So many changes again

res/shaders/fluid/AddSource.slang

@@ -0,0 +1,35 @@
+import FluidGridData;
+
+struct Params
+{
+    // read-write: phi to add source to
+    FluidGridData<float> phi;
+    FluidGridData<float> density;
+};
+ParameterBlock<Params> params;
+
+[shader("compute")]
+[numthreads(32, 8, 1)]
+void addSource(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    FluidGridData<float> phi = params.phi;
+    FluidGridData<float> density = params.density;
+    int x = dispatchThreadID.x + 1;
+    int y = dispatchThreadID.y + 1;
+    int z = dispatchThreadID.z + 1;
+    if(x >= gridParams.gridSize.x - 1 || y >= gridParams.gridSize.y - 1 || z >= gridParams.gridSize.z - 1) return;
+
+    // Add a spherical source and union it into the existing level set.
+    float3 center = float3(gridParams.gridSize) * 0.5f;
+    float radius = min(gridParams.gridSize.x, min(gridParams.gridSize.y, gridParams.gridSize.z)) * 0.25f;
+    float3 pos = float3(x, y, z);
+    float dist = length(pos - center);
+    float sourcePhi = dist - radius;
+    phi[x, y, z] = min(phi[x, y, z], sourcePhi);
+
+    if (sourcePhi < 0.0f)
+    {
+        density[x, y, z] += 0.5f;
+        density[x, y, z] = min(density[x, y, z], 1.0f);
+    }
+}