resources/sksl/compute/Desaturate.compute

layout(binding=0) readonly texture2D src;
layout(binding=1) writeonly texture2D dest;

half4 desaturate(half4 color) {
    color.rgb = half3(dot(color.rgb, half3(0.22, 0.67, 0.11)));
    return color;
}

void main() {
    if (sk_GlobalInvocationID.x < width(src) && sk_GlobalInvocationID.y < height(src)) {
        write(dest, sk_GlobalInvocationID.xy, desaturate(read(src, sk_GlobalInvocationID.xy)));
    }
}