source: trunk/src/opengl/gl2paintengineex/qglgradientcache.cpp@ 651

Last change on this file since 651 was 651, checked in by Dmitry A. Kuminov, 15 years ago

trunk: Merged in qt 4.6.2 sources.

File size: 7.3 KB
RevLine 
[2]1/****************************************************************************
2**
[651]3** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
[561]4** All rights reserved.
5** Contact: Nokia Corporation ([email protected])
[2]6**
7** This file is part of the QtOpenGL module of the Qt Toolkit.
8**
9** $QT_BEGIN_LICENSE:LGPL$
10** Commercial Usage
11** Licensees holding valid Qt Commercial licenses may use this file in
12** accordance with the Qt Commercial License Agreement provided with the
13** Software or, alternatively, in accordance with the terms contained in
14** a written agreement between you and Nokia.
15**
16** GNU Lesser General Public License Usage
17** Alternatively, this file may be used under the terms of the GNU Lesser
18** General Public License version 2.1 as published by the Free Software
19** Foundation and appearing in the file LICENSE.LGPL included in the
20** packaging of this file. Please review the following information to
21** ensure the GNU Lesser General Public License version 2.1 requirements
22** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
23**
[561]24** In addition, as a special exception, Nokia gives you certain additional
25** rights. These rights are described in the Nokia Qt LGPL Exception
26** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
[2]27**
28** GNU General Public License Usage
29** Alternatively, this file may be used under the terms of the GNU
30** General Public License version 3.0 as published by the Free Software
31** Foundation and appearing in the file LICENSE.GPL included in the
32** packaging of this file. Please review the following information to
33** ensure the GNU General Public License version 3.0 requirements will be
34** met: http://www.gnu.org/copyleft/gpl.html.
35**
[561]36** If you have questions regarding the use of this file, please contact
37** Nokia at [email protected].
[2]38** $QT_END_LICENSE$
39**
40****************************************************************************/
41
42#include <private/qdrawhelper_p.h>
43#include <private/qgl_p.h>
44
45#include "qglgradientcache_p.h"
46
[561]47QT_BEGIN_NAMESPACE
48
49static void QGL2GradientCache_free(void *ptr)
50{
51 delete reinterpret_cast<QGL2GradientCache *>(ptr);
52}
53
54Q_GLOBAL_STATIC_WITH_ARGS(QGLContextResource, qt_gradient_caches, (QGL2GradientCache_free))
55
56QGL2GradientCache *QGL2GradientCache::cacheForContext(const QGLContext *context)
57{
58 QGL2GradientCache *p = reinterpret_cast<QGL2GradientCache *>(qt_gradient_caches()->value(context));
59 if (!p) {
60 QGLShareContextScope scope(context);
61 p = new QGL2GradientCache;
62 qt_gradient_caches()->insert(context, p);
63 }
64 return p;
65}
66
67void QGL2GradientCache::cleanCache() {
[2]68 QGLGradientColorTableHash::const_iterator it = cache.constBegin();
69 for (; it != cache.constEnd(); ++it) {
70 const CacheInfo &cache_info = it.value();
71 glDeleteTextures(1, &cache_info.texId);
72 }
73 cache.clear();
74}
75
[561]76GLuint QGL2GradientCache::getBuffer(const QGradient &gradient, qreal opacity)
[2]77{
78 quint64 hash_val = 0;
79
80 QGradientStops stops = gradient.stops();
81 for (int i = 0; i < stops.size() && i <= 2; i++)
82 hash_val += stops[i].second.rgba();
83
84 QGLGradientColorTableHash::const_iterator it = cache.constFind(hash_val);
85
86 if (it == cache.constEnd())
87 return addCacheElement(hash_val, gradient, opacity);
88 else {
89 do {
90 const CacheInfo &cache_info = it.value();
91 if (cache_info.stops == stops && cache_info.opacity == opacity && cache_info.interpolationMode == gradient.interpolationMode()) {
92 return cache_info.texId;
93 }
94 ++it;
95 } while (it != cache.constEnd() && it.key() == hash_val);
96 // an exact match for these stops and opacity was not found, create new cache
97 return addCacheElement(hash_val, gradient, opacity);
98 }
99}
100
101
[561]102GLuint QGL2GradientCache::addCacheElement(quint64 hash_val, const QGradient &gradient, qreal opacity)
[2]103{
104 if (cache.size() == maxCacheSize()) {
105 int elem_to_remove = qrand() % maxCacheSize();
106 quint64 key = cache.keys()[elem_to_remove];
107
108 // need to call glDeleteTextures on each removed cache entry:
109 QGLGradientColorTableHash::const_iterator it = cache.constFind(key);
110 do {
111 glDeleteTextures(1, &it.value().texId);
112 } while (++it != cache.constEnd() && it.key() == key);
113 cache.remove(key); // may remove more than 1, but OK
114 }
115
116 CacheInfo cache_entry(gradient.stops(), opacity, gradient.interpolationMode());
117 uint buffer[1024];
118 generateGradientColorTable(gradient, buffer, paletteSize(), opacity);
119 glGenTextures(1, &cache_entry.texId);
120 glBindTexture(GL_TEXTURE_2D, cache_entry.texId);
121 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, paletteSize(), 1,
122 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
123 return cache.insert(hash_val, cache_entry).value().texId;
124}
125
126
[561]127// GL's expects pixels in RGBA (when using GL_RGBA), bin-endian (ABGR on x86).
128// Qt always stores in ARGB reguardless of the byte-order the mancine uses.
[2]129static inline uint qtToGlColor(uint c)
130{
131 uint o;
132#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
[561]133 o = (c & 0xff00ff00) // alpha & green already in the right place
134 | ((c >> 16) & 0x000000ff) // red
135 | ((c << 16) & 0x00ff0000); // blue
[2]136#else //Q_BIG_ENDIAN
[561]137 o = (c << 8)
138 | ((c >> 24) & 0x000000ff);
[2]139#endif // Q_BYTE_ORDER
140 return o;
141}
142
143//TODO: Let GL generate the texture using an FBO
[561]144void QGL2GradientCache::generateGradientColorTable(const QGradient& gradient, uint *colorTable, int size, qreal opacity) const
[2]145{
146 int pos = 0;
147 QGradientStops s = gradient.stops();
148 QVector<uint> colors(s.size());
149
150 for (int i = 0; i < s.size(); ++i)
[561]151 colors[i] = s[i].second.rgba(); // Qt LIES! It returns ARGB (on little-endian AND on big-endian)
[2]152
153 bool colorInterpolation = (gradient.interpolationMode() == QGradient::ColorInterpolation);
154
155 uint alpha = qRound(opacity * 256);
156 uint current_color = ARGB_COMBINE_ALPHA(colors[0], alpha);
157 qreal incr = 1.0 / qreal(size);
158 qreal fpos = 1.5 * incr;
159 colorTable[pos++] = qtToGlColor(PREMUL(current_color));
160
161 while (fpos <= s.first().first) {
162 colorTable[pos] = colorTable[pos - 1];
163 pos++;
164 fpos += incr;
165 }
166
167 if (colorInterpolation)
168 current_color = PREMUL(current_color);
169
170 for (int i = 0; i < s.size() - 1; ++i) {
171 qreal delta = 1/(s[i+1].first - s[i].first);
172 uint next_color = ARGB_COMBINE_ALPHA(colors[i+1], alpha);
173 if (colorInterpolation)
174 next_color = PREMUL(next_color);
175
176 while (fpos < s[i+1].first && pos < size) {
177 int dist = int(256 * ((fpos - s[i].first) * delta));
178 int idist = 256 - dist;
179 if (colorInterpolation)
180 colorTable[pos] = qtToGlColor(INTERPOLATE_PIXEL_256(current_color, idist, next_color, dist));
181 else
182 colorTable[pos] = qtToGlColor(PREMUL(INTERPOLATE_PIXEL_256(current_color, idist, next_color, dist)));
183 ++pos;
184 fpos += incr;
185 }
186 current_color = next_color;
187 }
188
189 Q_ASSERT(s.size() > 0);
190
191 uint last_color = qtToGlColor(PREMUL(ARGB_COMBINE_ALPHA(colors[s.size() - 1], alpha)));
192 for (;pos < size; ++pos)
193 colorTable[pos] = last_color;
194
195 // Make sure the last color stop is represented at the end of the table
196 colorTable[size-1] = last_color;
197}
[561]198
199QT_END_NAMESPACE
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