RGBtoHSL.dctl

// RGB to HSL

__DEVICE__ float3 transform(int p_Width, int p_Height, int p_X, int p_Y, float p_R, float p_G, float p_B)
{
    

    float Mx = _fmaxf(p_R, _fmaxf(p_G, p_B));			
    float mn = _fminf(p_R, _fminf(p_G, p_B));					
    float del_Mx = Mx - mn;
																
    float L = 0.5f * (Mx + mn);													
    	
    float S = L <= 0.5f ? del_Mx / (Mx + mn) : del_Mx / (2.0f - del_Mx);


    float del_R = ((Mx - p_R) / 6.0f + del_Mx / 2.0f) / del_Mx;
    float del_G = ((Mx - p_G) / 6.0f + del_Mx / 2.0f) / del_Mx;
    float del_B = ((Mx - p_B) / 6.0f + del_Mx / 2.0f) / del_Mx;
   
    float h = del_Mx == 0.0f ? 0.0f : p_R == Mx ? del_B - del_G : p_G == Mx ? 1.0f / 3.0f + del_R - del_B : 
    2.0f / 3.0f + del_G - del_R;

    float H = h < 0.0f ? h + 1.0f : h > 1.0f ? h - 1.0f : h;
    
    const float r = H;
    const float g = S;
    const float b = L;
    
    return make_float3(r, g, b);
}