Shadery04_HueShift01

half3 HueShift01(half3 c, half shift)
{
    half3 result = c;
    half u = cos(shift*3.14/180);
    half w = sin(shift*3.14/180);
    result.r =  (0.29 + 0.701*u + 0.168*w)*c.r +
                (0.587 - 0.587*u + 0.330*w)*c.g +
                (0.114 - 0.114*u - 0.497*w)*c.b;
    result.g =  (0.299 - 0.299*u - 0.328*w)*c.r +
                (0.587 + 0.413*u + 0.035*w)*c.g +
                (0.114 - 0.114*u + 0.292*w)*c.b;
    result.b =  (0.299 - 0.3*u + 1.25*w)*c.r +
                (0.587 - 0.588*u - 1.05*w)*c.g +
                (0.114 + 0.886*u - 0.203*w)*c.b;
    return result;
}