feat: vulkan is going to be the end of me bro

4 files changed, 114 insertions, 42 deletions

diff --git a/premake5.lua b/premake5.lua
index d0e17d3..2559098 100644
--- a/premake5.lua
+++ b/premake5.lua
@@ -363,10 +363,12 @@ project "Donut"
 		}
 
 	filter "system:macosx"
-		-- Objective-C++ (Metal) sources compile only on macOS.
+		-- Objective-C++ (Metal) sources + the ImGui Vulkan backend compile only
+		-- on macOS (Vulkan headers come from Homebrew there).
 		files
 		{
-			"src/**.mm"
+			"src/**.mm",
+			"ext/imgui/backends/imgui_impl_vulkan.cpp"
 		}
 
 		-- Compile the Slang shaders to assets/shaders/generated/ before building.
@@ -376,6 +378,10 @@ project "Donut"
 			'bash "%{wks.location}/tools/compile-shaders.sh"'
 		}
 
+		-- Vulkan (via MoltenVK) from Homebrew; see tools/vulkan-env.sh for runtime.
+		includedirs { "/opt/homebrew/include" }
+		libdirs     { "/opt/homebrew/lib" }
+
 		links
 		{
 			"Cocoa.framework",
@@ -383,7 +389,8 @@ project "Donut"
 			"CoreFoundation.framework",
 			"QuartzCore.framework",
 			"Metal.framework",
-			"Foundation.framework"
+			"Foundation.framework",
+			"vulkan"
 		}
 
 	filter "configurations:Debug"
diff --git a/src/core/application.cpp b/src/core/application.cpp
index fa5fd6e..0f07979 100644
--- a/src/core/application.cpp
+++ b/src/core/application.cpp
@@ -8,10 +8,14 @@
 #include "states/world_builder_state.h"
 
 #include <GLFW/glfw3.h>
+#include <imgui.h>
 #include <ImGuizmo.h>
 
+#include "platform/vulkan/vulkan_renderer.h"
+
 #ifdef __APPLE__
 #include "platform/metal/metal_context.h"
+#include "platform/vulkan/vulkan_context.h"
 #endif
 
 namespace Donut
@@ -23,8 +27,19 @@ namespace Donut
     {
         s_instance = this;
 
+        Logger::init();
+        SettingsManager::initialize();
+        {
+            const auto& settings = SettingsManager::get_settings_const();
+            RendererAPI::set_api(settings.graphics.render_api == "Vulkan"
+                                ? RendererAPI::API::Vulkan : RendererAPI::API::OpenGL);
+        }
+
+        if (RendererAPI::get_api() == RendererAPI::API::Vulkan)
+            vulkan_prepare_glfw();
+
         m_window = create_scope<Window>(name, width, height);
-        m_window->set_event_callback([this](Event& event) 
+        m_window->set_event_callback([this](Event& event)
         {
             on_event(event);
         });
@@ -42,16 +57,36 @@ namespace Donut
     {
         while (m_running)
         {
-            if (!m_minimized)
+            if (m_vulkan_renderer)
             {
-                on_update();
-                on_render();
+                glfwPollEvents();
+                if (!m_minimized)
+                    m_vulkan_renderer->draw_frame(glm::vec4(0.05f, 0.06f, 0.10f, 1.0f),
+                                                [this] { build_vulkan_ui(); });
+            }
+            else
+            {
+                if (!m_minimized)
+                {
+                    on_update();
+                    on_render();
+                }
+                m_window->on_update();
             }
-
-            m_window->on_update();
         }
     }
 
+    void Application::build_vulkan_ui()
+    {
+        ImGui::Begin("Donut - Vulkan backend");
+        ImGui::Text("Geodesic black hole through Vulkan (MoltenVK).");
+        ImGui::Text("%.1f FPS", ImGui::GetIO().Framerate);
+        ImGui::Separator();
+        ImGui::TextWrapped("Drag to orbit, scroll to zoom. HDRI starfield is live; "
+                           "next is porting the simulation UI to Vulkan.");
+        ImGui::End();
+    }
+
     void Application::close()
     {
         m_running = false;
@@ -73,15 +108,24 @@ namespace Donut
                 m_minimized = true;
             else
                 m_minimized = false;
-            
-            Renderer::on_window_resize(e.get_width(), e.get_height());
-            m_engine->set_window_dimensions(e.get_width(), e.get_height());
+
+            if (m_vulkan_renderer)
+            {
+                m_vulkan_renderer->on_resize(e.get_width(), e.get_height());
+            }
+            else
+            {
+                Renderer::on_window_resize(e.get_width(), e.get_height());
+                if (m_engine) m_engine->set_window_dimensions(e.get_width(), e.get_height());
+            }
             event.handled = true;
             return true;
         });
         
-        dispatcher.dispatch<KeyPressedEvent>([this, &event](KeyPressedEvent& e) 
+        dispatcher.dispatch<KeyPressedEvent>([this, &event](KeyPressedEvent& e)
         {
+            if (!m_state_manager)
+                return true;
             if (e.get_key_code() == GLFW_KEY_1)
             {
                 m_state_manager->switch_to_state("Config");
@@ -103,34 +147,34 @@ namespace Donut
             
             return true;
         });
-        
-        m_state_manager->on_event(event);
+
+        if (m_state_manager)
+            m_state_manager->on_event(event);
     }
 
     void Application::on_init()
     {
-        Logger::init();
+        if (RendererAPI::get_api() == RendererAPI::API::Vulkan)
+        {
+            int w = 0, h = 0;
+            glfwGetFramebufferSize((GLFWwindow*)m_window->get_native_window(), &w, &h);
+            m_vulkan_renderer = create_scope<VulkanRenderer>();
+            if (!m_vulkan_renderer->init(m_window->get_native_window(), w, h))
+                DONUT_ERROR("Vulkan renderer initialization failed");
+            else
+                m_vulkan_renderer->init_im_gui();
+            return;
+        }
 
-#ifdef __APPLE__
-        metal_probe();
-        metal_compute_self_test();
-#endif
-        
-        SettingsManager::initialize();
-        
-        const auto& settings = SettingsManager::get_settings_const();
-        RendererAPI::API api = (settings.graphics.render_api == "Vulkan") ? RendererAPI::API::Vulkan : RendererAPI::API::OpenGL;
-        RendererAPI::set_api(api);
-        
         Renderer::init();
         m_window->init_im_gui();
-        
+
         Renderer::on_window_resize(1280, 720);
         RenderCommand::set_face_culling(false);
 
         m_engine = create_scope<Engine>();
         m_engine->set_window_dimensions(1280, 720);
-        
+
         m_state_manager = create_scope<StateManager>();
         m_state_manager->register_state("Config",       create_scope<ConfigState>());
         m_state_manager->register_state("Simulation",   create_scope<SimulationState>());
@@ -138,12 +182,19 @@ namespace Donut
         m_state_manager->switch_to_state("Config");
     }
 
-    void Application::on_shutdown() 
-    { 
-        if (m_state_manager)
-            m_state_manager->shutdown();
-            
-        Renderer::shutdown();
+    void Application::on_shutdown()
+    {
+        if (m_vulkan_renderer)
+        {
+            m_vulkan_renderer->shutdown();
+            m_vulkan_renderer.reset();
+        }
+        else
+        {
+            if (m_state_manager)
+                m_state_manager->shutdown();
+            Renderer::shutdown();
+        }
         SettingsManager::shutdown();
         Logger::shutdown();
     }
diff --git a/src/core/application.h b/src/core/application.h
index 8e13f7b..3c76dcc 100644
--- a/src/core/application.h
+++ b/src/core/application.h
@@ -10,6 +10,8 @@
 
 namespace Donut
 {
+    class VulkanRenderer;
+
     class Application
     {
     public:
@@ -31,10 +33,12 @@ namespace Donut
         void on_render();
         void on_event(Event& event);
         void setup_docking_layout();
+        void build_vulkan_ui();
     private:
         Scope<StateManager> m_state_manager;
         Scope<Window> m_window;
         Scope<Engine> m_engine;
+        Scope<VulkanRenderer> m_vulkan_renderer;
 
         bool m_running;
         bool m_minimized;
diff --git a/src/core/window.cpp b/src/core/window.cpp
index cb93d04..0a9ac8b 100644
--- a/src/core/window.cpp
+++ b/src/core/window.cpp
@@ -1,6 +1,7 @@
 #include <glad/glad.h>
 #include "window.h"
 #include "theme_manager.h"
+#include "rendering/renderer.h"
 
 #include <cstdint>
 
@@ -42,12 +43,19 @@ namespace Donut
             DONUT_INFO("GLFW initialized successfully");
         }
 
+        if (RendererAPI::get_api() == RendererAPI::API::Vulkan)
+        {
+            glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
+        }
+        else
+        {
 #ifdef __APPLE__
-        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
-        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
-        glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
-        glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);
+            glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+            glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
+            glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+            glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);
 #endif
+        }
 
         m_window = glfwCreateWindow(m_width, m_height, m_title.c_str(), nullptr, nullptr);
         if (!m_window)
@@ -59,7 +67,8 @@ namespace Donut
         
         DONUT_INFO("GLFW window created successfully");
 
-        glfwMakeContextCurrent(m_window);
+        if (RendererAPI::get_api() != RendererAPI::API::Vulkan)
+            glfwMakeContextCurrent(m_window);
         glfwSetWindowUserPointer(m_window, this);
 
         glfwSetErrorCallback(glfw_error_callback);
@@ -96,7 +105,8 @@ namespace Donut
     void Window::on_update() const
     {
         glfwPollEvents();
-        glfwSwapBuffers(m_window);
+        if (RendererAPI::get_api() != RendererAPI::API::Vulkan)
+            glfwSwapBuffers(m_window);
     }
 
     bool Window::should_close() const
@@ -208,7 +218,7 @@ namespace Donut
 
     void Window::glfw_error_callback(int error, const char* description)
     {
-        DONUT_ERROR("GLFW Error (", error, "): ", description);
+        DONUT_ERROR("GLFW Error ({}): {}", error, description ? description : "");
     }
 
     void Window::glfw_window_close_callback(GLFWwindow* window)