resources/sksl/compute/DesaturateReadWrite.compute

layout(binding=0) texture2D tex;

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(tex) && sk_GlobalInvocationID.y < height(tex)) {
        write(tex, sk_GlobalInvocationID.xy, desaturate(read(tex, sk_GlobalInvocationID.xy)));
    }
}