#version 440 core
layout(std430) uniform;

layout(set=0, binding=0) uniform usampler2D uInput;
layout(set=0, rgba8ui, binding=1) writeonly uniform uimage3D uOutput;

layout(set=0, binding=2) readonly uniform constBuffer {
    ivec2 pad;
    ivec2 kernelSize;
    ivec2 stride;
    ivec2 dilate;
    ivec4 inputSize;
    ivec4 outputSize;
    uint inputZero;
} uConstant;

layout (local_size_x = 16, local_size_y = 16, local_size_z = 1) in;
#define UP_DIV(x, y) (((x)+(y)-1)/(y))

void main()
{
    ivec3 pos = ivec3(gl_GlobalInvocationID);
    ivec3 outputSize = uConstant.outputSize.xyz;
    int oz = pos.z % uConstant.outputSize.z;
    int ob = pos.z / uConstant.outputSize.z;

    if (all(lessThan(pos.xy, outputSize.xy)))
    {
        int sourceXIndex = pos.x + pos.y*uConstant.outputSize.x + ob*uConstant.outputSize.x*uConstant.outputSize.y;
        int sourceX = sourceXIndex / 4;
        int sourceY = 4*oz + sourceXIndex % 4;

        uvec4 color = texelFetch(uInput, ivec2(sourceX, sourceY), 0);
        imageStore(uOutput, pos, color);
    }
}