cocos2d::Color4F HelloWorld::RGB2HSL(cocos2d::Color4F c)
{
    float h, s, l;
    Color4F color;

    color.r = c.r;
    color.g = c.g;
    color.b = c.b;

    float cmax = fmax(fmax(color.r, color.g), color.b);
    float cmin = fmin(fmin(color.r, color.g), color.b);
    float delta = cmax - cmin;

    // Hue
    if (delta == 0)
        h = 0;
    else if (cmax == color.r)
        h = 60 * fmod((color.g - color.b) / delta, 6);
    else if (cmax == color.g)
        h = 60 * (((color.b - color.r) / delta) + 2);
    else if (cmax == color.b)
        h = 60 * (((color.r - color.g) / delta) + 4);

    // Lightness
    l = (cmax + cmin) / 2;

    // Saturation
    if (delta == 0)
        s = 0;
    else
        s = 1 - fabs(2 * l - 1);


    return Color4F(h, s, l, 0);
}

cocos2d::Color4F HelloWorld::HSL2RGB(cocos2d::Color4F color)
{
    float h, s, l;
    float c, x, m;
    float r, g, b;

    h = clampf(color.r, 0, 360);
    s = clampf(color.g, 0, 1);
    l = clampf(color.b, 0, 1);

    c = (1 - (fabs(2 * l) - 1)) * s;
    x = c * (1 - fabs(fmod(h / 60, 2) - 1));
    m = l - (c / 2);

    if (h >= 0 && h < 60)
    {
        r = c;
        g = x;
        b = 0;
    }
    else if (h >= 60 && h < 120)
    {
        r = x;
        g = c;
        b = 0;
    }
    else if (h >= 120 && h < 180)
    {
        r = 0;
        g = c;
        b = x;
    }
    else if (h >= 180 && h < 240)
    {
        r = 0;
        g = x;
        b = c;
    }
    else if (h >= 240 && h < 300)
    {
        r = x;
        g = 0;
        b = c;
    }
    else if (h >= 60 && h < 120)
    {
        r = c;
        g = 0;
        b = x;
    }

    r = (r + m);
    g = (g + m);
    b = (b + m);

    return Color4F(r, g, b, 1);
}