wehub-resource-sync
70 lines
1.6 KiB
HLSL
70 lines
1.6 KiB
HLSL
#include "shared/pbr.hlsl"
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struct FaceProperties {
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float normalizedFaceArea;
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float cdf;
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};
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cbuffer EmitParameter : register(b0)
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{
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float UseVertexSelection;
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};
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StructuredBuffer<PbrVertex> Vertices : t0;
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StructuredBuffer<int3> FaceIndices : t1;
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RWStructuredBuffer<FaceProperties> FaceData : u0;
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[numthreads(1,1,1)]
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void main(uint3 i : SV_DispatchThreadID)
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{
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uint faceCount, stride;
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FaceData.GetDimensions(faceCount, stride);
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if (i.x >= (uint)faceCount)
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return;
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float sum;
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for (int j = 0; j < faceCount; j++)
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{
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uint3 f = FaceIndices[j];
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float3 p0 = Vertices[f[0]].Position;
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float3 p1 = Vertices[f[1]].Position;
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float3 p2 = Vertices[f[2]].Position;
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float3 baseDir = p1 - p0;
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float a = length(baseDir);
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baseDir = normalize(baseDir);
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float3 heightStart = p0 + dot(p2 - p0, baseDir) * baseDir;
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float b = length(p2 - heightStart);
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float faceArea = a * b * 0.5;
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faceArea = isnan(faceArea) ? 0 : faceArea;
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float selection = UseVertexSelection > 0.5
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? (Vertices[f[0]].Selected
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+ Vertices[f[1]].Selected
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+ Vertices[f[2]].Selected)
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: 1;
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FaceData[j].normalizedFaceArea = faceArea * selection;
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sum += faceArea;
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}
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sum = 0;
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for (int j = 0; j < faceCount; j++)
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{
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sum += FaceData[j].normalizedFaceArea;
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}
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sum = 1.0/sum;
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float cdf = 0;
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for (int j = 0; j < faceCount; j++)
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{
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cdf += FaceData[j].normalizedFaceArea * sum;
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FaceData[j].cdf = cdf;
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}
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}
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