Add G-buffer feasibility analysis for SSAO and SSR#15
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Add G-buffer feasibility analysis for SSAO and SSR#15
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Comprehensive analysis of the engine's rendering pipeline, shaders, and framebuffer infrastructure to determine if a slim G-buffer can be added without overhauling the renderer design. Conclusion: feasible via extending the existing depth pre-pass with MRT normal output. https://claude.ai/code/session_01VdSEPfFdPX7fLLYN6x2ZfQ
Implements performant screen-space ambient occlusion and screen-space reflections for the forward rendering pipeline, requiring only the depth buffer (no G-buffer needed). SSAO: HBAO-style algorithm with 8 directions x 4 steps, bilateral blur, depth-reconstructed normals, and multiplicative scene compositing. SSR: Linear ray march with binary search refinement, Fresnel-based reflection strength, edge/distance fading, and premultiplied alpha compositing. New CVars: r_useSSAO, r_ssaoRadius, r_ssaoIntensity, r_ssaoBias, r_useSSR, r_ssrMaxDistance, r_ssrStride, r_ssrIntensity. https://claude.ai/code/session_01VdSEPfFdPX7fLLYN6x2ZfQ
CMake 4.x removed compatibility with versions below 3.5. Bump all cmake_minimum_required calls from 2.4.4/2.8/3.0/3.4 to 3.5 so the project configures correctly on modern CMake (tested with 4.1.0). https://claude.ai/code/session_01VdSEPfFdPX7fLLYN6x2ZfQ
Instead of each shader computing linear depth from the hardware depth buffer using the projection matrix, add a dedicated linearize-depth pass that writes to an RGBA16F texture. SSAO and SSR shaders now read pre-linearized depth directly, removing the dependency on rpProjectionMatrix vertex params and simplifying the depth reconstruction to a single texture fetch. The projection matrix diagonal is passed via rpUser2 for view-space position reconstruction. https://claude.ai/code/session_01VdSEPfFdPX7fLLYN6x2ZfQ
The linearizeDepth shader used -d/(c+ndcZ) which produces negative linear depth values. The correct formula is d/(c+ndcZ) which gives positive depth matching the inkEffect shader's proven approach. Negative depths caused SSAO to reconstruct wrong view positions and normals (dark gradient bands), and SSR to fail entirely (rays going behind the camera). Also fix SSR binary search refinement where refT was computed as (t - stepSize*0.5) + stepSize*0.5 = t (no-op), so the expected ray depth never updated during refinement iterations. https://claude.ai/code/session_01VdSEPfFdPX7fLLYN6x2ZfQ
This reverts commit 3db5a7d.
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Comprehensive analysis of the engine's rendering pipeline, shaders, and framebuffer infrastructure to determine if a slim G-buffer can be added without overhauling the renderer design. Conclusion: feasible via extending the existing depth pre-pass with MRT normal output.
https://claude.ai/code/session_01VdSEPfFdPX7fLLYN6x2ZfQ