirements im_req{};
-        vkGetImageMemoryRequirements(v.device, image, &im_req);
-        VkMemoryAllocateInfo im_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        im_alloc.allocationSize  = im_req.size;
-        im_alloc.memoryTypeIndex = v.find_memory_type(im_req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(v.device, &im_alloc, nullptr, &image_mem));
-        VK_CHECK(vkBindImageMemory(v.device, image, image_mem, 0));
-
-        VkImageView view = VK_NULL_HANDLE;
-        VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        vci.image    = image;
-        vci.viewType = VK_IMAGE_VIEW_TYPE_2D;
-        vci.format   = fmt;
-        vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-        VK_CHECK(vkCreateImageView(v.device, &vci, nullptr, &view));
-
-        // Render pass (clear -> store, leave in TRANSFER_SRC for readback)
-        VkAttachmentDescription color{};
-        color.format         = fmt;
-        color.samples        = VK_SAMPLE_COUNT_1_BIT;
-        color.loadOp         = VK_ATTACHMENT_LOAD_OP_CLEAR;
-        color.storeOp        = VK_ATTACHMENT_STORE_OP_STORE;
-        color.stencilLoadOp  = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
-        color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        color.initialLayout  = VK_IMAGE_LAYOUT_UNDEFINED;
-        color.finalLayout    = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
-
-        VkAttachmentReference color_ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{};
-        subpass.pipelineBindPoint    = VK_PIPELINE_BIND_POINT_GRAPHICS;
-        subpass.colorAttachmentCount = 1;
-        subpass.pColorAttachments    = &color_ref;
-
-        // Ensure colour writes finish before the read-back copy.
-        VkSubpassDependency dep{};
-        dep.srcSubpass    = 0;
-        dep.dstSubpass    = VK_SUBPASS_EXTERNAL;
-        dep.srcStageMask  = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
-        dep.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        dep.dstStageMask  = VK_PIPELINE_STAGE_TRANSFER_BIT;
-        dep.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
-
-        VkRenderPass render_pass = VK_NULL_HANDLE;
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 1; rpci.pAttachments = &color;
-        rpci.subpassCount    = 1; rpci.pSubpasses   = &subpass;
-        rpci.dependencyCount = 1; rpci.pDependencies = &dep;
-        VK_CHECK(vkCreateRenderPass(v.device, &rpci, nullptr, &render_pass));
-
-        VkFramebuffer fb = VK_NULL_HANDLE;
-        VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-        fbci.renderPass = render_pass;
-        fbci.attachmentCount = 1; fbci.pAttachments = &view;
-        fbci.width = W; fbci.height = H; fbci.layers = 1;
-        VK_CHECK(vkCreateFramebuffer(v.device, &fbci, nullptr, &fb));
-
-        // Host-visible staging buffer for read-back
-        VkBuffer staging = VK_NULL_HANDLE; VkDeviceMemory staging_mem = VK_NULL_HANDLE;
-        VkBufferCreateInfo bci{ VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
-        bci.size  = (VkDeviceSize)W * H * 4;
-        bci.usage = VK_BUFFER_USAGE_TRANSFER_DST_BIT;
-        bci.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
-        VK_CHECK(vkCreateBuffer(v.device, &bci, nullptr, &staging));
-        VkMemoryRequirements b_req{};
-        vkGetBufferMemoryRequirements(v.device, staging, &b_req);
-        VkMemoryAllocateInfo b_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        b_alloc.allocationSize  = b_req.size;
-        b_alloc.memoryTypeIndex = v.find_memory_type(b_req.memoryTypeBits,
-            VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);
-        VK_CHECK(vkAllocateMemory(v.device, &b_alloc, nullptr, &staging_mem));
-        VK_CHECK(vkBindBufferMemory(v.device, staging, staging_mem, 0));
-
-        // Command buffer: clear via render pass, then copy image -> buffer
-        VkCommandPool pool = VK_NULL_HANDLE;
-        VkCommandPoolCreateInfo pci{ VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO };
-        pci.queueFamilyIndex = v.graphics_family;
-        VK_CHECK(vkCreateCommandPool(v.device, &pci, nullptr, &pool));
-
-        VkCommandBuffer cmd = VK_NULL_HANDLE;
-        VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
-        cbai.commandPool = pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
-        VK_CHECK(vkAllocateCommandBuffers(v.device, &cbai, &cmd));
-
-        VkCommandBufferBeginInfo begin{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO };
-        begin.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
-        VK_CHECK(vkBeginCommandBuffer(cmd, &begin));
-
-        VkClearValue clear{};
-        clear.color = { { 0.2f, 0.4f, 0.8f, 1.0f } };   // -> RGBA8 (51, 102, 204, 255)
-        VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-        rpbi.renderPass = render_pass; rpbi.framebuffer = fb;
-        rpbi.renderArea = { { 0, 0 }, { W, H } };
-        rpbi.clearValueCount = 1; rpbi.pClearValues = &clear;
-        vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
-        vkCmdEndRenderPass(cmd);
-
-        VkBufferImageCopy region{};
-        region.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
-        region.imageExtent      = { W, H, 1 };
-        vkCmdCopyImageToBuffer(cmd, image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, staging, 1, &region);
-        VK_CHECK(vkEndCommandBuffer(cmd));
-
-        VkFence fence = VK_NULL_HANDLE;
-        VkFenceCreateInfo fci{ VK_STRUCTURE_TYPE_FENCE_CREATE_INFO };
-        VK_CHECK(vkCreateFence(v.device, &fci, nullptr, &fence));
-        VkSubmitInfo submit{ VK_STRUCTURE_TYPE_SUBMIT_INFO };
-        submit.commandBufferCount = 1; submit.pCommandBuffers = &cmd;
-        VK_CHECK(vkQueueSubmit(v.graphics_queue, 1, &submit, fence));
-        VK_CHECK(vkWaitForFences(v.device, 1, &fence, VK_TRUE, UINT64_MAX));
-
-        // Read back + verify
-        void* mapped = nullptr;
-        VK_CHECK(vkMapMemory(v.device, staging_mem, 0, bci.size, 0, &mapped));
-        const uint8_t* px = (const uint8_t*)mapped;
-        DONUT_INFO("Vulkan clear self-test: pixel RGBA = ({}, {}, {}, {})",
-                   (int)px[0], (int)px[1], (int)px[2], (int)px[3]);
-        bool ok = px[0] > 45 && px[0] < 60 && px[1] > 95 && px[1] < 110 &&
-                  px[2] > 195 && px[2] < 210 && px[3] == 255;
-        vkUnmapMemory(v.device, staging_mem);
-        DONUT_INFO("Vulkan clear self-test: {}", ok ? "PASS" : "FAIL");
-
-        // Cleanup
-        vkDestroyFence(v.device, fence, nullptr);
-        vkDestroyCommandPool(v.device, pool, nullptr);
-        vkDestroyBuffer(v.device, staging, nullptr);
-        vkFreeMemory(v.device, staging_mem, nullptr);
-        vkDestroyFramebuffer(v.device, fb, nullptr);
-        vkDestroyRenderPass(v.device, render_pass, nullptr);
-        vkDestroyImageView(v.device, view, nullptr);
-        vkDestroyImage(v.device, image, nullptr);
-        vkFreeMemory(v.device, image_mem, nullptr);
-        return ok;
-    }
-
-    static std::vector<uint32_t> load_spirv(const std::string& path)
-    {
-        std::ifstream f(path, std::ios::binary | std::ios::ate);
-        if (!f) return {};
-        size_t size = (size_t)f.tellg();
-        std::vector<uint32_t> data(size / 4);
-        f.seekg(0);
-        f.read((char*)data.data(), (std::streamsize)size);
-        return data;
-    }
-
-    auto VulkanContext::self_test_triangle() -> bool
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) return false;
-
-        const uint32_t W = 64, H = 64;
-        const VkFormat fmt = VK_FORMAT_R8G8B8A8_UNORM;
-
-        // Offscreen image + view (as in the clear test)
-        VkImage image = VK_NULL_HANDLE; VkDeviceMemory image_mem = VK_NULL_HANDLE;
-        VkImageCreateInfo ici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        ici.imageType = VK_IMAGE_TYPE_2D; ici.format = fmt; ici.extent = { W, H, 1 };
-        ici.mipLevels = 1; ici.arrayLayers = 1; ici.samples = VK_SAMPLE_COUNT_1_BIT;
-        ici.tiling = VK_IMAGE_TILING_OPTIMAL;
-        ici.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
-        VK_CHECK(vkCreateImage(v.device, &ici, nullptr, &image));
-        VkMemoryRequirements im_req{}; vkGetImageMemoryRequirements(v.device, image, &im_req);
-        VkMemoryAllocateInfo im_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        im_alloc.allocationSize = im_req.size;
-        im_alloc.memoryTypeIndex = v.find_memory_type(im_req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(v.device, &im_alloc, nullptr, &image_mem));
-        VK_CHECK(vkBindImageMemory(v.device, image, image_mem, 0));
-        VkImageView view = VK_NULL_HANDLE;
-        VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        vci.image = image; vci.viewType = VK_IMAGE_VIEW_TYPE_2D; vci.format = fmt;
-        vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-        VK_CHECK(vkCreateImageView(v.device, &vci, nullptr, &view));
-
-        // Render pass + framebuffer
-        VkAttachmentDescription color{};
-        color.format = fmt; color.samples = VK_SAMPLE_COUNT_1_BIT;
-        color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
-        color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; color.finalLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
-        VkAttachmentReference color_ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{};
-        subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
-        subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &color_ref;
-        VkSubpassDependency dep{};
-        dep.srcSubpass = 0; dep.dstSubpass = VK_SUBPASS_EXTERNAL;
-        dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; dep.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        dep.dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT; dep.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
-        VkRenderPass render_pass = VK_NULL_HANDLE;
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 1; rpci.pAttachments = &color;
-        rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
-        rpci.dependencyCount = 1; rpci.pDependencies = &dep;
-        VK_CHECK(vkCreateRenderPass(v.device, &rpci, nullptr, &render_pass));
-        VkFramebuffer fb = VK_NULL_HANDLE;
-        VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-        fbci.renderPass = render_pass; fbci.attachmentCount = 1; fbci.pAttachments = &view;
-        fbci.width = W; fbci.height = H; fbci.layers = 1;
-        VK_CHECK(vkCreateFramebuffer(v.device, &fbci, nullptr, &fb));
-
-        // Shader modules from Slang SPIR-V
-        auto vspv = load_spirv("assets/shaders/generated/VkPipelineTest.vertexMain.spv");
-        auto fspv = load_spirv("assets/shaders/generated/VkPipelineTest.fragmentMain.spv");
-        if (vspv.empty() || fspv.empty()) { DONUT_ERROR("Vulkan: VkPipelineTest SPIR-V not found"); return false; }
-        VkShaderModule vmod = VK_NULL_HANDLE, fmod = VK_NULL_HANDLE;
-        VkShaderModuleCreateInfo smci{ VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO };
-        smci.codeSize = vspv.size() * 4; smci.pCode = vspv.data();
-        VK_CHECK(vkCreateShaderModule(v.device, &smci, nullptr, &vmod));
-        smci.codeSize = fspv.size() * 4; smci.pCode = fspv.data();
-        VK_CHECK(vkCreateShaderModule(v.device, &smci, nullptr, &fmod));
-
-        // Graphics pipeline
-        VkPipelineShaderStageCreateInfo stages[2]{};
-        stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
-        stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
-        stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
-        stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
-
-        VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-        VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO };
-        ia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-        VkViewport vp{ 0, 0, (float)W, (float)H, 0, 1 };
-        VkRect2D scissor{ { 0, 0 }, { W, H } };
-        VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO };
-        vps.viewportCount = 1; vps.pViewports = &vp; vps.scissorCount = 1; vps.pScissors = &scissor;
-        VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO };
-        rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
-        VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO };
-        ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-        VkPipelineColorBlendAttachmentState cba{};
-        cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-        VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO };
-        cb.attachmentCount = 1; cb.pAttachments = &cba;
-
-        VkPipelineLayout layout = VK_NULL_HANDLE;
-        VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO };
-        VK_CHECK(vkCreatePipelineLayout(v.device, &plci, nullptr, &layout));
-
-        VkPipeline pipeline = VK_NULL_HANDLE;
-        VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-        gpci.stageCount = 2; gpci.pStages = stages;
-        gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia;
-        gpci.pViewportState = &vps; gpci.pRasterizationState = &rs;
-        gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb;
-        gpci.layout = layout; gpci.renderPass = render_pass; gpci.subpass = 0;
-        VK_CHECK(vkCreateGraphicsPipelines(v.device, VK_NULL_HANDLE, 1, &gpci, nullptr, &pipeline));
-
-        // Readback staging buffer
-        VkBuffer staging = VK_NULL_HANDLE; VkDeviceMemory staging_mem = VK_NULL_HANDLE;
-        VkBufferCreateInfo bci{ VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
-        bci.size = (VkDeviceSize)W * H * 4; bci.usage = VK_BUFFER_USAGE_TRANSFER_DST_BIT;
-        VK_CHECK(vkCreateBuffer(v.device, &bci, nullptr, &staging));
-        VkMemoryRequirements b_req{}; vkGetBufferMemoryRequirements(v.device, staging, &b_req);
-        VkMemoryAllocateInfo b_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        b_alloc.allocationSize = b_req.size;
-        b_alloc.memoryTypeIndex = v.find_memory_type(b_req.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);
-        VK_CHECK(vkAllocateMemory(v.device, &b_alloc, nullptr, &staging_mem));
-        VK_CHECK(vkBindBufferMemory(v.device, staging, staging_mem, 0));
-
-        // Record + submit
-        VkCommandPool pool = VK_NULL_HANDLE;
-        VkCommandPoolCreateInfo pci{ VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO };
-        pci.queueFamilyIndex = v.graphics_family;
-        VK_CHECK(vkCreateCommandPool(v.device, &pci, nullptr, &pool));
-        VkCommandBuffer cmd = VK_NULL_HANDLE;
-        VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
-        cbai.commandPool = pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
-        VK_CHECK(vkAllocateCommandBuffers(v.device, &cbai, &cmd));
-        VkCommandBufferBeginInfo begin{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO };
-        begin.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
-        VK_CHECK(vkBeginCommandBuffer(cmd, &begin));
-        VkClearValue clear{}; clear.color = { { 0.0f, 0.0f, 0.0f, 1.0f } };
-        VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-        rpbi.renderPass = render_pass; rpbi.framebuffer = fb;
-        rpbi.renderArea = { { 0, 0 }, { W, H } };
-        rpbi.clearValueCount = 1; rpbi.pClearValues = &clear;
-        vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
-        vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
-        vkCmdDraw(cmd, 3, 1, 0, 0);
-        vkCmdEndRenderPass(cmd);
-        VkBufferImageCopy region{};
-        region.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
-        region.imageExtent = { W, H, 1 };
-        vkCmdCopyImageToBuffer(cmd, image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, staging, 1, &region);
-        VK_CHECK(vkEndCommandBuffer(cmd));
-
-        VkFence fence = VK_NULL_HANDLE;
-        VkFenceCreateInfo fci{ VK_STRUCTURE_TYPE_FENCE_CREATE_INFO };
-        VK_CHECK(vkCreateFence(v.device, &fci, nullptr, &fence));
-        VkSubmitInfo submit{ VK_STRUCTURE_TYPE_SUBMIT_INFO };
-        submit.commandBufferCount = 1; submit.pCommandBuffers = &cmd;
-        VK_CHECK(vkQueueSubmit(v.graphics_queue, 1, &submit, fence));
-        VK_CHECK(vkWaitForFences(v.device, 1, &fence, VK_TRUE, UINT64_MAX));
-
-        // Verify: centre pixel should be the mid-gradient (not black)
-        void* mapped = nullptr;
-        VK_CHECK(vkMapMemory(v.device, staging_mem, 0, bci.size, 0, &mapped));
-        const uint8_t* px = (const uint8_t*)mapped;
-        size_t c = ((size_t)(H / 2) * W + (W / 2)) * 4;
-        DONUT_INFO("Vulkan triangle self-test: centre pixel RGBA = ({}, {}, {}, {})",
-                   (int)px[c + 0], (int)px[c + 1], (int)px[c + 2], (int)px[c + 3]);
-        bool ok = (px[c + 0] > 40 || px[c + 1] > 40) && px[c + 3] == 255;
-        vkUnmapMemory(v.device, staging_mem);
-        DONUT_INFO("Vulkan triangle self-test: {}", ok ? "PASS" : "FAIL");
-
-        // Cleanup
-        vkDestroyFence(v.device, fence, nullptr);
-        vkDestroyCommandPool(v.device, pool, nullptr);
-        vkDestroyBuffer(v.device, staging, nullptr);
-        vkFreeMemory(v.device, staging_mem, nullptr);
-        vkDestroyPipeline(v.device, pipeline, nullptr);
-        vkDestroyPipelineLayout(v.device, layout, nullptr);
-        vkDestroyShaderModule(v.device, vmod, nullptr);
-        vkDestroyShaderModule(v.device, fmod, nullptr);
-        vkDestroyFramebuffer(v.device, fb, nullptr);
-        vkDestroyRenderPass(v.device, render_pass, nullptr);
-        vkDestroyImageView(v.device, view, nullptr);
-        vkDestroyImage(v.device, image, nullptr);
-        vkFreeMemory(v.device, image_mem, nullptr);
-        return ok;
-    }
-
-    auto VulkanContext::render_geodesic(const char* png_path) -> bool
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) return false;
-
-        const uint32_t W = 384, H = 216;
-        const VkFormat fmt = VK_FORMAT_R8G8B8A8_UNORM;
-        const float SagA_rs = 1.269e10f;
-
-        // Offscreen colour target
-        VkImage image = VK_NULL_HANDLE; VkDeviceMemory image_mem = VK_NULL_HANDLE;
-        VkImageCreateInfo ici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        ici.imageType = VK_IMAGE_TYPE_2D; ici.format = fmt; ici.extent = { W, H, 1 };
-        ici.mipLevels = 1; ici.arrayLayers = 1; ici.samples = VK_SAMPLE_COUNT_1_BIT;
-        ici.tiling = VK_IMAGE_TILING_OPTIMAL;
-        ici.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
-        VK_CHECK(vkCreateImage(v.device, &ici, nullptr, &image));
-        VkMemoryRequirements im_req{}; vkGetImageMemoryRequirements(v.device, image, &im_req);
-        VkMemoryAllocateInfo im_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        im_alloc.allocationSize = im_req.size;
-        im_alloc.memoryTypeIndex = v.find_memory_type(im_req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(v.device, &im_alloc, nullptr, &image_mem));
-        VK_CHECK(vkBindImageMemory(v.device, image, image_mem, 0));
-        VkImageView view = VK_NULL_HANDLE;
-        VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        vci.image = image; vci.viewType = VK_IMAGE_VIEW_TYPE_2D; vci.format = fmt;
-        vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-        VK_CHECK(vkCreateImageView(v.device, &vci, nullptr, &view));
-
-        VkAttachmentDescription color{};
-        color.format = fmt; color.samples = VK_SAMPLE_COUNT_1_BIT;
-        color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
-        color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; color.finalLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
-        VkAttachmentReference color_ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
-        subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &color_ref;
-        VkSubpassDependency dep{};
-        dep.srcSubpass = 0; dep.dstSubpass = VK_SUBPASS_EXTERNAL;
-        dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; dep.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        dep.dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT; dep.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
-        VkRenderPass render_pass = VK_NULL_HANDLE;
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 1; rpci.pAttachments = &color;
-        rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
-        rpci.dependencyCount = 1; rpci.pDependencies = &dep;
-        VK_CHECK(vkCreateRenderPass(v.device, &rpci, nullptr, &render_pass));
-        VkFramebuffer fb = VK_NULL_HANDLE;
-        VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-        fbci.renderPass = render_pass; fbci.attachmentCount = 1; fbci.pAttachments = &view;
-        fbci.width = W; fbci.height = H; fbci.layers = 1;
-        VK_CHECK(vkCreateFramebuffer(v.device, &fbci, nullptr, &fb));
-
-        // Uniform buffers (host-visible), filled to match the shader's std140 layout
-        const VkMemoryPropertyFlags host_vis = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
-        VkBuffer cam_buf, disk_buf, obj_buf, sim_buf;
-        VkDeviceMemory cam_mem, disk_mem, obj_mem, sim_mem;
-        v.create_buffer(128, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, cam_buf, cam_mem);
-        v.create_buffer(32,  VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, disk_buf, disk_mem);
-        v.create_buffer(800, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, obj_buf, obj_mem);
-        v.create_buffer(16,  VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, sim_buf, sim_mem);
-
-        struct CamUBO {
-            glm::vec3 pos; float p0; glm::vec3 right; float p1;
-            glm::vec3 up; float p2; glm::vec3 fwd; float p3;
-            float tan_half_fov; float aspect; uint32_t moving; int p4;
-        } cam{};
-        glm::vec3 cam_pos(1e11f, 0.32e11f, 0.0f);
-        glm::vec3 fwd = glm::normalize(glm::vec3(0.0f) - cam_pos);
-        glm::vec3 right = glm::normalize(glm::cross(fwd, glm::vec3(0, 1, 0)));
-        glm::vec3 up = glm::cross(right, fwd);
-        cam.pos = cam_pos; cam.right = right; cam.up = up; cam.fwd = fwd;
-        cam.tan_half_fov = 0.57735f; cam.aspect = (float)W / (float)H; cam.moving = 0;
-        void* p = nullptr;
-        vkMapMemory(v.device, cam_mem, 0, 128, 0, &p); memcpy(p, &cam, sizeof(cam)); vkUnmapMemory(v.device, cam_mem);
-
-        float disk[8] = { SagA_rs * 2.2f, SagA_rs * 5.2f, 2.0f, SagA_rs * 0.1f, 0.1f, 0, 0, 0 };
-        vkMapMemory(v.device, disk_mem, 0, 32, 0, &p); memcpy(p, disk, sizeof(disk)); vkUnmapMemory(v.device, disk_mem);
-
-        std::vector<uint8_t> obj_data(800, 0);
-        int num_objects = 1; memcpy(obj_data.data(), &num_objects, 4);
-        float pos_radius[4] = { 0, 0, 0, SagA_rs }; memcpy(obj_data.data() + 16, pos_radius, 16);
-        float obj_color[4] = { 0, 0, 0, 1 };        memcpy(obj_data.data() + 272, obj_color, 16);
-        vkMapMemory(v.device, obj_mem, 0, 800, 0, &p); memcpy(p, obj_data.data(), 800); vkUnmapMemory(v.device, obj_mem);
-
-        struct SimUBO { int steps_moving; int steps_static; float early_exit; float time; } sim{ 6000, 6000, 5e12f, 0.0f };
-        vkMapMemory(v.device, sim_mem, 0, 16, 0, &p); memcpy(p, &sim, sizeof(sim)); vkUnmapMemory(v.device, sim_mem);
-
-        // Dark cubemap (stands in for the HDRI for now)
-        VkImage cube = VK_NULL_HANDLE; VkDeviceMemory cube_mem = VK_NULL_HANDLE;
-        VkImageCreateInfo cci{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        cci.flags = VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT;
-        cci.imageType = VK_IMAGE_TYPE_2D; cci.format = fmt; cci.extent = { 1, 1, 1 };
-        cci.mipLevels = 1; cci.arrayLayers = 6; cci.samples = VK_SAMPLE_COUNT_1_BIT;
-        cci.tiling = VK_IMAGE_TILING_OPTIMAL;
-        cci.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
-        VK_CHECK(vkCreateImage(v.device, &cci, nullptr, &cube));
-        VkMemoryRequirements cube_req{}; vkGetImageMemoryRequirements(v.device, cube, &cube_req);
-        VkMemoryAllocateInfo cube_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        cube_alloc.allocationSize = cube_req.size;
-        cube_alloc.memoryTypeIndex = v.find_memory_type(cube_req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(v.device, &cube_alloc, nullptr, &cube_mem));
-        VK_CHECK(vkBindImageMemory(v.device, cube, cube_mem, 0));
-        VkImageView cube_view = VK_NULL_HANDLE;
-        VkImageViewCreateInfo cvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        cvci.image = cube; cvci.viewType = VK_IMAGE_VIEW_TYPE_CUBE; cvci.format = fmt;
-        cvci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 6 };
-        VK_CHECK(vkCreateImageView(v.device, &cvci, nullptr, &cube_view));
-        VkSampler sampler = VK_NULL_HANDLE;
-        VkSamplerCreateInfo smci{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
-        smci.magFilter = VK_FILTER_LINEAR; smci.minFilter = VK_FILTER_LINEAR;
-        smci.addressModeU = smci.addressModeV = smci.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
-        VK_CHECK(vkCreateSampler(v.device, &smci, nullptr, &sampler));
-
-        VkBuffer cube_staging; VkDeviceMemory cube_staging_mem;
-        v.create_buffer(6 * 4, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, host_vis, cube_staging, cube_staging_mem);
-        uint8_t cube_pixels[6 * 4];
-        for (int i = 0; i < 6; ++i) { cube_pixels[i * 4 + 0] = 6; cube_pixels[i * 4 + 1] = 6; cube_pixels[i * 4 + 2] = 14; cube_pixels[i * 4 + 3] = 255; }
-        vkMapMemory(v.device, cube_staging_mem, 0, 24, 0, &p); memcpy(p, cube_pixels, 24); vkUnmapMemory(v.device, cube_staging_mem);
-
-        // Descriptor set: 4 UBOs (bindings 0-3) + cubemap sampler (binding 4)
-        VkDescriptorSetLayoutBinding binds[5]{};
-        for (int i = 0; i < 4; ++i) { binds[i].binding = i; binds[i].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; binds[i].descriptorCount = 1; binds[i].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT; }
-        binds[4].binding = 4; binds[4].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; binds[4].descriptorCount = 1; binds[4].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-        VkDescriptorSetLayout set_layout = VK_NULL_HANDLE;
-        VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO };
-        dslci.bindingCount = 5; dslci.pBindings = binds;
-        VK_CHECK(vkCreateDescriptorSetLayout(v.device, &dslci, nullptr, &set_layout));
-        VkDescriptorPoolSize psizes[2] = { { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 4 }, { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1 } };
-        VkDescriptorPool pool = VK_NULL_HANDLE;
-        VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO };
-        dpci.maxSets = 1; dpci.poolSizeCount = 2; dpci.pPoolSizes = psizes;
-        VK_CHECK(vkCreateDescriptorPool(v.device, &dpci, nullptr, &pool));
-        VkDescriptorSet set = VK_NULL_HANDLE;
-        VkDescriptorSetAllocateInfo dsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO };
-        dsai.descriptorPool = pool; dsai.descriptorSetCount = 1; dsai.pSetLayouts = &set_layout;
-        VK_CHECK(vkAllocateDescriptorSets(v.device, &dsai, &set));
-
-        // load geodesic SPIR-V + build the pipeline
-        auto vspv = load_spirv("assets/shaders/generated/Geodesic.vertexMain.spv");
-        auto fspv = load_spirv("assets/shaders/generated/Geodesic.fragmentMain.spv");
-        if (vspv.empty() || fspv.empty()) { DONUT_ERROR("Vulkan: geodesic SPIR-V not found"); return false; }
-        VkShaderModule vmod, fmod;
-        VkShaderModuleCreateInfo smci2{ VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO };
-        smci2.codeSize = vspv.size() * 4; smci2.pCode = vspv.data(); VK_CHECK(vkCreateShaderModule(v.device, &smci2, nullptr, &vmod));
-        smci2.codeSize = fspv.size() * 4; smci2.pCode = fspv.data(); VK_CHECK(vkCreateShaderModule(v.device, &smci2, nullptr, &fmod));
-
-        VkPipelineLayout layout = VK_NULL_HANDLE;
-        VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO };
-        plci.setLayoutCount = 1; plci.pSetLayouts = &set_layout;
-        VK_CHECK(vkCreatePipelineLayout(v.device, &plci, nullptr, &layout));
-
-        VkPipelineShaderStageCreateInfo stages[2]{};
-        stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
-        stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
-        VkVertexInputBindingDescription vib{ 0, 16, VK_VERTEX_INPUT_RATE_VERTEX };
-        VkVertexInputAttributeDescription via[2] = { { 0, 0, VK_FORMAT_R32G32_SFLOAT, 0 }, { 1, 0, VK_FORMAT_R32G32_SFLOAT, 8 } };
-        VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-        vin.vertexBindingDescriptionCount = 1; vin.pVertexBindingDescriptions = &vib;
-        vin.vertexAttributeDescriptionCount = 2; vin.pVertexAttributeDescriptions = via;
-        VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-        VkViewport vp{ 0, 0, (float)W, (float)H, 0, 1 }; VkRect2D sc{ { 0, 0 }, { W, H } };
-        VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.pViewports = &vp; vps.scissorCount = 1; vps.pScissors = &sc;
-        VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
-        VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-        VkPipelineColorBlendAttachmentState cba{}; cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-        VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
-        VkPipeline pipeline = VK_NULL_HANDLE;
-        VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-        gpci.stageCount = 2; gpci.pStages = stages;
-        gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
-        gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb;
-        gpci.layout = layout; gpci.renderPass = render_pass; gpci.subpass = 0;
-        VK_CHECK(vkCreateGraphicsPipelines(v.device, VK_NULL_HANDLE, 1, &gpci, nullptr, &pipeline));
-
-        // Fullscreen quad (position.xy, texcoord.uv)
-        float quad[] = {
-            -1.f,  1.f, 0.f, 1.f,  -1.f, -1.f, 0.f, 0.f,   1.f, -1.f, 1.f, 0.f,
-            -1.f,  1.f, 0.f, 1.f,   1.f, -1.f, 1.f, 0.f,   1.f,  1.f, 1.f, 1.f,
-        };
-        VkBuffer vbuf; VkDeviceMemory vbuf_mem;
-        v.create_buffer(sizeof(quad), VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, vbuf, vbuf_mem);
-        vkMapMemory(v.device, vbuf_mem, 0, sizeof(quad), 0, &p); memcpy(p, quad, sizeof(quad)); vkUnmapMemory(v.device, vbuf_mem);
-
-        // Write the descriptor set
-        VkDescriptorBufferInfo bi[4] = {
-            { cam_buf, 0, VK_WHOLE_SIZE }, { disk_buf, 0, VK_WHOLE_SIZE }, { obj_buf, 0, VK_WHOLE_SIZE }, { sim_buf, 0, VK_WHOLE_SIZE } };
-        VkDescriptorImageInfo ii{ sampler, cube_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-        VkWriteDescriptorSet writes[5]{};
-        for (int i = 0; i < 4; ++i) { writes[i].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; writes[i].dstSet = set; writes[i].dstBinding = i; writes[i].descriptorCount = 1; writes[i].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; writes[i].pBufferInfo = &bi[i]; }
-        writes[4].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; writes[4].dstSet = set; writes[4].dstBinding = 4; writes[4].descriptorCount = 1; writes[4].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; writes[4].pImageInfo = &ii;
-        vkUpdateDescriptorSets(v.device, 5, writes, 0, nullptr);
-
-        VkBuffer readback; VkDeviceMemory readback_mem;
-        v.create_buffer((VkDeviceSize)W * H * 4, VK_BUFFER_USAGE_TRANSFER_DST_BIT, host_vis, readback, readback_mem);
-
-        // Record + submit
-        VkCommandPool cpool = VK_NULL_HANDLE;
-        VkCommandPoolCreateInfo pci{ VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO }; pci.queueFamilyIndex = v.graphics_family;
-        VK_CHECK(vkCreateCommandPool(v.device, &pci, nullptr, &cpool));
-        VkCommandBuffer cmd = VK_NULL_HANDLE;
-        VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO }; cbai.commandPool = cpool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
-        VK_CHECK(vkAllocateCommandBuffers(v.device, &cbai, &cmd));
-        VkCommandBufferBeginInfo begin{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO }; begin.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
-        VK_CHECK(vkBeginCommandBuffer(cmd, &begin));
-
-        VkImageMemoryBarrier to_dst{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-        to_dst.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; to_dst.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
-        to_dst.image = cube; to_dst.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 6 };
-        to_dst.srcAccessMask = 0; to_dst.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
-        vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &to_dst);
-        VkBufferImageCopy cube_copy{}; cube_copy.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 6 }; cube_copy.imageExtent = { 1, 1, 1 };
-        vkCmdCopyBufferToImage(cmd, cube_staging, cube, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &cube_copy);
-        VkImageMemoryBarrier to_read = to_dst;
-        to_read.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; to_read.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-        to_read.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; to_read.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-        vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &to_read);
-
-        VkClearValue clear{}; clear.color = { { 0, 0, 0, 1 } };
-        VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-        rpbi.renderPass = render_pass; rpbi.framebuffer = fb; rpbi.renderArea = { { 0, 0 }, { W, H } };
-        rpbi.clearValueCount = 1; rpbi.pClearValues = &clear;
-        vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
-        vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
-        vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, layout, 0, 1, &set, 0, nullptr);
-        VkDeviceSize voff = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &vbuf, &voff);
-        vkCmdDraw(cmd, 6, 1, 0, 0);
-        vkCmdEndRenderPass(cmd);
-        VkBufferImageCopy region{}; region.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 }; region.imageExtent = { W, H, 1 };
-        vkCmdCopyImageToBuffer(cmd, image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, readback, 1, &region);
-        VK_CHECK(vkEndCommandBuffer(cmd));
-
-        VkFence fence = VK_NULL_HANDLE; VkFenceCreateInfo fci{ VK_STRUCTURE_TYPE_FENCE_CREATE_INFO };
-        VK_CHECK(vkCreateFence(v.device, &fci, nullptr, &fence));
-        VkSubmitInfo submit{ VK_STRUCTURE_TYPE_SUBMIT_INFO }; submit.commandBufferCount = 1; submit.pCommandBuffers = &cmd;
-        VK_CHECK(vkQueueSubmit(v.graphics_queue, 1, &submit, fence));
-        VK_CHECK(vkWaitForFences(v.device, 1, &fence, VK_TRUE, UINT64_MAX));
-
-        vkMapMemory(v.device, readback_mem, 0, (VkDeviceSize)W * H * 4, 0, &p);
-        stbi_write_png(png_path, W, H, 4, p, W * 4);
-        vkUnmapMemory(v.device, readback_mem);
-        DONUT_INFO("Vulkan geodesic render written to {}", png_path);
-
-        vkDestroyFence(v.device, fence, nullptr);
-        vkDestroyCommandPool(v.device, cpool, nullptr);
-        vkDestroyBuffer(v.device, readback, nullptr); vkFreeMemory(v.device, readback_mem, nullptr);
-        vkDestroyBuffer(v.device, vbuf, nullptr); vkFreeMemory(v.device, vbuf_mem, nullptr);
-        vkDestroyPipeline(v.device, pipeline, nullptr); vkDestroyPipelineLayout(v.device, layout, nullptr);
-        vkDestroyShaderModule(v.device, vmod, nullptr); vkDestroyShaderModule(v.device, fmod, nullptr);
-        vkDestroyDescriptorPool(v.device, pool, nullptr); vkDestroyDescriptorSetLayout(v.device, set_layout, nullptr);
-        vkDestroySampler(v.device, sampler, nullptr); vkDestroyImageView(v.device, cube_view, nullptr);
-        vkDestroyImage(v.device, cube, nullptr); vkFreeMemory(v.device, cube_mem, nullptr);
-        vkDestroyBuffer(v.device, cube_staging, nullptr); vkFreeMemory(v.device, cube_staging_mem, nullptr);
-        vkDestroyBuffer(v.device, cam_buf, nullptr); vkFreeMemory(v.device, cam_mem, nullptr);
-        vkDestroyBuffer(v.device, disk_buf, nullptr); vkFreeMemory(v.device, disk_mem, nullptr);
-        vkDestroyBuffer(v.device, obj_buf, nullptr); vkFreeMemory(v.device, obj_mem, nullptr);
-        vkDestroyBuffer(v.device, sim_buf, nullptr); vkFreeMemory(v.device, sim_mem, nullptr);
-        vkDestroyFramebuffer(v.device, fb, nullptr); vkDestroyRenderPass(v.device, render_pass, nullptr);
-        vkDestroyImageView(v.device, view, nullptr); vkDestroyImage(v.device, image, nullptr); vkFreeMemory(v.device, image_mem, nullptr);
-        return true;
-    }
-
-    auto VulkanContext::shutdown() -> void
-    {
-        Impl& v = *m_impl;
-        if (v.device)   { vkDestroyDevice(v.device, nullptr);   v.device = VK_NULL_HANDLE; }
-        if (v.instance) { vkDestroyInstance(v.instance, nullptr); v.instance = VK_NULL_HANDLE; }
-    }
-
-    auto vulkan_self_test() -> bool
-    {
-        VulkanContext ctx;
-        if (!ctx.init())
-        {
-            DONUT_ERROR("Vulkan: initialization failed");
-            return false;
-        }
-        bool ok = ctx.self_test_clear();
-        ok = ctx.self_test_triangle() && ok;
-        ctx.shutdown();
-        return ok;
-    }
-}
diff --git a/src/platform/vulkan/vulkan_context.h b/src/platform/vulkan/vulkan_context.h
deleted file mode 100644
index de57c90..0000000
--- a/src/platform/vulkan/vulkan_context.h
+++ /dev/null
@@ -1,41 +0,0 @@
-#pragma once
-
-// Pure-C++ interface to the Vulkan backend (no vulkan.h leaks into the rest of
-// the engine; the implementation lives in VulkanContext.cpp). On macOS Vulkan
-// runs through MoltenVK (Vulkan -> Metal).
-namespace Donut
-{
-    class VulkanContext
-    {
-    public:
-        VulkanContext();
-        ~VulkanContext();
-
-        // Creates the instance, picks a physical device, and creates the logical
-        // device + graphics queue. Returns false (and logs) on failure.
-        auto init() -> bool;
-        auto shutdown() -> void;
-
-        // Phase 1 verification: renders a known clear colour into an offscreen
-        // image and reads it back, confirming instance -> device -> render pass
-        // -> command buffer -> submit -> read-back all work end to end.
-        auto self_test_clear() -> bool;
-
-        // Phase 2/3 verification: builds a graphics pipeline from Slang-compiled
-        // SPIR-V and draws a full-screen gradient triangle into the offscreen
-        // image, confirming the SPIR-V -> pipeline -> draw path works.
-        auto self_test_triangle() -> bool;
-
-        // B-3: renders the geodesic (black hole) fragment shader through Vulkan
-        // into an offscreen image and writes it to pngPath. Exercises UBOs,
-        // descriptor sets, a cubemap sampler and the geodesic pipeline.
-        auto render_geodesic(const char* pngPath) -> bool;
-
-    private:
-        struct Impl;
-        Impl* m_impl = nullptr;
-    };
-
-    // Convenience one-shot: init() + self_test_clear() + shutdown(). Logs results.
-    auto vulkan_self_test() -> bool;
-}
diff --git a/src/platform/vulkan/vulkan_device.cpp b/src/platform/vulkan/vulkan_device.cpp
new file mode 100644
index 0000000..4311d0c
--- /dev/null
+++ b/src/platform/vulkan/vulkan_device.cpp
@@ -0,0 +1,1254 @@
+#include "vulkan_device.h"
+
+#include "core/log.h"
+
+#define GLFW_INCLUDE_VULKAN
+#include <GLFW/glfw3.h>
+
+#include <imgui.h>
+#include <imgui_impl_glfw.h>
+#include <imgui_impl_vulkan.h>
+
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include "stb_image.h"
+
+#include <vector>
+#include <array>
+#include <algorithm>
+#include <cstring>
+#include <cstdlib>
+#include <fstream>
+
+namespace Donut::RHI
+{
+    namespace
+    {
+        constexpr int MAX_FRAMES_IN_FLIGHT = 2;
+        constexpr uint32_t MAX_BINDINGS = 8;
+
+        #define VKD_CHECK(expr)                                            \
+            do {                                                           \
+                VkResult _r = (expr);                                      \
+                if (_r != VK_SUCCESS) {                                    \
+                    DONUT_ERROR("Vulkan RHI: {} failed ({})", #expr, (int)_r); \
+                    return false;                                          \
+                }                                                          \
+            } while (0)
+
+        auto vk_format(Format f) -> VkFormat
+        {
+            switch (f) {
+                case Format::RGBA16F: return VK_FORMAT_R16G16B16A16_SFLOAT;
+                case Format::D32:     return VK_FORMAT_D32_SFLOAT;
+                default:              return VK_FORMAT_R8G8B8A8_UNORM;
+            }
+        }
+        auto vk_attr_format(uint32_t comps) -> VkFormat
+        {
+            switch (comps) {
+                case 1:  return VK_FORMAT_R32_SFLOAT;
+                case 2:  return VK_FORMAT_R32G32_SFLOAT;
+                case 3:  return VK_FORMAT_R32G32B32_SFLOAT;
+                default: return VK_FORMAT_R32G32B32A32_SFLOAT;
+            }
+        }
+        auto vk_topology(Topology t) -> VkPrimitiveTopology
+        { return t == Topology::Lines ? VK_PRIMITIVE_TOPOLOGY_LINE_LIST : VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; }
+        auto vk_compare(CompareOp o) -> VkCompareOp
+        { return o == CompareOp::Always ? VK_COMPARE_OP_ALWAYS : o == CompareOp::LessEqual ? VK_COMPARE_OP_LESS_OR_EQUAL : VK_COMPARE_OP_LESS; }
+        auto vk_filter(Filter f) -> VkFilter { return f == Filter::Nearest ? VK_FILTER_NEAREST : VK_FILTER_LINEAR; }
+        auto vk_cull(CullMode c) -> VkCullModeFlags
+        { return c == CullMode::None ? VK_CULL_MODE_NONE : c == CullMode::Back ? VK_CULL_MODE_BACK_BIT : VK_CULL_MODE_FRONT_BIT; }
+
+        class VulkanDevice;
+
+        // ---- Buffer: host-visible + coherent, persistently mapped -----------
+        class VkBufferR : public Buffer
+        {
+        public:
+            VkBufferR(VkDevice d, VkBuffer b, VkDeviceMemory m, void* mapped, size_t size)
+                : m_device(d), m_buf(b), m_mem(m), m_mapped(mapped), m_size(size) {}
+            ~VkBufferR() override
+            {
+                if (m_mapped) vkUnmapMemory(m_device, m_mem);
+                if (m_buf) vkDestroyBuffer(m_device, m_buf, nullptr);
+                if (m_mem) vkFreeMemory(m_device, m_mem, nullptr);
+            }
+            auto update(const void* data, size_t size) -> void override
+            { if (m_mapped) std::memcpy(m_mapped, data, std::min(size, m_size)); }
+
+            VkDevice m_device; VkBuffer m_buf; VkDeviceMemory m_mem; void* m_mapped; size_t m_size;
+        };
+
+        // ---- Texture: sampled image (2D or cube). Owns its handles unless it is
+        //      a borrowed wrapper around a render-target view. ------------------
+        class VkTextureR : public Texture
+        {
+        public:
+            VkTextureR() = default;
+            ~VkTextureR() override
+            {
+                if (!m_owns) return;
+                if (m_sampler) vkDestroySampler(m_device, m_sampler, nullptr);
+                if (m_view)    vkDestroyImageView(m_device, m_view, nullptr);
+                if (m_image)   vkDestroyImage(m_device, m_image, nullptr);
+                if (m_mem)     vkFreeMemory(m_device, m_mem, nullptr);
+            }
+            VkDevice      m_device  = VK_NULL_HANDLE;
+            VkImage       m_image   = VK_NULL_HANDLE;
+            VkDeviceMemory m_mem    = VK_NULL_HANDLE;
+            VkImageView   m_view    = VK_NULL_HANDLE;
+            VkSampler     m_sampler = VK_NULL_HANDLE;
+            bool          m_owns    = true;
+        };
+
+        // ---- RenderTarget: off-screen colour image + framebuffer ------------
+        class VkRenderTargetR : public RenderTarget
+        {
+        public:
+            ~VkRenderTargetR() override
+            {
+                if (m_fb)      vkDestroyFramebuffer(m_device, m_fb, nullptr);
+                if (m_sampler) vkDestroySampler(m_device, m_sampler, nullptr);
+                if (m_view)    vkDestroyImageView(m_device, m_view, nullptr);
+                if (m_image)   vkDestroyImage(m_device, m_image, nullptr);
+                if (m_mem)     vkFreeMemory(m_device, m_mem, nullptr);
+            }
+            auto width()  const -> int override { return m_w; }
+            auto height() const -> int override { return m_h; }
+            auto color_texture() -> Texture* override { return &m_color; }
+
+            VkDevice       m_device  = VK_NULL_HANDLE;
+            int            m_w = 0, m_h = 0;
+            VkImage        m_image   = VK_NULL_HANDLE;
+            VkDeviceMemory m_mem     = VK_NULL_HANDLE;
+            VkImageView    m_view    = VK_NULL_HANDLE;
+            VkSampler      m_sampler = VK_NULL_HANDLE;
+            VkFramebuffer  m_fb      = VK_NULL_HANDLE;
+            VkTextureR     m_color;   // borrowed wrapper (view+sampler) for sampling
+        };
+
+        // ---- Pipeline -------------------------------------------------------
+        class VkPipelineR : public Pipeline
+        {
+        public:
+            ~VkPipelineR() override
+            {
+                if (m_pipeline)   vkDestroyPipeline(m_device, m_pipeline, nullptr);
+                if (m_layout)     vkDestroyPipelineLayout(m_device, m_layout, nullptr);
+                if (m_set_layout) vkDestroyDescriptorSetLayout(m_device, m_set_layout, nullptr);
+            }
+            VkDevice              m_device      = VK_NULL_HANDLE;
+            VkPipeline            m_pipeline    = VK_NULL_HANDLE;
+            VkPipelineLayout      m_layout      = VK_NULL_HANDLE;
+            VkDescriptorSetLayout m_set_layout  = VK_NULL_HANDLE;
+            std::vector<ResourceSlot> m_resources;
+        };
+
+        // ---- CommandList ----------------------------------------------------
+        class VkCommandListR : public CommandList
+        {
+        public:
+            auto begin_render_pass(RenderTarget* target, const glm::vec4& clear) -> void override
+            {
+                VkClearValue cvs[2]{};
+                cvs[0].color = { { clear.r, clear.g, clear.b, clear.a } };
+                cvs[1].depthStencil = { 1.0f, 0 };
+                VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
+                if (target)
+                {
+                    auto* rt = static_cast<VkRenderTargetR*>(target);
+                    rpbi.renderPass = m_offscreen_rp; rpbi.framebuffer = rt->m_fb;
+                    rpbi.renderArea = { { 0, 0 }, { (uint32_t)rt->m_w, (uint32_t)rt->m_h } };
+                    rpbi.clearValueCount = 1; rpbi.pClearValues = cvs;
+                }
+                else
+                {
+                    rpbi.renderPass = m_swapchain_rp; rpbi.framebuffer = m_swapchain_fb;
+                    rpbi.renderArea = { { 0, 0 }, m_extent };
+                    rpbi.clearValueCount = 2; rpbi.pClearValues = cvs;
+                }
+                vkCmdBeginRenderPass(m_cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
+            }
+            auto end_render_pass() -> void override { vkCmdEndRenderPass(m_cmd); }
+
+            auto bind_pipeline(Pipeline* p) -> void override
+            {
+                m_pipe = static_cast<VkPipelineR*>(p);
+                vkCmdBindPipeline(m_cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, m_pipe->m_pipeline);
+            }
+            auto set_viewport(int x, int y, int w, int h, bool flip_y) -> void override
+            {
+                VkViewport vp{ (float)x, flip_y ? (float)(y + h) : (float)y,
+                               (float)w, flip_y ? -(float)h : (float)h, 0.0f, 1.0f };
+                VkRect2D sc{ { x, y }, { (uint32_t)w, (uint32_t)h } };
+                vkCmdSetViewport(m_cmd, 0, 1, &vp);
+                vkCmdSetScissor(m_cmd, 0, 1, &sc);
+            }
+            auto bind_uniform(uint32_t binding, Buffer* ubo) -> void override
+            {
+                if (binding >= MAX_BINDINGS) return;
+                m_buf_info[binding] = { static_cast<VkBufferR*>(ubo)->m_buf, 0, VK_WHOLE_SIZE };
+            }
+            auto bind_texture(uint32_t binding, Texture* texture) -> void override
+            {
+                if (binding >= MAX_BINDINGS) return;
+                auto* t = static_cast<VkTextureR*>(texture);
+                m_img_info[binding] = { t->m_sampler, t->m_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
+            }
+            auto bind_vertex_buffer(Buffer* vb) -> void override
+            {
+                VkBuffer b = static_cast<VkBufferR*>(vb)->m_buf; VkDeviceSize off = 0;
+                vkCmdBindVertexBuffers(m_cmd, 0, 1, &b, &off);
+            }
+            auto bind_index_buffer(Buffer* ib) -> void override
+            { vkCmdBindIndexBuffer(m_cmd, static_cast<VkBufferR*>(ib)->m_buf, 0, VK_INDEX_TYPE_UINT32); }
+            auto draw(uint32_t vertex_count) -> void override
+            { flush_descriptors(); vkCmdDraw(m_cmd, vertex_count, 1, 0, 0); }
+            auto draw_indexed(uint32_t index_count) -> void override
+            { flush_descriptors(); vkCmdDrawIndexed(m_cmd, index_count, 1, 0, 0, 0); }
+
+            // Allocate + write + bind a descriptor set for the current pipeline's
+            // declared resources, using whatever was bound since bind_pipeline.
+            auto flush_descriptors() -> void
+            {
+                if (!m_pipe || m_pipe->m_resources.empty()) return;
+                VkDescriptorSetAllocateInfo ai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO };
+                ai.descriptorPool = m_frame_pool; ai.descriptorSetCount = 1; ai.pSetLayouts = &m_pipe->m_set_layout;
+                VkDescriptorSet set = VK_NULL_HANDLE;
+                if (vkAllocateDescriptorSets(m_device, &ai, &set) != VK_SUCCESS)
+                { DONUT_ERROR("Vulkan RHI: descriptor set allocation failed"); return; }
+
+                std::array<VkWriteDescriptorSet, MAX_BINDINGS> writes{};
+                uint32_t n = 0;
+                for (const auto& r : m_pipe->m_resources)
+                {
+                    VkWriteDescriptorSet& w = writes[n++];
+                    w.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
+                    w.dstSet = set; w.dstBinding = r.binding; w.descriptorCount = 1;
+                    if (r.kind == ResourceKind::UniformBuffer)
+                    { w.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; w.pBufferInfo = &m_buf_info[r.binding]; }
+                    else
+                    { w.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; w.pImageInfo = &m_img_info[r.binding]; }
+                }
+                vkUpdateDescriptorSets(m_device, n, writes.data(), 0, nullptr);
+                vkCmdBindDescriptorSets(m_cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, m_pipe->m_layout, 0, 1, &set, 0, nullptr);
+            }
+
+            // Set by the device at begin_frame:
+            VkDevice        m_device       = VK_NULL_HANDLE;
+            VkCommandBuffer m_cmd          = VK_NULL_HANDLE;
+            VkRenderPass    m_swapchain_rp = VK_NULL_HANDLE;
+            VkRenderPass    m_offscreen_rp = VK_NULL_HANDLE;
+            VkFramebuffer   m_swapchain_fb = VK_NULL_HANDLE;
+            VkExtent2D      m_extent{};
+            VkDescriptorPool m_frame_pool  = VK_NULL_HANDLE;
+
+            VkPipelineR* m_pipe = nullptr;
+            VkDescriptorBufferInfo m_buf_info[MAX_BINDINGS]{};
+            VkDescriptorImageInfo  m_img_info[MAX_BINDINGS]{};
+        };
+
+        // ---- Device ---------------------------------------------------------
+        class VulkanDevice : public Device
+        {
+        public:
+            auto init(void* glfwWindow, int width, int height) -> bool override;
+            auto shutdown() -> void override;
+            auto resize(int width, int height) -> void override { m_framebuffer_resized = true; m_width = width; m_height = height; }
+            auto wait_idle() -> void override { if (m_device) vkDeviceWaitIdle(m_device); }
+
+            auto create_buffer(BufferType type, size_t size, const void* data) -> Ref<Buffer> override;
+            auto create_texture(int w, int h, Format format, Filter filter, const void* data) -> Ref<Texture> override;
+            auto create_cubemap_from_hdri(const std::string& path) -> Ref<Texture> override;
+            auto create_render_target(int w, int h, Format color, bool with_depth, Filter filter, int mips) -> Ref<RenderTarget> override;
+            auto create_pipeline(const PipelineDesc& desc) -> Ref<Pipeline> override;
+
+            auto begin_frame(const glm::vec4& clear) -> CommandList* override;
+            auto end_frame() -> void override;
+
+            auto init_imgui() -> void override;
+            auto imgui_new_frame() -> void override;
+            auto imgui_render(CommandList& cmds) -> void override;
+
+            auto device_name() const -> const std::string& override { return m_gpu_name; }
+
+            // --- internals ---
+            auto find_memory_type(uint32_t filter, VkMemoryPropertyFlags flags) const -> uint32_t;
+            auto create_buffer_raw(VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags props, VkBuffer& buf, VkDeviceMemory& mem) const -> bool;
+            auto load_spirv(const std::string& path) const -> std::vector<uint32_t>;
+            auto create_shader_module(const std::string& path, VkShaderModule& out) const -> bool;
+
+            auto create_instance() -> bool;
+            auto pick_physical_and_device() -> bool;
+            auto create_swapchain() -> bool;
+            auto create_image_views() -> bool;
+            auto create_swapchain_render_pass() -> bool;
+            auto create_offscreen_render_pass() -> bool;
+            auto create_depth_and_framebuffers() -> bool;
+            auto create_command_and_sync() -> bool;
+            auto recreate_swapchain() -> bool;
+            auto cleanup_swapchain() -> void;
+
+            GLFWwindow* m_window = nullptr;
+            int m_width = 0, m_height = 0;
+            bool m_framebuffer_resized = false;
+            std::string m_gpu_name;
+
+            VkInstance       m_instance = VK_NULL_HANDLE;
+            VkSurfaceKHR     m_surface  = VK_NULL_HANDLE;
+            VkPhysicalDevice m_physical = VK_NULL_HANDLE;
+            VkDevice         m_device   = VK_NULL_HANDLE;
+            uint32_t         m_graphics_family = 0, m_present_family = 0;
+            VkQueue          m_graphics_queue = VK_NULL_HANDLE, m_present_queue = VK_NULL_HANDLE;
+            VkPhysicalDeviceMemoryProperties m_mem_props{};
+
+            VkSwapchainKHR m_swapchain = VK_NULL_HANDLE;
+            VkFormat       m_swapchain_format = VK_FORMAT_B8G8R8A8_UNORM;
+            VkExtent2D     m_extent{};
+            std::vector<VkImage>       m_images;
+            std::vector<VkImageView>   m_image_views;
+            VkRenderPass               m_swapchain_rp = VK_NULL_HANDLE;
+            VkRenderPass               m_offscreen_rp = VK_NULL_HANDLE;
+            std::vector<VkFramebuffer> m_framebuffers;
+            VkImage m_depth_image = VK_NULL_HANDLE; VkDeviceMemory m_depth_mem = VK_NULL_HANDLE; VkImageView m_depth_view = VK_NULL_HANDLE;
+
+            VkCommandPool m_command_pool = VK_NULL_HANDLE;
+            std::vector<VkCommandBuffer> m_command_buffers;
+            std::vector<VkSemaphore> m_image_available;
+            std::vector<VkSemaphore> m_render_finished;
+            std::vector<VkFence>     m_in_flight;
+            std::vector<VkFence>     m_images_in_flight;
+            VkFence m_geo_in_use = VK_NULL_HANDLE;
+            uint32_t m_current_frame = 0, m_image_index = 0;
+
+            std::vector<VkDescriptorPool> m_frame_pools;    // one per frame in flight
+            VkDescriptorPool m_imgui_pool = VK_NULL_HANDLE;
+            bool m_imgui = false;
+
+            VkCommandListR m_cmds;
+        };
+
+        // ==================================================================
+        auto VulkanDevice::find_memory_type(uint32_t filter, VkMemoryPropertyFlags flags) const -> uint32_t
+        {
+            for (uint32_t i = 0; i < m_mem_props.memoryTypeCount; ++i)
+                if ((filter & (1u << i)) && (m_mem_props.memoryTypes[i].propertyFlags & flags) == flags)
+                    return i;
+            return UINT32_MAX;
+        }
+
+        auto VulkanDevice::create_buffer_raw(VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags props,
+                                             VkBuffer& buf, VkDeviceMemory& mem) const -> bool
+        {
+            VkBufferCreateInfo bci{ VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
+            bci.size = size; bci.usage = usage; bci.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
+            if (vkCreateBuffer(m_device, &bci, nullptr, &buf) != VK_SUCCESS) return false;
+            VkMemoryRequirements req{}; vkGetBufferMemoryRequirements(m_device, buf, &req);
+            VkMemoryAllocateInfo ai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
+            ai.allocationSize = req.size; ai.memoryTypeIndex = find_memory_type(req.memoryTypeBits, props);
+            if (vkAllocateMemory(m_device, &ai, nullptr, &mem) != VK_SUCCESS) return false;
+            vkBindBufferMemory(m_device, buf, mem, 0);
+            return true;
+        }
+
+        auto VulkanDevice::load_spirv(const std::string& path) const -> std::vector<uint32_t>
+        {
+            std::ifstream file(path, std::ios::ate | std::ios::binary);
+            if (!file.is_open()) return {};
+            size_t size = (size_t)file.tellg();
+            std::vector<uint32_t> data(size / 4);
+            file.seekg(0); file.read(reinterpret_cast<char*>(data.data()), size);
+            return data;
+        }
+
+        auto VulkanDevice::create_shader_module(const std::string& path, VkShaderModule& out) const -> bool
+        {
+            auto spv = load_spirv(path);
+            if (spv.empty()) { DONUT_ERROR("Vulkan RHI: failed to load SPIR-V {}", path); return false; }
+            VkShaderModuleCreateInfo ci{ VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO };
+            ci.codeSize = spv.size() * 4; ci.pCode = spv.data();
+            return vkCreateShaderModule(m_device, &ci, nullptr, &out) == VK_SUCCESS;
+        }
+
+        auto VulkanDevice::create_instance() -> bool
+        {
+            VkApplicationInfo app{ VK_STRUCTURE_TYPE_APPLICATION_INFO };
+            app.pApplicationName = "Donut"; app.apiVersion = VK_API_VERSION_1_2;
+
+            uint32_t glfwExtCount = 0;
+            const char** glfwExts = glfwGetRequiredInstanceExtensions(&glfwExtCount);
+            if (!glfwExts) { DONUT_ERROR("Vulkan RHI: GLFW reports no surface support"); return false; }
+            std::vector<const char*> exts(glfwExts, glfwExts + glfwExtCount);
+            exts.push_back(VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME);
+            exts.push_back(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME);
+
+            std::vector<const char*> layers;
+            uint32_t layer_count = 0; vkEnumerateInstanceLayerProperties(&layer_count, nullptr);
+            std::vector<VkLayerProperties> avail(layer_count);
+            vkEnumerateInstanceLayerProperties(&layer_count, avail.data());
+            for (const auto& l : avail)
+                if (std::strcmp(l.layerName, "VK_LAYER_KHRONOS_validation") == 0)
+                    layers.push_back("VK_LAYER_KHRONOS_validation");
+
+            VkInstanceCreateInfo ici{ VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO };
+            ici.flags = VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR;
+            ici.pApplicationInfo = &app;
+            ici.enabledExtensionCount = (uint32_t)exts.size(); ici.ppEnabledExtensionNames = exts.data();
+            ici.enabledLayerCount = (uint32_t)layers.size(); ici.ppEnabledLayerNames = layers.data();
+            VkResult r = vkCreateInstance(&ici, nullptr, &m_instance);
+            if (r != VK_SUCCESS && !layers.empty())
+            {
+                DONUT_WARN("Vulkan RHI: validation layer unavailable, continuing without it");
+                ici.enabledLayerCount = 0; ici.ppEnabledLayerNames = nullptr;
+                r = vkCreateInstance(&ici, nullptr, &m_instance);
+            }
+            if (r != VK_SUCCESS) { DONUT_ERROR("Vulkan RHI: vkCreateInstance failed ({})", (int)r); return false; }
+            VKD_CHECK(glfwCreateWindowSurface(m_instance, m_window, nullptr, &m_surface));
+            DONUT_INFO("Vulkan RHI: instance + surface created (validation {})", layers.empty() ? "off" : "on");
+            return true;
+        }
+
+        auto VulkanDevice::pick_physical_and_device() -> bool
+        {
+            uint32_t count = 0; vkEnumeratePhysicalDevices(m_instance, &count, nullptr);
+            if (count == 0) { DONUT_ERROR("Vulkan RHI: no physical devices"); return false; }
+            std::vector<VkPhysicalDevice> devices(count);
+            vkEnumeratePhysicalDevices(m_instance, &count, devices.data());
+            m_physical = devices[0];
+
+            uint32_t q = 0; vkGetPhysicalDeviceQueueFamilyProperties(m_physical, &q, nullptr);
+            std::vector<VkQueueFamilyProperties> qfams(q);
+            vkGetPhysicalDeviceQueueFamilyProperties(m_physical, &q, qfams.data());
+            bool fg = false, fp = false;
+            for (uint32_t i = 0; i < q; ++i)
+            {
+                if (!fg && (qfams[i].queueFlags & VK_QUEUE_GRAPHICS_BIT)) { m_graphics_family = i; fg = true; }
+                VkBool32 present = VK_FALSE; vkGetPhysicalDeviceSurfaceSupportKHR(m_physical, i, m_surface, &present);
+                if (!fp && present) { m_present_family = i; fp = true; }
+            }
+            if (!fg || !fp) { DONUT_ERROR("Vulkan RHI: no graphics/present queue"); return false; }
+
+            std::vector<const char*> dev_exts = { VK_KHR_SWAPCHAIN_EXTENSION_NAME };
+            uint32_t dec = 0; vkEnumerateDeviceExtensionProperties(m_physical, nullptr, &dec, nullptr);
+            std::vector<VkExtensionProperties> dep(dec);
+            vkEnumerateDeviceExtensionProperties(m_physical, nullptr, &dec, dep.data());
+            for (const auto& e : dep)
+                if (std::strcmp(e.extensionName, "VK_KHR_portability_subset") == 0)
+                    dev_exts.push_back("VK_KHR_portability_subset");
+
+            float priority = 1.0f;
+            std::vector<VkDeviceQueueCreateInfo> qcis;
+            uint32_t families[2] = { m_graphics_family, m_present_family };
+            for (uint32_t i = 0; i < (m_graphics_family == m_present_family ? 1u : 2u); ++i)
+            {
+                VkDeviceQueueCreateInfo qci{ VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO };
+                qci.queueFamilyIndex = families[i]; qci.queueCount = 1; qci.pQueuePriorities = &priority;
+                qcis.push_back(qci);
+            }
+            VkDeviceCreateInfo dci{ VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO };
+            dci.queueCreateInfoCount = (uint32_t)qcis.size(); dci.pQueueCreateInfos = qcis.data();
+            dci.enabledExtensionCount = (uint32_t)dev_exts.size(); dci.ppEnabledExtensionNames = dev_exts.data();
+            VKD_CHECK(vkCreateDevice(m_physical, &dci, nullptr, &m_device));
+            vkGetDeviceQueue(m_device, m_graphics_family, 0, &m_graphics_queue);
+            vkGetDeviceQueue(m_device, m_present_family, 0, &m_present_queue);
+
+            VkPhysicalDeviceProperties props{}; vkGetPhysicalDeviceProperties(m_physical, &props);
+            vkGetPhysicalDeviceMemoryProperties(m_physical, &m_mem_props);
+            m_gpu_name = props.deviceName;
+            DONUT_INFO("Vulkan RHI device: {}", m_gpu_name);
+            return true;
+        }
+
+        auto VulkanDevice::create_swapchain() -> bool
+        {
+            VkSurfaceCapabilitiesKHR caps{};
+            vkGetPhysicalDeviceSurfaceCapabilitiesKHR(m_physical, m_surface, &caps);
+            uint32_t fc = 0; vkGetPhysicalDeviceSurfaceFormatsKHR(m_physical, m_surface, &fc, nullptr);
+            std::vector<VkSurfaceFormatKHR> formats(fc);
+            vkGetPhysicalDeviceSurfaceFormatsKHR(m_physical, m_surface, &fc, formats.data());
+            VkSurfaceFormatKHR chosen = formats[0];
+            for (const auto& f : formats)
+                if (f.format == VK_FORMAT_B8G8R8A8_UNORM && f.colorSpace == VK_COLOR_SPACE_SRGB_NONLINEAR_KHR) chosen = f;
+            m_swapchain_format = chosen.format;
+
+            if (caps.currentExtent.width != UINT32_MAX) m_extent = caps.currentExtent;
+            else {
+                m_extent.width  = std::clamp((uint32_t)m_width,  caps.minImageExtent.width,  caps.maxImageExtent.width);
+                m_extent.height = std::clamp((uint32_t)m_height, caps.minImageExtent.height, caps.maxImageExtent.height);
+            }
+            uint32_t image_count = caps.minImageCount + 1;
+            if (caps.maxImageCount > 0 && image_count > caps.maxImageCount) image_count = caps.maxImageCount;
+
+            VkSwapchainCreateInfoKHR sci{ VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR };
+            sci.surface = m_surface; sci.minImageCount = image_count;
+            sci.imageFormat = chosen.format; sci.imageColorSpace = chosen.colorSpace;
+            sci.imageExtent = m_extent; sci.imageArrayLayers = 1;
+            sci.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
+            sci.preTransform = caps.currentTransform; sci.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
+            sci.presentMode = VK_PRESENT_MODE_FIFO_KHR; sci.clipped = VK_TRUE;
+            uint32_t fam[2] = { m_graphics_family, m_present_family };
+            if (m_graphics_family != m_present_family)
+            { sci.imageSharingMode = VK_SHARING_MODE_CONCURRENT; sci.queueFamilyIndexCount = 2; sci.pQueueFamilyIndices = fam; }
+            else sci.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
+            VKD_CHECK(vkCreateSwapchainKHR(m_device, &sci, nullptr, &m_swapchain));
+            uint32_t n = 0; vkGetSwapchainImagesKHR(m_device, m_swapchain, &n, nullptr);
+            m_images.resize(n); vkGetSwapchainImagesKHR(m_device, m_swapchain, &n, m_images.data());
+            return true;
+        }
+
+        auto VulkanDevice::create_image_views() -> bool
+        {
+            m_image_views.resize(m_images.size());
+            for (size_t i = 0; i < m_images.size(); ++i)
+            {
+                VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+                vci.image = m_images[i]; vci.viewType = VK_IMAGE_VIEW_TYPE_2D; vci.format = m_swapchain_format;
+                vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+                VKD_CHECK(vkCreateImageView(m_device, &vci, nullptr, &m_image_views[i]));
+            }
+            return true;
+        }
+
+        // Swapchain pass: colour + depth. Scene geometry uses the depth; the
+        // black-hole present + ImGui simply don't test it.
+        auto VulkanDevice::create_swapchain_render_pass() -> bool
+        {
+            VkAttachmentDescription atts[2]{};
+            atts[0].format = m_swapchain_format; atts[0].samples = VK_SAMPLE_COUNT_1_BIT;
+            atts[0].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; atts[0].storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+            atts[0].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; atts[0].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
+            atts[0].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; atts[0].finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
+            atts[1].format = VK_FORMAT_D32_SFLOAT; atts[1].samples = VK_SAMPLE_COUNT_1_BIT;
+            atts[1].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; atts[1].storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
+            atts[1].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; atts[1].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
+            atts[1].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; atts[1].finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
+            VkAttachmentReference color_ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
+            VkAttachmentReference depth_ref{ 1, VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL };
+            VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
+            subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &color_ref; subpass.pDepthStencilAttachment = &depth_ref;
+            VkSubpassDependency dep{};
+            dep.srcSubpass = VK_SUBPASS_EXTERNAL; dep.dstSubpass = 0;
+            dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT | VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT;
+            dep.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT | VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT;
+            dep.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
+            VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
+            rpci.attachmentCount = 2; rpci.pAttachments = atts; rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
+            rpci.dependencyCount = 1; rpci.pDependencies = &dep;
+            VKD_CHECK(vkCreateRenderPass(m_device, &rpci, nullptr, &m_swapchain_rp));
+            return true;
+        }
+
+        // Off-screen colour pass (RGBA8), leaving the image SHADER_READ_ONLY so the
+        // present pass can sample it. Shared by every render target.
+        auto VulkanDevice::create_offscreen_render_pass() -> bool
+        {
+            VkAttachmentDescription color{};
+            color.format = VK_FORMAT_R8G8B8A8_UNORM; color.samples = VK_SAMPLE_COUNT_1_BIT;
+            color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+            color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
+            color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; color.finalLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+            VkAttachmentReference ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
+            VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
+            subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &ref;
+            VkSubpassDependency deps[2]{};
+            deps[0].srcSubpass = VK_SUBPASS_EXTERNAL; deps[0].dstSubpass = 0;
+            deps[0].srcStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT; deps[0].srcAccessMask = VK_ACCESS_SHADER_READ_BIT;
+            deps[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; deps[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+            deps[1].srcSubpass = 0; deps[1].dstSubpass = VK_SUBPASS_EXTERNAL;
+            deps[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; deps[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+            deps[1].dstStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT; deps[1].dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+            VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
+            rpci.attachmentCount = 1; rpci.pAttachments = &color; rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
+            rpci.dependencyCount = 2; rpci.pDependencies = deps;
+            VKD_CHECK(vkCreateRenderPass(m_device, &rpci, nullptr, &m_offscreen_rp));
+            return true;
+        }
+
+        auto VulkanDevice::create_depth_and_framebuffers() -> bool
+        {
+            VkImageCreateInfo dici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
+            dici.imageType = VK_IMAGE_TYPE_2D; dici.format = VK_FORMAT_D32_SFLOAT;
+            dici.extent = { m_extent.width, m_extent.height, 1 };
+            dici.mipLevels = 1; dici.arrayLayers = 1; dici.samples = VK_SAMPLE_COUNT_1_BIT;
+            dici.tiling = VK_IMAGE_TILING_OPTIMAL; dici.usage = VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
+            VKD_CHECK(vkCreateImage(m_device, &dici, nullptr, &m_depth_image));
+            VkMemoryRequirements dreq{}; vkGetImageMemoryRequirements(m_device, m_depth_image, &dreq);
+            VkMemoryAllocateInfo dai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
+            dai.allocationSize = dreq.size; dai.memoryTypeIndex = find_memory_type(dreq.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+            VKD_CHECK(vkAllocateMemory(m_device, &dai, nullptr, &m_depth_mem));
+            VKD_CHECK(vkBindImageMemory(m_device, m_depth_image, m_depth_mem, 0));
+            VkImageViewCreateInfo dvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+            dvci.image = m_depth_image; dvci.viewType = VK_IMAGE_VIEW_TYPE_2D; dvci.format = VK_FORMAT_D32_SFLOAT;
+            dvci.subresourceRange = { VK_IMAGE_ASPECT_DEPTH_BIT, 0, 1, 0, 1 };
+            VKD_CHECK(vkCreateImageView(m_device, &dvci, nullptr, &m_depth_view));
+
+            m_framebuffers.resize(m_image_views.size());
+            for (size_t i = 0; i < m_image_views.size(); ++i)
+            {
+                VkImageView att[2] = { m_image_views[i], m_depth_view };
+                VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
+                fbci.renderPass = m_swapchain_rp; fbci.attachmentCount = 2; fbci.pAttachments = att;
+                fbci.width = m_extent.width; fbci.height = m_extent.height; fbci.layers = 1;
+                VKD_CHECK(vkCreateFramebuffer(m_device, &fbci, nullptr, &m_framebuffers[i]));
+            }
+            return true;
+        }
+
+        auto VulkanDevice::create_command_and_sync() -> bool
+        {
+            VkCommandPoolCreateInfo pci{ VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO };
+            pci.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT; pci.queueFamilyIndex = m_graphics_family;
+            VKD_CHECK(vkCreateCommandPool(m_device, &pci, nullptr, &m_command_pool));
+            m_command_buffers.resize(MAX_FRAMES_IN_FLIGHT);
+            VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
+            cbai.commandPool = m_command_pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = MAX_FRAMES_IN_FLIGHT;
+            VKD_CHECK(vkAllocateCommandBuffers(m_device, &cbai, m_command_buffers.data()));
+
+            m_image_available.resize(MAX_FRAMES_IN_FLIGHT);
+            m_in_flight.resize(MAX_FRAMES_IN_FLIGHT);
+            m_render_finished.resize(m_images.size());
+            m_images_in_flight.assign(m_images.size(), VK_NULL_HANDLE);
+            VkSemaphoreCreateInfo sci{ VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO };
+            VkFenceCreateInfo fci{ VK_STRUCTURE_TYPE_FENCE_CREATE_INFO }; fci.flags = VK_FENCE_CREATE_SIGNALED_BIT;
+            for (int i = 0; i < MAX_FRAMES_IN_FLIGHT; ++i)
+            { VKD_CHECK(vkCreateSemaphore(m_device, &sci, nullptr, &m_image_available[i])); VKD_CHECK(vkCreateFence(m_device, &fci, nullptr, &m_in_flight[i])); }
+            for (size_t i = 0; i < m_images.size(); ++i)
+                VKD_CHECK(vkCreateSemaphore(m_device, &sci, nullptr, &m_render_finished[i]));
+
+            m_frame_pools.resize(MAX_FRAMES_IN_FLIGHT);
+            VkDescriptorPoolSize sizes[2] = {
+                { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 512 },
+                { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 256 },
+            };
+            for (int i = 0; i < MAX_FRAMES_IN_FLIGHT; ++i)
+            {
+                VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO };
+                dpci.maxSets = 256; dpci.poolSizeCount = 2; dpci.pPoolSizes = sizes;
+                VKD_CHECK(vkCreateDescriptorPool(m_device, &dpci, nullptr, &m_frame_pools[i]));
+            }
+            return true;
+        }
+
+        auto VulkanDevice::init(void* glfwWindow, int width, int height) -> bool
+        {
+            m_window = (GLFWwindow*)glfwWindow; m_width = width; m_height = height;
+            if (!create_instance())              return false;
+            if (!pick_physical_and_device())     return false;
+            if (!create_swapchain())             return false;
+            if (!create_image_views())           return false;
+            if (!create_swapchain_render_pass()) return false;
+            if (!create_offscreen_render_pass()) return false;
+            if (!create_depth_and_framebuffers())return false;
+            if (!create_command_and_sync())      return false;
+            DONUT_INFO("Vulkan RHI device ready: {} swapchain images, {}x{}", (int)m_images.size(), m_extent.width, m_extent.height);
+            return true;
+        }
+
+        auto VulkanDevice::cleanup_swapchain() -> void
+        {
+            for (auto fb : m_framebuffers) vkDestroyFramebuffer(m_device, fb, nullptr);
+            m_framebuffers.clear();
+            if (m_depth_view)  { vkDestroyImageView(m_device, m_depth_view, nullptr); m_depth_view = VK_NULL_HANDLE; }
+            if (m_depth_image) { vkDestroyImage(m_device, m_depth_image, nullptr); m_depth_image = VK_NULL_HANDLE; }
+            if (m_depth_mem)   { vkFreeMemory(m_device, m_depth_mem, nullptr); m_depth_mem = VK_NULL_HANDLE; }
+            for (auto iv : m_image_views) vkDestroyImageView(m_device, iv, nullptr);
+            m_image_views.clear();
+            if (m_swapchain) { vkDestroySwapchainKHR(m_device, m_swapchain, nullptr); m_swapchain = VK_NULL_HANDLE; }
+        }
+
+        auto VulkanDevice::recreate_swapchain() -> bool
+        {
+            int w = 0, h = 0; glfwGetFramebufferSize(m_window, &w, &h);
+            while (w == 0 || h == 0) { glfwGetFramebufferSize(m_window, &w, &h); glfwWaitEvents(); }
+            m_width = w; m_height = h;
+            vkDeviceWaitIdle(m_device);
+            cleanup_swapchain();
+            if (!create_swapchain())             return false;
+            if (!create_image_views())           return false;
+            if (!create_depth_and_framebuffers())return false;
+            m_images_in_flight.assign(m_images.size(), VK_NULL_HANDLE);
+            return true;
+        }
+
+        auto VulkanDevice::create_buffer(BufferType type, size_t size, const void* data) -> Ref<Buffer>
+        {
+            VkBufferUsageFlags usage = type == BufferType::Index ? VK_BUFFER_USAGE_INDEX_BUFFER_BIT
+                                     : type == BufferType::Uniform ? VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT
+                                     : VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
+            VkBuffer buf = VK_NULL_HANDLE; VkDeviceMemory mem = VK_NULL_HANDLE;
+            create_buffer_raw(size, usage, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, buf, mem);
+            void* mapped = nullptr; vkMapMemory(m_device, mem, 0, size, 0, &mapped);
+            if (data && mapped) std::memcpy(mapped, data, size);
+            return create_ref<VkBufferR>(m_device, buf, mem, mapped, size);
+        }
+
+        auto VulkanDevice::create_texture(int w, int h, Format format, Filter filter, const void* data) -> Ref<Texture>
+        {
+            auto tex = create_ref<VkTextureR>(); tex->m_device = m_device;
+            VkFormat fmt = vk_format(format);
+            VkImageCreateInfo ici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
+            ici.imageType = VK_IMAGE_TYPE_2D; ici.format = fmt; ici.extent = { (uint32_t)w, (uint32_t)h, 1 };
+            ici.mipLevels = 1; ici.arrayLayers = 1; ici.samples = VK_SAMPLE_COUNT_1_BIT;
+            ici.tiling = VK_IMAGE_TILING_OPTIMAL; ici.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
+            vkCreateImage(m_device, &ici, nullptr, &tex->m_image);
+            VkMemoryRequirements req{}; vkGetImageMemoryRequirements(m_device, tex->m_image, &req);
+            VkMemoryAllocateInfo ai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
+            ai.allocationSize = req.size; ai.memoryTypeIndex = find_memory_type(req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+            vkAllocateMemory(m_device, &ai, nullptr, &tex->m_mem);
+            vkBindImageMemory(m_device, tex->m_image, tex->m_mem, 0);
+
+            size_t bpp = format == Format::RGBA16F ? 8 : 4;
+            VkDeviceSize sz = (VkDeviceSize)w * h * bpp;
+            VkBuffer staging = VK_NULL_HANDLE; VkDeviceMemory staging_mem = VK_NULL_HANDLE;
+            create_buffer_raw(sz, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, staging, staging_mem);
+            void* mp = nullptr; vkMapMemory(m_device, staging_mem, 0, sz, 0, &mp);
+            if (data) std::memcpy(mp, data, sz); else std::memset(mp, 0, sz);
+            vkUnmapMemory(m_device, staging_mem);
+
+            VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
+            cbai.commandPool = m_command_pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
+            VkCommandBuffer cmd; vkAllocateCommandBuffers(m_device, &cbai, &cmd);
+            VkCommandBufferBeginInfo bi{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO }; bi.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
+            vkBeginCommandBuffer(cmd, &bi);
+            VkImageMemoryBarrier b{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+            b.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; b.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
+            b.image = tex->m_image; b.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+            b.srcAccessMask = 0; b.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
+            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &b);
+            VkBufferImageCopy copy{}; copy.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 }; copy.imageExtent = { (uint32_t)w, (uint32_t)h, 1 };
+            vkCmdCopyBufferToImage(cmd, staging, tex->m_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &copy);
+            VkImageMemoryBarrier r = b; r.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; r.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+            r.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; r.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &r);
+            vkEndCommandBuffer(cmd);
+            VkSubmitInfo si{ VK_STRUCTURE_TYPE_SUBMIT_INFO }; si.commandBufferCount = 1; si.pCommandBuffers = &cmd;
+            vkQueueSubmit(m_graphics_queue, 1, &si, VK_NULL_HANDLE); vkQueueWaitIdle(m_graphics_queue);
+            vkFreeCommandBuffers(m_device, m_command_pool, 1, &cmd);
+            vkDestroyBuffer(m_device, staging, nullptr); vkFreeMemory(m_device, staging_mem, nullptr);
+
+            VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+            vci.image = tex->m_image; vci.viewType = VK_IMAGE_VIEW_TYPE_2D; vci.format = fmt;
+            vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+            vkCreateImageView(m_device, &vci, nullptr, &tex->m_view);
+            VkSamplerCreateInfo smci{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
+            smci.magFilter = vk_filter(filter); smci.minFilter = vk_filter(filter);
+            smci.addressModeU = smci.addressModeV = smci.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+            vkCreateSampler(m_device, &smci, nullptr, &tex->m_sampler);
+            return tex;
+        }
+
+        auto VulkanDevice::create_render_target(int w, int h, Format color, bool /*with_depth*/, Filter filter, int /*mips*/) -> Ref<RenderTarget>
+        {
+            auto rt = create_ref<VkRenderTargetR>();
+            rt->m_device = m_device; rt->m_w = w; rt->m_h = h;
+            VkFormat fmt = vk_format(color);
+            VkImageCreateInfo ici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
+            ici.imageType = VK_IMAGE_TYPE_2D; ici.format = fmt; ici.extent = { (uint32_t)w, (uint32_t)h, 1 };
+            ici.mipLevels = 1; ici.arrayLayers = 1; ici.samples = VK_SAMPLE_COUNT_1_BIT;
+            ici.tiling = VK_IMAGE_TILING_OPTIMAL; ici.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
+            vkCreateImage(m_device, &ici, nullptr, &rt->m_image);
+            VkMemoryRequirements req{}; vkGetImageMemoryRequirements(m_device, rt->m_image, &req);
+            VkMemoryAllocateInfo ai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
+            ai.allocationSize = req.size; ai.memoryTypeIndex = find_memory_type(req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+            vkAllocateMemory(m_device, &ai, nullptr, &rt->m_mem);
+            vkBindImageMemory(m_device, rt->m_image, rt->m_mem, 0);
+            VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+            vci.image = rt->m_image; vci.viewType = VK_IMAGE_VIEW_TYPE_2D; vci.format = fmt;
+            vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+            vkCreateImageView(m_device, &vci, nullptr, &rt->m_view);
+            VkSamplerCreateInfo smci{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
+            smci.magFilter = vk_filter(filter); smci.minFilter = vk_filter(filter);
+            smci.addressModeU = smci.addressModeV = smci.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+            vkCreateSampler(m_device, &smci, nullptr, &rt->m_sampler);
+            VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
+            fbci.renderPass = m_offscreen_rp; fbci.attachmentCount = 1; fbci.pAttachments = &rt->m_view;
+            fbci.width = w; fbci.height = h; fbci.layers = 1;
+            vkCreateFramebuffer(m_device, &fbci, nullptr, &rt->m_fb);
+
+            rt->m_color.m_device = m_device; rt->m_color.m_view = rt->m_view; rt->m_color.m_sampler = rt->m_sampler; rt->m_color.m_owns = false;
+            return rt;
+        }
+
+        // Builds an environment cubemap from an equirectangular HDRI: render the 6
+        // faces with the EquirectToCubemap pipeline, then a full mip chain by
+        // linear down-blits (so divergence-based LOD reads a blurred sky). Returns
+        // a Texture owning the cube image/view/sampler.
+        auto VulkanDevice::create_cubemap_from_hdri(const std::string& path) -> Ref<Texture>
+        {
+            auto tex = create_ref<VkTextureR>(); tex->m_device = m_device;
+            const VkMemoryPropertyFlags host_vis = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
+            const uint32_t FACE = 1024;
+            const VkFormat cube_fmt = VK_FORMAT_R16G16B16A16_SFLOAT;
+            uint32_t CUBE_MIPS = 1; for (uint32_t s = FACE; s > 1; s >>= 1) ++CUBE_MIPS;
+
+            VkImageCreateInfo cci{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
+            cci.flags = VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT;
+            cci.imageType = VK_IMAGE_TYPE_2D; cci.format = cube_fmt; cci.extent = { FACE, FACE, 1 };
+            cci.mipLevels = CUBE_MIPS; cci.arrayLayers = 6; cci.samples = VK_SAMPLE_COUNT_1_BIT;
+            cci.tiling = VK_IMAGE_TILING_OPTIMAL;
+            cci.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT
+                      | VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
+            vkCreateImage(m_device, &cci, nullptr, &tex->m_image);
+            VkMemoryRequirements creq{}; vkGetImageMemoryRequirements(m_device, tex->m_image, &creq);
+            VkMemoryAllocateInfo cai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
+            cai.allocationSize = creq.size; cai.memoryTypeIndex = find_memory_type(creq.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+            vkAllocateMemory(m_device, &cai, nullptr, &tex->m_mem);
+            vkBindImageMemory(m_device, tex->m_image, tex->m_mem, 0);
+            VkImageViewCreateInfo cvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+            cvci.image = tex->m_image; cvci.viewType = VK_IMAGE_VIEW_TYPE_CUBE; cvci.format = cube_fmt;
+            cvci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, CUBE_MIPS, 0, 6 };
+            vkCreateImageView(m_device, &cvci, nullptr, &tex->m_view);
+            VkSamplerCreateInfo csm{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
+            csm.magFilter = VK_FILTER_LINEAR; csm.minFilter = VK_FILTER_LINEAR;
+            csm.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR; csm.minLod = 0.0f; csm.maxLod = (float)CUBE_MIPS;
+            csm.addressModeU = csm.addressModeV = csm.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+            vkCreateSampler(m_device, &csm, nullptr, &tex->m_sampler);
+
+            int w = 0, h = 0, ch = 0;
+            float* pixels = stbi_loadf(path.c_str(), &w, &h, &ch, 4);
+            if (!pixels)
+            {
+                DONUT_WARN("Vulkan RHI: HDRI '{}' could not be loaded; using a dark background", path);
+                VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
+                cbai.commandPool = m_command_pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
+                VkCommandBuffer cmd; vkAllocateCommandBuffers(m_device, &cbai, &cmd);
+                VkCommandBufferBeginInfo bi{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO }; bi.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
+                vkBeginCommandBuffer(cmd, &bi);
+                VkImageMemoryBarrier tb{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+                tb.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; tb.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
+                tb.image = tex->m_image; tb.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, CUBE_MIPS, 0, 6 };
+                tb.srcAccessMask = 0; tb.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
+                vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &tb);
+                VkClearColorValue dark{}; dark.float32[0] = 0.02f; dark.float32[1] = 0.02f; dark.float32[2] = 0.05f; dark.float32[3] = 1.0f;
+                VkImageSubresourceRange rng{ VK_IMAGE_ASPECT_COLOR_BIT, 0, CUBE_MIPS, 0, 6 };
+                vkCmdClearColorImage(cmd, tex->m_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, &dark, 1, &rng);
+                VkImageMemoryBarrier rb = tb; rb.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; rb.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+                rb.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; rb.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+                vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &rb);
+                vkEndCommandBuffer(cmd);
+                VkSubmitInfo si{ VK_STRUCTURE_TYPE_SUBMIT_INFO }; si.commandBufferCount = 1; si.pCommandBuffers = &cmd;
+                vkQueueSubmit(m_graphics_queue, 1, &si, VK_NULL_HANDLE); vkQueueWaitIdle(m_graphics_queue);
+                vkFreeCommandBuffers(m_device, m_command_pool, 1, &cmd);
+                return tex;
+            }
+
+            const VkFormat eq_fmt = VK_FORMAT_R16G16B16A16_SFLOAT;
+            size_t texel_count = (size_t)w * h * 4;
+            VkDeviceSize eq_size = (VkDeviceSize)texel_count * sizeof(uint16_t);
+            VkBuffer eq_staging; VkDeviceMemory eq_staging_mem;
+            create_buffer_raw(eq_size, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, host_vis, eq_staging, eq_staging_mem);
+            void* mp = nullptr; vkMapMemory(m_device, eq_staging_mem, 0, eq_size, 0, &mp);
+            uint16_t* dst = (uint16_t*)mp;
+            for (size_t i = 0; i < texel_count; ++i) { __fp16 hf = (__fp16)pixels[i]; std::memcpy(&dst[i], &hf, sizeof(uint16_t)); }
+            vkUnmapMemory(m_device, eq_staging_mem);
+            stbi_image_free(pixels);
+
+            VkImage eq_image; VkDeviceMemory eq_mem;
+            VkImageCreateInfo eci{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
+            eci.imageType = VK_IMAGE_TYPE_2D; eci.format = eq_fmt; eci.extent = { (uint32_t)w, (uint32_t)h, 1 };
+            eci.mipLevels = 1; eci.arrayLayers = 1; eci.samples = VK_SAMPLE_COUNT_1_BIT;
+            eci.tiling = VK_IMAGE_TILING_OPTIMAL; eci.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
+            vkCreateImage(m_device, &eci, nullptr, &eq_image);
+            VkMemoryRequirements ereq{}; vkGetImageMemoryRequirements(m_device, eq_image, &ereq);
+            VkMemoryAllocateInfo eai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
+            eai.allocationSize = ereq.size; eai.memoryTypeIndex = find_memory_type(ereq.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+            vkAllocateMemory(m_device, &eai, nullptr, &eq_mem);
+            vkBindImageMemory(m_device, eq_image, eq_mem, 0);
+            VkImageView eq_view;
+            VkImageViewCreateInfo evci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+            evci.image = eq_image; evci.viewType = VK_IMAGE_VIEW_TYPE_2D; evci.format = eq_fmt;
+            evci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+            vkCreateImageView(m_device, &evci, nullptr, &eq_view);
+            VkSampler eq_sampler;
+            VkSamplerCreateInfo esm{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
+            esm.magFilter = VK_FILTER_LINEAR; esm.minFilter = VK_FILTER_LINEAR;
+            esm.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;
+            esm.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+            esm.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+            vkCreateSampler(m_device, &esm, nullptr, &eq_sampler);
+
+            VkImageView face_views[6];
+            for (uint32_t i = 0; i < 6; ++i)
+            {
+                VkImageViewCreateInfo fvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
+                fvci.image = tex->m_image; fvci.viewType = VK_IMAGE_VIEW_TYPE_2D; fvci.format = cube_fmt;
+                fvci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, i, 1 };
+                vkCreateImageView(m_device, &fvci, nullptr, &face_views[i]);
+            }
+
+            VkAttachmentDescription color{};
+            color.format = cube_fmt; color.samples = VK_SAMPLE_COUNT_1_BIT;
+            color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+            color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
+            color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; color.finalLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+            VkAttachmentReference ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
+            VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS; subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &ref;
+            VkSubpassDependency dep{}; dep.srcSubpass = 0; dep.dstSubpass = VK_SUBPASS_EXTERNAL;
+            dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; dep.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+            dep.dstStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT; dep.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+            VkRenderPass rp;
+            VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
+            rpci.attachmentCount = 1; rpci.pAttachments = &color; rpci.subpassCount = 1; rpci.pSubpasses = &subpass; rpci.dependencyCount = 1; rpci.pDependencies = &dep;
+            vkCreateRenderPass(m_device, &rpci, nullptr, &rp);
+            VkFramebuffer face_fb[6];
+            for (uint32_t i = 0; i < 6; ++i)
+            {
+                VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
+                fbci.renderPass = rp; fbci.attachmentCount = 1; fbci.pAttachments = &face_views[i]; fbci.width = FACE; fbci.height = FACE; fbci.layers = 1;
+                vkCreateFramebuffer(m_device, &fbci, nullptr, &face_fb[i]);
+            }
+
+            VkDescriptorSetLayoutBinding binds[2]{};
+            binds[0].binding = 0; binds[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; binds[0].descriptorCount = 1; binds[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
+            binds[1].binding = 1; binds[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; binds[1].descriptorCount = 1; binds[1].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
+            VkDescriptorSetLayout set_layout;
+            VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO }; dslci.bindingCount = 2; dslci.pBindings = binds;
+            vkCreateDescriptorSetLayout(m_device, &dslci, nullptr, &set_layout);
+            VkDescriptorPoolSize psizes[2] = { { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 6 }, { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 6 } };
+            VkDescriptorPool pool;
+            VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO }; dpci.maxSets = 6; dpci.poolSizeCount = 2; dpci.pPoolSizes = psizes;
+            vkCreateDescriptorPool(m_device, &dpci, nullptr, &pool);
+
+            VkShaderModule vmod, fmod;
+            create_shader_module("assets/shaders/generated/equirect_to_cubemap.vertexMain.spv", vmod);
+            create_shader_module("assets/shaders/generated/equirect_to_cubemap.fragmentMain.spv", fmod);
+            VkPipelineLayout playout;
+            VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO }; plci.setLayoutCount = 1; plci.pSetLayouts = &set_layout;
+            vkCreatePipelineLayout(m_device, &plci, nullptr, &playout);
+            VkPipelineShaderStageCreateInfo stages[2]{};
+            stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
+            stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
+            VkVertexInputBindingDescription vib{ 0, 12, VK_VERTEX_INPUT_RATE_VERTEX };
+            VkVertexInputAttributeDescription via{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 };
+            VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
+            vin.vertexBindingDescriptionCount = 1; vin.pVertexBindingDescriptions = &vib; vin.vertexAttributeDescriptionCount = 1; vin.pVertexAttributeDescriptions = &via;
+            VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
+            VkViewport vp{ 0, 0, (float)FACE, (float)FACE, 0, 1 }; VkRect2D sc{ { 0, 0 }, { FACE, FACE } };
+            VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.pViewports = &vp; vps.scissorCount = 1; vps.pScissors = &sc;
+            VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
+            VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
+            VkPipelineColorBlendAttachmentState cba{}; cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
+            VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
+            VkPipeline pipeline;
+            VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
+            gpci.stageCount = 2; gpci.pStages = stages; gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
+            gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb; gpci.layout = playout; gpci.renderPass = rp; gpci.subpass = 0;
+            vkCreateGraphicsPipelines(m_device, VK_NULL_HANDLE, 1, &gpci, nullptr, &pipeline);
+            vkDestroyShaderModule(m_device, vmod, nullptr); vkDestroyShaderModule(m_device, fmod, nullptr);
+
+            float cube_verts[] = {
+                -1,1,-1, -1,-1,-1, 1,-1,-1, 1,-1,-1, 1,1,-1, -1,1,-1,
+                -1,-1,1, -1,-1,-1, -1,1,-1, -1,1,-1, -1,1,1, -1,-1,1,
+                 1,-1,-1, 1,-1,1, 1,1,1, 1,1,1, 1,1,-1, 1,-1,-1,
+                -1,-1,1, -1,1,1, 1,1,1, 1,1,1, 1,-1,1, -1,-1,1,
+                -1,1,-1, 1,1,-1, 1,1,1, 1,1,1, -1,1,1, -1,1,-1,
+                -1,-1,-1, -1,-1,1, 1,-1,-1, 1,-1,-1, -1,-1,1, 1,-1,1,
+            };
+            VkBuffer cube_vb; VkDeviceMemory cube_vb_mem;
+            create_buffer_raw(sizeof(cube_verts), VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, cube_vb, cube_vb_mem);
+            vkMapMemory(m_device, cube_vb_mem, 0, sizeof(cube_verts), 0, &mp); std::memcpy(mp, cube_verts, sizeof(cube_verts)); vkUnmapMemory(m_device, cube_vb_mem);
+
+            glm::mat4 proj = glm::perspective(glm::radians(90.0f), 1.0f, 0.1f, 10.0f);
+            proj[1][1] *= -1.0f;
+            glm::mat4 views[6] = {
+                glm::lookAt(glm::vec3(0), glm::vec3( 1, 0, 0), glm::vec3(0, -1, 0)),
+                glm::lookAt(glm::vec3(0), glm::vec3(-1, 0, 0), glm::vec3(0, -1, 0)),
+                glm::lookAt(glm::vec3(0), glm::vec3( 0, 1, 0), glm::vec3(0, 0, 1)),
+                glm::lookAt(glm::vec3(0), glm::vec3( 0, -1, 0), glm::vec3(0, 0, -1)),
+                glm::lookAt(glm::vec3(0), glm::vec3( 0, 0, 1), glm::vec3(0, -1, 0)),
+                glm::lookAt(glm::vec3(0), glm::vec3( 0, 0, -1), glm::vec3(0, -1, 0)),
+            };
+            VkBuffer ubo[6]; VkDeviceMemory ubo_mem[6]; VkDescriptorSet sets[6];
+            for (uint32_t i = 0; i < 6; ++i)
+            {
+                create_buffer_raw(128, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, ubo[i], ubo_mem[i]);
+                glm::mat4 mats[2] = { glm::transpose(proj), glm::transpose(views[i]) };
+                vkMapMemory(m_device, ubo_mem[i], 0, 128, 0, &mp); std::memcpy(mp, mats, 128); vkUnmapMemory(m_device, ubo_mem[i]);
+                VkDescriptorSetAllocateInfo dsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO }; dsai.descriptorPool = pool; dsai.descriptorSetCount = 1; dsai.pSetLayouts = &set_layout;
+                vkAllocateDescriptorSets(m_device, &dsai, &sets[i]);
+                VkDescriptorBufferInfo buf_info{ ubo[i], 0, VK_WHOLE_SIZE };
+                VkDescriptorImageInfo img_info{ eq_sampler, eq_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
+                VkWriteDescriptorSet ws[2]{};
+                ws[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; ws[0].dstSet = sets[i]; ws[0].dstBinding = 0; ws[0].descriptorCount = 1; ws[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; ws[0].pBufferInfo = &buf_info;
+                ws[1].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; ws[1].dstSet = sets[i]; ws[1].dstBinding = 1; ws[1].descriptorCount = 1; ws[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; ws[1].pImageInfo = &img_info;
+                vkUpdateDescriptorSets(m_device, 2, ws, 0, nullptr);
+            }
+
+            VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
+            cbai.commandPool = m_command_pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
+            VkCommandBuffer cmd; vkAllocateCommandBuffers(m_device, &cbai, &cmd);
+            VkCommandBufferBeginInfo bi{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO }; bi.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
+            vkBeginCommandBuffer(cmd, &bi);
+            VkImageMemoryBarrier to_dst{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+            to_dst.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; to_dst.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
+            to_dst.image = eq_image; to_dst.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+            to_dst.srcAccessMask = 0; to_dst.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
+            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &to_dst);
+            VkBufferImageCopy copy{}; copy.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 }; copy.imageExtent = { (uint32_t)w, (uint32_t)h, 1 };
+            vkCmdCopyBufferToImage(cmd, eq_staging, eq_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &copy);
+            VkImageMemoryBarrier to_read = to_dst; to_read.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; to_read.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+            to_read.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; to_read.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &to_read);
+
+            VkClearValue clear{}; clear.color = { { 0, 0, 0, 1 } };
+            for (uint32_t i = 0; i < 6; ++i)
+            {
+                VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
+                rpbi.renderPass = rp; rpbi.framebuffer = face_fb[i]; rpbi.renderArea = { { 0, 0 }, { FACE, FACE } }; rpbi.clearValueCount = 1; rpbi.pClearValues = &clear;
+                vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
+                vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
+                vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, playout, 0, 1, &sets[i], 0, nullptr);
+                VkDeviceSize off = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &cube_vb, &off);
+                vkCmdDraw(cmd, 36, 1, 0, 0);
+                vkCmdEndRenderPass(cmd);
+            }
+
+            {
+                VkImageMemoryBarrier src0{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+                src0.image = tex->m_image; src0.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 6 };
+                src0.oldLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL; src0.newLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
+                src0.srcAccessMask = VK_ACCESS_SHADER_READ_BIT; src0.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
+                vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &src0);
+                int32_t mipW = (int32_t)FACE, mipH = (int32_t)FACE;
+                for (uint32_t m = 1; m < CUBE_MIPS; ++m)
+                {
+                    int32_t nW = mipW > 1 ? mipW / 2 : 1, nH = mipH > 1 ? mipH / 2 : 1;
+                    VkImageMemoryBarrier bd{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+                    bd.image = tex->m_image; bd.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, m, 1, 0, 6 };
+                    bd.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; bd.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
+                    bd.srcAccessMask = 0; bd.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
+                    vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &bd);
+                    VkImageBlit blit{};
+                    blit.srcOffsets[1] = { mipW, mipH, 1 }; blit.srcSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, m - 1, 0, 6 };
+                    blit.dstOffsets[1] = { nW, nH, 1 };     blit.dstSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, m, 0, 6 };
+                    vkCmdBlitImage(cmd, tex->m_image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, tex->m_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &blit, VK_FILTER_LINEAR);
+                    VkImageMemoryBarrier bs{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+                    bs.image = tex->m_image; bs.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, m, 1, 0, 6 };
+                    bs.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; bs.newLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
+                    bs.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; bs.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
+                    vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &bs);
+                    mipW = nW; mipH = nH;
+                }
+                VkImageMemoryBarrier fin{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
+                fin.image = tex->m_image; fin.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, CUBE_MIPS, 0, 6 };
+                fin.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL; fin.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+                fin.srcAccessMask = VK_ACCESS_TRANSFER_READ_BIT; fin.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+                vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &fin);
+            }
+
+            vkEndCommandBuffer(cmd);
+            VkSubmitInfo si{ VK_STRUCTURE_TYPE_SUBMIT_INFO }; si.commandBufferCount = 1; si.pCommandBuffers = &cmd;
+            vkQueueSubmit(m_graphics_queue, 1, &si, VK_NULL_HANDLE); vkQueueWaitIdle(m_graphics_queue);
+
+            vkFreeCommandBuffers(m_device, m_command_pool, 1, &cmd);
+            for (uint32_t i = 0; i < 6; ++i) { vkDestroyBuffer(m_device, ubo[i], nullptr); vkFreeMemory(m_device, ubo_mem[i], nullptr); vkDestroyFramebuffer(m_device, face_fb[i], nullptr); vkDestroyImageView(m_device, face_views[i], nullptr); }
+            vkDestroyBuffer(m_device, cube_vb, nullptr); vkFreeMemory(m_device, cube_vb_mem, nullptr);
+            vkDestroyPipeline(m_device, pipeline, nullptr); vkDestroyPipelineLayout(m_device, playout, nullptr);
+            vkDestroyDescriptorPool(m_device, pool, nullptr); vkDestroyDescriptorSetLayout(m_device, set_layout, nullptr);
+            vkDestroyRenderPass(m_device, rp, nullptr);
+            vkDestroySampler(m_device, eq_sampler, nullptr); vkDestroyImageView(m_device, eq_view, nullptr);
+            vkDestroyImage(m_device, eq_image, nullptr); vkFreeMemory(m_device, eq_mem, nullptr);
+            vkDestroyBuffer(m_device, eq_staging, nullptr); vkFreeMemory(m_device, eq_staging_mem, nullptr);
+            DONUT_INFO("Vulkan RHI: HDRI cubemap built from {} ({}x{} equirect -> {}^2 cube)", path, w, h, (int)FACE);
+            return tex;
+        }
+
+        auto VulkanDevice::create_pipeline(const PipelineDesc& desc) -> Ref<Pipeline>
+        {
+            auto p = create_ref<VkPipelineR>(); p->m_device = m_device; p->m_resources = desc.resources;
+
+            std::vector<VkDescriptorSetLayoutBinding> binds;
+            for (const auto& r : desc.resources)
+            {
+                VkDescriptorSetLayoutBinding b{};
+                b.binding = r.binding; b.descriptorCount = 1;
+                b.descriptorType = r.kind == ResourceKind::UniformBuffer ? VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER : VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
+                b.stageFlags = VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT;
+                binds.push_back(b);
+            }
+            VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO };
+            dslci.bindingCount = (uint32_t)binds.size(); dslci.pBindings = binds.data();
+            vkCreateDescriptorSetLayout(m_device, &dslci, nullptr, &p->m_set_layout);
+            VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO };
+            plci.setLayoutCount = 1; plci.pSetLayouts = &p->m_set_layout;
+            vkCreatePipelineLayout(m_device, &plci, nullptr, &p->m_layout);
+
+            VkShaderModule vmod = VK_NULL_HANDLE, fmod = VK_NULL_HANDLE;
+            if (!create_shader_module("assets/shaders/generated/" + desc.shader + ".vertexMain.spv", vmod) ||
+                !create_shader_module("assets/shaders/generated/" + desc.shader + ".fragmentMain.spv", fmod))
+            { DONUT_ERROR("Vulkan RHI: shader '{}' modules failed", desc.shader); return p; }
+            VkPipelineShaderStageCreateInfo stages[2]{};
+            stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
+            stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
+
+            VkVertexInputBindingDescription vib{ 0, desc.vertex_layout.stride, VK_VERTEX_INPUT_RATE_VERTEX };
+            std::vector<VkVertexInputAttributeDescription> vias;
+            for (const auto& a : desc.vertex_layout.attributes)
+                vias.push_back({ a.location, 0, vk_attr_format(a.components), a.offset });
+            VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
+            vin.vertexBindingDescriptionCount = desc.vertex_layout.stride ? 1 : 0; vin.pVertexBindingDescriptions = &vib;
+            vin.vertexAttributeDescriptionCount = (uint32_t)vias.size(); vin.pVertexAttributeDescriptions = vias.data();
+
+            VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = vk_topology(desc.topology);
+            VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.scissorCount = 1;
+            VkDynamicState dyn[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
+            VkPipelineDynamicStateCreateInfo dsci{ VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO }; dsci.dynamicStateCount = 2; dsci.pDynamicStates = dyn;
+            VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO };
+            rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = vk_cull(desc.cull); rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
+            VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
+            VkPipelineDepthStencilStateCreateInfo ds{ VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO };
+            ds.depthTestEnable = desc.depth_test ? VK_TRUE : VK_FALSE; ds.depthWriteEnable = desc.depth_write ? VK_TRUE : VK_FALSE; ds.depthCompareOp = vk_compare(desc.depth_op);
+            VkPipelineColorBlendAttachmentState cba{};
+            cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
+            if (desc.blend == BlendMode::AlphaBlend)
+            {
+                cba.blendEnable = VK_TRUE;
+                cba.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA; cba.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA; cba.colorBlendOp = VK_BLEND_OP_ADD;
+                cba.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE; cba.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO; cba.alphaBlendOp = VK_BLEND_OP_ADD;
+            }
+            VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
+
+            VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
+            gpci.stageCount = 2; gpci.pStages = stages;
+            gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
+            gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb; gpci.pDynamicState = &dsci;
+            if (desc.has_depth) gpci.pDepthStencilState = &ds;
+            gpci.layout = p->m_layout;
+            gpci.renderPass = desc.has_depth ? m_swapchain_rp : m_offscreen_rp;
+            gpci.subpass = 0;
+            VkResult pr = vkCreateGraphicsPipelines(m_device, VK_NULL_HANDLE, 1, &gpci, nullptr, &p->m_pipeline);
+            vkDestroyShaderModule(m_device, vmod, nullptr); vkDestroyShaderModule(m_device, fmod, nullptr);
+            if (pr != VK_SUCCESS) DONUT_ERROR("Vulkan RHI: pipeline '{}' creation failed ({})", desc.shader, (int)pr);
+            return p;
+        }
+
+        auto VulkanDevice::begin_frame(const glm::vec4&) -> CommandList*
+        {
+            if (m_device == VK_NULL_HANDLE) return nullptr;
+            vkWaitForFences(m_device, 1, &m_in_flight[m_current_frame], VK_TRUE, UINT64_MAX);
+            VkResult r = vkAcquireNextImageKHR(m_device, m_swapchain, UINT64_MAX, m_image_available[m_current_frame], VK_NULL_HANDLE, &m_image_index);
+            if (r == VK_ERROR_OUT_OF_DATE_KHR) { recreate_swapchain(); return nullptr; }
+            if (r != VK_SUCCESS && r != VK_SUBOPTIMAL_KHR) { DONUT_ERROR("Vulkan RHI: acquire failed ({})", (int)r); return nullptr; }
+            if (m_images_in_flight[m_image_index] != VK_NULL_HANDLE)
+                vkWaitForFences(m_device, 1, &m_images_in_flight[m_image_index], VK_TRUE, UINT64_MAX);
+            m_images_in_flight[m_image_index] = m_in_flight[m_current_frame];
+            if (m_geo_in_use != VK_NULL_HANDLE)
+                vkWaitForFences(m_device, 1, &m_geo_in_use, VK_TRUE, UINT64_MAX);
+
+            vkResetDescriptorPool(m_device, m_frame_pools[m_current_frame], 0);
+            VkCommandBuffer cmd = m_command_buffers[m_current_frame];
+            vkResetCommandBuffer(cmd, 0);
+            VkCommandBufferBeginInfo bi{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO };
+            vkBeginCommandBuffer(cmd, &bi);
+
+            m_cmds.m_device = m_device; m_cmds.m_cmd = cmd;
+            m_cmds.m_swapchain_rp = m_swapchain_rp; m_cmds.m_offscreen_rp = m_offscreen_rp;
+            m_cmds.m_swapchain_fb = m_framebuffers[m_image_index]; m_cmds.m_extent = m_extent;
+            m_cmds.m_frame_pool = m_frame_pools[m_current_frame]; m_cmds.m_pipe = nullptr;
+            return &m_cmds;
+        }
+
+        auto VulkanDevice::end_frame() -> void
+        {
+            VkCommandBuffer cmd = m_command_buffers[m_current_frame];
+            vkEndCommandBuffer(cmd);
+            VkPipelineStageFlags wait_stage = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
+            VkSubmitInfo submit{ VK_STRUCTURE_TYPE_SUBMIT_INFO };
+            submit.waitSemaphoreCount = 1; submit.pWaitSemaphores = &m_image_available[m_current_frame]; submit.pWaitDstStageMask = &wait_stage;
+            submit.commandBufferCount = 1; submit.pCommandBuffers = &cmd;
+            submit.signalSemaphoreCount = 1; submit.pSignalSemaphores = &m_render_finished[m_image_index];
+            vkResetFences(m_device, 1, &m_in_flight[m_current_frame]);
+            if (vkQueueSubmit(m_graphics_queue, 1, &submit, m_in_flight[m_current_frame]) != VK_SUCCESS)
+            { DONUT_ERROR("Vulkan RHI: queue submit failed"); return; }
+            m_geo_in_use = m_in_flight[m_current_frame];
+
+            VkPresentInfoKHR present{ VK_STRUCTURE_TYPE_PRESENT_INFO_KHR };
+            present.waitSemaphoreCount = 1; present.pWaitSemaphores = &m_render_finished[m_image_index];
+            present.swapchainCount = 1; present.pSwapchains = &m_swapchain; present.pImageIndices = &m_image_index;
+            VkResult r = vkQueuePresentKHR(m_present_queue, &present);
+            if (r == VK_ERROR_OUT_OF_DATE_KHR || r == VK_SUBOPTIMAL_KHR || m_framebuffer_resized)
+            { m_framebuffer_resized = false; recreate_swapchain(); }
+            m_current_frame = (m_current_frame + 1) % MAX_FRAMES_IN_FLIGHT;
+        }
+
+        auto VulkanDevice::init_imgui() -> void
+        {
+            VkDescriptorPoolSize pool_size{ VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1000 };
+            VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO };
+            dpci.flags = VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT; dpci.maxSets = 1000;
+            dpci.poolSizeCount = 1; dpci.pPoolSizes = &pool_size;
+            vkCreateDescriptorPool(m_device, &dpci, nullptr, &m_imgui_pool);
+
+            IMGUI_CHECKVERSION(); ImGui::CreateContext();
+            ImGui::GetIO().ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
+            ImGui::GetIO().ConfigFlags |= ImGuiConfigFlags_DockingEnable;
+            ImGui::StyleColorsDark();
+            ImGui_ImplGlfw_InitForVulkan(m_window, true);
+            ImGui_ImplVulkan_InitInfo info{};
+            info.ApiVersion = VK_API_VERSION_1_2; info.Instance = m_instance; info.PhysicalDevice = m_physical;
+            info.Device = m_device; info.QueueFamily = m_graphics_family; info.Queue = m_graphics_queue;
+            info.DescriptorPool = m_imgui_pool; info.RenderPass = m_swapchain_rp;
+            info.MinImageCount = 2; info.ImageCount = (uint32_t)m_images.size(); info.MSAASamples = VK_SAMPLE_COUNT_1_BIT;
+            if (!ImGui_ImplVulkan_Init(&info)) { DONUT_ERROR("Vulkan RHI: ImGui_ImplVulkan_Init failed"); return; }
+            m_imgui = true;
+            DONUT_INFO("Vulkan RHI: ImGui backend initialized");
+        }
+
+        auto VulkanDevice::imgui_new_frame() -> void
+        {
+            if (!m_imgui) return;
+            ImGui_ImplVulkan_NewFrame(); ImGui_ImplGlfw_NewFrame(); ImGui::NewFrame();
+        }
+
+        auto VulkanDevice::imgui_render(CommandList& cmds) -> void
+        {
+            if (!m_imgui) return;
+            ImGui::Render();
+            ImGui_ImplVulkan_RenderDrawData(ImGui::GetDrawData(), static_cast<VkCommandListR&>(cmds).m_cmd);
+        }
+
+        auto VulkanDevice::shutdown() -> void
+        {
+            if (m_device == VK_NULL_HANDLE)
+            {
+                if (m_instance && m_surface) { vkDestroySurfaceKHR(m_instance, m_surface, nullptr); m_surface = VK_NULL_HANDLE; }
+                if (m_instance) { vkDestroyInstance(m_instance, nullptr); m_instance = VK_NULL_HANDLE; }
+                return;
+            }
+            vkDeviceWaitIdle(m_device);
+            if (m_imgui) { ImGui_ImplVulkan_Shutdown(); ImGui_ImplGlfw_Shutdown(); ImGui::DestroyContext(); m_imgui = false; }
+            if (m_imgui_pool) vkDestroyDescriptorPool(m_device, m_imgui_pool, nullptr);
+            for (auto p : m_frame_pools) vkDestroyDescriptorPool(m_device, p, nullptr);
+            m_frame_pools.clear();
+            for (auto s : m_render_finished) vkDestroySemaphore(m_device, s, nullptr);
+            for (auto s : m_image_available) vkDestroySemaphore(m_device, s, nullptr);
+            for (auto f : m_in_flight)       vkDestroyFence(m_device, f, nullptr);
+            m_render_finished.clear(); m_image_available.clear(); m_in_flight.clear();
+            if (m_command_pool) vkDestroyCommandPool(m_device, m_command_pool, nullptr);
+            if (m_offscreen_rp) vkDestroyRenderPass(m_device, m_offscreen_rp, nullptr);
+            if (m_swapchain_rp) vkDestroyRenderPass(m_device, m_swapchain_rp, nullptr);
+            cleanup_swapchain();
+            vkDestroyDevice(m_device, nullptr); m_device = VK_NULL_HANDLE;
+            if (m_surface)  vkDestroySurfaceKHR(m_instance, m_surface, nullptr);
+            if (m_instance) vkDestroyInstance(m_instance, nullptr);
+            m_surface = VK_NULL_HANDLE; m_instance = VK_NULL_HANDLE;
+        }
+    }
+
+    auto create_vulkan_device() -> Scope<Device> { return create_scope<VulkanDevice>(); }
+
+    auto vulkan_prepare_glfw() -> void
+    {
+#ifdef __APPLE__
+        if (!getenv("VK_ICD_FILENAMES"))
+            setenv("VK_ICD_FILENAMES", "/opt/homebrew/etc/vulkan/icd.d/MoltenVK_icd.json", 0);
+        if (!getenv("VK_LAYER_PATH"))
+            setenv("VK_LAYER_PATH", "/opt/homebrew/share/vulkan/explicit_layer.d", 0);
+        if (!getenv("DYLD_LIBRARY_PATH"))
+            setenv("DYLD_LIBRARY_PATH", "/opt/homebrew/lib", 0);
+#endif
+        glfwInitVulkanLoader(vkGetInstanceProcAddr);
+    }
+}
diff --git a/src/platform/vulkan/vulkan_device.h b/src/platform/vulkan/vulkan_device.h
new file mode 100644
index 0000000..efc2433
--- /dev/null
+++ b/src/platform/vulkan/vulkan_device.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include "rendering/rhi.h"
+
+namespace Donut::RHI
+{
+    // Vulkan implementation of the RHI Device (MoltenVK on macOS). Owns the
+    // instance/device/swapchain and translates the RHI's baked pipelines +
+    // recorded command lists into native Vulkan; the geometry it draws is the
+    // shared SceneRenderer / BlackHoleRenderer, identical to every other backend.
+    auto create_vulkan_device() -> Scope<Device>;
+
+    // Must run BEFORE glfwInit() when Vulkan is the selected API: points GLFW at
+    // the loader the app links against (its own dlopen fails on macOS/Homebrew)
+    // and configures the MoltenVK ICD / layer paths.
+    auto vulkan_prepare_glfw() -> void;
+}
diff --git a/src/platform/vulkan/vulkan_renderer.cpp b/src/platform/vulkan/vulkan_renderer.cpp
deleted file mode 100644
index 8b0d0c0..0000000
--- a/src/platform/vulkan/vulkan_renderer.cpp
+++ /dev/null
@@ -1,2038 +0,0 @@
-#include "vulkan_renderer.h"
-#include "core/log.h"
-#include "core/camera.h"
-#include "core/settings_manager.h"
-
-#define GLFW_INCLUDE_VULKAN
-#include <GLFW/glfw3.h>
-
-#include <imgui.h>
-#include <imgui_impl_glfw.h>
-#include <imgui_impl_vulkan.h>
-
-#include <glm/glm.hpp>
-#include <glm/gtc/matrix_transform.hpp>
-#include "stb_image.h"
-
-#include <vector>
-#include <algorithm>
-#include <cstring>
-#include <cstdlib>
-#include <fstream>
-
-namespace Donut
-{
-    #define VK_CHECK(expr)                                             \
-        do {                                                           \
-            VkResult _r = (expr);                                      \
-            if (_r != VK_SUCCESS) {                                    \
-                DONUT_ERROR("Vulkan: {} failed ({})", #expr, (int)_r); \
-                return false;                                          \
-            }                                                          \
-        } while (0)
-
-    static constexpr int MAX_FRAMES_IN_FLIGHT = 2;
-
-    auto vulkan_prepare_glfw() -> void
-    {
-#ifdef __APPLE__
-        if (!getenv("VK_ICD_FILENAMES"))
-            setenv("VK_ICD_FILENAMES", "/opt/homebrew/etc/vulkan/icd.d/MoltenVK_icd.json", 0);
-        if (!getenv("VK_LAYER_PATH"))
-            setenv("VK_LAYER_PATH", "/opt/homebrew/share/vulkan/explicit_layer.d", 0);
-        if (!getenv("DYLD_LIBRARY_PATH"))
-            setenv("DYLD_LIBRARY_PATH", "/opt/homebrew/lib", 0);
-#endif
-        // GLFW dlopen's the Vulkan loader by bare name, which fails on
-        // mac_os/Homebrew; hand it the loader entry point we already link against.
-        glfwInitVulkanLoader(vkGetInstanceProcAddr);
-    }
-
-    struct VulkanRenderer::Impl
-    {
-        GLFWwindow* window = nullptr;
-        int width = 0, height = 0;
-        bool framebuffer_resized = false;
-
-        VkInstance       instance = VK_NULL_HANDLE;
-        VkSurfaceKHR     surface  = VK_NULL_HANDLE;
-        VkPhysicalDevice physical = VK_NULL_HANDLE;
-        VkDevice         device   = VK_NULL_HANDLE;
-        uint32_t         graphics_family = 0, present_family = 0;
-        VkQueue          graphics_queue = VK_NULL_HANDLE, present_queue = VK_NULL_HANDLE;
-
-        VkSwapchainKHR   swapchain = VK_NULL_HANDLE;
-        VkFormat         swapchain_format = VK_FORMAT_B8G8R8A8_UNORM;
-        VkExtent2D       swapchain_extent{};
-        std::vector<VkImage>       images;
-        std::vector<VkImageView>   image_views;
-        VkRenderPass               render_pass = VK_NULL_HANDLE;
-        std::vector<VkFramebuffer> framebuffers;
-
-        VkCommandPool                command_pool = VK_NULL_HANDLE;
-        std::vector<VkCommandBuffer> command_buffers;   // MAX_FRAMES_IN_FLIGHT
-
-        std::vector<VkSemaphore> image_available;        // per frame in flight
-        std::vector<VkSemaphore> render_finished;        // per swapchain image
-        std::vector<VkFence>     in_flight;              // per frame in flight
-        std::vector<VkFence>     images_in_flight;        // per swapchain image
-        uint32_t current_frame = 0;
-
-        VkDescriptorPool imgui_pool = VK_NULL_HANDLE;
-        bool imgui_init = false;
-
-        VkPhysicalDeviceMemoryProperties mem_props{};
-
-        // The geodesic is rendered every frame into an offscreen image, then
-        // upscaled onto the swapchain by the present pass. Progressive resolution:
-        // low-res while the camera moves (keeps dragging responsive and each draw
-        // well under the Metal GPU watchdog) and high-res once it settles (resolves
-        // the photon ring cleanly). Both are 16:9 so the camera aspect is shared.
-        static constexpr uint32_t GEO_LO_W = 480, GEO_LO_H = 270;
-        static constexpr uint32_t GEO_HI_W = 960, GEO_HI_H = 540;
-        struct GeoTarget
-        {
-            uint32_t        w = 0, h = 0;
-            VkImage         image = VK_NULL_HANDLE;
-            VkDeviceMemory  mem   = VK_NULL_HANDLE;
-            VkImageView     view  = VK_NULL_HANDLE;
-            VkFramebuffer   fb    = VK_NULL_HANDLE;
-            VkDescriptorSet present_set = VK_NULL_HANDLE;  // present pass samples this target
-        };
-        GeoTarget     geo_lo, geo_hi;
-        VkRenderPass  geo_render_pass = VK_NULL_HANDLE;    // shared (resolution-independent)
-        VkBuffer cam_buf = VK_NULL_HANDLE, disk_buf = VK_NULL_HANDLE, obj_buf = VK_NULL_HANDLE, sim_buf = VK_NULL_HANDLE;
-        VkDeviceMemory cam_mem = VK_NULL_HANDLE, disk_mem = VK_NULL_HANDLE, obj_mem = VK_NULL_HANDLE, sim_mem = VK_NULL_HANDLE;
-        void* cam_mapped = nullptr;
-        void* sim_mapped = nullptr;
-        void* disk_mapped = nullptr;            // disk UBO, refilled from bh_params each frame
-        BlackHoleParams bh_params;              // live UI-tunable disk/camera parameters
-        std::string gpu_name;                   // physical device name for the UI
-        Camera camera{ 60.0f, (float)GEO_HI_W / (float)GEO_HI_H, 0.1f, 100.0f };
-        bool left_was_down = false;
-        double last_frame_time = 0.0;               // for free-fly dt
-        double fps_last_x = 0.0, fps_last_y = 0.0;  // cursor tracking for free-fly look
-        bool user_moving = false;                   // camera moved/looked this frame (drives step count)
-        VkImage cube_image = VK_NULL_HANDLE; VkDeviceMemory cube_mem = VK_NULL_HANDLE;
-        VkImageView cube_view = VK_NULL_HANDLE; VkSampler cube_sampler = VK_NULL_HANDLE;
-        std::string hdri_path;  // path backing the current cubemap (UI display + no-op switch guard)
-        VkDescriptorSetLayout geo_set_layout = VK_NULL_HANDLE;
-        VkDescriptorPool geo_pool = VK_NULL_HANDLE;
-        VkDescriptorSet geo_set = VK_NULL_HANDLE;
-        VkPipelineLayout geo_pipeline_layout = VK_NULL_HANDLE;
-        VkPipeline geo_pipeline = VK_NULL_HANDLE;
-        VkBuffer quad_vb = VK_NULL_HANDLE; VkDeviceMemory quad_vb_mem = VK_NULL_HANDLE;
-        double start_time = 0.0;
-        VkFence geo_in_use = VK_NULL_HANDLE;  // previous frame's fence; guards the shared geodesic image
-
-        // Present pass: samples the geodesic image with a full-screen textured
-        // quad, drawn into the swapchain render pass just before the ImGui UI.
-        VkSampler present_sampler = VK_NULL_HANDLE;
-        VkDescriptorSetLayout present_set_layout = VK_NULL_HANDLE;
-        VkDescriptorPool present_pool = VK_NULL_HANDLE;
-        VkPipelineLayout present_pipeline_layout = VK_NULL_HANDLE;
-        VkPipeline present_pipeline = VK_NULL_HANDLE;
-
-        // World-builder scene view (grid now; sphere/skybox next). Normal-scale
-        // orbital camera; geometry drawn straight into the swapchain render pass.
-        bool scene_mode = false;
-        Camera scene_camera{ 45.0f, (float)GEO_HI_W / (float)GEO_HI_H, 0.1f, 1000.0f };
-        VkBuffer grid_vb = VK_NULL_HANDLE; VkDeviceMemory grid_vb_mem = VK_NULL_HANDLE;
-        uint32_t grid_vertex_count = 0;
-        VkBuffer grid_ubo = VK_NULL_HANDLE; VkDeviceMemory grid_ubo_mem = VK_NULL_HANDLE;
-        void* grid_ubo_mapped = nullptr;
-        VkDescriptorSetLayout grid_set_layout = VK_NULL_HANDLE;
-        VkDescriptorPool grid_pool = VK_NULL_HANDLE;
-        VkDescriptorSet grid_set = VK_NULL_HANDLE;
-        VkPipelineLayout grid_pipeline_layout = VK_NULL_HANDLE;
-        VkPipeline grid_pipeline = VK_NULL_HANDLE;
-
-        // Scene color+depth pass into the swapchain (the grid is coplanar, but the
-        // sphere needs real depth). Depth image + framebuffers track the swapchain.
-        VkImage scene_depth_image = VK_NULL_HANDLE; VkDeviceMemory scene_depth_mem = VK_NULL_HANDLE;
-        VkImageView scene_depth_view = VK_NULL_HANDLE;
-        VkRenderPass scene_render_pass = VK_NULL_HANDLE;
-        std::vector<VkFramebuffer> scene_framebuffers;
-
-        // Lit sphere (Sphere.slang): pos+normal indexed mesh; samples the HDRI
-        // cubemap for ambient at binding 1 (shares the geodesic cube).
-        VkBuffer sphere_vb = VK_NULL_HANDLE; VkDeviceMemory sphere_vb_mem = VK_NULL_HANDLE;
-        VkBuffer sphere_ib = VK_NULL_HANDLE; VkDeviceMemory sphere_ib_mem = VK_NULL_HANDLE;
-        uint32_t sphere_index_count = 0;
-        static constexpr uint32_t MAX_SCENE_OBJECTS = 64;
-        std::vector<SceneObject> scene_objects{ SceneObject{} };  // one default sphere
-        int selected_object = 0;
-        VkDeviceSize sphere_ubo_stride = 0;  // aligned per-object UBO slot (dynamic offset)
-        VkBuffer sphere_ubo = VK_NULL_HANDLE; VkDeviceMemory sphere_ubo_mem = VK_NULL_HANDLE;
-        void* sphere_ubo_mapped = nullptr;
-        VkDescriptorSetLayout sphere_set_layout = VK_NULL_HANDLE;
-        VkDescriptorPool sphere_pool = VK_NULL_HANDLE;
-        VkDescriptorSet sphere_set = VK_NULL_HANDLE;
-        VkPipelineLayout sphere_pipeline_layout = VK_NULL_HANDLE;
-        VkPipeline sphere_pipeline = VK_NULL_HANDLE;
-
-        // Skybox (Skybox.slang): a cube sampling the HDRI cubemap at the far plane
-        // (pos.xyww -> depth 1), drawn first as the scene background.
-        VkBuffer skybox_vb = VK_NULL_HANDLE; VkDeviceMemory skybox_vb_mem = VK_NULL_HANDLE;
-        VkBuffer skybox_ubo = VK_NULL_HANDLE; VkDeviceMemory skybox_ubo_mem = VK_NULL_HANDLE;
-        void* skybox_ubo_mapped = nullptr;
-        VkDescriptorSetLayout skybox_set_layout = VK_NULL_HANDLE;
-        VkDescriptorPool skybox_pool = VK_NULL_HANDLE;
-        VkDescriptorSet skybox_set = VK_NULL_HANDLE;
-        VkPipelineLayout skybox_pipeline_layout = VK_NULL_HANDLE;
-        VkPipeline skybox_pipeline = VK_NULL_HANDLE;
-
-        auto find_memory_type(uint32_t type_filter, VkMemoryPropertyFlags flags) const -> uint32_t;
-        auto create_buffer(VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags props, VkBuffer& buf, VkDeviceMemory& mem) const -> bool;
-        static auto load_spirv(const std::string& path) -> std::vector<uint32_t>;
-        auto create_shader_module(const std::string& path, VkShaderModule& out) const -> bool;
-
-        auto create_instance() -> bool;
-        auto pick_physical_and_device() -> bool;
-        auto create_swapchain() -> bool;
-        auto create_image_views() -> bool;
-        auto create_render_pass() -> bool;
-        auto create_framebuffers() -> bool;
-        auto create_command_buffers() -> bool;
-        auto create_sync_objects() -> bool;
-        auto create_geodesic_resources() -> bool;
-        auto create_geo_target(GeoTarget& target, uint32_t w, uint32_t h) -> bool;
-        auto create_hdri_cubemap(const char* path) -> bool;
-        auto rebuild_hdri_cubemap(const char* path) -> void;
-        auto create_present_resources() -> bool;
-        auto create_scene_resources() -> bool;
-        auto create_scene_targets() -> bool;
-        auto destroy_scene_targets() -> void;
-        auto process_input() -> void;
-        auto update_geodesic_uniforms() -> void;
-        auto update_scene_uniforms() -> void;
-        auto destroy_geodesic_resources() -> void;
-        auto recreate_swapchain() -> bool;
-        auto cleanup_swapchain() -> void;
-        auto record_command_buffer(VkCommandBuffer cmd, uint32_t image_index, const glm::vec4& clear, ImDrawData* draw_data) -> bool;
-    };
-
-    auto VulkanRenderer::Impl::create_instance() -> bool
-    {
-#ifdef __APPLE__
-        if (!getenv("VK_ICD_FILENAMES"))
-            setenv("VK_ICD_FILENAMES", "/opt/homebrew/etc/vulkan/icd.d/MoltenVK_icd.json", 0);
-        if (!getenv("VK_LAYER_PATH"))
-            setenv("VK_LAYER_PATH", "/opt/homebrew/share/vulkan/explicit_layer.d", 0);
-        // The Homebrew validation-layer manifest names the dylib without a path;
-        // let dlopen find it in the Homebrew lib dir.
-        if (!getenv("DYLD_LIBRARY_PATH"))
-            setenv("DYLD_LIBRARY_PATH", "/opt/homebrew/lib", 0);
-#endif
-        VkApplicationInfo app{ VK_STRUCTURE_TYPE_APPLICATION_INFO };
-        app.pApplicationName = "Donut";
-        app.apiVersion       = VK_API_VERSION_1_2;
-
-        uint32_t glfwExtCount = 0;
-        const char** glfwExts = glfwGetRequiredInstanceExtensions(&glfwExtCount);
-        if (!glfwExts) { DONUT_ERROR("Vulkan: GLFW reports no surface support"); return false; }
-        std::vector<const char*> exts;
-        for (uint32_t i = 0; i < glfwExtCount; ++i) exts.push_back(glfwExts[i]);
-        exts.push_back(VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME);
-        exts.push_back(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME);
-
-        std::vector<const char*> layers;
-        uint32_t layer_count = 0;
-        vkEnumerateInstanceLayerProperties(&layer_count, nullptr);
-        std::vector<VkLayerProperties> avail(layer_count);
-        vkEnumerateInstanceLayerProperties(&layer_count, avail.data());
-        for (const auto& l : avail)
-            if (std::strcmp(l.layerName, "VK_LAYER_KHRONOS_validation") == 0)
-                layers.push_back("VK_LAYER_KHRONOS_validation");
-
-        VkInstanceCreateInfo ici{ VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO };
-        ici.flags                   = VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR;
-        ici.pApplicationInfo        = &app;
-        ici.enabledExtensionCount   = (uint32_t)exts.size();
-        ici.ppEnabledExtensionNames = exts.data();
-        ici.enabledLayerCount       = (uint32_t)layers.size();
-        ici.ppEnabledLayerNames     = layers.data();
-
-        VkResult r = vkCreateInstance(&ici, nullptr, &instance);
-        if (r != VK_SUCCESS && !layers.empty())
-        {
-            // The validation layer failed to load (its dylib isn't on the loader
-            // search path); it is optional, so retry without it.
-            DONUT_WARN("Vulkan: validation layer unavailable, continuing without it");
-            layers.clear();
-            ici.enabledLayerCount = 0;
-            ici.ppEnabledLayerNames = nullptr;
-            r = vkCreateInstance(&ici, nullptr, &instance);
-        }
-        if (r != VK_SUCCESS) { DONUT_ERROR("Vulkan: vkCreateInstance failed ({})", (int)r); return false; }
-
-        VK_CHECK(glfwCreateWindowSurface(instance, window, nullptr, &surface));
-        DONUT_INFO("Vulkan: instance + surface created (validation {})", layers.empty() ? "off" : "on");
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::pick_physical_and_device() -> bool
-    {
-        uint32_t count = 0;
-        vkEnumeratePhysicalDevices(instance, &count, nullptr);
-        if (count == 0) { DONUT_ERROR("Vulkan: no physical devices"); return false; }
-        std::vector<VkPhysicalDevice> devices(count);
-        vkEnumeratePhysicalDevices(instance, &count, devices.data());
-        physical = devices[0];
-
-        uint32_t q_count = 0;
-        vkGetPhysicalDeviceQueueFamilyProperties(physical, &q_count, nullptr);
-        std::vector<VkQueueFamilyProperties> qfams(q_count);
-        vkGetPhysicalDeviceQueueFamilyProperties(physical, &q_count, qfams.data());
-        bool found_g = false, found_p = false;
-        for (uint32_t i = 0; i < q_count; ++i)
-        {
-            if (!found_g && (qfams[i].queueFlags & VK_QUEUE_GRAPHICS_BIT)) { graphics_family = i; found_g = true; }
-            VkBool32 present = VK_FALSE;
-            vkGetPhysicalDeviceSurfaceSupportKHR(physical, i, surface, &present);
-            if (!found_p && present) { present_family = i; found_p = true; }
-        }
-        if (!found_g || !found_p) { DONUT_ERROR("Vulkan: no graphics/present queue"); return false; }
-
-        std::vector<const char*> dev_exts = { VK_KHR_SWAPCHAIN_EXTENSION_NAME };
-        uint32_t dev_ext_count = 0;
-        vkEnumerateDeviceExtensionProperties(physical, nullptr, &dev_ext_count, nullptr);
-        std::vector<VkExtensionProperties> dev_ext_props(dev_ext_count);
-        vkEnumerateDeviceExtensionProperties(physical, nullptr, &dev_ext_count, dev_ext_props.data());
-        for (const auto& e : dev_ext_props)
-            if (std::strcmp(e.extensionName, "VK_KHR_portability_subset") == 0)
-                dev_exts.push_back("VK_KHR_portability_subset");
-
-        float priority = 1.0f;
-        std::vector<VkDeviceQueueCreateInfo> qcis;
-        uint32_t families[2] = { graphics_family, present_family };
-        for (uint32_t i = 0; i < (graphics_family == present_family ? 1u : 2u); ++i)
-        {
-            VkDeviceQueueCreateInfo qci{ VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO };
-            qci.queueFamilyIndex = families[i];
-            qci.queueCount = 1;
-            qci.pQueuePriorities = &priority;
-            qcis.push_back(qci);
-        }
-        VkDeviceCreateInfo dci{ VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO };
-        dci.queueCreateInfoCount    = (uint32_t)qcis.size();
-        dci.pQueueCreateInfos       = qcis.data();
-        dci.enabledExtensionCount   = (uint32_t)dev_exts.size();
-        dci.ppEnabledExtensionNames = dev_exts.data();
-        VK_CHECK(vkCreateDevice(physical, &dci, nullptr, &device));
-        vkGetDeviceQueue(device, graphics_family, 0, &graphics_queue);
-        vkGetDeviceQueue(device, present_family, 0, &present_queue);
-
-        VkPhysicalDeviceProperties props{};
-        vkGetPhysicalDeviceProperties(physical, &props);
-        vkGetPhysicalDeviceMemoryProperties(physical, &mem_props);
-        gpu_name = props.deviceName;
-        DONUT_INFO("Vulkan device: {}", gpu_name);
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_swapchain() -> bool
-    {
-        VkSurfaceCapabilitiesKHR caps{};
-        vkGetPhysicalDeviceSurfaceCapabilitiesKHR(physical, surface, &caps);
-
-        uint32_t fmt_count = 0;
-        vkGetPhysicalDeviceSurfaceFormatsKHR(physical, surface, &fmt_count, nullptr);
-        std::vector<VkSurfaceFormatKHR> formats(fmt_count);
-        vkGetPhysicalDeviceSurfaceFormatsKHR(physical, surface, &fmt_count, formats.data());
-        VkSurfaceFormatKHR chosen = formats[0];
-        for (const auto& f : formats)
-            if (f.format == VK_FORMAT_B8G8R8A8_UNORM && f.colorSpace == VK_COLOR_SPACE_SRGB_NONLINEAR_KHR)
-                chosen = f;
-        swapchain_format = chosen.format;
-
-        if (caps.currentExtent.width != UINT32_MAX)
-            swapchain_extent = caps.currentExtent;
-        else
-        {
-            swapchain_extent.width  = std::clamp((uint32_t)width,  caps.minImageExtent.width,  caps.maxImageExtent.width);
-            swapchain_extent.height = std::clamp((uint32_t)height, caps.minImageExtent.height, caps.maxImageExtent.height);
-        }
-
-        uint32_t image_count = caps.minImageCount + 1;
-        if (caps.maxImageCount > 0 && image_count > caps.maxImageCount)
-            image_count = caps.maxImageCount;
-
-        VkSwapchainCreateInfoKHR sci{ VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR };
-        sci.surface          = surface;
-        sci.minImageCount    = image_count;
-        sci.imageFormat      = chosen.format;
-        sci.imageColorSpace  = chosen.colorSpace;
-        sci.imageExtent      = swapchain_extent;
-        sci.imageArrayLayers = 1;
-        sci.imageUsage       = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
-        sci.preTransform     = caps.currentTransform;
-        sci.compositeAlpha   = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
-        sci.presentMode      = VK_PRESENT_MODE_FIFO_KHR;   // always supported, vsync
-        sci.clipped          = VK_TRUE;
-
-        uint32_t fam_idx[2] = { graphics_family, present_family };
-        if (graphics_family != present_family)
-        {
-            sci.imageSharingMode      = VK_SHARING_MODE_CONCURRENT;
-            sci.queueFamilyIndexCount = 2;
-            sci.pQueueFamilyIndices   = fam_idx;
-        }
-        else
-            sci.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
-
-        VK_CHECK(vkCreateSwapchainKHR(device, &sci, nullptr, &swapchain));
-        uint32_t n = 0;
-        vkGetSwapchainImagesKHR(device, swapchain, &n, nullptr);
-        images.resize(n);
-        vkGetSwapchainImagesKHR(device, swapchain, &n, images.data());
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_image_views() -> bool
-    {
-        image_views.resize(images.size());
-        for (size_t i = 0; i < images.size(); ++i)
-        {
-            VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-            vci.image = images[i];
-            vci.viewType = VK_IMAGE_VIEW_TYPE_2D;
-            vci.format = swapchain_format;
-            vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-            VK_CHECK(vkCreateImageView(device, &vci, nullptr, &image_views[i]));
-        }
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_render_pass() -> bool
-    {
-        VkAttachmentDescription color{};
-        color.format = swapchain_format;
-        color.samples = VK_SAMPLE_COUNT_1_BIT;
-        color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
-        color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
-        color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
-        color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
-        color.finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
-
-        VkAttachmentReference ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{};
-        subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
-        subpass.colorAttachmentCount = 1;
-        subpass.pColorAttachments = &ref;
-
-        VkSubpassDependency dep{};
-        dep.srcSubpass = VK_SUBPASS_EXTERNAL;
-        dep.dstSubpass = 0;
-        dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
-        dep.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
-        dep.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 1; rpci.pAttachments = &color;
-        rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
-        rpci.dependencyCount = 1; rpci.pDependencies = &dep;
-        VK_CHECK(vkCreateRenderPass(device, &rpci, nullptr, &render_pass));
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_framebuffers() -> bool
-    {
-        framebuffers.resize(image_views.size());
-        for (size_t i = 0; i < image_views.size(); ++i)
-        {
-            VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-            fbci.renderPass = render_pass;
-            fbci.attachmentCount = 1; fbci.pAttachments = &image_views[i];
-            fbci.width = swapchain_extent.width; fbci.height = swapchain_extent.height; fbci.layers = 1;
-            VK_CHECK(vkCreateFramebuffer(device, &fbci, nullptr, &framebuffers[i]));
-        }
-        return true;
-    }
-
-    // Depth image + a color+depth render pass + per-image framebuffers for the
-    // scene view. Swapchain-sized, so recreated alongside the swapchain.
-    auto VulkanRenderer::Impl::create_scene_targets() -> bool
-    {
-        const VkFormat depth_fmt = VK_FORMAT_D32_SFLOAT;
-
-        VkImageCreateInfo dici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        dici.imageType = VK_IMAGE_TYPE_2D; dici.format = depth_fmt;
-        dici.extent = { swapchain_extent.width, swapchain_extent.height, 1 };
-        dici.mipLevels = 1; dici.arrayLayers = 1; dici.samples = VK_SAMPLE_COUNT_1_BIT;
-        dici.tiling = VK_IMAGE_TILING_OPTIMAL; dici.usage = VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
-        VK_CHECK(vkCreateImage(device, &dici, nullptr, &scene_depth_image));
-        VkMemoryRequirements dreq{}; vkGetImageMemoryRequirements(device, scene_depth_image, &dreq);
-        VkMemoryAllocateInfo dai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        dai.allocationSize = dreq.size; dai.memoryTypeIndex = find_memory_type(dreq.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(device, &dai, nullptr, &scene_depth_mem));
-        VK_CHECK(vkBindImageMemory(device, scene_depth_image, scene_depth_mem, 0));
-        VkImageViewCreateInfo dvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        dvci.image = scene_depth_image; dvci.viewType = VK_IMAGE_VIEW_TYPE_2D; dvci.format = depth_fmt;
-        dvci.subresourceRange = { VK_IMAGE_ASPECT_DEPTH_BIT, 0, 1, 0, 1 };
-        VK_CHECK(vkCreateImageView(device, &dvci, nullptr, &scene_depth_view));
-
-        VkAttachmentDescription atts[2]{};
-        atts[0].format = swapchain_format; atts[0].samples = VK_SAMPLE_COUNT_1_BIT;
-        atts[0].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; atts[0].storeOp = VK_ATTACHMENT_STORE_OP_STORE;
-        atts[0].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; atts[0].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        atts[0].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; atts[0].finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
-        atts[1].format = depth_fmt; atts[1].samples = VK_SAMPLE_COUNT_1_BIT;
-        atts[1].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; atts[1].storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        atts[1].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; atts[1].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        atts[1].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; atts[1].finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
-        VkAttachmentReference color_ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkAttachmentReference depth_ref{ 1, VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
-        subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &color_ref; subpass.pDepthStencilAttachment = &depth_ref;
-        VkSubpassDependency dep{};
-        dep.srcSubpass = VK_SUBPASS_EXTERNAL; dep.dstSubpass = 0;
-        dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT | VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT;
-        dep.dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT | VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT;
-        dep.srcAccessMask = 0;
-        dep.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 2; rpci.pAttachments = atts; rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
-        rpci.dependencyCount = 1; rpci.pDependencies = &dep;
-        VK_CHECK(vkCreateRenderPass(device, &rpci, nullptr, &scene_render_pass));
-
-        scene_framebuffers.resize(image_views.size());
-        for (size_t i = 0; i < image_views.size(); ++i)
-        {
-            VkImageView att[2] = { image_views[i], scene_depth_view };
-            VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-            fbci.renderPass = scene_render_pass; fbci.attachmentCount = 2; fbci.pAttachments = att;
-            fbci.width = swapchain_extent.width; fbci.height = swapchain_extent.height; fbci.layers = 1;
-            VK_CHECK(vkCreateFramebuffer(device, &fbci, nullptr, &scene_framebuffers[i]));
-        }
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::destroy_scene_targets() -> void
-    {
-        for (auto fb : scene_framebuffers) vkDestroyFramebuffer(device, fb, nullptr);
-        scene_framebuffers.clear();
-        if (scene_render_pass) { vkDestroyRenderPass(device, scene_render_pass, nullptr); scene_render_pass = VK_NULL_HANDLE; }
-        if (scene_depth_view)  { vkDestroyImageView(device, scene_depth_view, nullptr); scene_depth_view = VK_NULL_HANDLE; }
-        if (scene_depth_image) { vkDestroyImage(device, scene_depth_image, nullptr); scene_depth_image = VK_NULL_HANDLE; }
-        if (scene_depth_mem)   { vkFreeMemory(device, scene_depth_mem, nullptr); scene_depth_mem = VK_NULL_HANDLE; }
-    }
-
-    auto VulkanRenderer::Impl::create_command_buffers() -> bool
-    {
-        VkCommandPoolCreateInfo pci{ VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO };
-        pci.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;
-        pci.queueFamilyIndex = graphics_family;
-        VK_CHECK(vkCreateCommandPool(device, &pci, nullptr, &command_pool));
-
-        command_buffers.resize(MAX_FRAMES_IN_FLIGHT);
-        VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
-        cbai.commandPool = command_pool;
-        cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
-        cbai.commandBufferCount = MAX_FRAMES_IN_FLIGHT;
-        VK_CHECK(vkAllocateCommandBuffers(device, &cbai, command_buffers.data()));
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_sync_objects() -> bool
-    {
-        image_available.resize(MAX_FRAMES_IN_FLIGHT);
-        in_flight.resize(MAX_FRAMES_IN_FLIGHT);
-        render_finished.resize(images.size());
-        images_in_flight.assign(images.size(), VK_NULL_HANDLE);
-
-        VkSemaphoreCreateInfo sci{ VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO };
-        VkFenceCreateInfo fci{ VK_STRUCTURE_TYPE_FENCE_CREATE_INFO };
-        fci.flags = VK_FENCE_CREATE_SIGNALED_BIT;
-        for (int i = 0; i < MAX_FRAMES_IN_FLIGHT; ++i)
-        {
-            VK_CHECK(vkCreateSemaphore(device, &sci, nullptr, &image_available[i]));
-            VK_CHECK(vkCreateFence(device, &fci, nullptr, &in_flight[i]));
-        }
-        for (size_t i = 0; i < images.size(); ++i)
-            VK_CHECK(vkCreateSemaphore(device, &sci, nullptr, &render_finished[i]));
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::find_memory_type(uint32_t type_filter, VkMemoryPropertyFlags flags) const -> uint32_t
-    {
-        for (uint32_t i = 0; i < mem_props.memoryTypeCount; ++i)
-            if ((type_filter & (1u << i)) && (mem_props.memoryTypes[i].propertyFlags & flags) == flags)
-                return i;
-        return UINT32_MAX;
-    }
-
-    auto VulkanRenderer::Impl::create_buffer(VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags props,
-                                            VkBuffer& buf, VkDeviceMemory& mem) const -> bool
-    {
-        VkBufferCreateInfo bci{ VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
-        bci.size = size; bci.usage = usage; bci.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
-        if (vkCreateBuffer(device, &bci, nullptr, &buf) != VK_SUCCESS) return false;
-        VkMemoryRequirements req{}; vkGetBufferMemoryRequirements(device, buf, &req);
-        VkMemoryAllocateInfo ai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        ai.allocationSize = req.size;
-        ai.memoryTypeIndex = find_memory_type(req.memoryTypeBits, props);
-        if (vkAllocateMemory(device, &ai, nullptr, &mem) != VK_SUCCESS) return false;
-        vkBindBufferMemory(device, buf, mem, 0);
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::load_spirv(const std::string& path) -> std::vector<uint32_t>
-    {
-        std::ifstream file(path, std::ios::ate | std::ios::binary);
-        if (!file.is_open()) return {};
-        size_t size = (size_t)file.tellg();
-        std::vector<uint32_t> data(size / 4);
-        file.seekg(0);
-        file.read(reinterpret_cast<char*>(data.data()), size);
-        return data;
-    }
-
-    auto VulkanRenderer::Impl::create_shader_module(const std::string& path, VkShaderModule& out) const -> bool
-    {
-        auto spv = load_spirv(path);
-        if (spv.empty()) { DONUT_ERROR("Vulkan: failed to load SPIR-V {}", path); return false; }
-        VkShaderModuleCreateInfo ci{ VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO };
-        ci.codeSize = spv.size() * 4; ci.pCode = spv.data();
-        return vkCreateShaderModule(device, &ci, nullptr, &out) == VK_SUCCESS;
-    }
-
-    // Creates one geodesic render target (image + memory + view + framebuffer)
-    // at w x h against the shared geo_render_pass. Used for the low- and high-res
-    // progressive targets.
-    auto VulkanRenderer::Impl::create_geo_target(GeoTarget& t, uint32_t w, uint32_t h) -> bool
-    {
-        const VkFormat fmt = VK_FORMAT_R8G8B8A8_UNORM;
-        t.w = w; t.h = h;
-
-        VkImageCreateInfo ici{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        ici.imageType = VK_IMAGE_TYPE_2D; ici.format = fmt; ici.extent = { w, h, 1 };
-        ici.mipLevels = 1; ici.arrayLayers = 1; ici.samples = VK_SAMPLE_COUNT_1_BIT;
-        ici.tiling = VK_IMAGE_TILING_OPTIMAL;
-        ici.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
-        VK_CHECK(vkCreateImage(device, &ici, nullptr, &t.image));
-        VkMemoryRequirements im_req{}; vkGetImageMemoryRequirements(device, t.image, &im_req);
-        VkMemoryAllocateInfo im_alloc{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        im_alloc.allocationSize = im_req.size;
-        im_alloc.memoryTypeIndex = find_memory_type(im_req.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(device, &im_alloc, nullptr, &t.mem));
-        VK_CHECK(vkBindImageMemory(device, t.image, t.mem, 0));
-        VkImageViewCreateInfo vci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        vci.image = t.image; vci.viewType = VK_IMAGE_VIEW_TYPE_2D; vci.format = fmt;
-        vci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-        VK_CHECK(vkCreateImageView(device, &vci, nullptr, &t.view));
-        VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-        fbci.renderPass = geo_render_pass; fbci.attachmentCount = 1; fbci.pAttachments = &t.view;
-        fbci.width = w; fbci.height = h; fbci.layers = 1;
-        VK_CHECK(vkCreateFramebuffer(device, &fbci, nullptr, &t.fb));
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_geodesic_resources() -> bool
-    {
-        const VkFormat fmt = VK_FORMAT_R8G8B8A8_UNORM;
-        const VkMemoryPropertyFlags host_vis = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
-        const float SagA_rs = 1.269e10f;
-
-        VkAttachmentDescription color{};
-        color.format = fmt; color.samples = VK_SAMPLE_COUNT_1_BIT;
-        color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
-        color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; color.finalLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-        VkAttachmentReference ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
-        subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &ref;
-        VkSubpassDependency deps[2]{};
-        deps[0].srcSubpass = VK_SUBPASS_EXTERNAL; deps[0].dstSubpass = 0;
-        deps[0].srcStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT; deps[0].srcAccessMask = VK_ACCESS_SHADER_READ_BIT;
-        deps[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; deps[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        deps[1].srcSubpass = 0; deps[1].dstSubpass = VK_SUBPASS_EXTERNAL;
-        deps[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; deps[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        deps[1].dstStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT; deps[1].dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 1; rpci.pAttachments = &color;
-        rpci.subpassCount = 1; rpci.pSubpasses = &subpass;
-        rpci.dependencyCount = 2; rpci.pDependencies = deps;
-        VK_CHECK(vkCreateRenderPass(device, &rpci, nullptr, &geo_render_pass));
-
-        if (!create_geo_target(geo_lo, GEO_LO_W, GEO_LO_H)) return false;
-        if (!create_geo_target(geo_hi, GEO_HI_W, GEO_HI_H)) return false;
-
-        create_buffer(128, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, cam_buf, cam_mem);
-        create_buffer(32,  VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, disk_buf, disk_mem);
-        create_buffer(800, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, obj_buf, obj_mem);
-        create_buffer(16,  VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, sim_buf, sim_mem);
-
-        camera.set_camera_mode(CameraMode::Orbital);
-        camera.set_orbital_target(glm::vec3(0.0f));
-        camera.set_orbital_radius(4e11);          // ~31 r_s: outside the 12 r_s disk
-        camera.set_orbital_limits(2.2e11, 1.5e12);
-        camera.set_orbital_speed(0.01f);
-        camera.set_zoom_speed(3e10);
-        camera.set_azimuth(0.0f);
-        camera.set_elevation(1.25f);
-
-        void* p = nullptr;
-        vkMapMemory(device, cam_mem, 0, 128, 0, &cam_mapped);   // camera UBO refilled every frame
-        vkMapMemory(device, disk_mem, 0, 32, 0, &disk_mapped);  // disk UBO refilled from bh_params every frame
-
-        std::vector<uint8_t> obj_data(800, 0);
-        int num_objects = 1; memcpy(obj_data.data(), &num_objects, 4);
-        float pos_radius[4] = { 0, 0, 0, SagA_rs }; memcpy(obj_data.data() + 16, pos_radius, 16);
-        float obj_color[4] = { 0, 0, 0, 1 };        memcpy(obj_data.data() + 272, obj_color, 16);
-        vkMapMemory(device, obj_mem, 0, 800, 0, &p); memcpy(p, obj_data.data(), 800); vkUnmapMemory(device, obj_mem);
-
-        vkMapMemory(device, sim_mem, 0, 16, 0, &sim_mapped);
-
-        if (!create_hdri_cubemap("assets/hdri/HDR_blue_nebulae-1.hdr")) return false;
-
-        VkDescriptorSetLayoutBinding binds[5]{};
-        for (int i = 0; i < 4; ++i) { binds[i].binding = i; binds[i].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; binds[i].descriptorCount = 1; binds[i].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT; }
-        binds[4].binding = 4; binds[4].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; binds[4].descriptorCount = 1; binds[4].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-        VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO };
-        dslci.bindingCount = 5; dslci.pBindings = binds;
-        VK_CHECK(vkCreateDescriptorSetLayout(device, &dslci, nullptr, &geo_set_layout));
-        VkDescriptorPoolSize psizes[2] = { { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 4 }, { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1 } };
-        VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO };
-        dpci.maxSets = 1; dpci.poolSizeCount = 2; dpci.pPoolSizes = psizes;
-        VK_CHECK(vkCreateDescriptorPool(device, &dpci, nullptr, &geo_pool));
-        VkDescriptorSetAllocateInfo dsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO };
-        dsai.descriptorPool = geo_pool; dsai.descriptorSetCount = 1; dsai.pSetLayouts = &geo_set_layout;
-        VK_CHECK(vkAllocateDescriptorSets(device, &dsai, &geo_set));
-        VkDescriptorBufferInfo bi[4] = { { cam_buf, 0, VK_WHOLE_SIZE }, { disk_buf, 0, VK_WHOLE_SIZE }, { obj_buf, 0, VK_WHOLE_SIZE }, { sim_buf, 0, VK_WHOLE_SIZE } };
-        VkDescriptorImageInfo cube_info{ cube_sampler, cube_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-        VkWriteDescriptorSet writes[5]{};
-        for (int i = 0; i < 4; ++i) { writes[i].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; writes[i].dstSet = geo_set; writes[i].dstBinding = i; writes[i].descriptorCount = 1; writes[i].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; writes[i].pBufferInfo = &bi[i]; }
-        writes[4].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; writes[4].dstSet = geo_set; writes[4].dstBinding = 4; writes[4].descriptorCount = 1; writes[4].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; writes[4].pImageInfo = &cube_info;
-        vkUpdateDescriptorSets(device, 5, writes, 0, nullptr);
-
-        float quad[] = {
-            -1.f,  1.f, 0.f, 1.f,  -1.f, -1.f, 0.f, 0.f,   1.f, -1.f, 1.f, 0.f,
-            -1.f,  1.f, 0.f, 1.f,   1.f, -1.f, 1.f, 0.f,   1.f,  1.f, 1.f, 1.f,
-        };
-        create_buffer(sizeof(quad), VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, quad_vb, quad_vb_mem);
-        vkMapMemory(device, quad_vb_mem, 0, sizeof(quad), 0, &p); memcpy(p, quad, sizeof(quad)); vkUnmapMemory(device, quad_vb_mem);
-
-        VkShaderModule vmod, fmod;
-        if (!create_shader_module("assets/shaders/generated/Geodesic.vertexMain.spv", vmod)) return false;
-        if (!create_shader_module("assets/shaders/generated/Geodesic.fragmentMain.spv", fmod)) return false;
-        VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO };
-        plci.setLayoutCount = 1; plci.pSetLayouts = &geo_set_layout;
-        VK_CHECK(vkCreatePipelineLayout(device, &plci, nullptr, &geo_pipeline_layout));
-        VkPipelineShaderStageCreateInfo stages[2]{};
-        stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
-        stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
-        VkVertexInputBindingDescription vib{ 0, 16, VK_VERTEX_INPUT_RATE_VERTEX };
-        VkVertexInputAttributeDescription via[2] = { { 0, 0, VK_FORMAT_R32G32_SFLOAT, 0 }, { 1, 0, VK_FORMAT_R32G32_SFLOAT, 8 } };
-        VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-        vin.vertexBindingDescriptionCount = 1; vin.pVertexBindingDescriptions = &vib;
-        vin.vertexAttributeDescriptionCount = 2; vin.pVertexAttributeDescriptions = via;
-        VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-        // Dynamic viewport/scissor: the same pipeline renders into either the
-        // low- or high-res target, sized per frame in record_command_buffer.
-        VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.scissorCount = 1;
-        VkDynamicState dyn_states[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
-        VkPipelineDynamicStateCreateInfo dyn{ VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO }; dyn.dynamicStateCount = 2; dyn.pDynamicStates = dyn_states;
-        VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
-        VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-        VkPipelineColorBlendAttachmentState cba{}; cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-        VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
-        VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-        gpci.stageCount = 2; gpci.pStages = stages;
-        gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
-        gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb;
-        gpci.pDynamicState = &dyn;
-        gpci.layout = geo_pipeline_layout; gpci.renderPass = geo_render_pass; gpci.subpass = 0;
-        VkResult pr = vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &gpci, nullptr, &geo_pipeline);
-        vkDestroyShaderModule(device, vmod, nullptr); vkDestroyShaderModule(device, fmod, nullptr);
-        if (pr != VK_SUCCESS) { DONUT_ERROR("Vulkan: geodesic pipeline creation failed ({})", (int)pr); return false; }
-
-        start_time = glfwGetTime();
-        update_geodesic_uniforms();
-        DONUT_INFO("Vulkan: geodesic resources ready ({}x{} moving / {}x{} settled)",
-                   (int)GEO_LO_W, (int)GEO_LO_H, (int)GEO_HI_W, (int)GEO_HI_H);
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_hdri_cubemap(const char* path) -> bool
-    {
-        hdri_path = path;
-        const VkMemoryPropertyFlags host_vis = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
-        const uint32_t FACE = 1024;
-        const VkFormat cube_fmt = VK_FORMAT_R16G16B16A16_SFLOAT;
-        uint32_t CUBE_MIPS = 1; for (uint32_t s = FACE; s > 1; s >>= 1) ++CUBE_MIPS;  // full chain (11 for 1024)
-
-        VkImageCreateInfo cci{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        cci.flags = VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT;
-        cci.imageType = VK_IMAGE_TYPE_2D; cci.format = cube_fmt; cci.extent = { FACE, FACE, 1 };
-        cci.mipLevels = CUBE_MIPS; cci.arrayLayers = 6; cci.samples = VK_SAMPLE_COUNT_1_BIT;
-        cci.tiling = VK_IMAGE_TILING_OPTIMAL;
-        // COLOR_ATTACHMENT renders the 6 faces (mip 0); TRANSFER_SRC/DST build the
-        // mip chain by blitting; SAMPLED for shader reads (incl. mip-LOD sampling).
-        cci.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT
-                  | VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
-        VK_CHECK(vkCreateImage(device, &cci, nullptr, &cube_image));
-        VkMemoryRequirements creq{}; vkGetImageMemoryRequirements(device, cube_image, &creq);
-        VkMemoryAllocateInfo cai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        cai.allocationSize = creq.size; cai.memoryTypeIndex = find_memory_type(creq.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(device, &cai, nullptr, &cube_mem));
-        VK_CHECK(vkBindImageMemory(device, cube_image, cube_mem, 0));
-        VkImageViewCreateInfo cvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        cvci.image = cube_image; cvci.viewType = VK_IMAGE_VIEW_TYPE_CUBE; cvci.format = cube_fmt;
-        cvci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, CUBE_MIPS, 0, 6 };
-        VK_CHECK(vkCreateImageView(device, &cvci, nullptr, &cube_view));
-        VkSamplerCreateInfo csm{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
-        csm.magFilter = VK_FILTER_LINEAR; csm.minFilter = VK_FILTER_LINEAR;
-        csm.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR; csm.minLod = 0.0f; csm.maxLod = (float)CUBE_MIPS;
-        csm.addressModeU = csm.addressModeV = csm.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
-        VK_CHECK(vkCreateSampler(device, &csm, nullptr, &cube_sampler));
-
-        int w = 0, h = 0, ch = 0;
-        float* pixels = stbi_loadf(path, &w, &h, &ch, 4);
-        if (!pixels)
-        {
-            DONUT_WARN("Vulkan: HDRI '{}' could not be loaded; using a dark background", path);
-            VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
-            cbai.commandPool = command_pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
-            VkCommandBuffer cmd; VK_CHECK(vkAllocateCommandBuffers(device, &cbai, &cmd));
-            VkCommandBufferBeginInfo bi{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO }; bi.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
-            vkBeginCommandBuffer(cmd, &bi);
-            VkImageMemoryBarrier tb{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-            tb.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; tb.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
-            tb.image = cube_image; tb.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 6 };
-            tb.srcAccessMask = 0; tb.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
-            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &tb);
-            VkClearColorValue dark{}; dark.float32[0] = 0.02f; dark.float32[1] = 0.02f; dark.float32[2] = 0.05f; dark.float32[3] = 1.0f;
-            VkImageSubresourceRange rng{ VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 6 };
-            vkCmdClearColorImage(cmd, cube_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, &dark, 1, &rng);
-            VkImageMemoryBarrier rb = tb; rb.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; rb.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-            rb.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; rb.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &rb);
-            vkEndCommandBuffer(cmd);
-            VkSubmitInfo si{ VK_STRUCTURE_TYPE_SUBMIT_INFO }; si.commandBufferCount = 1; si.pCommandBuffers = &cmd;
-            vkQueueSubmit(graphics_queue, 1, &si, VK_NULL_HANDLE); vkQueueWaitIdle(graphics_queue);
-            vkFreeCommandBuffers(device, command_pool, 1, &cmd);
-            return true;
-        }
-
-        // Apple GPUs can't linearly filter RGBA32F, so store the equirect as
-        // RGBA16F (convert the loaded floats to half on the way into staging).
-        const VkFormat eq_fmt = VK_FORMAT_R16G16B16A16_SFLOAT;
-        size_t texel_count = (size_t)w * h * 4;
-        VkDeviceSize eq_size = (VkDeviceSize)texel_count * sizeof(uint16_t);
-        VkBuffer eq_staging; VkDeviceMemory eq_staging_mem;
-        if (!create_buffer(eq_size, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, host_vis, eq_staging, eq_staging_mem)) { stbi_image_free(pixels); return false; }
-        void* mp = nullptr; vkMapMemory(device, eq_staging_mem, 0, eq_size, 0, &mp);
-        uint16_t* dst = (uint16_t*)mp;
-        for (size_t i = 0; i < texel_count; ++i) { __fp16 hf = (__fp16)pixels[i]; memcpy(&dst[i], &hf, sizeof(uint16_t)); }
-        vkUnmapMemory(device, eq_staging_mem);
-        stbi_image_free(pixels);
-
-        VkImage eq_image; VkDeviceMemory eq_mem;
-        VkImageCreateInfo eci{ VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
-        eci.imageType = VK_IMAGE_TYPE_2D; eci.format = eq_fmt; eci.extent = { (uint32_t)w, (uint32_t)h, 1 };
-        eci.mipLevels = 1; eci.arrayLayers = 1; eci.samples = VK_SAMPLE_COUNT_1_BIT;
-        eci.tiling = VK_IMAGE_TILING_OPTIMAL; eci.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
-        VK_CHECK(vkCreateImage(device, &eci, nullptr, &eq_image));
-        VkMemoryRequirements ereq{}; vkGetImageMemoryRequirements(device, eq_image, &ereq);
-        VkMemoryAllocateInfo eai{ VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
-        eai.allocationSize = ereq.size; eai.memoryTypeIndex = find_memory_type(ereq.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-        VK_CHECK(vkAllocateMemory(device, &eai, nullptr, &eq_mem));
-        VK_CHECK(vkBindImageMemory(device, eq_image, eq_mem, 0));
-        VkImageView eq_view;
-        VkImageViewCreateInfo evci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-        evci.image = eq_image; evci.viewType = VK_IMAGE_VIEW_TYPE_2D; evci.format = eq_fmt;
-        evci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-        VK_CHECK(vkCreateImageView(device, &evci, nullptr, &eq_view));
-        VkSampler eq_sampler;
-        VkSamplerCreateInfo esm{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
-        esm.magFilter = VK_FILTER_LINEAR; esm.minFilter = VK_FILTER_LINEAR;
-        esm.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;         // longitude wraps
-        esm.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;  // latitude clamps
-        esm.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
-        VK_CHECK(vkCreateSampler(device, &esm, nullptr, &eq_sampler));
-
-        VkImageView face_views[6];
-        for (uint32_t i = 0; i < 6; ++i)
-        {
-            VkImageViewCreateInfo fvci{ VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO };
-            fvci.image = cube_image; fvci.viewType = VK_IMAGE_VIEW_TYPE_2D; fvci.format = cube_fmt;
-            fvci.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, i, 1 };
-            VK_CHECK(vkCreateImageView(device, &fvci, nullptr, &face_views[i]));
-        }
-
-        VkAttachmentDescription color{};
-        color.format = cube_fmt; color.samples = VK_SAMPLE_COUNT_1_BIT;
-        color.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR; color.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
-        color.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE; color.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-        color.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; color.finalLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-        VkAttachmentReference ref{ 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };
-        VkSubpassDescription subpass{}; subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS; subpass.colorAttachmentCount = 1; subpass.pColorAttachments = &ref;
-        VkSubpassDependency dep{}; dep.srcSubpass = 0; dep.dstSubpass = VK_SUBPASS_EXTERNAL;
-        dep.srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT; dep.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        dep.dstStageMask = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT; dep.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-        VkRenderPass rp;
-        VkRenderPassCreateInfo rpci{ VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO };
-        rpci.attachmentCount = 1; rpci.pAttachments = &color; rpci.subpassCount = 1; rpci.pSubpasses = &subpass; rpci.dependencyCount = 1; rpci.pDependencies = &dep;
-        VK_CHECK(vkCreateRenderPass(device, &rpci, nullptr, &rp));
-        VkFramebuffer face_fb[6];
-        for (uint32_t i = 0; i < 6; ++i)
-        {
-            VkFramebufferCreateInfo fbci{ VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO };
-            fbci.renderPass = rp; fbci.attachmentCount = 1; fbci.pAttachments = &face_views[i]; fbci.width = FACE; fbci.height = FACE; fbci.layers = 1;
-            VK_CHECK(vkCreateFramebuffer(device, &fbci, nullptr, &face_fb[i]));
-        }
-
-        VkDescriptorSetLayoutBinding binds[2]{};
-        binds[0].binding = 0; binds[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; binds[0].descriptorCount = 1; binds[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
-        binds[1].binding = 1; binds[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; binds[1].descriptorCount = 1; binds[1].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-        VkDescriptorSetLayout set_layout;
-        VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO }; dslci.bindingCount = 2; dslci.pBindings = binds;
-        VK_CHECK(vkCreateDescriptorSetLayout(device, &dslci, nullptr, &set_layout));
-        VkDescriptorPoolSize psizes[2] = { { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 6 }, { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 6 } };
-        VkDescriptorPool pool;
-        VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO }; dpci.maxSets = 6; dpci.poolSizeCount = 2; dpci.pPoolSizes = psizes;
-        VK_CHECK(vkCreateDescriptorPool(device, &dpci, nullptr, &pool));
-
-        VkShaderModule vmod, fmod;
-        if (!create_shader_module("assets/shaders/generated/EquirectToCubemap.vertexMain.spv", vmod)) return false;
-        if (!create_shader_module("assets/shaders/generated/EquirectToCubemap.fragmentMain.spv", fmod)) return false;
-        VkPipelineLayout playout;
-        VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO }; plci.setLayoutCount = 1; plci.pSetLayouts = &set_layout;
-        VK_CHECK(vkCreatePipelineLayout(device, &plci, nullptr, &playout));
-        VkPipelineShaderStageCreateInfo stages[2]{};
-        stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
-        stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
-        VkVertexInputBindingDescription vib{ 0, 12, VK_VERTEX_INPUT_RATE_VERTEX };
-        VkVertexInputAttributeDescription via{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 };
-        VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-        vin.vertexBindingDescriptionCount = 1; vin.pVertexBindingDescriptions = &vib; vin.vertexAttributeDescriptionCount = 1; vin.pVertexAttributeDescriptions = &via;
-        VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-        VkViewport vp{ 0, 0, (float)FACE, (float)FACE, 0, 1 }; VkRect2D sc{ { 0, 0 }, { FACE, FACE } };
-        VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.pViewports = &vp; vps.scissorCount = 1; vps.pScissors = &sc;
-        VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
-        VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-        VkPipelineColorBlendAttachmentState cba{}; cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-        VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
-        VkPipeline pipeline;
-        VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-        gpci.stageCount = 2; gpci.pStages = stages; gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
-        gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb; gpci.layout = playout; gpci.renderPass = rp; gpci.subpass = 0;
-        VkResult pr = vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &gpci, nullptr, &pipeline);
-        vkDestroyShaderModule(device, vmod, nullptr); vkDestroyShaderModule(device, fmod, nullptr);
-        if (pr != VK_SUCCESS) { DONUT_ERROR("Vulkan: equirect pipeline failed ({})", (int)pr); return false; }
-
-        float cube_verts[] = {
-            -1,1,-1, -1,-1,-1, 1,-1,-1, 1,-1,-1, 1,1,-1, -1,1,-1,
-            -1,-1,1, -1,-1,-1, -1,1,-1, -1,1,-1, -1,1,1, -1,-1,1,
-             1,-1,-1, 1,-1,1, 1,1,1, 1,1,1, 1,1,-1, 1,-1,-1,
-            -1,-1,1, -1,1,1, 1,1,1, 1,1,1, 1,-1,1, -1,-1,1,
-            -1,1,-1, 1,1,-1, 1,1,1, 1,1,1, -1,1,1, -1,1,-1,
-            -1,-1,-1, -1,-1,1, 1,-1,-1, 1,-1,-1, -1,-1,1, 1,-1,1,
-        };
-        VkBuffer cube_vb; VkDeviceMemory cube_vb_mem;
-        create_buffer(sizeof(cube_verts), VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, cube_vb, cube_vb_mem);
-        vkMapMemory(device, cube_vb_mem, 0, sizeof(cube_verts), 0, &mp); memcpy(mp, cube_verts, sizeof(cube_verts)); vkUnmapMemory(device, cube_vb_mem);
-
-        glm::mat4 proj = glm::perspective(glm::radians(90.0f), 1.0f, 0.1f, 10.0f);
-        proj[1][1] *= -1.0f;  // Vulkan clip space is Y-down vs OpenGL
-        glm::mat4 views[6] = {
-            glm::lookAt(glm::vec3(0), glm::vec3( 1, 0, 0), glm::vec3(0, -1, 0)),
-            glm::lookAt(glm::vec3(0), glm::vec3(-1, 0, 0), glm::vec3(0, -1, 0)),
-            glm::lookAt(glm::vec3(0), glm::vec3( 0, 1, 0), glm::vec3(0, 0, 1)),
-            glm::lookAt(glm::vec3(0), glm::vec3( 0, -1, 0), glm::vec3(0, 0, -1)),
-            glm::lookAt(glm::vec3(0), glm::vec3( 0, 0, 1), glm::vec3(0, -1, 0)),
-            glm::lookAt(glm::vec3(0), glm::vec3( 0, 0, -1), glm::vec3(0, -1, 0)),
-        };
-        VkBuffer ubo[6]; VkDeviceMemory ubo_mem[6]; VkDescriptorSet sets[6];
-        for (uint32_t i = 0; i < 6; ++i)
-        {
-            create_buffer(128, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, ubo[i], ubo_mem[i]);
-            glm::mat4 mats[2] = { glm::transpose(proj), glm::transpose(views[i]) };  // SPIR-V expects row-major
-            vkMapMemory(device, ubo_mem[i], 0, 128, 0, &mp); memcpy(mp, mats, 128); vkUnmapMemory(device, ubo_mem[i]);
-            VkDescriptorSetAllocateInfo dsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO }; dsai.descriptorPool = pool; dsai.descriptorSetCount = 1; dsai.pSetLayouts = &set_layout;
-            VK_CHECK(vkAllocateDescriptorSets(device, &dsai, &sets[i]));
-            VkDescriptorBufferInfo buf_info{ ubo[i], 0, VK_WHOLE_SIZE };
-            VkDescriptorImageInfo img_info{ eq_sampler, eq_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-            VkWriteDescriptorSet ws[2]{};
-            ws[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; ws[0].dstSet = sets[i]; ws[0].dstBinding = 0; ws[0].descriptorCount = 1; ws[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; ws[0].pBufferInfo = &buf_info;
-            ws[1].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; ws[1].dstSet = sets[i]; ws[1].dstBinding = 1; ws[1].descriptorCount = 1; ws[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; ws[1].pImageInfo = &img_info;
-            vkUpdateDescriptorSets(device, 2, ws, 0, nullptr);
-        }
-
-        VkCommandBufferAllocateInfo cbai{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO };
-        cbai.commandPool = command_pool; cbai.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY; cbai.commandBufferCount = 1;
-        VkCommandBuffer cmd; VK_CHECK(vkAllocateCommandBuffers(device, &cbai, &cmd));
-        VkCommandBufferBeginInfo bi{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO }; bi.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
-        VK_CHECK(vkBeginCommandBuffer(cmd, &bi));
-        VkImageMemoryBarrier to_dst{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-        to_dst.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; to_dst.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
-        to_dst.image = eq_image; to_dst.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-        to_dst.srcAccessMask = 0; to_dst.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
-        vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &to_dst);
-        VkBufferImageCopy copy{}; copy.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 }; copy.imageExtent = { (uint32_t)w, (uint32_t)h, 1 };
-        vkCmdCopyBufferToImage(cmd, eq_staging, eq_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &copy);
-        VkImageMemoryBarrier to_read = to_dst; to_read.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; to_read.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-        to_read.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; to_read.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-        vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &to_read);
-
-        VkClearValue clear{}; clear.color = { { 0, 0, 0, 1 } };
-        for (uint32_t i = 0; i < 6; ++i)
-        {
-            VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-            rpbi.renderPass = rp; rpbi.framebuffer = face_fb[i]; rpbi.renderArea = { { 0, 0 }, { FACE, FACE } }; rpbi.clearValueCount = 1; rpbi.pClearValues = &clear;
-            vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
-            vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
-            vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, playout, 0, 1, &sets[i], 0, nullptr);
-            VkDeviceSize off = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &cube_vb, &off);
-            vkCmdDraw(cmd, 36, 1, 0, 0);
-            vkCmdEndRenderPass(cmd);
-        }
-
-        // Build the mip chain (all 6 faces) by successive linear down-blits, so
-        // divergence-based LOD sampling can read a blurred sky for lensed rays.
-        // Mip 0 (every layer) is SHADER_READ_ONLY from the render passes above.
-        {
-            VkImageMemoryBarrier src0{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-            src0.image = cube_image; src0.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 6 };
-            src0.oldLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL; src0.newLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
-            src0.srcAccessMask = VK_ACCESS_SHADER_READ_BIT; src0.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
-            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &src0);
-
-            int32_t mipW = (int32_t)FACE, mipH = (int32_t)FACE;
-            for (uint32_t m = 1; m < CUBE_MIPS; ++m)
-            {
-                int32_t nW = mipW > 1 ? mipW / 2 : 1, nH = mipH > 1 ? mipH / 2 : 1;
-                VkImageMemoryBarrier bd{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-                bd.image = cube_image; bd.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, m, 1, 0, 6 };
-                bd.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; bd.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
-                bd.srcAccessMask = 0; bd.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
-                vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &bd);
-
-                VkImageBlit blit{};
-                blit.srcOffsets[1] = { mipW, mipH, 1 }; blit.srcSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, m - 1, 0, 6 };
-                blit.dstOffsets[1] = { nW, nH, 1 };     blit.dstSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, m, 0, 6 };
-                vkCmdBlitImage(cmd, cube_image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
-                                    cube_image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &blit, VK_FILTER_LINEAR);
-
-                VkImageMemoryBarrier bs{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-                bs.image = cube_image; bs.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, m, 1, 0, 6 };
-                bs.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL; bs.newLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL;
-                bs.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; bs.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
-                vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, &bs);
-                mipW = nW; mipH = nH;
-            }
-            VkImageMemoryBarrier fin{ VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER };
-            fin.image = cube_image; fin.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, CUBE_MIPS, 0, 6 };
-            fin.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL; fin.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-            fin.srcAccessMask = VK_ACCESS_TRANSFER_READ_BIT; fin.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-            vkCmdPipelineBarrier(cmd, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &fin);
-        }
-
-        VK_CHECK(vkEndCommandBuffer(cmd));
-        VkSubmitInfo si{ VK_STRUCTURE_TYPE_SUBMIT_INFO }; si.commandBufferCount = 1; si.pCommandBuffers = &cmd;
-        VK_CHECK(vkQueueSubmit(graphics_queue, 1, &si, VK_NULL_HANDLE));
-        VK_CHECK(vkQueueWaitIdle(graphics_queue));
-
-        vkFreeCommandBuffers(device, command_pool, 1, &cmd);
-        for (uint32_t i = 0; i < 6; ++i) { vkDestroyBuffer(device, ubo[i], nullptr); vkFreeMemory(device, ubo_mem[i], nullptr); vkDestroyFramebuffer(device, face_fb[i], nullptr); vkDestroyImageView(device, face_views[i], nullptr); }
-        vkDestroyBuffer(device, cube_vb, nullptr); vkFreeMemory(device, cube_vb_mem, nullptr);
-        vkDestroyPipeline(device, pipeline, nullptr); vkDestroyPipelineLayout(device, playout, nullptr);
-        vkDestroyDescriptorPool(device, pool, nullptr); vkDestroyDescriptorSetLayout(device, set_layout, nullptr);
-        vkDestroyRenderPass(device, rp, nullptr);
-        vkDestroySampler(device, eq_sampler, nullptr); vkDestroyImageView(device, eq_view, nullptr);
-        vkDestroyImage(device, eq_image, nullptr); vkFreeMemory(device, eq_mem, nullptr);
-        vkDestroyBuffer(device, eq_staging, nullptr); vkFreeMemory(device, eq_staging_mem, nullptr);
-        DONUT_INFO("Vulkan: HDRI cubemap built from {} ({}x{} equirect -> {}^2 cube)", path, w, h, (int)FACE);
-        return true;
-    }
-
-    // Runtime HDRI switch: drain the device, tear down the old cubemap, build the
-    // new one, and repoint the geodesic set's samplerCube (binding 4) at it.
-    auto VulkanRenderer::Impl::rebuild_hdri_cubemap(const char* path) -> void
-    {
-        vkDeviceWaitIdle(device);
-
-        if (cube_sampler) vkDestroySampler(device, cube_sampler, nullptr);
-        if (cube_view)    vkDestroyImageView(device, cube_view, nullptr);
-        if (cube_image)   vkDestroyImage(device, cube_image, nullptr);
-        if (cube_mem)     vkFreeMemory(device, cube_mem, nullptr);
-        cube_sampler = VK_NULL_HANDLE; cube_view = VK_NULL_HANDLE;
-        cube_image   = VK_NULL_HANDLE; cube_mem  = VK_NULL_HANDLE;
-
-        create_hdri_cubemap(path);
-
-        VkDescriptorImageInfo cube_info{ cube_sampler, cube_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-        VkWriteDescriptorSet write{ VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET };
-        write.dstSet = geo_set; write.dstBinding = 4; write.descriptorCount = 1;
-        write.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; write.pImageInfo = &cube_info;
-        vkUpdateDescriptorSets(device, 1, &write, 0, nullptr);
-
-        // The scene sphere samples the same cube (binding 1) — repoint it too.
-        if (sphere_set)
-        {
-            VkWriteDescriptorSet sw{ VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET };
-            sw.dstSet = sphere_set; sw.dstBinding = 1; sw.descriptorCount = 1;
-            sw.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; sw.pImageInfo = &cube_info;
-            vkUpdateDescriptorSets(device, 1, &sw, 0, nullptr);
-        }
-        if (skybox_set)
-        {
-            VkWriteDescriptorSet kw{ VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET };
-            kw.dstSet = skybox_set; kw.dstBinding = 1; kw.descriptorCount = 1;
-            kw.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; kw.pImageInfo = &cube_info;
-            vkUpdateDescriptorSets(device, 1, &kw, 0, nullptr);
-        }
-    }
-
-    auto VulkanRenderer::Impl::create_present_resources() -> bool
-    {
-        VkSamplerCreateInfo smci{ VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO };
-        smci.magFilter = VK_FILTER_LINEAR; smci.minFilter = VK_FILTER_LINEAR;
-        smci.addressModeU = smci.addressModeV = smci.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
-        VK_CHECK(vkCreateSampler(device, &smci, nullptr, &present_sampler));
-
-        VkDescriptorSetLayoutBinding bind{}; bind.binding = 0; bind.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; bind.descriptorCount = 1; bind.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-        VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO };
-        dslci.bindingCount = 1; dslci.pBindings = &bind;
-        VK_CHECK(vkCreateDescriptorSetLayout(device, &dslci, nullptr, &present_set_layout));
-        // One present set per geodesic target (low-/high-res), each sampling its
-        // own image; record_command_buffer binds whichever was rendered this frame.
-        VkDescriptorPoolSize psize{ VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 2 };
-        VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO };
-        dpci.maxSets = 2; dpci.poolSizeCount = 1; dpci.pPoolSizes = &psize;
-        VK_CHECK(vkCreateDescriptorPool(device, &dpci, nullptr, &present_pool));
-        for (GeoTarget* t : { &geo_lo, &geo_hi })
-        {
-            VkDescriptorSetAllocateInfo dsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO };
-            dsai.descriptorPool = present_pool; dsai.descriptorSetCount = 1; dsai.pSetLayouts = &present_set_layout;
-            VK_CHECK(vkAllocateDescriptorSets(device, &dsai, &t->present_set));
-            VkDescriptorImageInfo ii{ present_sampler, t->view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-            VkWriteDescriptorSet write{ VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET };
-            write.dstSet = t->present_set; write.dstBinding = 0; write.descriptorCount = 1; write.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; write.pImageInfo = &ii;
-            vkUpdateDescriptorSets(device, 1, &write, 0, nullptr);
-        }
-
-        VkShaderModule vmod, fmod;
-        if (!create_shader_module("assets/shaders/generated/TexturedQuad.vertexMain.spv", vmod)) return false;
-        if (!create_shader_module("assets/shaders/generated/TexturedQuad.fragmentMain.spv", fmod)) return false;
-        VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO };
-        plci.setLayoutCount = 1; plci.pSetLayouts = &present_set_layout;
-        VK_CHECK(vkCreatePipelineLayout(device, &plci, nullptr, &present_pipeline_layout));
-        VkPipelineShaderStageCreateInfo stages[2]{};
-        stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
-        stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
-        VkVertexInputBindingDescription vib{ 0, 16, VK_VERTEX_INPUT_RATE_VERTEX };
-        VkVertexInputAttributeDescription via[2] = { { 0, 0, VK_FORMAT_R32G32_SFLOAT, 0 }, { 1, 0, VK_FORMAT_R32G32_SFLOAT, 8 } };
-        VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-        vin.vertexBindingDescriptionCount = 1; vin.pVertexBindingDescriptions = &vib;
-        vin.vertexAttributeDescriptionCount = 2; vin.pVertexAttributeDescriptions = via;
-        VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-        VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.scissorCount = 1;
-        VkDynamicState dyn[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
-        VkPipelineDynamicStateCreateInfo dsci{ VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO }; dsci.dynamicStateCount = 2; dsci.pDynamicStates = dyn;
-        VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
-        VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-        VkPipelineColorBlendAttachmentState cba{}; cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-        VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
-        VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-        gpci.stageCount = 2; gpci.pStages = stages;
-        gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
-        gpci.pDynamicState = &dsci;
-        gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb;
-        gpci.layout = present_pipeline_layout; gpci.renderPass = render_pass; gpci.subpass = 0;
-        VkResult pr = vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &gpci, nullptr, &present_pipeline);
-        vkDestroyShaderModule(device, vmod, nullptr); vkDestroyShaderModule(device, fmod, nullptr);
-        if (pr != VK_SUCCESS) { DONUT_ERROR("Vulkan: present pipeline creation failed ({})", (int)pr); return false; }
-        DONUT_INFO("Vulkan: present pipeline ready");
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::create_scene_resources() -> bool
-    {
-        const VkMemoryPropertyFlags host_vis = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
-
-        // Scene camera: normal-scale orbital viewer (matches the OpenGL world-builder).
-        scene_camera.set_camera_mode(CameraMode::Orbital);
-        scene_camera.set_orbital_target(glm::vec3(0.0f));
-        scene_camera.set_orbital_radius(15.0);
-        scene_camera.set_orbital_limits(2.0, 200.0);
-        scene_camera.set_orbital_speed(0.01f);
-        scene_camera.set_zoom_speed(2.0);
-        scene_camera.set_azimuth(0.0f);
-        scene_camera.set_elevation((float)std::numbers::pi / 3.0f);
-        scene_camera.update_orbital();
-
-        // Line grid on the XZ plane (+/-50 units, 1-unit cells). Grid.slang scales
-        // the position by u_GridSize/50, so u_GridSize = 50 keeps it 1:1.
-        std::vector<glm::vec3> lines;
-        const int N = 50;
-        for (int i = -N; i <= N; ++i)
-        {
-            lines.push_back({ (float)i, 0.0f, (float)-N });
-            lines.push_back({ (float)i, 0.0f, (float) N });
-            lines.push_back({ (float)-N, 0.0f, (float)i });
-            lines.push_back({ (float) N, 0.0f, (float)i });
-        }
-        grid_vertex_count = (uint32_t)lines.size();
-        VkDeviceSize vbsize = lines.size() * sizeof(glm::vec3);
-        if (!create_buffer(vbsize, VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, grid_vb, grid_vb_mem)) return false;
-        void* mp = nullptr; vkMapMemory(device, grid_vb_mem, 0, vbsize, 0, &mp); memcpy(mp, lines.data(), vbsize); vkUnmapMemory(device, grid_vb_mem);
-
-        // $Globals UBO (set 0, binding 0), std140, 176 bytes; refilled each frame.
-        if (!create_buffer(176, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, grid_ubo, grid_ubo_mem)) return false;
-        vkMapMemory(device, grid_ubo_mem, 0, 176, 0, &grid_ubo_mapped);
-
-        VkDescriptorSetLayoutBinding b{}; b.binding = 0; b.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; b.descriptorCount = 1; b.stageFlags = VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT;
-        VkDescriptorSetLayoutCreateInfo dslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO }; dslci.bindingCount = 1; dslci.pBindings = &b;
-        VK_CHECK(vkCreateDescriptorSetLayout(device, &dslci, nullptr, &grid_set_layout));
-        VkDescriptorPoolSize psize{ VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1 };
-        VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO }; dpci.maxSets = 1; dpci.poolSizeCount = 1; dpci.pPoolSizes = &psize;
-        VK_CHECK(vkCreateDescriptorPool(device, &dpci, nullptr, &grid_pool));
-        VkDescriptorSetAllocateInfo dsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO }; dsai.descriptorPool = grid_pool; dsai.descriptorSetCount = 1; dsai.pSetLayouts = &grid_set_layout;
-        VK_CHECK(vkAllocateDescriptorSets(device, &dsai, &grid_set));
-        VkDescriptorBufferInfo bi{ grid_ubo, 0, VK_WHOLE_SIZE };
-        VkWriteDescriptorSet w{ VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET }; w.dstSet = grid_set; w.dstBinding = 0; w.descriptorCount = 1; w.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; w.pBufferInfo = &bi;
-        vkUpdateDescriptorSets(device, 1, &w, 0, nullptr);
-
-        VkShaderModule vmod, fmod;
-        if (!create_shader_module("assets/shaders/generated/Grid.vertexMain.spv", vmod)) return false;
-        if (!create_shader_module("assets/shaders/generated/Grid.fragmentMain.spv", fmod)) return false;
-        VkPipelineLayoutCreateInfo plci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO }; plci.setLayoutCount = 1; plci.pSetLayouts = &grid_set_layout;
-        VK_CHECK(vkCreatePipelineLayout(device, &plci, nullptr, &grid_pipeline_layout));
-        VkPipelineShaderStageCreateInfo stages[2]{};
-        stages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   stages[0].module = vmod; stages[0].pName = "main";
-        stages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; stages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; stages[1].module = fmod; stages[1].pName = "main";
-        VkVertexInputBindingDescription vib{ 0, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX };
-        VkVertexInputAttributeDescription via{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 };
-        VkPipelineVertexInputStateCreateInfo vin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-        vin.vertexBindingDescriptionCount = 1; vin.pVertexBindingDescriptions = &vib;
-        vin.vertexAttributeDescriptionCount = 1; vin.pVertexAttributeDescriptions = &via;
-        VkPipelineInputAssemblyStateCreateInfo ia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; ia.topology = VK_PRIMITIVE_TOPOLOGY_LINE_LIST;
-        VkPipelineViewportStateCreateInfo vps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; vps.viewportCount = 1; vps.scissorCount = 1;
-        VkDynamicState dyn[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
-        VkPipelineDynamicStateCreateInfo dsci{ VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO }; dsci.dynamicStateCount = 2; dsci.pDynamicStates = dyn;
-        VkPipelineRasterizationStateCreateInfo rs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; rs.polygonMode = VK_POLYGON_MODE_FILL; rs.cullMode = VK_CULL_MODE_NONE; rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; rs.lineWidth = 1.0f;
-        VkPipelineMultisampleStateCreateInfo ms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; ms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-        VkPipelineDepthStencilStateCreateInfo ds{ VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO };
-        ds.depthTestEnable = VK_TRUE; ds.depthWriteEnable = VK_FALSE; ds.depthCompareOp = VK_COMPARE_OP_LESS_OR_EQUAL; // transparent lines: test but don't write
-        VkPipelineColorBlendAttachmentState cba{};
-        cba.blendEnable = VK_TRUE;
-        cba.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA; cba.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA; cba.colorBlendOp = VK_BLEND_OP_ADD;
-        cba.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE; cba.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO; cba.alphaBlendOp = VK_BLEND_OP_ADD;
-        cba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-        VkPipelineColorBlendStateCreateInfo cb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; cb.attachmentCount = 1; cb.pAttachments = &cba;
-        VkGraphicsPipelineCreateInfo gpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-        gpci.stageCount = 2; gpci.pStages = stages;
-        gpci.pVertexInputState = &vin; gpci.pInputAssemblyState = &ia; gpci.pViewportState = &vps;
-        gpci.pDynamicState = &dsci;
-        gpci.pRasterizationState = &rs; gpci.pMultisampleState = &ms; gpci.pColorBlendState = &cb; gpci.pDepthStencilState = &ds;
-        gpci.layout = grid_pipeline_layout; gpci.renderPass = scene_render_pass; gpci.subpass = 0;
-        VkResult pr = vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &gpci, nullptr, &grid_pipeline);
-        vkDestroyShaderModule(device, vmod, nullptr); vkDestroyShaderModule(device, fmod, nullptr);
-        if (pr != VK_SUCCESS) { DONUT_ERROR("Vulkan: grid pipeline creation failed ({})", (int)pr); return false; }
-
-        // Lit sphere: unit UV-sphere mesh (pos+normal, stride 24), placed/scaled by
-        // u_Transform; samples the geodesic HDRI cubemap for ambient (binding 1).
-        {
-            std::vector<float> sv; std::vector<uint32_t> si;
-            const int RINGS = 24, SECTORS = 48;
-            for (int r = 0; r <= RINGS; ++r)
-            {
-                float phi = (float)std::numbers::pi * r / RINGS;
-                for (int s = 0; s <= SECTORS; ++s)
-                {
-                    float theta = 2.0f * (float)std::numbers::pi * s / SECTORS;
-                    float x = sinf(phi) * cosf(theta), y = cosf(phi), z = sinf(phi) * sinf(theta);
-                    sv.push_back(x); sv.push_back(y); sv.push_back(z);   // position (unit)
-                    sv.push_back(x); sv.push_back(y); sv.push_back(z);   // normal == position
-                }
-            }
-            for (int r = 0; r < RINGS; ++r)
-                for (int s = 0; s < SECTORS; ++s)
-                {
-                    uint32_t a = r * (SECTORS + 1) + s, b = a + SECTORS + 1;
-                    si.push_back(a); si.push_back(b); si.push_back(a + 1);
-                    si.push_back(b); si.push_back(b + 1); si.push_back(a + 1);
-                }
-            sphere_index_count = (uint32_t)si.size();
-            VkDeviceSize svsz = sv.size() * sizeof(float), sisz = si.size() * sizeof(uint32_t);
-            if (!create_buffer(svsz, VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, sphere_vb, sphere_vb_mem)) return false;
-            if (!create_buffer(sisz, VK_BUFFER_USAGE_INDEX_BUFFER_BIT,  host_vis, sphere_ib, sphere_ib_mem)) return false;
-            void* sp = nullptr;
-            vkMapMemory(device, sphere_vb_mem, 0, svsz, 0, &sp); memcpy(sp, sv.data(), svsz); vkUnmapMemory(device, sphere_vb_mem);
-            vkMapMemory(device, sphere_ib_mem, 0, sisz, 0, &sp); memcpy(sp, si.data(), sisz); vkUnmapMemory(device, sphere_ib_mem);
-
-            VkPhysicalDeviceProperties pdp{}; vkGetPhysicalDeviceProperties(physical, &pdp);
-            VkDeviceSize min_align = pdp.limits.minUniformBufferOffsetAlignment;
-            sphere_ubo_stride = ((208 + min_align - 1) / min_align) * min_align;  // per-object slot
-            VkDeviceSize sphere_ubo_size = sphere_ubo_stride * MAX_SCENE_OBJECTS;
-            if (!create_buffer(sphere_ubo_size, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, sphere_ubo, sphere_ubo_mem)) return false;
-            vkMapMemory(device, sphere_ubo_mem, 0, sphere_ubo_size, 0, &sphere_ubo_mapped);
-
-            VkDescriptorSetLayoutBinding sb[2]{};
-            sb[0].binding = 0; sb[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC; sb[0].descriptorCount = 1; sb[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT;
-            sb[1].binding = 1; sb[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; sb[1].descriptorCount = 1; sb[1].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-            VkDescriptorSetLayoutCreateInfo sdslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO }; sdslci.bindingCount = 2; sdslci.pBindings = sb;
-            VK_CHECK(vkCreateDescriptorSetLayout(device, &sdslci, nullptr, &sphere_set_layout));
-            VkDescriptorPoolSize sps[2] = { { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC, 1 }, { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1 } };
-            VkDescriptorPoolCreateInfo sdpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO }; sdpci.maxSets = 1; sdpci.poolSizeCount = 2; sdpci.pPoolSizes = sps;
-            VK_CHECK(vkCreateDescriptorPool(device, &sdpci, nullptr, &sphere_pool));
-            VkDescriptorSetAllocateInfo sdsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO }; sdsai.descriptorPool = sphere_pool; sdsai.descriptorSetCount = 1; sdsai.pSetLayouts = &sphere_set_layout;
-            VK_CHECK(vkAllocateDescriptorSets(device, &sdsai, &sphere_set));
-            VkDescriptorBufferInfo sbi{ sphere_ubo, 0, 208 };  // per-draw size; the dynamic offset selects the object slot
-            VkDescriptorImageInfo sii{ cube_sampler, cube_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-            VkWriteDescriptorSet sw[2]{};
-            sw[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; sw[0].dstSet = sphere_set; sw[0].dstBinding = 0; sw[0].descriptorCount = 1; sw[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC; sw[0].pBufferInfo = &sbi;
-            sw[1].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; sw[1].dstSet = sphere_set; sw[1].dstBinding = 1; sw[1].descriptorCount = 1; sw[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; sw[1].pImageInfo = &sii;
-            vkUpdateDescriptorSets(device, 2, sw, 0, nullptr);
-
-            VkShaderModule svmod, sfmod;
-            if (!create_shader_module("assets/shaders/generated/Sphere.vertexMain.spv", svmod)) return false;
-            if (!create_shader_module("assets/shaders/generated/Sphere.fragmentMain.spv", sfmod)) return false;
-            VkPipelineLayoutCreateInfo splci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO }; splci.setLayoutCount = 1; splci.pSetLayouts = &sphere_set_layout;
-            VK_CHECK(vkCreatePipelineLayout(device, &splci, nullptr, &sphere_pipeline_layout));
-            VkPipelineShaderStageCreateInfo sstages[2]{};
-            sstages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; sstages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   sstages[0].module = svmod; sstages[0].pName = "main";
-            sstages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; sstages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; sstages[1].module = sfmod; sstages[1].pName = "main";
-            VkVertexInputBindingDescription svib{ 0, 6 * (uint32_t)sizeof(float), VK_VERTEX_INPUT_RATE_VERTEX };
-            VkVertexInputAttributeDescription svia[2] = { { 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 }, { 1, 0, VK_FORMAT_R32G32B32_SFLOAT, 3 * (uint32_t)sizeof(float) } };
-            VkPipelineVertexInputStateCreateInfo svin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-            svin.vertexBindingDescriptionCount = 1; svin.pVertexBindingDescriptions = &svib;
-            svin.vertexAttributeDescriptionCount = 2; svin.pVertexAttributeDescriptions = svia;
-            VkPipelineInputAssemblyStateCreateInfo sia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; sia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-            VkPipelineViewportStateCreateInfo svps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; svps.viewportCount = 1; svps.scissorCount = 1;
-            VkDynamicState sdyn[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
-            VkPipelineDynamicStateCreateInfo sdsci{ VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO }; sdsci.dynamicStateCount = 2; sdsci.pDynamicStates = sdyn;
-            VkPipelineRasterizationStateCreateInfo srs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; srs.polygonMode = VK_POLYGON_MODE_FILL; srs.cullMode = VK_CULL_MODE_NONE; srs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; srs.lineWidth = 1.0f;
-            VkPipelineMultisampleStateCreateInfo sms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; sms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-            VkPipelineDepthStencilStateCreateInfo sds{ VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO };
-            sds.depthTestEnable = VK_TRUE; sds.depthWriteEnable = VK_TRUE; sds.depthCompareOp = VK_COMPARE_OP_LESS;
-            VkPipelineColorBlendAttachmentState scba{}; scba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-            VkPipelineColorBlendStateCreateInfo scb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; scb.attachmentCount = 1; scb.pAttachments = &scba;
-            VkGraphicsPipelineCreateInfo sgpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-            sgpci.stageCount = 2; sgpci.pStages = sstages;
-            sgpci.pVertexInputState = &svin; sgpci.pInputAssemblyState = &sia; sgpci.pViewportState = &svps;
-            sgpci.pDynamicState = &sdsci;
-            sgpci.pRasterizationState = &srs; sgpci.pMultisampleState = &sms; sgpci.pColorBlendState = &scb; sgpci.pDepthStencilState = &sds;
-            sgpci.layout = sphere_pipeline_layout; sgpci.renderPass = scene_render_pass; sgpci.subpass = 0;
-            VkResult spr = vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &sgpci, nullptr, &sphere_pipeline);
-            vkDestroyShaderModule(device, svmod, nullptr); vkDestroyShaderModule(device, sfmod, nullptr);
-            if (spr != VK_SUCCESS) { DONUT_ERROR("Vulkan: sphere pipeline creation failed ({})", (int)spr); return false; }
-        }
-
-        // Skybox: a unit cube (36 verts) sampling the HDRI cubemap; the vertex
-        // shader forces depth 1 (pos.xyww) so it sits behind all scene geometry.
-        {
-            const float cube[] = {
-                -1,-1,-1,  1,-1,-1,  1, 1,-1,  1, 1,-1, -1, 1,-1, -1,-1,-1,
-                -1,-1, 1,  1,-1, 1,  1, 1, 1,  1, 1, 1, -1, 1, 1, -1,-1, 1,
-                -1, 1, 1, -1, 1,-1, -1,-1,-1, -1,-1,-1, -1,-1, 1, -1, 1, 1,
-                 1, 1, 1,  1, 1,-1,  1,-1,-1,  1,-1,-1,  1,-1, 1,  1, 1, 1,
-                -1,-1,-1,  1,-1,-1,  1,-1, 1,  1,-1, 1, -1,-1, 1, -1,-1,-1,
-                -1, 1,-1,  1, 1,-1,  1, 1, 1,  1, 1, 1, -1, 1, 1, -1, 1,-1
-            };
-            if (!create_buffer(sizeof(cube), VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, host_vis, skybox_vb, skybox_vb_mem)) return false;
-            void* kp = nullptr; vkMapMemory(device, skybox_vb_mem, 0, sizeof(cube), 0, &kp); memcpy(kp, cube, sizeof(cube)); vkUnmapMemory(device, skybox_vb_mem);
-
-            // $Globals UBO (128 B: u_Projection@0, u_View@64); u_Skybox at binding 1.
-            if (!create_buffer(128, VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, host_vis, skybox_ubo, skybox_ubo_mem)) return false;
-            vkMapMemory(device, skybox_ubo_mem, 0, 128, 0, &skybox_ubo_mapped);
-
-            VkDescriptorSetLayoutBinding kb[2]{};
-            kb[0].binding = 0; kb[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; kb[0].descriptorCount = 1; kb[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
-            kb[1].binding = 1; kb[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; kb[1].descriptorCount = 1; kb[1].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-            VkDescriptorSetLayoutCreateInfo kdslci{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO }; kdslci.bindingCount = 2; kdslci.pBindings = kb;
-            VK_CHECK(vkCreateDescriptorSetLayout(device, &kdslci, nullptr, &skybox_set_layout));
-            VkDescriptorPoolSize kps[2] = { { VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1 }, { VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1 } };
-            VkDescriptorPoolCreateInfo kdpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO }; kdpci.maxSets = 1; kdpci.poolSizeCount = 2; kdpci.pPoolSizes = kps;
-            VK_CHECK(vkCreateDescriptorPool(device, &kdpci, nullptr, &skybox_pool));
-            VkDescriptorSetAllocateInfo kdsai{ VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO }; kdsai.descriptorPool = skybox_pool; kdsai.descriptorSetCount = 1; kdsai.pSetLayouts = &skybox_set_layout;
-            VK_CHECK(vkAllocateDescriptorSets(device, &kdsai, &skybox_set));
-            VkDescriptorBufferInfo kbi{ skybox_ubo, 0, VK_WHOLE_SIZE };
-            VkDescriptorImageInfo kii{ cube_sampler, cube_view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL };
-            VkWriteDescriptorSet kw[2]{};
-            kw[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; kw[0].dstSet = skybox_set; kw[0].dstBinding = 0; kw[0].descriptorCount = 1; kw[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER; kw[0].pBufferInfo = &kbi;
-            kw[1].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET; kw[1].dstSet = skybox_set; kw[1].dstBinding = 1; kw[1].descriptorCount = 1; kw[1].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; kw[1].pImageInfo = &kii;
-            vkUpdateDescriptorSets(device, 2, kw, 0, nullptr);
-
-            VkShaderModule kvmod, kfmod;
-            if (!create_shader_module("assets/shaders/generated/Skybox.vertexMain.spv", kvmod)) return false;
-            if (!create_shader_module("assets/shaders/generated/Skybox.fragmentMain.spv", kfmod)) return false;
-            VkPipelineLayoutCreateInfo kplci{ VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO }; kplci.setLayoutCount = 1; kplci.pSetLayouts = &skybox_set_layout;
-            VK_CHECK(vkCreatePipelineLayout(device, &kplci, nullptr, &skybox_pipeline_layout));
-            VkPipelineShaderStageCreateInfo kstages[2]{};
-            kstages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; kstages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;   kstages[0].module = kvmod; kstages[0].pName = "main";
-            kstages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; kstages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT; kstages[1].module = kfmod; kstages[1].pName = "main";
-            VkVertexInputBindingDescription kvib{ 0, 3 * (uint32_t)sizeof(float), VK_VERTEX_INPUT_RATE_VERTEX };
-            VkVertexInputAttributeDescription kvia{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 };
-            VkPipelineVertexInputStateCreateInfo kvin{ VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO };
-            kvin.vertexBindingDescriptionCount = 1; kvin.pVertexBindingDescriptions = &kvib;
-            kvin.vertexAttributeDescriptionCount = 1; kvin.pVertexAttributeDescriptions = &kvia;
-            VkPipelineInputAssemblyStateCreateInfo kia{ VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO }; kia.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-            VkPipelineViewportStateCreateInfo kvps{ VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO }; kvps.viewportCount = 1; kvps.scissorCount = 1;
-            VkDynamicState kdyn[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
-            VkPipelineDynamicStateCreateInfo kdsci{ VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO }; kdsci.dynamicStateCount = 2; kdsci.pDynamicStates = kdyn;
-            VkPipelineRasterizationStateCreateInfo krs{ VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO }; krs.polygonMode = VK_POLYGON_MODE_FILL; krs.cullMode = VK_CULL_MODE_NONE; krs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE; krs.lineWidth = 1.0f;
-            VkPipelineMultisampleStateCreateInfo kms{ VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO }; kms.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
-            VkPipelineDepthStencilStateCreateInfo kds{ VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO };
-            kds.depthTestEnable = VK_FALSE; kds.depthWriteEnable = VK_FALSE; // background: neither tests nor writes depth
-            VkPipelineColorBlendAttachmentState kcba{}; kcba.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
-            VkPipelineColorBlendStateCreateInfo kcb{ VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO }; kcb.attachmentCount = 1; kcb.pAttachments = &kcba;
-            VkGraphicsPipelineCreateInfo kgpci{ VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO };
-            kgpci.stageCount = 2; kgpci.pStages = kstages;
-            kgpci.pVertexInputState = &kvin; kgpci.pInputAssemblyState = &kia; kgpci.pViewportState = &kvps;
-            kgpci.pDynamicState = &kdsci;
-            kgpci.pRasterizationState = &krs; kgpci.pMultisampleState = &kms; kgpci.pColorBlendState = &kcb; kgpci.pDepthStencilState = &kds;
-            kgpci.layout = skybox_pipeline_layout; kgpci.renderPass = scene_render_pass; kgpci.subpass = 0;
-            VkResult kpr = vkCreateGraphicsPipelines(device, VK_NULL_HANDLE, 1, &kgpci, nullptr, &skybox_pipeline);
-            vkDestroyShaderModule(device, kvmod, nullptr); vkDestroyShaderModule(device, kfmod, nullptr);
-            if (kpr != VK_SUCCESS) { DONUT_ERROR("Vulkan: skybox pipeline creation failed ({})", (int)kpr); return false; }
-        }
-
-        DONUT_INFO("Vulkan: scene resources ready ({} grid verts, {} sphere indices, skybox)", grid_vertex_count, sphere_index_count);
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::update_scene_uniforms() -> void
-    {
-        struct GridUBO {
-            glm::mat4 view_projection;    // 0    (SPIR-V RowMajor -> upload transposed)
-            glm::mat4 transform;          // 64
-            float grid_size; float p0[3]; // 128
-            glm::vec3 grid_color;         // 144
-            float grid_alpha;             // 156
-            glm::vec3 camera_pos;         // 160
-            float p1;                     // 172
-        } g{};
-        static_assert(sizeof(GridUBO) == 176, "GridUBO std140 layout mismatch");
-
-        uint32_t h = swapchain_extent.height ? swapchain_extent.height : 1;
-        float aspect = (float)swapchain_extent.width / (float)h;
-        scene_camera.set_projection(45.0f, aspect, 0.1f, 1000.0f);
-        glm::mat4 vp = scene_camera.get_projection_matrix() * scene_camera.get_view_matrix();
-
-        // Slang's mul(M,v) + the SPIR-V RowMajor decoration means glm's column-major
-        // matrices upload directly here (no transpose) to read as the intended M.
-        g.view_projection = vp;
-        g.transform       = glm::mat4(1.0f);
-        g.grid_size       = 50.0f;
-        g.grid_color      = glm::vec3(0.55f, 0.55f, 0.6f);
-        g.grid_alpha      = 0.75f;
-        g.camera_pos      = scene_camera.get_orbital_position();
-        if (grid_ubo_mapped) memcpy(grid_ubo_mapped, &g, sizeof(g));
-
-        struct SphereUBO {
-            glm::mat4 view_projection;                    // 0
-            glm::mat4 transform;                          // 64
-            glm::vec3 color; float specular;              // 128, 140
-            float emission; float p0[3];                  // 144
-            glm::vec3 light_pos; float p1;                // 160, 172
-            glm::vec3 camera_pos; int is_selected;        // 176, 188
-            glm::vec3 outline_color; float outline_width; // 192, 204
-        };
-        static_assert(sizeof(SphereUBO) == 208, "SphereUBO std140 layout mismatch");
-        glm::vec3 cam_pos = scene_camera.get_orbital_position();
-        uint32_t obj_count = (uint32_t)std::min(scene_objects.size(), (size_t)MAX_SCENE_OBJECTS);
-        for (uint32_t i = 0; i < obj_count; ++i)
-        {
-            const SceneObject& o = scene_objects[i];
-            SphereUBO s{};
-            s.view_projection = vp;  // same no-transpose rule as the grid
-            s.transform       = glm::translate(glm::mat4(1.0f), o.position) * glm::scale(glm::mat4(1.0f), glm::vec3(o.radius));
-            s.color           = o.color;
-            s.specular        = 0.6f;
-            s.emission        = 0.0f;
-            s.light_pos       = glm::vec3(10.0f, 20.0f, 10.0f);
-            s.camera_pos      = cam_pos;
-            s.is_selected     = ((int)i == selected_object) ? 1 : 0;
-            s.outline_color   = glm::vec3(1.0f, 1.0f, 0.0f);
-            s.outline_width   = 0.15f;
-            if (sphere_ubo_mapped) memcpy((char*)sphere_ubo_mapped + (VkDeviceSize)i * sphere_ubo_stride, &s, sizeof(s));
-        }
-
-        struct SkyboxUBO { glm::mat4 projection; glm::mat4 view; } sky{};
-        static_assert(sizeof(SkyboxUBO) == 128, "SkyboxUBO std140 layout mismatch");
-        sky.projection = scene_camera.get_projection_matrix();                 // no transpose (mul(M,v))
-        sky.view       = glm::mat4(glm::mat3(scene_camera.get_view_matrix())); // strip translation so the sky stays centered
-        if (skybox_ubo_mapped) memcpy(skybox_ubo_mapped, &sky, sizeof(sky));
-    }
-
-    auto VulkanRenderer::Impl::update_geodesic_uniforms() -> void
-    {
-        struct CamUBO {
-            glm::vec3 pos; float p0; glm::vec3 right; float p1;
-            glm::vec3 up; float p2; glm::vec3 fwd; float p3;
-            float tan_half_fov; float aspect; uint32_t moving; int p4;
-        } cam_data{};
-        glm::vec3 pos, fwd;
-        if (camera.get_camera_mode() == CameraMode::FPS)
-        {
-            pos = camera.get_position();
-            fwd = camera.get_forward_direction();
-        }
-        else
-        {
-            pos = camera.get_orbital_position();
-            fwd = glm::normalize(camera.get_orbital_target() - pos);
-        }
-        glm::vec3 right = glm::normalize(glm::cross(fwd, glm::vec3(0, 1, 0)));
-        cam_data.pos = pos; cam_data.right = right; cam_data.up = glm::cross(right, fwd); cam_data.fwd = fwd;
-        cam_data.tan_half_fov = (float)tan(glm::radians(bh_params.fov_degrees * 0.5f));
-        cam_data.aspect = (float)GEO_HI_W / (float)GEO_HI_H;  // 16:9, same for both targets
-        cam_data.moving = user_moving ? 1u : 0u;
-        if (cam_mapped) memcpy(cam_mapped, &cam_data, sizeof(cam_data));
-
-        // Integration budget drives how deep the geodesics are traced: too few
-        // steps and grazing rays exhaust the loop mid-lensing, so the shader
-        // paints them with the HDRI (Geodesic.slang) and the hole looks sliced
-        // off "up to a certain depth" -- and near face-on it vanishes entirely.
-        // Measured: at ~8000 steps the disk disappears at steep poses, ~15000 is
-        // needed for it to resolve, INDEPENDENT of resolution. So we DON'T drop
-        // steps while moving (that would make the hole flicker out mid-drag);
-        // responsiveness comes from the lower-res target instead (see record).
-        // Sourced from settings.toml (max_steps_static), capped GPU-safe.
-        constexpr int kStepCeil = 15000;
-        struct SimUBO { int steps_moving; int steps_static; float early_exit; float time; } sim;
-        sim.steps_static = std::clamp(bh_params.quality_steps, 1000, kStepCeil);
-        sim.steps_moving = sim.steps_static;  // same budget both frames; resolution is the lever
-        sim.early_exit   = SettingsManager::get_early_exit_distance();
-        sim.time = (float)(glfwGetTime() - start_time);
-        if (sim_mapped) memcpy(sim_mapped, &sim, sizeof(sim));
-
-        // Disk UBO, refilled live from the UI-tunable parameters. Layout matches
-        // the shader Disk struct: r1, r2, turbulence, slab thickness, brightness,
-        // temperature. Radii are in Schwarzschild radii (x SagA_rs).
-        const float SagA_rs = 1.269e10f;
-        float disk_data[8] = {
-            std::max(bh_params.disk_inner_rs, 3.0f) * SagA_rs,
-            std::max(bh_params.disk_outer_rs, bh_params.disk_inner_rs + 0.5f) * SagA_rs,
-            std::max(bh_params.turbulence, 0.0f),
-            SagA_rs * 0.1f,                       // slab half-thickness (fixed)
-            std::max(bh_params.brightness, 0.0f),
-            std::max(bh_params.temperature, 1000.0f),
-            0.0f, 0.0f,
-        };
-        if (disk_mapped) memcpy(disk_mapped, disk_data, sizeof(disk_data));
-    }
-
-    static double g_ScrollAccum = 0.0;
-    static GLFWscrollfun g_PrevScroll = nullptr;
-    static void donut_vk_scroll_callback(GLFWwindow* w, double x, double y)
-    {
-        if (g_PrevScroll) g_PrevScroll(w, x, y);  // keep ImGui's scroll handling intact
-        g_ScrollAccum += y;
-    }
-
-    auto VulkanRenderer::Impl::process_input() -> void
-    {
-        bool over_ui = imgui_init && ImGui::GetIO().WantCaptureMouse;
-
-        double now = glfwGetTime();
-        float dt = last_frame_time > 0.0 ? (float)(now - last_frame_time) : 0.0f;
-        last_frame_time = now;
-
-        double mx = 0, my = 0;
-        glfwGetCursorPos(window, &mx, &my);
-        bool left_down = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS;
-
-        if (!scene_mode && camera.get_camera_mode() == CameraMode::FPS)
-        {
-            // Left-drag looks around (screen-up looks up); WASD/QE move.
-            if (left_down && !left_was_down) { fps_last_x = mx; fps_last_y = my; }
-            if (left_down && !over_ui)
-                camera.on_mouse_move(float(mx - fps_last_x), float(fps_last_y - my));
-            fps_last_x = mx; fps_last_y = my;
-            left_was_down = left_down;
-
-            bool over_kb = imgui_init && ImGui::GetIO().WantCaptureKeyboard;
-            bool moved = false;
-            if (!over_kb && dt > 0.0f)
-            {
-                float mdt = dt * (glfwGetKey(window, GLFW_KEY_LEFT_SHIFT) == GLFW_PRESS ? 4.0f : 1.0f);
-                if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) { camera.move_forward(mdt);  moved = true; }
-                if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) { camera.move_backward(mdt); moved = true; }
-                if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) { camera.move_left(mdt);     moved = true; }
-                if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) { camera.move_right(mdt);    moved = true; }
-                if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS) { camera.move_up(mdt);       moved = true; }
-                if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS) { camera.move_down(mdt);     moved = true; }
-            }
-            g_ScrollAccum = 0.0;  // scroll unused in free-fly
-            user_moving = moved || (left_down && !over_ui);
-        }
-        else
-        {
-            Camera& cam = scene_mode ? scene_camera : camera;
-            if (left_down && !left_was_down && !over_ui)
-                cam.process_orbital_mouse_button(GLFW_MOUSE_BUTTON_LEFT, GLFW_PRESS, 0);
-            else if (!left_down && left_was_down)
-                cam.process_orbital_mouse_button(GLFW_MOUSE_BUTTON_LEFT, GLFW_RELEASE, 0);
-            left_was_down = left_down;
-
-            cam.process_orbital_mouse_move(mx, my);  // orbits only while dragging
-
-            double scroll = g_ScrollAccum; g_ScrollAccum = 0.0;
-            if (scroll != 0.0 && !over_ui)
-                cam.process_orbital_scroll(0.0, scroll);
-
-            user_moving = cam.is_dragging() || cam.is_panning();
-        }
-    }
-
-    auto VulkanRenderer::Impl::destroy_geodesic_resources() -> void
-    {
-        if (grid_pipeline) vkDestroyPipeline(device, grid_pipeline, nullptr);
-        if (grid_pipeline_layout) vkDestroyPipelineLayout(device, grid_pipeline_layout, nullptr);
-        if (grid_pool) vkDestroyDescriptorPool(device, grid_pool, nullptr);
-        if (grid_set_layout) vkDestroyDescriptorSetLayout(device, grid_set_layout, nullptr);
-        if (grid_ubo_mapped) { vkUnmapMemory(device, grid_ubo_mem); grid_ubo_mapped = nullptr; }
-        if (grid_ubo) vkDestroyBuffer(device, grid_ubo, nullptr);
-        if (grid_ubo_mem) vkFreeMemory(device, grid_ubo_mem, nullptr);
-        if (grid_vb) vkDestroyBuffer(device, grid_vb, nullptr);
-        if (grid_vb_mem) vkFreeMemory(device, grid_vb_mem, nullptr);
-
-        if (sphere_pipeline) vkDestroyPipeline(device, sphere_pipeline, nullptr);
-        if (sphere_pipeline_layout) vkDestroyPipelineLayout(device, sphere_pipeline_layout, nullptr);
-        if (sphere_pool) vkDestroyDescriptorPool(device, sphere_pool, nullptr);
-        if (sphere_set_layout) vkDestroyDescriptorSetLayout(device, sphere_set_layout, nullptr);
-        if (sphere_ubo_mapped) { vkUnmapMemory(device, sphere_ubo_mem); sphere_ubo_mapped = nullptr; }
-        if (sphere_ubo) vkDestroyBuffer(device, sphere_ubo, nullptr);
-        if (sphere_ubo_mem) vkFreeMemory(device, sphere_ubo_mem, nullptr);
-        if (sphere_ib) vkDestroyBuffer(device, sphere_ib, nullptr);
-        if (sphere_ib_mem) vkFreeMemory(device, sphere_ib_mem, nullptr);
-        if (sphere_vb) vkDestroyBuffer(device, sphere_vb, nullptr);
-        if (sphere_vb_mem) vkFreeMemory(device, sphere_vb_mem, nullptr);
-
-        if (skybox_pipeline) vkDestroyPipeline(device, skybox_pipeline, nullptr);
-        if (skybox_pipeline_layout) vkDestroyPipelineLayout(device, skybox_pipeline_layout, nullptr);
-        if (skybox_pool) vkDestroyDescriptorPool(device, skybox_pool, nullptr);
-        if (skybox_set_layout) vkDestroyDescriptorSetLayout(device, skybox_set_layout, nullptr);
-        if (skybox_ubo_mapped) { vkUnmapMemory(device, skybox_ubo_mem); skybox_ubo_mapped = nullptr; }
-        if (skybox_ubo) vkDestroyBuffer(device, skybox_ubo, nullptr);
-        if (skybox_ubo_mem) vkFreeMemory(device, skybox_ubo_mem, nullptr);
-        if (skybox_vb) vkDestroyBuffer(device, skybox_vb, nullptr);
-        if (skybox_vb_mem) vkFreeMemory(device, skybox_vb_mem, nullptr);
-
-        if (present_pipeline) vkDestroyPipeline(device, present_pipeline, nullptr);
-        if (present_pipeline_layout) vkDestroyPipelineLayout(device, present_pipeline_layout, nullptr);
-        if (present_pool) vkDestroyDescriptorPool(device, present_pool, nullptr);
-        if (present_set_layout) vkDestroyDescriptorSetLayout(device, present_set_layout, nullptr);
-        if (present_sampler) vkDestroySampler(device, present_sampler, nullptr);
-
-        if (geo_pipeline) vkDestroyPipeline(device, geo_pipeline, nullptr);
-        if (geo_pipeline_layout) vkDestroyPipelineLayout(device, geo_pipeline_layout, nullptr);
-        if (geo_pool) vkDestroyDescriptorPool(device, geo_pool, nullptr);
-        if (geo_set_layout) vkDestroyDescriptorSetLayout(device, geo_set_layout, nullptr);
-        if (quad_vb) vkDestroyBuffer(device, quad_vb, nullptr);
-        if (quad_vb_mem) vkFreeMemory(device, quad_vb_mem, nullptr);
-        if (cube_sampler) vkDestroySampler(device, cube_sampler, nullptr);
-        if (cube_view) vkDestroyImageView(device, cube_view, nullptr);
-        if (cube_image) vkDestroyImage(device, cube_image, nullptr);
-        if (cube_mem) vkFreeMemory(device, cube_mem, nullptr);
-        if (cam_mapped) { vkUnmapMemory(device, cam_mem); cam_mapped = nullptr; }
-        if (sim_mapped) { vkUnmapMemory(device, sim_mem); sim_mapped = nullptr; }
-        if (disk_mapped) { vkUnmapMemory(device, disk_mem); disk_mapped = nullptr; }
-        VkBuffer ubos[4] = { cam_buf, disk_buf, obj_buf, sim_buf };
-        VkDeviceMemory umem[4] = { cam_mem, disk_mem, obj_mem, sim_mem };
-        for (int i = 0; i < 4; ++i) { if (ubos[i]) vkDestroyBuffer(device, ubos[i], nullptr); if (umem[i]) vkFreeMemory(device, umem[i], nullptr); }
-        for (GeoTarget* t : { &geo_lo, &geo_hi })
-        {
-            if (t->fb)    vkDestroyFramebuffer(device, t->fb, nullptr);
-            if (t->view)  vkDestroyImageView(device, t->view, nullptr);
-            if (t->image) vkDestroyImage(device, t->image, nullptr);
-            if (t->mem)   vkFreeMemory(device, t->mem, nullptr);
-        }
-        if (geo_render_pass) vkDestroyRenderPass(device, geo_render_pass, nullptr);
-    }
-
-    auto VulkanRenderer::Impl::record_command_buffer(VkCommandBuffer cmd, uint32_t image_index, const glm::vec4& clear, ImDrawData* draw_data) -> bool
-    {
-        VkCommandBufferBeginInfo begin{ VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO };
-        VK_CHECK(vkBeginCommandBuffer(cmd, &begin));
-
-        if (scene_mode)
-        {
-            // Scene view: opaque sphere (writes depth) then the transparent grid on
-            // top, into a color+depth swapchain pass, then ImGui.
-            VkClearValue cvs[2]{};
-            cvs[0].color = { { clear.r, clear.g, clear.b, clear.a } };
-            cvs[1].depthStencil = { 1.0f, 0 };
-            VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-            rpbi.renderPass = scene_render_pass; rpbi.framebuffer = scene_framebuffers[image_index];
-            rpbi.renderArea = { { 0, 0 }, swapchain_extent };
-            rpbi.clearValueCount = 2; rpbi.pClearValues = cvs;
-            vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
-
-            // Negative-height viewport flips Y so the scene reads like the GL path.
-            VkViewport gvp{ 0, (float)swapchain_extent.height, (float)swapchain_extent.width, -(float)swapchain_extent.height, 0, 1 };
-            VkRect2D gsc{ { 0, 0 }, swapchain_extent };
-            vkCmdSetViewport(cmd, 0, 1, &gvp);
-            vkCmdSetScissor(cmd, 0, 1, &gsc);
-
-            // Skybox background first (forces depth 1; no depth test/write).
-            vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, skybox_pipeline);
-            vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, skybox_pipeline_layout, 0, 1, &skybox_set, 0, nullptr);
-            VkDeviceSize skoff = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &skybox_vb, &skoff);
-            vkCmdDraw(cmd, 36, 1, 0, 0);
-
-            vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, sphere_pipeline);
-            VkDeviceSize soff = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &sphere_vb, &soff);
-            vkCmdBindIndexBuffer(cmd, sphere_ib, 0, VK_INDEX_TYPE_UINT32);
-            uint32_t obj_count = (uint32_t)std::min(scene_objects.size(), (size_t)MAX_SCENE_OBJECTS);
-            for (uint32_t i = 0; i < obj_count; ++i)
-            {
-                uint32_t dyn = (uint32_t)((VkDeviceSize)i * sphere_ubo_stride);  // select this object's UBO slot
-                vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, sphere_pipeline_layout, 0, 1, &sphere_set, 1, &dyn);
-                vkCmdDrawIndexed(cmd, sphere_index_count, 1, 0, 0, 0);
-            }
-
-            vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, grid_pipeline);
-            vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, grid_pipeline_layout, 0, 1, &grid_set, 0, nullptr);
-            VkDeviceSize goff = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &grid_vb, &goff);
-            vkCmdDraw(cmd, grid_vertex_count, 1, 0, 0);
-
-            if (draw_data)
-                ImGui_ImplVulkan_RenderDrawData(draw_data, cmd);
-            vkCmdEndRenderPass(cmd);
-            VK_CHECK(vkEndCommandBuffer(cmd));
-            return true;
-        }
-
-        // Geodesic offscreen pass. Progressive resolution: low-res while the
-        // camera moves (4x fewer pixels -> responsive), high-res once it settles
-        // (resolves the photon ring). Step count is the same for both (the disk
-        // vanishes below ~15000 steps at steep poses), so resolution is the lever.
-        GeoTarget& gt = user_moving ? geo_lo : geo_hi;
-        VkClearValue geo_clear{}; geo_clear.color = { { 0, 0, 0, 1 } };
-        VkRenderPassBeginInfo grp{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-        grp.renderPass = geo_render_pass; grp.framebuffer = gt.fb;
-        grp.renderArea = { { 0, 0 }, { gt.w, gt.h } };
-        grp.clearValueCount = 1; grp.pClearValues = &geo_clear;
-        vkCmdBeginRenderPass(cmd, &grp, VK_SUBPASS_CONTENTS_INLINE);
-        vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, geo_pipeline);
-        VkViewport gvp{ 0, 0, (float)gt.w, (float)gt.h, 0, 1 }; VkRect2D gsc{ { 0, 0 }, { gt.w, gt.h } };
-        vkCmdSetViewport(cmd, 0, 1, &gvp); vkCmdSetScissor(cmd, 0, 1, &gsc);
-        vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, geo_pipeline_layout, 0, 1, &geo_set, 0, nullptr);
-        VkDeviceSize off = 0; vkCmdBindVertexBuffers(cmd, 0, 1, &quad_vb, &off);
-        vkCmdDraw(cmd, 6, 1, 0, 0);
-        vkCmdEndRenderPass(cmd);
-
-        // Swapchain pass: upscale the geodesic image, then the ImGui UI on top
-        VkClearValue cv{}; cv.color = { { clear.r, clear.g, clear.b, clear.a } };
-        VkRenderPassBeginInfo rpbi{ VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO };
-        rpbi.renderPass = render_pass;
-        rpbi.framebuffer = framebuffers[image_index];
-        rpbi.renderArea = { { 0, 0 }, swapchain_extent };
-        rpbi.clearValueCount = 1; rpbi.pClearValues = &cv;
-        vkCmdBeginRenderPass(cmd, &rpbi, VK_SUBPASS_CONTENTS_INLINE);
-        vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, present_pipeline);
-        // Negative-height viewport flips the geodesic image vertically so the scene
-        // reads the same as the OpenGL path (Vulkan's clip space is Y-down). Only
-        // this draw is affected; ImGui sets its own viewport.
-        VkViewport vp{ 0, (float)swapchain_extent.height, (float)swapchain_extent.width, -(float)swapchain_extent.height, 0, 1 };
-        VkRect2D scissor{ { 0, 0 }, swapchain_extent };
-        vkCmdSetViewport(cmd, 0, 1, &vp);
-        vkCmdSetScissor(cmd, 0, 1, &scissor);
-        vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, present_pipeline_layout, 0, 1, &gt.present_set, 0, nullptr);
-        vkCmdBindVertexBuffers(cmd, 0, 1, &quad_vb, &off);
-        vkCmdDraw(cmd, 6, 1, 0, 0);
-        if (draw_data)
-            ImGui_ImplVulkan_RenderDrawData(draw_data, cmd);
-        vkCmdEndRenderPass(cmd);
-
-        VK_CHECK(vkEndCommandBuffer(cmd));
-        return true;
-    }
-
-    auto VulkanRenderer::Impl::cleanup_swapchain() -> void
-    {
-        destroy_scene_targets();
-        for (auto fb : framebuffers) vkDestroyFramebuffer(device, fb, nullptr);
-        framebuffers.clear();
-        for (auto iv : image_views) vkDestroyImageView(device, iv, nullptr);
-        image_views.clear();
-        if (render_pass) { vkDestroyRenderPass(device, render_pass, nullptr); render_pass = VK_NULL_HANDLE; }
-        if (swapchain)  { vkDestroySwapchainKHR(device, swapchain, nullptr); swapchain = VK_NULL_HANDLE; }
-    }
-
-    auto VulkanRenderer::Impl::recreate_swapchain() -> bool
-    {
-        // Wait until the window has a non-zero size (e.g. after un-minimizing).
-        int w = 0, h = 0;
-        glfwGetFramebufferSize(window, &w, &h);
-        while (w == 0 || h == 0)
-        {
-            glfwGetFramebufferSize(window, &w, &h);
-            glfwWaitEvents();
-        }
-        width = w; height = h;
-        vkDeviceWaitIdle(device);
-
-        cleanup_swapchain();
-        // render_finished are tied to image count; recreate below via sync if it changed.
-        if (!create_swapchain())   return false;
-        if (!create_image_views())  return false;
-        if (!create_render_pass())  return false;
-        if (!create_framebuffers())return false;
-        if (!create_scene_targets())return false;
-        images_in_flight.assign(images.size(), VK_NULL_HANDLE);
-        return true;
-    }
-
-    VulkanRenderer::VulkanRenderer()  { m_impl = new Impl(); }
-    VulkanRenderer::~VulkanRenderer() { shutdown(); delete m_impl; m_impl = nullptr; }
-
-    auto VulkanRenderer::init(void* glfwWindow, int width, int height) -> bool
-    {
-        Impl& v = *m_impl;
-        v.window = (GLFWwindow*)glfwWindow;
-        v.width = width; v.height = height;
-
-        if (!v.create_instance())        return false;
-        if (!v.pick_physical_and_device()) return false;
-        if (!v.create_swapchain())       return false;
-        if (!v.create_image_views())      return false;
-        if (!v.create_render_pass())      return false;
-        if (!v.create_framebuffers())    return false;
-        if (!v.create_scene_targets())    return false;
-        if (!v.create_command_buffers())  return false;
-        if (!v.create_sync_objects())     return false;
-        if (!v.create_geodesic_resources()) return false;
-        if (!v.create_present_resources())  return false;
-        if (!v.create_scene_resources())    return false;
-
-        DONUT_INFO("Vulkan renderer ready: {} swapchain images, {}x{}",
-                   (int)v.images.size(), v.swapchain_extent.width, v.swapchain_extent.height);
-        return true;
-    }
-
-    auto VulkanRenderer::init_ui() -> bool
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) return false;
-
-        VkDescriptorPoolSize pool_size{ VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1000 };
-        VkDescriptorPoolCreateInfo dpci{ VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO };
-        dpci.flags = VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT;
-        dpci.maxSets = 1000;
-        dpci.poolSizeCount = 1; dpci.pPoolSizes = &pool_size;
-        VK_CHECK(vkCreateDescriptorPool(v.device, &dpci, nullptr, &v.imgui_pool));
-
-        IMGUI_CHECKVERSION();
-        ImGui::CreateContext();
-        ImGuiIO& io = ImGui::GetIO();
-        io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
-        io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
-        ImGui::StyleColorsDark();
-
-        ImGui_ImplGlfw_InitForVulkan(v.window, true);
-        g_PrevScroll = glfwSetScrollCallback(v.window, donut_vk_scroll_callback);  // chain ImGui + camera zoom
-        ImGui_ImplVulkan_InitInfo info{};
-        info.ApiVersion     = VK_API_VERSION_1_2;
-        info.Instance       = v.instance;
-        info.PhysicalDevice = v.physical;
-        info.Device         = v.device;
-        info.QueueFamily    = v.graphics_family;
-        info.Queue          = v.graphics_queue;
-        info.DescriptorPool = v.imgui_pool;
-        info.RenderPass     = v.render_pass;
-        info.MinImageCount  = 2;
-        info.ImageCount     = (uint32_t)v.images.size();
-        info.MSAASamples    = VK_SAMPLE_COUNT_1_BIT;
-        if (!ImGui_ImplVulkan_Init(&info))
-        {
-            DONUT_ERROR("Vulkan: ImGui_ImplVulkan_Init failed");
-            return false;
-        }
-
-        v.imgui_init = true;
-        DONUT_INFO("Vulkan: ImGui backend initialized");
-        return true;
-    }
-
-    auto VulkanRenderer::resize(int width, int height) -> void
-    {
-        m_impl->framebuffer_resized = true;
-        m_impl->width = width; m_impl->height = height;
-    }
-
-    auto VulkanRenderer::set_hdri(const std::string& path) -> void
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE || v.geo_set == VK_NULL_HANDLE) return;
-        if (v.hdri_path == path) return;
-        v.rebuild_hdri_cubemap(path.c_str());
-    }
-
-    auto VulkanRenderer::current_hdri() const -> const std::string&
-    {
-        return m_impl->hdri_path;
-    }
-
-    auto VulkanRenderer::set_free_fly(bool enabled) -> void
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) return;
-        const bool is_fps = v.camera.get_camera_mode() == CameraMode::FPS;
-        if (enabled == is_fps) return;
-
-        if (enabled)
-        {
-            // Seed the fly pose from the current orbital framing so the view is continuous.
-            glm::vec3 pos = v.camera.get_orbital_position();
-            glm::vec3 fwd = glm::normalize(v.camera.get_orbital_target() - pos);
-            float pitch = glm::degrees(asin(glm::clamp(fwd.y, -1.0f, 1.0f)));
-            float yaw   = glm::degrees(atan2(fwd.z, fwd.x));
-            v.camera.set_camera_mode(CameraMode::FPS);
-            v.camera.set_movement_speed(2.0e10f);   // scene spans ~1e11 units
-            v.camera.set_mouse_sensitivity(0.15f);
-            v.camera.set_position(pos);
-            v.camera.set_rotation(glm::vec3(pitch, yaw, 0.0f));
-        }
-        else
-        {
-            v.camera.set_camera_mode(CameraMode::Orbital);  // orbital state was left intact
-        }
-    }
-
-    auto VulkanRenderer::is_free_fly() const -> bool
-    {
-        return m_impl->camera.get_camera_mode() == CameraMode::FPS;
-    }
-
-    auto VulkanRenderer::set_scene_mode(bool enabled) -> void
-    {
-        if (m_impl) m_impl->scene_mode = enabled;
-    }
-
-    auto VulkanRenderer::is_scene_mode() const -> bool
-    {
-        return m_impl && m_impl->scene_mode;
-    }
-
-    auto VulkanRenderer::scene_objects() -> std::vector<SceneObject>&
-    {
-        return m_impl->scene_objects;
-    }
-
-    auto VulkanRenderer::set_selected_object(int index) -> void
-    {
-        if (m_impl) m_impl->selected_object = index;
-    }
-
-    auto VulkanRenderer::black_hole_params() -> BlackHoleParams&
-    {
-        return m_impl->bh_params;
-    }
-
-    auto VulkanRenderer::reset_camera() -> void
-    {
-        if (!m_impl) return;
-        Camera& cam = m_impl->camera;
-        cam.set_camera_mode(CameraMode::Orbital);  // also flips is_free_fly() back
-        cam.set_orbital_radius(4e11);
-        cam.set_azimuth(0.0f);
-        cam.set_elevation(1.25f);
-    }
-
-    auto VulkanRenderer::device_name() const -> const std::string&
-    {
-        return m_impl->gpu_name;
-    }
-
-    auto VulkanRenderer::draw_frame(const glm::vec4& clear_color, const std::function<void()>& build_ui) -> void
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) return;
-
-        ImDrawData* draw_data = nullptr;
-        if (v.imgui_init)
-        {
-            ImGui_ImplVulkan_NewFrame();
-            ImGui_ImplGlfw_NewFrame();
-            ImGui::NewFrame();
-            if (build_ui) build_ui();
-            ImGui::Render();
-            draw_data = ImGui::GetDrawData();
-        }
-
-        vkWaitForFences(v.device, 1, &v.in_flight[v.current_frame], VK_TRUE, UINT64_MAX);
-
-        uint32_t image_index = 0;
-        VkResult r = vkAcquireNextImageKHR(v.device, v.swapchain, UINT64_MAX,
-                                           v.image_available[v.current_frame], VK_NULL_HANDLE, &image_index);
-        if (r == VK_ERROR_OUT_OF_DATE_KHR) { v.recreate_swapchain(); return; }
-        if (r != VK_SUCCESS && r != VK_SUBOPTIMAL_KHR) { DONUT_ERROR("Vulkan: acquire failed ({})", (int)r); return; }
-
-        if (v.images_in_flight[image_index] != VK_NULL_HANDLE)
-            vkWaitForFences(v.device, 1, &v.images_in_flight[image_index], VK_TRUE, UINT64_MAX);
-        v.images_in_flight[image_index] = v.in_flight[v.current_frame];
-
-        // The geodesic offscreen image is shared across frames in flight; wait for
-        // the previous frame to finish reading it before overwriting it this frame.
-        if (v.geo_in_use != VK_NULL_HANDLE)
-            vkWaitForFences(v.device, 1, &v.geo_in_use, VK_TRUE, UINT64_MAX);
-        v.process_input();
-        if (v.scene_mode) v.update_scene_uniforms(); else v.update_geodesic_uniforms();
-
-        vkResetCommandBuffer(v.command_buffers[v.current_frame], 0);
-        if (!v.record_command_buffer(v.command_buffers[v.current_frame], image_index, clear_color, draw_data)) return;
-
-        VkPipelineStageFlags wait_stage = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
-        VkSubmitInfo submit{ VK_STRUCTURE_TYPE_SUBMIT_INFO };
-        submit.waitSemaphoreCount   = 1;
-        submit.pWaitSemaphores      = &v.image_available[v.current_frame];
-        submit.pWaitDstStageMask    = &wait_stage;
-        submit.commandBufferCount   = 1;
-        submit.pCommandBuffers      = &v.command_buffers[v.current_frame];
-        submit.signalSemaphoreCount = 1;
-        submit.pSignalSemaphores    = &v.render_finished[image_index];
-
-        vkResetFences(v.device, 1, &v.in_flight[v.current_frame]);
-        if (vkQueueSubmit(v.graphics_queue, 1, &submit, v.in_flight[v.current_frame]) != VK_SUCCESS)
-        { DONUT_ERROR("Vulkan: queue submit failed"); return; }
-        v.geo_in_use = v.in_flight[v.current_frame];
-
-        VkPresentInfoKHR present{ VK_STRUCTURE_TYPE_PRESENT_INFO_KHR };
-        present.waitSemaphoreCount = 1;
-        present.pWaitSemaphores    = &v.render_finished[image_index];
-        present.swapchainCount     = 1;
-        present.pSwapchains        = &v.swapchain;
-        present.pImageIndices      = &image_index;
-        r = vkQueuePresentKHR(v.present_queue, &present);
-        if (r == VK_ERROR_OUT_OF_DATE_KHR || r == VK_SUBOPTIMAL_KHR || v.framebuffer_resized)
-        {
-            v.framebuffer_resized = false;
-            v.recreate_swapchain();
-        }
-
-        v.current_frame = (v.current_frame + 1) % MAX_FRAMES_IN_FLIGHT;
-    }
-
-    auto VulkanRenderer::shutdown() -> void
-    {
-        Impl& v = *m_impl;
-        if (v.device == VK_NULL_HANDLE) { if (v.instance && v.surface) { vkDestroySurfaceKHR(v.instance, v.surface, nullptr); v.surface = VK_NULL_HANDLE; } if (v.instance) { vkDestroyInstance(v.instance, nullptr); v.instance = VK_NULL_HANDLE; } return; }
-
-        vkDeviceWaitIdle(v.device);
-        v.destroy_geodesic_resources();
-        if (v.imgui_init)
-        {
-            ImGui_ImplVulkan_Shutdown();
-            ImGui_ImplGlfw_Shutdown();
-            ImGui::DestroyContext();
-            v.imgui_init = false;
-        }
-        if (v.imgui_pool) { vkDestroyDescriptorPool(v.device, v.imgui_pool, nullptr); v.imgui_pool = VK_NULL_HANDLE; }
-        for (auto s : v.render_finished) vkDestroySemaphore(v.device, s, nullptr);
-        for (auto s : v.image_available) vkDestroySemaphore(v.device, s, nullptr);
-        for (auto f : v.in_flight)       vkDestroyFence(v.device, f, nullptr);
-        v.render_finished.clear(); v.image_available.clear(); v.in_flight.clear();
-        if (v.command_pool) { vkDestroyCommandPool(v.device, v.command_pool, nullptr); v.command_pool = VK_NULL_HANDLE; }
-        v.cleanup_swapchain();
-        vkDestroyDevice(v.device, nullptr); v.device = VK_NULL_HANDLE;
-        if (v.surface)  { vkDestroySurfaceKHR(v.instance, v.surface, nullptr); v.surface = VK_NULL_HANDLE; }
-        if (v.instance) { vkDestroyInstance(v.instance, nullptr); v.instance = VK_NULL_HANDLE; }
-    }
-}
diff --git a/src/platform/vulkan/vulkan_renderer.h b/src/platform/vulkan/vulkan_renderer.h
deleted file mode 100644
index d583f07..0000000
--- a/src/platform/vulkan/vulkan_renderer.h
+++ /dev/null
@@ -1,50 +0,0 @@
-#pragma once
-
-#include "rendering/renderer_backend.h"
-
-// Live-window Vulkan backend: owns the instance, surface, device, swapchain,
-// render pass, framebuffers and per-frame synchronization, and drives the
-// acquire -> record -> submit -> present loop. Implements the shared
-// RendererBackend interface (SceneObject / BlackHoleParams live there). Pure-C++
-// header (no vulkan.h / glfw leak); the GLFW window is passed as an opaque handle.
-namespace Donut
-{
-    // Must be called BEFORE glfwInit() when the Vulkan API is selected: points
-    // GLFW at the loader the app links against (GLFW's own dlopen fails on
-    // macOS/Homebrew) and configures the MoltenVK ICD / layer paths.
-    auto vulkan_prepare_glfw() -> void;
-
-    class VulkanRenderer : public RendererBackend
-    {
-    public:
-        VulkanRenderer();
-        ~VulkanRenderer() override;
-
-        // glfwWindow must be a GLFW window created with GLFW_NO_API.
-        auto init(void* glfwWindow, int width, int height) -> bool override;
-        auto init_ui() -> bool override;
-        auto shutdown() -> void override;
-        auto resize(int width, int height) -> void override;
-
-        auto draw_frame(const glm::vec4& clear_color,
-                        const std::function<void()>& build_ui) -> void override;
-
-        auto set_scene_mode(bool enabled) -> void override;
-        auto is_scene_mode() const -> bool override;
-        auto set_free_fly(bool enabled) -> void override;   // seeds the fly pose from the orbital framing
-        auto is_free_fly() const -> bool override;
-        auto reset_camera() -> void override;
-
-        auto set_hdri(const std::string& path) -> void override;  // rebuilds the cubemap (device-idle)
-        auto current_hdri() const -> const std::string& override;
-        auto scene_objects() -> std::vector<SceneObject>& override;
-        auto set_selected_object(int index) -> void override;
-        auto black_hole_params() -> BlackHoleParams& override;
-
-        auto device_name() const -> const std::string& override;
-
-    private:
-        struct Impl;
-        Impl* m_impl = nullptr;
-    };
-}