half4 main(half4 hsl) {
    // HSL-to-RGB conversion algorithm lifted from sksl_shared $hsl_to_rgb.
    half      C = (1 - abs(2 * hsl.z - 1)) * hsl.y;
    half3     p = hsl.xxx + half3(0, 2/3.0, 1/3.0);
    half3     q = saturate(abs(fract(p) * 6 - 3) - 1);

    return half4((q - 0.5) * C + hsl.z, 1);
}