/////////////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
/// Copyright (c) 2005 - 2015 G-Truc Creation (www.g-truc.net)
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
/// 
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
/// 
/// Restrictions:
///             By making use of the Software for military purposes, you choose to make
///             a Bunny unhappy.
/// 
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.
///
/// @ref gtx_color_space
/// @file glm/gtx/color_space.inl
/// @date 2005-12-21 / 2011-06-07
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////////////////////

namespace glm
{
        template <typename T, precision P>
        GLM_FUNC_QUALIFIER tvec3<T, P> rgbColor(const tvec3<T, P>& hsvColor)
        {
                tvec3<T, P> hsv = hsvColor;
                tvec3<T, P> rgbColor;

                if(hsv.y == static_cast<T>(0))
                        // achromatic (grey)
                        rgbColor = tvec3<T, P>(hsv.z);
                else
                {
                        T sector = floor(hsv.x / T(60));
                        T frac = (hsv.x / 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, precision P>
        GLM_FUNC_QUALIFIER tvec3<T, P> hsvColor(const tvec3<T, P>& rgbColor)
        {
                tvec3<T, P> 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 tmat4x4<T, defaultp> saturation(T const s)
        {
                tvec3<T, defaultp> rgbw = tvec3<T, defaultp>(T(0.2126), T(0.7152), T(0.0722));

                T col0 = (T(1) - s) * rgbw.r;
                T col1 = (T(1) - s) * rgbw.g;
                T col2 = (T(1) - s) * rgbw.b;

                tmat4x4<T, defaultp> result(T(1));
                result[0][0] = col0 + s;
                result[0][1] = col0;
                result[0][2] = col0;
                result[1][0] = col1;
                result[1][1] = col1 + s;
                result[1][2] = col1;
                result[2][0] = col2;
                result[2][1] = col2;
                result[2][2] = col2 + s;
                return result;
        }

        template <typename T, precision P>
        GLM_FUNC_QUALIFIER tvec3<T, P> saturation(const T s, const tvec3<T, P>& color)
        {
                return tvec3<T, P>(saturation(s) * tvec4<T, P>(color, T(0)));
        }

        template <typename T, precision P>
        GLM_FUNC_QUALIFIER tvec4<T, P> saturation(const T s, const tvec4<T, P>& color)
        {
                return saturation(s) * color;
        }

        template <typename T, precision P> 
        GLM_FUNC_QUALIFIER T luminosity(const tvec3<T, P>& color)
        {
                const tvec3<T, P> tmp = tvec3<T, P>(0.33, 0.59, 0.11);
                return dot(color, tmp);
        }
}//namespace glm