uniform vec2 PREFIX(num_repeats); vec4 FUNCNAME(vec2 tc) { vec4 pixel = INPUT1(tc); vec2 pattern = INPUT2(tc * PREFIX(num_repeats)).xy; // Complex multiplication between each of (pixel.xy, pixel.zw) and pattern.xy. return pattern.x * pixel + pattern.y * vec4(-pixel.y, pixel.x, -pixel.w, pixel.z); }