1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
//
// libavg - Media Playback Engine.
// Copyright (C) 2003-2011 Ulrich von Zadow
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Current versions can be found at www.libavg.de
//
void unPreMultiplyAlpha(inout vec4 color)
{
if (color.a > 0.0) {
color.rgb /= color.a;
}
}
void preMultiplyAlpha(inout vec4 color)
{
color.rgb *= color.a;
}
void rgb2hsl(vec4 rgba, out float h, out float s, out float l)
{
float maxComp = max(rgba.r, max(rgba.g, rgba.b));
float minComp = min(rgba.r, min(rgba.g, rgba.b));
l = (maxComp+minComp)/2.0;
if (maxComp == minComp) {
s = 0.0;
h = 0.0;
} else {
float delta = maxComp-minComp;
if (l < 0.5) {
s = delta/(maxComp+minComp);
} else {
s = delta/(2.0-(maxComp+minComp));
}
if (rgba.r == maxComp) {
h = (rgba.g-rgba.b)/delta;
if (h < 0.0) {
h += 6.0;
}
} else if (rgba.g == maxComp) {
h = 2.0+(rgba.b-rgba.r)/delta;
} else {
h = 4.0+(rgba.r-rgba.g)/delta;
}
h *= 60.0;
}
}
vec3 hsl2rgb(float h, float s, float l)
{
vec3 rgb = vec3(0.0, 0.0, 0.0);
float v;
if (l <= 0.5) {
v = l*(1.0+s);
} else {
v = l+s-l*s;
}
if (v > 0.0) {
float m = 2.0*l-v;
float sv = (v-m)/v;
h /= 60.0;
int sextant = int(h);
float fract = h-float(sextant);
float vsf = v * sv * fract;
float mid1 = m + vsf;
float mid2 = v - vsf;
if (sextant == 0) {
rgb.r = v;
rgb.g = mid1;
rgb.b = m;
} else if (sextant == 1) {
rgb.r = mid2;
rgb.g = v;
rgb.b = m;
} else if (sextant == 2) {
rgb.r = m;
rgb.g = v;
rgb.b = mid1;
} else if (sextant == 3) {
rgb.r = m;
rgb.g = mid2;
rgb.b = v;
} else if (sextant == 4) {
rgb.r = mid1;
rgb.g = m;
rgb.b = v;
} else if (sextant == 5) {
rgb.r = v;
rgb.g = m;
rgb.b = mid2;
}
}
return rgb;
}
|
