/// @ref gtx_color_space
/// @file glm/gtx/color_space.inl
namespace glm
{
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<3, T, Q> rgbColor(const vec<3, T, Q>& hsvColor)
{
vec<3, T, Q> hsv = hsvColor;
vec<3, T, Q> rgbColor;
if(hsv.y == static_cast<T>(0))
// achromatic (grey)
rgbColor = vec<3, T, Q>(hsv.z);
else
{
T sector = floor(hsv.x * (T(1) / T(60)));
T frac = (hsv.x * (T(1) / T(60))) - sector;
// factorial part of h
T o = hsv.z * (T(1) - hsv.y);
T p = hsv.z * (T(1) - hsv.y * frac);
T q = hsv.z * (T(1) - hsv.y * (T(1) - frac));
switch(int(sector))
{
default:
case 0:
rgbColor.r = hsv.z;
rgbColor.g = q;
rgbColor.b = o;
break;
case 1:
rgbColor.r = p;
rgbColor.g = hsv.z;
rgbColor.b = o;
break;
case 2:
rgbColor.r = o;
rgbColor.g = hsv.z;
rgbColor.b = q;
break;
case 3:
rgbColor.r = o;
rgbColor.g = p;
rgbColor.b = hsv.z;
break;
case 4:
rgbColor.r = q;
rgbColor.g = o;
rgbColor.b = hsv.z;
break;
case 5:
rgbColor.r = hsv.z;
rgbColor.g = o;
rgbColor.b = p;
break;
}
}
return rgbColor;
}
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<3, T, Q> hsvColor(const vec<3, T, Q>& rgbColor)
{
vec<3, T, Q> hsv = rgbColor;
float Min = min(min(rgbColor.r, rgbColor.g), rgbColor.b);
float Max = max(max(rgbColor.r, rgbColor.g), rgbColor.b);
float Delta = Max - Min;
hsv.z = Max;
if(Max != static_cast<T>(0))
{
hsv.y = Delta / hsv.z;
T h = static_cast<T>(0);
if(rgbColor.r == Max)
// between yellow & magenta
h = static_cast<T>(0) + T(60) * (rgbColor.g - rgbColor.b) / Delta;
else if(rgbColor.g == Max)
// between cyan & yellow
h = static_cast<T>(120) + T(60) * (rgbColor.b - rgbColor.r) / Delta;
else
// between magenta & cyan
h = static_cast<T>(240) + T(60) * (rgbColor.r - rgbColor.g) / Delta;
if(h < T(0))
hsv.x = h + T(360);
else
hsv.x = h;
}
else
{
// If r = g = b = 0 then s = 0, h is undefined
hsv.y = static_cast<T>(0);
hsv.x = static_cast<T>(0);
}
return hsv;
}
template<typename T>
GLM_FUNC_QUALIFIER mat<4, 4, T, defaultp> saturation(T const s)
{
vec<3, T, defaultp> rgbw = vec<3, T, defaultp>(T(0.2126), T(0.7152), T(0.0722));
vec<3, T, defaultp> const col((T(1) - s) * rgbw);
mat<4, 4, T, defaultp> result(T(1));
result[0][0] = col.x + s;
result[0][1] = col.x;
result[0][2] = col.x;
result[1][0] = col.y;
result[1][1] = col.y + s;
result[1][2] = col.y;
result[2][0] = col.z;
result[2][1] = col.z;
result[2][2] = col.z + s;
return result;
}
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<3, T, Q> saturation(const T s, const vec<3, T, Q>& color)
{
return vec<3, T, Q>(saturation(s) * vec<4, T, Q>(color, T(0)));
}
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<4, T, Q> saturation(const T s, const vec<4, T, Q>& color)
{
return saturation(s) * color;
}
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER T luminosity(const vec<3, T, Q>& color)
{
const vec<3, T, Q> tmp = vec<3, T, Q>(0.33, 0.59, 0.11);
return dot(color, tmp);
}
}//namespace glm
