GLSL utility for checkered patterns.
uniform vec2 iResolution;
#pragma glslify: checker = require('glsl-checker')
void main() {
vec2 uv = vec2(gl_FragCoord.xy / iResolution.xy);
//optionally fix aspect ratio
uv.x *= iResolution.x / iResolution.y;
//18x18 checkered background
float gray = mix(0.8, 1.0, checker(uv, 18.0));
gl_FragColor.rgb = vec3(gray);
gl_FragColor.a = 1.0;
}
Creates a checkered n x n pattern with the given UV coordinates, returning a float 0.0 or 1.0.
MIT, see LICENSE.md for details.