1  #version 450 core
 2  
 3  layout (std140, binding = 0) uniform sample_counts_log2_in
 4  {
 5      ivec4 sample_counts_log2;
 6  };
 7  
 8  layout (set = 2, binding = 0) uniform usampler2DMS srcMS;
 9  layout (set = 3, binding = 0) writeonly uniform uimage2D dst;
10  
11  layout (local_size_x = 32, local_size_y = 32, local_size_z = 1) in;
12  
13  void main()
14  {
15      uvec2 coords = gl_GlobalInvocationID.xy;
16      ivec2 imageSz = imageSize(dst);
17  
18      if (int(coords.x) >= imageSz.x || int(coords.y) >= imageSz.y)
19      {
20          return;
21      }
22  
23      int deltaX = sample_counts_log2.x - sample_counts_log2.z;
24      int deltaY = sample_counts_log2.y - sample_counts_log2.w;
25      int samplesInXLog2 = sample_counts_log2.z;
26      int samplesInYLog2 = sample_counts_log2.w;
27      int samplesInX = 1 << samplesInXLog2;
28      int samplesInY = 1 << samplesInYLog2;
29      int sampleIdx = ((int(coords.x) >> deltaX) & (samplesInX - 1)) | (((int(coords.y) >> deltaY) & (samplesInY - 1)) << samplesInXLog2);
30  
31      samplesInXLog2 = sample_counts_log2.x;
32      samplesInYLog2 = sample_counts_log2.y;
33  
34      ivec2 shiftedCoords = ivec2(int(coords.x) >> samplesInXLog2, int(coords.y) >> samplesInYLog2);
35  
36      imageStore(dst, ivec2(coords), texelFetch(srcMS, shiftedCoords, sampleIdx));
37  }