Initial commit

res/shaders/Divergence.slang

@@ -0,0 +1,35 @@
+import FluidGridData;
+
+struct Params
+{
+    // read-only
+    FluidGridData<float> velocityX;
+    // read-only
+    FluidGridData<float> velocityY;
+    // read-only
+    FluidGridData<float> velocityZ;
+    // read-write
+    FluidGridData<float> divergence;
+    // read-write
+    FluidGridData<float> pressure;
+};
+ParameterBlock<Params> params;
+
+[shader("compute")]
+[numthreads(32, 8, 1)]
+void computeDivergence(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    FluidGridData<float> velocityX = params.velocityX;
+    FluidGridData<float> velocityY = params.velocityY;
+    FluidGridData<float> velocityZ = params.velocityZ;
+    FluidGridData<float> divergence = params.divergence;
+    FluidGridData<float> pressure = params.pressure;
+
+    int x = dispatchThreadID.x + 1;
+    int y = dispatchThreadID.y + 1;
+    int z = dispatchThreadID.z + 1;
+    if(x >= gridSize.x - 1 || y >= gridSize.y - 1 || z >= gridSize.z - 1) return;
+
+    divergence[x, y, z] = -0.5f * (velocityX[x + 1, y, z] - velocityX[x - 1, y, z] + velocityY[x, y + 1, z] - velocityY[x, y - 1, z] + velocityZ[x, y, z + 1] - velocityZ[x, y, z - 1]) / gridSize.x;
+    pressure[x, y, z] = 0;
+}