#version 450

// iter4 fragment shader: sample 4x4 source texture via texelFetch
// (no filter, no addressing — direct integer-coord image read).
// Output is the texel at (col%4, row%4) where col,row are gl_FragCoord.

layout(set = 0, binding = 0) uniform sampler2D tex;
layout(location = 0) out vec4 outColor;

void main() {
    ivec2 src = ivec2(gl_FragCoord.xy) % 4;
    outColor = texelFetch(tex, src, 0);
}