atdunbg
f73e52926f
- App/editor: move 7 panels into panels/ (Editor core stays at root) - shaders/: group into pbr/ post/ debug/ env/ (runtime load paths updated) - Delete outdated duplicate Engine/src/Renderer/VulkanAssetUploader.h
55 lines
1.9 KiB
Plaintext
55 lines
1.9 KiB
Plaintext
#version 450
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// IBL ④：BRDF 积分 LUT（2D，纯数学，与环境内容无关）。
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// (NdotV, roughness) → (F 缩放 A, F 偏置 B)：specular = prefiltered·(F·A + B)。
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// 与环境切换无关，但随生成链一起跑（GPU 亚毫秒级），省去跨环境缓存。
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#include "ibl_common.glsl"
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layout(local_size_x = 8, local_size_y = 8) in;
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layout(set = 0, binding = 0, rg16f) uniform restrict writeonly image2D outLut;
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const uint SAMPLES = 128;
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void main()
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{
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ivec2 gid = ivec2(gl_GlobalInvocationID);
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if (gid.x >= imageSize(outLut).x || gid.y >= imageSize(outLut).y) return;
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vec2 uv = (vec2(gid) + 0.5) / vec2(imageSize(outLut));
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float nDotV = uv.x;
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float roughness = uv.y;
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// V 在以 N 为 +Z 的切线空间里（积分只依赖这两角度）
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vec3 V = vec3(sqrt(1.0 - nDotV * nDotV), 0.0, nDotV);
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vec3 Nz = vec3(0.0, 0.0, 1.0);
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float a = 0.0, b = 0.0;
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float k = roughness * roughness * 0.5; // IBL 版 Smith k
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for (uint i = 0u; i < SAMPLES; ++i) {
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vec3 H = iblImportanceSampleGGX(iblHammersley(i, SAMPLES), Nz, roughness);
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vec3 L = normalize(2.0 * dot(V, H) * H - V);
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float lDotN = L.z;
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float nDotL = max(lDotN, 0.0);
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float nDotH = max(H.z, 0.0);
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float vDotH = max(dot(V, H), 0.0);
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if (nDotL <= 0.0) continue;
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float g = (nDotV / (nDotV * (1.0 - k) + k)) *
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(nDotL / (nDotL * (1.0 - k) + k));
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// 高 roughness 时部分样本 H.z 恰为 0（g 也为 0），0/0 = NaN
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// 会累进 LUT——分母钳 epsilon（与 CPU 版一致）
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float gVis = g * vDotH / max(nDotH * nDotV, 1e-6);
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float fc = 1.0 - vDotH;
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float f = fc * fc * fc * fc * fc; // (1-vDotH)⁵
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a += (1.0 - f) * gVis;
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b += f * gVis;
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}
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imageStore(outLut, gid, vec4(a / float(SAMPLES), b / float(SAMPLES), 0.0, 1.0));
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}
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