#version 450

layout(location=0) in vec2 frag_texcoord;
layout(location=0) out vec4 out_color;

layout(set = 3, binding = 0) uniform PushConstants {
    vec4 lightcol;
    vec4 darkcol;
    vec2 fragSize;
    float gridsize;
} pc;

void main() {
    vec2 pos = frag_texcoord * pc.fragSize;
    float total = floor(pos.x / pc.gridsize) + floor(pos.y / pc.gridsize);
    bool isEven = mod(total, 2.0) == 0.0;
    out_color = (isEven)? pc.lightcol : pc.darkcol;
}