#version 450 core
#define PRECISION ${PRECISION}
#define FORMAT ${FORMAT}

layout(std430) buffer;

/* Qualifiers: layout - storage - precision - memory */

layout(set = 0, binding = 0, FORMAT) uniform PRECISION restrict writeonly image3D uOutput;
layout(set = 0, binding = 1) uniform PRECISION sampler3D uInput;
layout(set = 0, binding = 2) uniform PRECISION restrict Block {
  // depth_info.x: output texture x extent
  // depth_info.y: output texture y extent
  // depth_info.z: output texture z extent
  // depth_info.w: output texture w extent
  ivec4 depth_info;
}
uBlock;

layout(local_size_x_id = 0, local_size_y_id = 1, local_size_z_id = 2) in;

void main() {
  const ivec3 pos = ivec3(gl_GlobalInvocationID);

  if (all(lessThan(pos, uBlock.depth_info.xyz))) {
    const int tex = uBlock.depth_info.w / 4;
    const int ind = uBlock.depth_info.w % 4;
    const float v = texelFetch(uInput, ivec3(pos.x, pos.y, tex), 0)[ind];

    imageStore(uOutput, ivec3(pos.x, pos.y, 0), vec4(v, 0, 0, 0));
  }
}