resources/sksl/compute/DesaturateReadWrite.compute

layout(local_size_x = 16, local_size_y = 16) in;

layout(binding=0, rgba32f) readonly texture2D texIn;
layout(binding=1, rgba32f) writeonly texture2D texOut;

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 < textureWidth(texIn) &&
        sk_GlobalInvocationID.y < textureHeight(texIn)) {
        half4 gray = desaturate(textureRead(texIn, sk_GlobalInvocationID.xy));
        textureWrite(texOut, sk_GlobalInvocationID.xy, gray);
    }
}