1  #version 450 core
 2  
 3  #extension GL_ARB_shader_stencil_export : require
 4  
 5  layout (std140, binding = 0) uniform sample_counts_log2_in
 6  {
 7      ivec4 sample_counts_log2;
 8  };
 9  
10  layout (set = 2, binding = 0) uniform isampler2DMS srcMS;
11  
12  void main()
13  {
14      uvec2 coords = uvec2(gl_FragCoord.xy);
15  
16      int deltaX = sample_counts_log2.x - sample_counts_log2.z;
17      int deltaY = sample_counts_log2.y - sample_counts_log2.w;
18      int samplesInXLog2 = sample_counts_log2.z;
19      int samplesInYLog2 = sample_counts_log2.w;
20      int samplesInX = 1 << samplesInXLog2;
21      int samplesInY = 1 << samplesInYLog2;
22      int sampleIdx = ((int(coords.x) >> deltaX) & (samplesInX - 1)) | (((int(coords.y) >> deltaY) & (samplesInY - 1)) << samplesInXLog2);
23  
24      samplesInXLog2 = sample_counts_log2.x;
25      samplesInYLog2 = sample_counts_log2.y;
26  
27      ivec2 shiftedCoords = ivec2(int(coords.x) >> samplesInXLog2, int(coords.y) >> samplesInYLog2);
28  
29      gl_FragStencilRefARB = texelFetch(srcMS, shiftedCoords, sampleIdx).r;
30  }