Simple GL compute shader

gistfile1.txt

#version 430 core

layout(local_size_x=8, local_size_y=8) in;
layout(binding=0) uniform writeonly uimage2D o_img;

layout(location=0) uniform uvec4 i_col;

void main()
{
    ivec2 pos = ivec2(gl_GlobalInvocationID.xy);
    ivec2 rpos = pos.xy + ivec2(i_col.xy);
    imageStore(o_img, pos, uvec4((rpos.x ^ rpos.y) & 255, 0, 0, 0));
}