55 lines
1.8 KiB
Plaintext
55 lines
1.8 KiB
Plaintext
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import FluidGridData;
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struct Params
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{
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// read-write
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FluidGridData<float> density;
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// read-only
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FluidGridData<float> density0;
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// read-only
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FluidGridData<float> velocityX;
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// read-only
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FluidGridData<float> velocityY;
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// read-only
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FluidGridData<float> velocityZ;
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float dt;
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};
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ParameterBlock<Params> params;
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[shader("compute")]
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[numthreads(32, 8, 1)]
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void advect(uint3 dispatchThreadID : SV_DispatchThreadID)
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{
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FluidGridData<float> density = params.density;
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FluidGridData<float> density0 = params.density0;
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FluidGridData<float> velocityX = params.velocityX;
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FluidGridData<float> velocityY = params.velocityY;
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FluidGridData<float> velocityZ = params.velocityZ;
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float dt = params.dt;
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int x = dispatchThreadID.x + 1;
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int y = dispatchThreadID.y + 1;
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int z = dispatchThreadID.z + 1;
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if(x >= gridSize.x - 1 || y >= gridSize.y - 1 || z >= gridSize.z - 1) return;
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float dt0x = dt * (gridSize.x - 2);
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float dt0y = dt * (gridSize.y - 2);
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float dt0z = dt * (gridSize.z - 2);
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float3 pos = float3(x - dt0x * velocityX[x, y, z], y - dt0y * velocityY[x, y, z], z - dt0z * velocityZ[x, y, z]);
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pos.x = clamp(pos.x, 0.5f, gridSize.x - 1.5f);
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pos.y = clamp(pos.y, 0.5f, gridSize.y - 1.5f);
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pos.z = clamp(pos.z, 0.5f, gridSize.z - 1.5f);
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int3 i0 = int3(pos);
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int3 i1 = i0 + int3(1, 1, 1);
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float3 s1 = pos - i0;
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float3 s0 = 1 - s1;
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density[x, y, z] =
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s0.x * (s0.y * (s0.z * density0[i0.x, i0.y, i0.z] + s1.z * density0[i0.x, i0.y, i1.z]) +
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s1.y * (s0.z * density0[i0.x, i1.y, i0.z] + s1.z * density0[i0.x, i1.y, i1.z])) +
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s1.x * (s0.y * (s0.z * density0[i1.x, i0.y, i0.z] + s1.z * density0[i1.x, i0.y, i1.z]) +
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s1.y * (s0.z * density0[i1.x, i1.y, i0.z] + s1.z * density0[i1.x, i1.y, i1.z]));
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}
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