uniform shader child;

half4 main(float2 xy) {
    half4 color = child.eval(xy);
    color.rgb = toLinearSrgb(color.rgb);

    // Alter the color so that the back-and-forth conversions are meaningful.
    color.br = color.rb * 0.75;

    return half4(fromLinearSrgb(color.rgb), color.a);
}