From 3fd33ecff7472e4d6fc9e6b3905f56982e497ef2 Mon Sep 17 00:00:00 2001
From: hachem <im@hachem.wtf>
Date: Sun, 23 Aug 2026 17:21:37 +0200
Subject: [feat]: complete RHI api

---
 src/rendering/black_hole_renderer.h | 55 +++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 src/rendering/black_hole_renderer.h

(limited to 'src/rendering/black_hole_renderer.h')

diff --git a/src/rendering/black_hole_renderer.h b/src/rendering/black_hole_renderer.h
new file mode 100644
index 0000000..b9c158b
--- /dev/null
+++ b/src/rendering/black_hole_renderer.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include "rhi.h"
+#include "renderer_backend.h"   // BlackHoleParams
+#include <glm/glm.hpp>
+
+namespace Donut
+{
+    // The black-hole view, written ONCE against the RHI. Each frame it ray-traces
+    // the geodesic shader into an off-screen target (progressive resolution: a
+    // small target while the camera moves, a larger one once it settles) and then
+    // upscales that target onto the swapchain. The Application owns the camera and
+    // the HDRI cubemap and passes them in.
+    struct GeodesicView
+    {
+        glm::vec3 position, right, up, forward;
+        float tan_half_fov = 1.0f;
+        float aspect       = 16.0f / 9.0f;
+        bool  moving       = false;
+        float time         = 0.0f;
+    };
+
+    class BlackHoleRenderer
+    {
+    public:
+        static constexpr int GEO_LO_W = 480, GEO_LO_H = 270;
+        static constexpr int GEO_HI_W = 960, GEO_HI_H = 540;
+
+        auto init(RHI::Device& device) -> bool;
+
+        // Off-screen geodesic pass (opens/closes its own render pass). Call before
+        // the swapchain pass; `cubemap` is the shared HDRI environment.
+        auto render_geodesic(RHI::CommandList& cmd, const GeodesicView& view,
+                             const BlackHoleParams& params, RHI::Texture* cubemap) -> void;
+
+        // Upscales the geodesic target onto the swapchain (call inside the open
+        // swapchain render pass, before ImGui).
+        auto blit(RHI::CommandList& cmd, int fb_width, int fb_height) -> void;
+
+    private:
+        RHI::Device* m_device = nullptr;
+
+        Ref<RHI::Pipeline>     m_geo_pipeline;
+        Ref<RHI::RenderTarget> m_geo_lo;
+        Ref<RHI::RenderTarget> m_geo_hi;
+        Ref<RHI::Buffer>       m_quad_vb;
+        Ref<RHI::Buffer>       m_cam_ubo;
+        Ref<RHI::Buffer>       m_disk_ubo;
+        Ref<RHI::Buffer>       m_obj_ubo;
+        Ref<RHI::Buffer>       m_sim_ubo;
+
+        Ref<RHI::Pipeline>     m_present_pipeline;
+        RHI::RenderTarget*     m_last_target = nullptr;   // target chosen this frame
+    };
+}
-- 
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