import FluidGridData;

struct Params
{
    // read-write
    FluidGridData<float> next;
    // read-only
    FluidGridData<float> current;
    // read-only
    FluidGridData<float> grid0;
    float a;
    float c;
};
ParameterBlock<Params> params;

[shader("compute")]
[numthreads(32, 8, 1)]
void linearSolve(uint3 dispatchThreadID : SV_DispatchThreadID)
{
    FluidGridData<float> next = params.next;
    FluidGridData<float> current = params.current;
    FluidGridData<float> grid0 = params.grid0;
    float a = params.a;
    float cRecip = 1.0f / params.c;

    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;

    next[x, y, z] = (grid0[x, y, z] + a * (current[x + 1, y, z] + current[x - 1, y, z] + current[x, y + 1, z] + current[x, y - 1, z] + current[x, y, z + 1] + current[x, y, z - 1])) * cRecip;
}