1///////////////////////////////////////////////////////////////////////////////////////////////////
2// OpenGL Mathematics Copyright (c) 2005 - 2014 G-Truc Creation (www.g-truc.net)
3///////////////////////////////////////////////////////////////////////////////////////////////////
4// Created : 2005-12-21
5// Updated : 2007-02-22
6// Licence : This source is under MIT License
7// File    : glm/gtx/color_space.inl
8///////////////////////////////////////////////////////////////////////////////////////////////////
9
10namespace glm
11{
12	template <typename T, precision P>
13	GLM_FUNC_QUALIFIER detail::tvec3<T, P> rgbColor(const detail::tvec3<T, P>& hsvColor)
14	{
15		detail::tvec3<T, P> hsv = hsvColor;
16		detail::tvec3<T, P> rgbColor;
17
18		if(hsv.y == static_cast<T>(0))
19			// achromatic (grey)
20			rgbColor = detail::tvec3<T, P>(hsv.z);
21		else
22		{
23			T sector = floor(hsv.x / T(60));
24			T frac = (hsv.x / T(60)) - sector;
25			// factorial part of h
26			T o = hsv.z * (T(1) - hsv.y);
27			T p = hsv.z * (T(1) - hsv.y * frac);
28			T q = hsv.z * (T(1) - hsv.y * (T(1) - frac));
29
30			switch(int(sector))
31			{
32			default:
33			case 0:
34				rgbColor.r = hsv.z;
35				rgbColor.g = q;
36				rgbColor.b = o;
37				break;
38			case 1:
39				rgbColor.r = p;
40				rgbColor.g = hsv.z;
41				rgbColor.b = o;
42				break;
43			case 2:
44				rgbColor.r = o;
45				rgbColor.g = hsv.z;
46				rgbColor.b = q;
47				break;
48			case 3:
49				rgbColor.r = o;
50				rgbColor.g = p;
51				rgbColor.b = hsv.z;
52				break;
53			case 4:
54				rgbColor.r = q;
55				rgbColor.g = o;
56				rgbColor.b = hsv.z;
57				break;
58			case 5:
59				rgbColor.r = hsv.z;
60				rgbColor.g = o;
61				rgbColor.b = p;
62				break;
63			}
64		}
65
66		return rgbColor;
67	}
68
69	template <typename T, precision P>
70	GLM_FUNC_QUALIFIER detail::tvec3<T, P> hsvColor(const detail::tvec3<T, P>& rgbColor)
71	{
72		detail::tvec3<T, P> hsv = rgbColor;
73		float Min   = min(min(rgbColor.r, rgbColor.g), rgbColor.b);
74		float Max   = max(max(rgbColor.r, rgbColor.g), rgbColor.b);
75		float Delta = Max - Min;
76
77		hsv.z = Max;
78
79		if(Max != static_cast<T>(0))
80		{
81			hsv.y = Delta / hsv.z;
82			T h = static_cast<T>(0);
83
84			if(rgbColor.r == Max)
85				// between yellow & magenta
86				h = static_cast<T>(0) + T(60) * (rgbColor.g - rgbColor.b) / Delta;
87			else if(rgbColor.g == Max)
88				// between cyan & yellow
89				h = static_cast<T>(120) + T(60) * (rgbColor.b - rgbColor.r) / Delta;
90			else
91				// between magenta & cyan
92				h = static_cast<T>(240) + T(60) * (rgbColor.r - rgbColor.g) / Delta;
93
94			if(h < T(0))
95				hsv.x = h + T(360);
96			else
97				hsv.x = h;
98		}
99		else
100		{
101			// If r = g = b = 0 then s = 0, h is undefined
102			hsv.y = static_cast<T>(0);
103			hsv.x = static_cast<T>(0);
104		}
105
106		return hsv;
107	}
108
109	template <typename T, precision P>
110	GLM_FUNC_QUALIFIER detail::tmat4x4<T, P> saturation(const T s)
111	{
112		detail::tvec3<T, P> rgbw = detail::tvec3<T, P>(T(0.2126), T(0.7152), T(0.0722));
113
114		T col0 = (T(1) - s) * rgbw.r;
115		T col1 = (T(1) - s) * rgbw.g;
116		T col2 = (T(1) - s) * rgbw.b;
117
118		detail::tmat4x4<T, P> result(T(1));
119		result[0][0] = col0 + s;
120		result[0][1] = col0;
121		result[0][2] = col0;
122		result[1][0] = col1;
123		result[1][1] = col1 + s;
124		result[1][2] = col1;
125		result[2][0] = col2;
126		result[2][1] = col2;
127		result[2][2] = col2 + s;
128		return result;
129	}
130
131	template <typename T, precision P>
132	GLM_FUNC_QUALIFIER detail::tvec3<T, P> saturation(const T s, const detail::tvec3<T, P>& color)
133	{
134		return detail::tvec3<T, P>(saturation(s) * detail::tvec4<T, P>(color, T(0)));
135	}
136
137	template <typename T, precision P>
138	GLM_FUNC_QUALIFIER detail::tvec4<T, P> saturation(const T s, const detail::tvec4<T, P>& color)
139	{
140		return saturation(s) * color;
141	}
142
143	template <typename T, precision P>
144	GLM_FUNC_QUALIFIER T luminosity(const detail::tvec3<T, P>& color)
145	{
146		const detail::tvec3<T, P> tmp = detail::tvec3<T, P>(0.33, 0.59, 0.11);
147		return dot(color, tmp);
148	}
149}//namespace glm
150