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Diffstat (limited to 'src/shader/code/extra.glsl')
-rw-r--r-- | src/shader/code/extra.glsl | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/src/shader/code/extra.glsl b/src/shader/code/extra.glsl new file mode 100644 index 0000000..5ba6207 --- /dev/null +++ b/src/shader/code/extra.glsl @@ -0,0 +1,53 @@ +static const std::string EXTRA_SHADER_CODE = R"( +#version 430 + +layout (local_size_x = 1, local_size_y = 1) in; + +layout (std430, binding=3) buffer bufferFluid { float fluidCells[]; }; +layout (std430, binding=4) buffer bufferExtra { float extraCells[]; }; + +uniform uint nX; +uniform uint nY; + +const float convLength = 1.0 / float(max(nX,nY)); + +/// Array indexing + +uint indexOfDirection(int i, int j) { + return 3*(i+1) + (j+1); +} + +uint indexOfFluidVertex(uint x, uint y) { + return 3*nX*y + 3*x; +} + +/// Data access + +vec2 getFluidVelocity(uint x, uint y) { + const uint idx = indexOfFluidVertex(x, y); + return vec2( + fluidCells[idx + 0], + fluidCells[idx + 1] + ); +} + +void setFluidExtra(uint x, uint y, float curl) { + const uint idx = indexOfFluidVertex(x, y); + extraCells[idx + 0] = curl; +} + +void main() { + const uint x = gl_GlobalInvocationID.x; + const uint y = gl_GlobalInvocationID.y; + + if ( !(x < nX && y < nY) ) { + return; + } + + // simple central difference discretization of the 2d curl operator + const float dxvy = (getFluidVelocity(x+1,y).y - getFluidVelocity(x-1,y).y) / (2*convLength); + const float dyvx = (getFluidVelocity(x,y+1).x - getFluidVelocity(x,y-1).x) / (2*convLength); + + setFluidExtra(x, y, dxvy - dyvx); +} +)"; |