56 lines
1.5 KiB
Plaintext
56 lines
1.5 KiB
Plaintext
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Texture2D<float4> InputTex;
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RWTexture2D<float4> OutputTex;
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float dt;
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float diff;
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float2 texDim;
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// Gauss-Seidel vs Jacobi method:
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// https://www3.nd.edu/~zxu2/acms40390F12/Lec-7.3.pdf
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// other options: conjugate gradient, multigrid methods
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//jacobi
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//void jacobi(half2 coords : WPOS, // grid coordinates
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//
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// out
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// half4 xNew : COLOR, // result
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//
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// uniform
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// half alpha,
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// uniform
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// half rBeta, // reciprocal beta
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//
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// uniform samplerRECT x, // x vector (Ax = b)
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//
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// uniform samplerRECT b) // b vector (Ax = b)
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//{
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// // left, right, bottom, and top x samples
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//
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// half4 xL = h4texRECT(x, coords - half2(1, 0));
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// half4 xR = h4texRECT(x, coords + half2(1, 0));
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// half4 xB = h4texRECT(x, coords - half2(0, 1));
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// half4 xT = h4texRECT(x, coords + half2(0, 1));
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//
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// // b sample, from center
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//
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// half4 bC = h4texRECT(b, coords);
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//
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// // evaluate Jacobi iteration
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// xNew = (xL + xR + xB + xT + alpha * bC) * rBeta;
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//}
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// diffuse / blur
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// Gauss-Seidel relaxation
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#pragma kernel Diffuse
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[numthreads(8, 8, 1)]
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void Diffuse(uint3 id : SV_DispatchThreadID)
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{
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float4 hCenter = InputTex[id.xy];
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float4 hLeft = InputTex[uint2(id.x - 1, id.y)]; //TODO: bounds checking
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float4 hRight = InputTex[uint2(id.x + 1, id.y)];
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float4 hTop = InputTex[uint2(id.x, id.y + 1)];
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float4 hBottom = InputTex[uint2(id.x, id.y - 1)];
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float alpha = dt * diff * texDim[0] * texDim[1];
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OutputTex[id.xy] = (hCenter + alpha * (hLeft + hRight + hTop + hBottom)) / (1.0f + 4.0f * alpha);
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}
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