summaryrefslogtreecommitdiffstats
path: root/src/gui/kernel/qopenglcontext.cpp
blob: 39dd2a2dfa701ee8a2bdc37b1d55e0a746c4a209 (plain)
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
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <qpa/qplatformopenglcontext.h>
#include <qpa/qplatformintegration.h>
#include "qopenglcontext.h"
#include "qopenglcontext_p.h"
#include "qwindow.h"

#include <QtCore/QThreadStorage>
#include <QtCore/QThread>

#include <QtGui/private/qguiapplication_p.h>
#include <QtGui/private/qopengl_p.h>
#include <QtGui/private/qwindow_p.h>
#include <QtGui/QScreen>

#include <private/qopenglextensions_p.h>
#include <private/qopenglversionfunctionsfactory_p.h>

#include <private/qopengltexturehelper_p.h>

#include <QDebug>

QT_BEGIN_NAMESPACE

class QOpenGLVersionProfilePrivate
{
public:
    QOpenGLVersionProfilePrivate()
        : majorVersion(0),
          minorVersion(0),
          profile(QSurfaceFormat::NoProfile)
    {}

    int majorVersion;
    int minorVersion;
    QSurfaceFormat::OpenGLContextProfile profile;
};


/*!
    \class QOpenGLVersionProfile
    \inmodule QtGui
    \since 5.1
    \brief The QOpenGLVersionProfile class represents the version and if applicable
           the profile of an OpenGL context.

    An object of this class can be passed to QOpenGLContext::versionFunctions() to
    request a functions object for a specific version and profile of OpenGL.

    It also contains some helper functions to check if a version supports profiles
    or is a legacy version.
*/

/*!
    Creates a default invalid QOpenGLVersionProfile object.
*/
QOpenGLVersionProfile::QOpenGLVersionProfile()
    : d(new QOpenGLVersionProfilePrivate)
{
}

/*!
    Creates a QOpenGLVersionProfile object initialised with the version and profile
    from \a format.
*/
QOpenGLVersionProfile::QOpenGLVersionProfile(const QSurfaceFormat &format)
    : d(new QOpenGLVersionProfilePrivate)
{
    d->majorVersion = format.majorVersion();
    d->minorVersion = format.minorVersion();
    d->profile = format.profile();
}

/*!
    Constructs a copy of \a other.
*/
QOpenGLVersionProfile::QOpenGLVersionProfile(const QOpenGLVersionProfile &other)
    : d(new QOpenGLVersionProfilePrivate)
{
    *d = *(other.d);
}

/*!
    Destroys the QOpenGLVersionProfile object.
*/
QOpenGLVersionProfile::~QOpenGLVersionProfile()
{
    delete d;
}

/*!
    Assigns the version and profile of \a rhs to this QOpenGLVersionProfile object.
*/
QOpenGLVersionProfile &QOpenGLVersionProfile::operator=(const QOpenGLVersionProfile &rhs)
{
    if (this == &rhs)
        return *this;
    *d = *(rhs.d);
    return *this;
}

/*!
    Returns a QPair<int,int> where the components represent the major and minor OpenGL
    version numbers respectively.

    \sa setVersion()
*/
QPair<int, int> QOpenGLVersionProfile::version() const
{
    return qMakePair( d->majorVersion, d->minorVersion);
}

/*!
    Sets the major and minor version numbers to \a majorVersion and \a minorVersion respectively.

    \sa version()
*/
void QOpenGLVersionProfile::setVersion(int majorVersion, int minorVersion)
{
    d->majorVersion = majorVersion;
    d->minorVersion = minorVersion;
}

/*!
    Returns the OpenGL profile. Only make sense if profiles are supported by this version.

    \sa setProfile(), supportsProfiles()
*/
QSurfaceFormat::OpenGLContextProfile QOpenGLVersionProfile::profile() const
{
    return d->profile;
}

/*!
    Sets the profile.  Only make sense if profiles are supported by this version.

    \sa profile(), supportsProfiles()
*/
void QOpenGLVersionProfile::setProfile(QSurfaceFormat::OpenGLContextProfile profile)
{
    d->profile = profile;
}

/*!
    Returns \c true if profiles are supported by the OpenGL version returned by version(). Only
    OpenGL versions >= 3.2 support profiles.

    \sa profile(), version()
*/
bool QOpenGLVersionProfile::hasProfiles() const
{
    return ( d->majorVersion > 3
             || (d->majorVersion == 3 && d->minorVersion > 1));
}

/*!
    Returns \c true is the OpenGL version returned by version() contains deprecated functions
    and does not support profiles i.e. if the OpenGL version is <= 3.1.
*/
bool QOpenGLVersionProfile::isLegacyVersion() const
{
    return (d->majorVersion < 3 || (d->majorVersion == 3 && d->minorVersion == 0));
}

/*!
    Returns \c true if the version number is valid. Note that for a default constructed
    QOpenGLVersionProfile object this function will return false.

    \sa setVersion(), version()
*/
bool QOpenGLVersionProfile::isValid() const
{
    return d->majorVersion > 0 && d->minorVersion >= 0;
}

class QGuiGLThreadContext
{
public:
    QGuiGLThreadContext()
        : context(0)
    {
    }
    ~QGuiGLThreadContext() {
        if (context)
            context->doneCurrent();
    }
    QOpenGLContext *context;
};

static QThreadStorage<QGuiGLThreadContext *> qwindow_context_storage;

#ifndef QT_NO_DEBUG
QHash<QOpenGLContext *, bool> QOpenGLContextPrivate::makeCurrentTracker;
QMutex QOpenGLContextPrivate::makeCurrentTrackerMutex;
#endif

/*!
    \class QOpenGLContext
    \inmodule QtGui
    \since 5.0
    \brief The QOpenGLContext class represents a native OpenGL context, enabling
           OpenGL rendering on a QSurface.

    QOpenGLContext represents the OpenGL state of an underlying OpenGL context.
    To set up a context, set its screen and format such that they match those
    of the surface or surfaces with which the context is meant to be used, if
    necessary make it share resources with other contexts with
    setShareContext(), and finally call create(). Use isValid() to check if the
    context was successfully initialized.

    A context can be made current against a given surface by calling
    makeCurrent(). When OpenGL rendering is done, call swapBuffers() to swap
    the front and back buffers of the surface, so that the newly rendered
    content becomes visible. To be able to support certain platforms,
    QOpenGLContext requires that you call makeCurrent() again before starting
    rendering a new frame, after calling swapBuffers().

    If the context is temporarily not needed, such as when the application is
    not rendering, it can be useful to call destroy() to free resources.
    However, if you do so you will need to call create() again before the
    context can be used, and you might need to recreate any OpenGL resources
    and reinitialize the OpenGL state. You can connect to the
    aboutToBeDestroyed() signal to clean up any resources that have been
    allocated with different ownership from the QOpenGLContext itself.

    Once a QOpenGLContext has been made current, you can render to it in a
    platform independent way by using Qt's OpenGL enablers such as
    QOpenGLFunctions, QOpenGLBuffer, QOpenGLShaderProgram, and
    QOpenGLFramebufferObject. It is also possible to use the platform's OpenGL
    API directly, without using the Qt enablers, although potentially at the
    cost of portability. The latter is necessary when wanting to use OpenGL 1.x
    or OpenGL ES 1.x.

    For more information about the OpenGL API, refer to the official
    \l{http://www.opengl.org}{OpenGL documentation}.

    For an example of how to use QOpenGLContext see the
    \l{OpenGL Window Example}{OpenGL Window} example.

    \section1 Thread affinity

    QOpenGLContext can be moved to a different thread with moveToThread(). Do
    not call makeCurrent() from a different thread than the one to which the
    QOpenGLContext object belongs. A context can only be current in one thread
    and against one surface at a time, and a thread only has one context
    current at a time.

    \section1 Context resource sharing

    Resources, such as framebuffer objects, textures, and vertex buffer objects
    can be shared between contexts.  Use setShareContext() before calling
    create() to specify that the contexts should share these resources.
    QOpenGLContext internally keeps track of a QOpenGLContextGroup object which
    can be accessed with shareGroup(), and which can be used to find all the
    contexts in a given share group. A share group consists of all contexts that
    have been successfully initialized and are sharing with an existing context in
    the share group. A non-sharing context has a share group consisting of a
    single context.

    \section1 Default framebuffer

    On certain platforms, a framebuffer other than 0 might be the default frame
    buffer depending on the current surface. Instead of calling
    glBindFramebuffer(0), it is recommended that you use
    glBindFramebuffer(ctx->defaultFramebufferObject()), to ensure that your
    application is portable between different platforms. However, if you use
    QOpenGLFunctions::glBindFramebuffer(), this is done automatically for you.

    \sa QOpenGLFunctions, QOpenGLBuffer, QOpenGLShaderProgram, QOpenGLFramebufferObject
*/

/*!
    \internal

    Set the current context. Returns the previously current context.
*/
QOpenGLContext *QOpenGLContextPrivate::setCurrentContext(QOpenGLContext *context)
{
    QGuiGLThreadContext *threadContext = qwindow_context_storage.localData();
    if (!threadContext) {
        if (!QThread::currentThread()) {
            qWarning("No QTLS available. currentContext won't work");
            return 0;
        }
        threadContext = new QGuiGLThreadContext;
        qwindow_context_storage.setLocalData(threadContext);
    }
    QOpenGLContext *previous = threadContext->context;
    threadContext->context = context;
    return previous;
}

int QOpenGLContextPrivate::maxTextureSize()
{
    if (max_texture_size != -1)
        return max_texture_size;

    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);

#if defined(QT_OPENGL_ES)
    return max_texture_size;
#else
    GLenum proxy = GL_PROXY_TEXTURE_2D;

    GLint size;
    GLint next = 64;
    glTexImage2D(proxy, 0, GL_RGBA, next, next, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
    glGetTexLevelParameteriv(proxy, 0, GL_TEXTURE_WIDTH, &size);
    if (size == 0) {
        return max_texture_size;
    }
    do {
        size = next;
        next = size * 2;

        if (next > max_texture_size)
            break;
        glTexImage2D(proxy, 0, GL_RGBA, next, next, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
        glGetTexLevelParameteriv(proxy, 0, GL_TEXTURE_WIDTH, &next);
    } while (next > size);

    max_texture_size = size;
    return max_texture_size;
#endif
}

/*!
    Returns the last context which called makeCurrent in the current thread,
    or 0, if no context is current.
*/
QOpenGLContext* QOpenGLContext::currentContext()
{
    QGuiGLThreadContext *threadContext = qwindow_context_storage.localData();
    if(threadContext) {
        return threadContext->context;
    }
    return 0;
}

/*!
    Returns \c true if the \a first and \a second contexts are sharing OpenGL resources.
*/
bool QOpenGLContext::areSharing(QOpenGLContext *first, QOpenGLContext *second)
{
    return first->shareGroup() == second->shareGroup();
}

/*!
    Returns the underlying platform context.

    \internal
*/
QPlatformOpenGLContext *QOpenGLContext::handle() const
{
    Q_D(const QOpenGLContext);
    return d->platformGLContext;
}

/*!
    Returns the underlying platform context with which this context is sharing.

    \internal
*/

QPlatformOpenGLContext *QOpenGLContext::shareHandle() const
{
    Q_D(const QOpenGLContext);
    if (d->shareContext)
        return d->shareContext->handle();
    return 0;
}

/*!
    Creates a new OpenGL context instance with parent object \a parent.

    Before it can be used you need to set the proper format and call create().

    \sa create(), makeCurrent()
*/
QOpenGLContext::QOpenGLContext(QObject *parent)
    : QObject(*new QOpenGLContextPrivate(), parent)
{
    Q_D(QOpenGLContext);
    d->screen = QGuiApplication::primaryScreen();
}

/*!
    Sets the \a format the OpenGL context should be compatible with. You need
    to call create() before it takes effect.
*/
void QOpenGLContext::setFormat(const QSurfaceFormat &format)
{
    Q_D(QOpenGLContext);
    d->requestedFormat = format;
}

/*!
    Makes this context share textures, shaders, and other OpenGL resources
    with \a shareContext. You need to call create() before it takes effect.
*/
void QOpenGLContext::setShareContext(QOpenGLContext *shareContext)
{
    Q_D(QOpenGLContext);
    d->shareContext = shareContext;
}

/*!
    Sets the \a screen the OpenGL context should be valid for. You need to call
    create() before it takes effect.
*/
void QOpenGLContext::setScreen(QScreen *screen)
{
    Q_D(QOpenGLContext);
    d->screen = screen;
    if (!d->screen)
        d->screen = QGuiApplication::primaryScreen();
}

/*!
    Attempts to create the OpenGL context with the current configuration.

    The current configuration includes the format, the share context, and the
    screen.

    If the OpenGL implementation on your system does not support the requested
    version of OpenGL context, then QOpenGLContext will try to create the closest
    matching version. The actual created context properties can be queried
    using the QSurfaceFormat returned by the format() function. For example, if
    you request a context that supports OpenGL 4.3 Core profile but the driver
    and/or hardware only supports version 3.2 Core profile contexts then you will
    get a 3.2 Core profile context.

    Returns \c true if the native context was successfully created and is ready to
    be used with makeCurrent(), swapBuffers(), etc.

    \sa makeCurrent(), destroy(), format()
*/
bool QOpenGLContext::create()
{
    destroy();

    Q_D(QOpenGLContext);
    d->platformGLContext = QGuiApplicationPrivate::platformIntegration()->createPlatformOpenGLContext(this);
    if (!d->platformGLContext)
        return false;
    d->platformGLContext->setContext(this);
    if (!d->platformGLContext->isSharing())
        d->shareContext = 0;
    d->shareGroup = d->shareContext ? d->shareContext->shareGroup() : new QOpenGLContextGroup;
    d->shareGroup->d_func()->addContext(this);
    return d->platformGLContext;
}

/*!
    Destroy the underlying platform context associated with this context.

    If any other context is directly or indirectly sharing resources with this
    context, the shared resources, which includes vertex buffer objects, shader
    objects, textures, and framebuffer objects, are not freed. However,
    destroying the underlying platform context frees any state associated with
    the context.

    After destroy() has been called, you must call create() if you wish to
    use the context again.

    \note This implicitly calls doneCurrent() if the context is current.

    \sa create()
*/
void QOpenGLContext::destroy()
{
    Q_D(QOpenGLContext);
    if (d->platformGLContext)
        emit aboutToBeDestroyed();
    if (QOpenGLContext::currentContext() == this)
        doneCurrent();
    if (d->shareGroup)
        d->shareGroup->d_func()->removeContext(this);
    d->shareGroup = 0;
    delete d->platformGLContext;
    d->platformGLContext = 0;
    delete d->functions;
    d->functions = 0;
    qDeleteAll(d->versionFunctions);
    d->versionFunctions.clear();
    qDeleteAll(d->versionFunctionsBackend);
    d->versionFunctionsBackend.clear();
    delete d->textureFunctions;
    d->textureFunctions = 0;
}

/*!
    \fn void QOpenGLContext::aboutToBeDestroyed()

    This signal is emitted before the underlying native OpenGL context is
    destroyed, such that users may clean up OpenGL resources that might
    otherwise be left dangling in the case of shared OpenGL contexts.

    If you wish to make the context current in order to do clean-up, make sure
    to only connect to the signal using a direct connection.
*/

/*!
    Destroys the QOpenGLContext object.

    This implicitly calls destroy(), so if this is the current context for the
    thread, doneCurrent() is also called.

    \sa destroy()
*/
QOpenGLContext::~QOpenGLContext()
{
    destroy();

#ifndef QT_NO_DEBUG
    QOpenGLContextPrivate::cleanMakeCurrentTracker(this);
#endif
}

/*!
    Returns if this context is valid, i.e. has been successfully created.

    \sa create()
*/
bool QOpenGLContext::isValid() const
{
    Q_D(const QOpenGLContext);
    return d->platformGLContext && d->platformGLContext->isValid();
}

/*!
    Get the QOpenGLFunctions instance for this context.

    QOpenGLContext offers this as a convenient way to access QOpenGLFunctions
    without having to manage it manually.

    The context or a sharing context must be current.
*/
QOpenGLFunctions *QOpenGLContext::functions() const
{
    Q_D(const QOpenGLContext);
    if (!d->functions)
        const_cast<QOpenGLFunctions *&>(d->functions) = new QOpenGLExtensions(QOpenGLContext::currentContext());
    return d->functions;
}

/*!
    \fn T *QOpenGLContext::versionFunctions() const

    \overload versionFunctions()

    Returns a pointer to an object that provides access to all functions for
    the version and profile of this context. Before using any of the functions
    they must be initialized by calling QAbstractOpenGLFunctions::initializeOpenGLFunctions().

    Usually one would use the template version of this function to automatically
    have the result cast to the correct type.

    \code
        QOpenGLFunctions_3_3_Core* funcs = 0;
        funcs = context->versionFunctions<QOpenGLFunctions_3_3_Core>();
        if (!funcs) {
            qWarning() << "Could not obtain required OpenGL context version";
            exit(1);
        }
        funcs->initializeOpenGLFunctions(context);
    \endcode

    It is possible to request a functions object for a different version and profile
    than that for which the context was created. To do this either use the template
    version of this function specifying the desired functions object type as the
    template parameter or by passing in a QOpenGLVersionProfile object as an argument
    to the non-template function.

    Note that requests for function objects of other versions or profiles can fail and
    in doing so will return a null pointer. Situations in which creation of the functions
    object can fail are if the request cannot be satisfied due to asking for functions
    that are not in the version or profile of this context. For example:

    \list
        \li Requesting a 3.3 core profile functions object would succeed.
        \li Requesting a 3.3 compatibility profile functions object would fail. We would fail
            to resolve the deprecated functions.
        \li Requesting a 4.3 core profile functions object would fail. We would fail to resolve
            the new core functions introduced in versions 4.0-4.3.
        \li Requesting a 3.1 functions object would succeed. There is nothing in 3.1 that is not
            also in 3.3 core.
    \endlist

    Note that if creating a functions object via this method that the QOpenGLContext
    retains ownership of the object. This is to allow the object to be cached and shared.
*/

/*!
    Returns a pointer to an object that provides access to all functions for
    the version of the current context. Before using any of the functions
    they must be initialized by calling QAbstractOpenGLFunctions::initializeOpenGLFunctions().

    Usually one would use the template version of this function to automatically
    have the result cast to the correct type.
*/
QAbstractOpenGLFunctions *QOpenGLContext::versionFunctions(const QOpenGLVersionProfile &versionProfile) const
{
    Q_D(const QOpenGLContext);
    const QSurfaceFormat f = format();

    // Ensure we have a valid version and profile. Default to context's if none specified
    QOpenGLVersionProfile vp = versionProfile;
    if (!vp.isValid())
        vp = QOpenGLVersionProfile(f);

    // Check that context is compatible with requested version
    const QPair<int, int> v = qMakePair(f.majorVersion(), f.minorVersion());
    if (v < vp.version())
        return 0;

    // If this context only offers core profile functions then we can't create
    // function objects for legacy or compatibility profile requests
    if (((vp.hasProfiles() && vp.profile() != QSurfaceFormat::CoreProfile) || vp.isLegacyVersion())
        && f.profile() == QSurfaceFormat::CoreProfile)
        return 0;

    // Create object if suitable one not cached
    QAbstractOpenGLFunctions* funcs = 0;
    if (!d->versionFunctions.contains(vp)) {
        funcs = QOpenGLVersionFunctionsFactory::create(vp);
        if (funcs) {
            funcs->setOwningContext(this);
            d->versionFunctions.insert(vp, funcs);
        }
    } else {
        funcs = d->versionFunctions.value(vp);
    }

    return funcs;
}

/*!
    Returns the set of OpenGL extensions supported by this context.

    The context or a sharing context must be current.

    \sa hasExtension()
*/
QSet<QByteArray> QOpenGLContext::extensions() const
{
    Q_D(const QOpenGLContext);
    if (d->extensionNames.isEmpty()) {
        QOpenGLExtensionMatcher matcher;
        d->extensionNames = matcher.extensions();
    }

    return d->extensionNames;
}

/*!
    Returns \c true if this OpenGL context supports the specified OpenGL
    \a extension, false otherwise.

    The context or a sharing context must be current.

    \sa extensions()
*/
bool QOpenGLContext::hasExtension(const QByteArray &extension) const
{
    return extensions().contains(extension);
}

/*!
    Call this to get the default framebuffer object for the current surface.

    On some platforms the default framebuffer object depends on the surface
    being rendered to, and might be different from 0. Thus, instead of calling
    glBindFramebuffer(0), you should call
    glBindFramebuffer(ctx->defaultFramebufferObject()) if you want your
    application to work across different Qt platforms.

    If you use the glBindFramebuffer() in QOpenGLFunctions you do not have to
    worry about this, as it automatically binds the current context's
    defaultFramebufferObject() when 0 is passed.
*/
GLuint QOpenGLContext::defaultFramebufferObject() const
{
    if (!isValid())
        return 0;

    Q_D(const QOpenGLContext);
    if (!d->surface || !d->surface->surfaceHandle())
        return 0;

    return d->platformGLContext->defaultFramebufferObject(d->surface->surfaceHandle());
}

/*!
    Makes the context current in the current thread, against the given
    \a surface. Returns \c true if successful.

    If \a surface is 0 this is equivalent to calling doneCurrent().

    Do not call this function from a different thread than the one the
    QOpenGLContext instance lives in. If you wish to use QOpenGLContext from a
    different thread you should first call make sure it's not current in the
    current thread, by calling doneCurrent() if necessary. Then call
    moveToThread(otherThread) before using it in the other thread.

    \sa functions(), doneCurrent()
*/
bool QOpenGLContext::makeCurrent(QSurface *surface)
{
    Q_D(QOpenGLContext);
    if (!isValid())
        return false;

    if (thread() != QThread::currentThread())
        qFatal("Cannot make QOpenGLContext current in a different thread");

    if (!surface) {
        doneCurrent();
        return true;
    }

    if (!surface->surfaceHandle())
        return false;

    if (surface->surfaceType() != QSurface::OpenGLSurface) {
        qWarning() << "QOpenGLContext::makeCurrent() called with non-opengl surface" << surface;
        return false;
    }

    QOpenGLContext *previous = QOpenGLContextPrivate::setCurrentContext(this);

    if (d->platformGLContext->makeCurrent(surface->surfaceHandle())) {
        d->surface = surface;

        d->shareGroup->d_func()->deletePendingResources(this);

#ifndef QT_NO_DEBUG
        QOpenGLContextPrivate::toggleMakeCurrentTracker(this, true);
#endif

        return true;
    }

    QOpenGLContextPrivate::setCurrentContext(previous);

    return false;
}

/*!
    Convenience function for calling makeCurrent with a 0 surface.

    This results in no context being current in the current thread.

    \sa makeCurrent(), currentContext()
*/
void QOpenGLContext::doneCurrent()
{
    Q_D(QOpenGLContext);
    if (!isValid())
        return;

    if (QOpenGLContext::currentContext() == this)
        d->shareGroup->d_func()->deletePendingResources(this);

    d->platformGLContext->doneCurrent();
    QOpenGLContextPrivate::setCurrentContext(0);

    d->surface = 0;
}

/*!
    Returns the surface the context has been made current with.

    This is the surface passed as an argument to makeCurrent().
*/
QSurface *QOpenGLContext::surface() const
{
    Q_D(const QOpenGLContext);
    return d->surface;
}


/*!
    Swap the back and front buffers of \a surface.

    Call this to finish a frame of OpenGL rendering, and make sure to
    call makeCurrent() again before you begin a new frame.
*/
void QOpenGLContext::swapBuffers(QSurface *surface)
{
    Q_D(QOpenGLContext);
    if (!isValid())
        return;

    if (!surface) {
        qWarning() << "QOpenGLContext::swapBuffers() called with null argument";
        return;
    }

    if (surface->surfaceType() != QSurface::OpenGLSurface) {
         qWarning() << "QOpenGLContext::swapBuffers() called with non-opengl surface";
         return;
    }

    if (surface->surfaceClass() == QSurface::Window
        && !qt_window_private(static_cast<QWindow *>(surface))->receivedExpose)
    {
        qWarning() << "QOpenGLContext::swapBuffers() called with non-exposed window, behavior is undefined";
    }

    QPlatformSurface *surfaceHandle = surface->surfaceHandle();
    if (!surfaceHandle)
        return;

#if !defined(QT_NO_DEBUG)
    if (!QOpenGLContextPrivate::toggleMakeCurrentTracker(this, false))
        qWarning() << "QOpenGLContext::swapBuffers() called without corresponding makeCurrent()";
#endif
    if (surface->format().swapBehavior() == QSurfaceFormat::SingleBuffer)
        glFlush();
    d->platformGLContext->swapBuffers(surfaceHandle);
}

/*!
    Resolves the function pointer to an OpenGL extension function, identified by \a procName

    Returns 0 if no such function can be found.
*/
QFunctionPointer QOpenGLContext::getProcAddress(const QByteArray &procName) const
{
    Q_D(const QOpenGLContext);
    if (!d->platformGLContext)
        return 0;
    return d->platformGLContext->getProcAddress(procName);
}

/*!
    Returns the format of the underlying platform context, if create() has been called.

    Otherwise, returns the requested format.
*/
QSurfaceFormat QOpenGLContext::format() const
{
    Q_D(const QOpenGLContext);
    if (!d->platformGLContext)
        return d->requestedFormat;
    return d->platformGLContext->format();
}

/*!
    Returns the share group this context belongs to.
*/
QOpenGLContextGroup *QOpenGLContext::shareGroup() const
{
    Q_D(const QOpenGLContext);
    return d->shareGroup;
}

/*!
    Returns the share context this context was created with.

    If the underlying platform was not able to support the requested
    sharing, this will return 0.
*/
QOpenGLContext *QOpenGLContext::shareContext() const
{
    Q_D(const QOpenGLContext);
    return d->shareContext;
}

/*!
    Returns the screen the context was created for.
*/
QScreen *QOpenGLContext::screen() const
{
    Q_D(const QOpenGLContext);
    return d->screen;
}

/*!
    internal: Needs to have a pointer to qGLContext. But since this is in Qt GUI we can't
    have any type information.

    \internal
*/
void *QOpenGLContext::qGLContextHandle() const
{
    Q_D(const QOpenGLContext);
    return d->qGLContextHandle;
}

/*!
    \internal
*/
void QOpenGLContext::setQGLContextHandle(void *handle,void (*qGLContextDeleteFunction)(void *))
{
    Q_D(QOpenGLContext);
    d->qGLContextHandle = handle;
    d->qGLContextDeleteFunction = qGLContextDeleteFunction;
}

/*!
    \internal
*/
void QOpenGLContext::deleteQGLContext()
{
    Q_D(QOpenGLContext);
    if (d->qGLContextDeleteFunction && d->qGLContextHandle) {
        d->qGLContextDeleteFunction(d->qGLContextHandle);
        d->qGLContextDeleteFunction = 0;
        d->qGLContextHandle = 0;
    }
}

/*!
    \internal
*/
QOpenGLVersionFunctionsBackend *QOpenGLContext::functionsBackend(const QOpenGLVersionStatus &v) const
{
    Q_D(const QOpenGLContext);
    return d->versionFunctionsBackend.value(v, 0);
}

/*!
    \internal
*/
void QOpenGLContext::insertFunctionsBackend(const QOpenGLVersionStatus &v,
                                            QOpenGLVersionFunctionsBackend *backend)
{
    Q_D(QOpenGLContext);
    d->versionFunctionsBackend.insert(v, backend);
}

/*!
    \internal
*/
void QOpenGLContext::removeFunctionsBackend(const QOpenGLVersionStatus &v)
{
    Q_D(QOpenGLContext);
    d->versionFunctionsBackend.remove(v);
}

/*!
    \internal
*/
QOpenGLTextureHelper* QOpenGLContext::textureFunctions() const
{
    Q_D(const QOpenGLContext);
    return d->textureFunctions;
}

/*!
    \internal
*/
void QOpenGLContext::setTextureFunctions(QOpenGLTextureHelper* textureFuncs)
{
    Q_D(QOpenGLContext);
    d->textureFunctions = textureFuncs;
}

/*!
    \class QOpenGLContextGroup
    \since 5.0
    \brief The QOpenGLContextGroup class represents a group of contexts sharing
    OpenGL resources.
    \inmodule QtGui

    QOpenGLContextGroup is automatically created and managed by QOpenGLContext
    instances.  Its purpose is to identify all the contexts that are sharing
    resources.

    \sa QOpenGLContext::shareGroup()
*/
QOpenGLContextGroup::QOpenGLContextGroup()
    : QObject(*new QOpenGLContextGroupPrivate())
{
}

/*!
    \internal
*/
QOpenGLContextGroup::~QOpenGLContextGroup()
{
    Q_D(QOpenGLContextGroup);
    d->cleanup();
}

/*!
    Returns all the QOpenGLContext objects in this share group.
*/
QList<QOpenGLContext *> QOpenGLContextGroup::shares() const
{
    Q_D(const QOpenGLContextGroup);
    return d->m_shares;
}

/*!
    Returns the QOpenGLContextGroup corresponding to the current context.

    \sa QOpenGLContext::currentContext()
*/
QOpenGLContextGroup *QOpenGLContextGroup::currentContextGroup()
{
    QOpenGLContext *current = QOpenGLContext::currentContext();
    return current ? current->shareGroup() : 0;
}

void QOpenGLContextGroupPrivate::addContext(QOpenGLContext *ctx)
{
    QMutexLocker locker(&m_mutex);
    m_refs.ref();
    m_shares << ctx;
}

void QOpenGLContextGroupPrivate::removeContext(QOpenGLContext *ctx)
{
    Q_Q(QOpenGLContextGroup);

    bool deleteObject = false;

    {
        QMutexLocker locker(&m_mutex);
        m_shares.removeOne(ctx);

        if (ctx == m_context && !m_shares.isEmpty())
            m_context = m_shares.first();

        if (!m_refs.deref()) {
            cleanup();
            deleteObject = true;
        }
    }

    if (deleteObject) {
        if (q->thread() == QThread::currentThread())
            delete q; // Delete directly to prevent leak, refer to QTBUG-29056
        else
            q->deleteLater();
    }
}

void QOpenGLContextGroupPrivate::cleanup()
{
    Q_Q(QOpenGLContextGroup);
    {
        QHash<QOpenGLMultiGroupSharedResource *, QOpenGLSharedResource *>::const_iterator it, end;
        end = m_resources.constEnd();
        for (it = m_resources.constBegin(); it != end; ++it)
            it.key()->cleanup(q, it.value());
        m_resources.clear();
    }

    QList<QOpenGLSharedResource *>::iterator it = m_sharedResources.begin();
    QList<QOpenGLSharedResource *>::iterator end = m_sharedResources.end();

    while (it != end) {
        (*it)->invalidateResource();
        (*it)->m_group = 0;
        ++it;
    }

    m_sharedResources.clear();

    qDeleteAll(m_pendingDeletion.begin(), m_pendingDeletion.end());
    m_pendingDeletion.clear();
}

void QOpenGLContextGroupPrivate::deletePendingResources(QOpenGLContext *ctx)
{
    QMutexLocker locker(&m_mutex);

    QList<QOpenGLSharedResource *> pending = m_pendingDeletion;
    m_pendingDeletion.clear();

    QList<QOpenGLSharedResource *>::iterator it = pending.begin();
    QList<QOpenGLSharedResource *>::iterator end = pending.end();
    while (it != end) {
        (*it)->freeResource(ctx);
        delete *it;
        ++it;
    }
}

/*!
    \class QOpenGLSharedResource
    \internal
    \since 5.0
    \brief The QOpenGLSharedResource class is used to keep track of resources
    that are shared between OpenGL contexts (like textures, framebuffer
    objects, shader programs, etc), and clean them up in a safe way when
    they're no longer needed.
    \inmodule QtGui

    The QOpenGLSharedResource instance should never be deleted, instead free()
    should be called when it's no longer needed. Thus it will be put on a queue
    and freed at an appropriate time (when a context in the share group becomes
    current).

    The sub-class needs to implement two pure virtual functions. The first,
    freeResource() must be implemented to actually do the freeing, for example
    call glDeleteTextures() on a texture id. Qt makes sure a valid context in
    the resource's share group is current at the time. The other,
    invalidateResource(), is called by Qt in the circumstance when the last
    context in the share group is destroyed before free() has been called. The
    implementation of invalidateResource() should set any identifiers to 0 or
    set a flag to prevent them from being used later on.
*/
QOpenGLSharedResource::QOpenGLSharedResource(QOpenGLContextGroup *group)
    : m_group(group)
{
    QMutexLocker locker(&m_group->d_func()->m_mutex);
    m_group->d_func()->m_sharedResources << this;
}

QOpenGLSharedResource::~QOpenGLSharedResource()
{
}

// schedule the resource for deletion at an appropriate time
void QOpenGLSharedResource::free()
{
    if (!m_group) {
        delete this;
        return;
    }

    QMutexLocker locker(&m_group->d_func()->m_mutex);
    m_group->d_func()->m_sharedResources.removeOne(this);
    m_group->d_func()->m_pendingDeletion << this;

    // can we delete right away?
    QOpenGLContext *current = QOpenGLContext::currentContext();
    if (current && current->shareGroup() == m_group) {
        m_group->d_func()->deletePendingResources(current);
    }
}

/*!
    \class QOpenGLSharedResourceGuard
    \internal
    \since 5.0
    \brief The QOpenGLSharedResourceGuard class is a convenience sub-class of
    QOpenGLSharedResource to be used to track a single OpenGL object with a
    GLuint identifier. The constructor takes a function pointer to a function
    that will be used to free the resource if and when necessary.
    \inmodule QtGui

*/
void QOpenGLSharedResourceGuard::freeResource(QOpenGLContext *context)
{
    if (m_id) {
        QOpenGLFunctions functions(context);
        m_func(&functions, m_id);
        m_id = 0;
    }
}

/*!
    \class QOpenGLMultiGroupSharedResource
    \internal
    \since 5.0
    \brief The QOpenGLMultiGroupSharedResource keeps track of a shared resource
    that might be needed from multiple contexts, like a glyph cache or gradient
    cache. One instance of the object is created for each group when necessary.
    The shared resource instance should have a constructor that takes a
    QOpenGLContext *. To get an instance for a given context one calls
    T *QOpenGLMultiGroupSharedResource::value<T>(context), where T is a sub-class
    of QOpenGLSharedResource.
    \inmodule QtGui

    You should not call free() on QOpenGLSharedResources owned by a
    QOpenGLMultiGroupSharedResource instance.
*/
QOpenGLMultiGroupSharedResource::QOpenGLMultiGroupSharedResource()
    : active(0)
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Creating context group resource object %p.", this);
#endif
}

QOpenGLMultiGroupSharedResource::~QOpenGLMultiGroupSharedResource()
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Deleting context group resource %p. Group size: %d.", this, m_groups.size());
#endif
    for (int i = 0; i < m_groups.size(); ++i) {
        if (!m_groups.at(i)->shares().isEmpty()) {
            QOpenGLContext *context = m_groups.at(i)->shares().first();
            QOpenGLSharedResource *resource = value(context);
            if (resource)
                resource->free();
        }
        m_groups.at(i)->d_func()->m_resources.remove(this);
        active.deref();
    }
#ifndef QT_NO_DEBUG
    if (active.load() != 0) {
        qWarning("QtGui: Resources are still available at program shutdown.\n"
                 "          This is possibly caused by a leaked QOpenGLWidget, \n"
                 "          QOpenGLFramebufferObject or QOpenGLPixelBuffer.");
    }
#endif
}

void QOpenGLMultiGroupSharedResource::insert(QOpenGLContext *context, QOpenGLSharedResource *value)
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Inserting context group resource %p for context %p, managed by %p.", value, context, this);
#endif
    QOpenGLContextGroup *group = context->shareGroup();
    Q_ASSERT(!group->d_func()->m_resources.contains(this));
    group->d_func()->m_resources.insert(this, value);
    m_groups.append(group);
    active.ref();
}

QOpenGLSharedResource *QOpenGLMultiGroupSharedResource::value(QOpenGLContext *context)
{
    QOpenGLContextGroup *group = context->shareGroup();
    return group->d_func()->m_resources.value(this, 0);
}

QList<QOpenGLSharedResource *> QOpenGLMultiGroupSharedResource::resources() const
{
    QList<QOpenGLSharedResource *> result;
    for (QList<QOpenGLContextGroup *>::const_iterator it = m_groups.constBegin(); it != m_groups.constEnd(); ++it) {
        QOpenGLSharedResource *resource = (*it)->d_func()->m_resources.value(const_cast<QOpenGLMultiGroupSharedResource *>(this), 0);
        if (resource)
            result << resource;
    }
    return result;
}

void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContextGroup *group, QOpenGLSharedResource *value)
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Cleaning up context group resource %p, for group %p in thread %p.", this, group, QThread::currentThread());
#endif
    value->invalidateResource();
    value->free();
    active.deref();

    Q_ASSERT(m_groups.contains(group));
    m_groups.removeOne(group);
}

QT_END_NAMESPACE