summaryrefslogtreecommitdiffstats
path: root/src/gui/opengl/qopenglframebufferobject.cpp
blob: 9ba429e53a5f51865118e2e146765ec2127f6b59 (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
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
/****************************************************************************
**
** 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 "qopenglframebufferobject.h"
#include "qopenglframebufferobject_p.h"

#include <qdebug.h>
#include <private/qopengl_p.h>
#include <private/qopenglcontext_p.h>
#include <private/qopenglextensions_p.h>
#include <private/qfont_p.h>

#include <qwindow.h>
#include <qlibrary.h>
#include <qimage.h>

QT_BEGIN_NAMESPACE

#ifndef QT_NO_DEBUG
#define QT_RESET_GLERROR()                                \
{                                                         \
    while (QOpenGLContext::currentContext()->functions()->glGetError() != GL_NO_ERROR) {} \
}
#define QT_CHECK_GLERROR()                                \
{                                                         \
    GLenum err = QOpenGLContext::currentContext()->functions()->glGetError(); \
    if (err != GL_NO_ERROR) {                             \
        qDebug("[%s line %d] OpenGL Error: %d",           \
               __FILE__, __LINE__, (int)err);             \
    }                                                     \
}
#else
#define QT_RESET_GLERROR() {}
#define QT_CHECK_GLERROR() {}
#endif

#ifndef GL_MAX_SAMPLES
#define GL_MAX_SAMPLES 0x8D57
#endif

#ifndef GL_RENDERBUFFER_SAMPLES
#define GL_RENDERBUFFER_SAMPLES 0x8CAB
#endif

#ifndef GL_DEPTH24_STENCIL8
#define GL_DEPTH24_STENCIL8 0x88F0
#endif

#ifndef GL_DEPTH_COMPONENT24
#define GL_DEPTH_COMPONENT24 0x81A6
#endif

#ifndef GL_READ_FRAMEBUFFER
#define GL_READ_FRAMEBUFFER 0x8CA8
#endif

#ifndef GL_DRAW_FRAMEBUFFER
#define GL_DRAW_FRAMEBUFFER 0x8CA9
#endif

/*!
    \class QOpenGLFramebufferObjectFormat
    \brief The QOpenGLFramebufferObjectFormat class specifies the format of an OpenGL
    framebuffer object.
    \inmodule QtGui

    \since 5.0

    \ingroup painting-3D

    A framebuffer object has several characteristics:
    \list
    \li \l{setSamples()}{Number of samples per pixels.}
    \li \l{setAttachment()}{Depth and/or stencil attachments.}
    \li \l{setTextureTarget()}{Texture target.}
    \li \l{setInternalTextureFormat()}{Internal texture format.}
    \endlist

    Note that the desired attachments or number of samples per pixels might not
    be supported by the hardware driver. Call QOpenGLFramebufferObject::format()
    after creating a QOpenGLFramebufferObject to find the exact format that was
    used to create the frame buffer object.

    \sa QOpenGLFramebufferObject
*/

/*!
    \internal
*/
void QOpenGLFramebufferObjectFormat::detach()
{
    if (d->ref.load() != 1) {
        QOpenGLFramebufferObjectFormatPrivate *newd
            = new QOpenGLFramebufferObjectFormatPrivate(d);
        if (!d->ref.deref())
            delete d;
        d = newd;
    }
}

/*!
    Creates a QOpenGLFramebufferObjectFormat object for specifying
    the format of an OpenGL framebuffer object.

    By default the format specifies a non-multisample framebuffer object with no
    attachments, texture target \c GL_TEXTURE_2D, and internal format \c GL_RGBA8.
    On OpenGL/ES systems, the default internal format is \c GL_RGBA.

    \sa samples(), attachment(), internalTextureFormat()
*/

QOpenGLFramebufferObjectFormat::QOpenGLFramebufferObjectFormat()
{
    d = new QOpenGLFramebufferObjectFormatPrivate;
}

/*!
    Constructs a copy of \a other.
*/

QOpenGLFramebufferObjectFormat::QOpenGLFramebufferObjectFormat(const QOpenGLFramebufferObjectFormat &other)
{
    d = other.d;
    d->ref.ref();
}

/*!
    Assigns \a other to this object.
*/

QOpenGLFramebufferObjectFormat &QOpenGLFramebufferObjectFormat::operator=(const QOpenGLFramebufferObjectFormat &other)
{
    if (d != other.d) {
        other.d->ref.ref();
        if (!d->ref.deref())
            delete d;
        d = other.d;
    }
    return *this;
}

/*!
    Destroys the QOpenGLFramebufferObjectFormat.
*/
QOpenGLFramebufferObjectFormat::~QOpenGLFramebufferObjectFormat()
{
    if (!d->ref.deref())
        delete d;
}

/*!
    Sets the number of samples per pixel for a multisample framebuffer object
    to \a samples.  The default sample count of 0 represents a regular
    non-multisample framebuffer object.

    If the desired amount of samples per pixel is not supported by the hardware
    then the maximum number of samples per pixel will be used. Note that
    multisample framebuffer objects can not be bound as textures. Also, the
    \c{GL_EXT_framebuffer_multisample} extension is required to create a
    framebuffer with more than one sample per pixel.

    \sa samples()
*/
void QOpenGLFramebufferObjectFormat::setSamples(int samples)
{
    detach();
    d->samples = samples;
}

/*!
    Returns the number of samples per pixel if a framebuffer object
    is a multisample framebuffer object. Otherwise, returns 0.
    The default value is 0.

    \sa setSamples()
*/
int QOpenGLFramebufferObjectFormat::samples() const
{
    return d->samples;
}

/*!
    Enables mipmapping if \a enabled is true; otherwise disables it.

    Mipmapping is disabled by default.

    If mipmapping is enabled, additional memory will be allocated for
    the mipmap levels. The mipmap levels can be updated by binding the
    texture and calling glGenerateMipmap(). Mipmapping cannot be enabled
    for multisampled framebuffer objects.

    \sa mipmap(), QOpenGLFramebufferObject::texture()
*/
void QOpenGLFramebufferObjectFormat::setMipmap(bool enabled)
{
    detach();
    d->mipmap = enabled;
}

/*!
    Returns \c true if mipmapping is enabled.

    \sa setMipmap()
*/
bool QOpenGLFramebufferObjectFormat::mipmap() const
{
    return d->mipmap;
}

/*!
    Sets the attachment configuration of a framebuffer object to \a attachment.

    \sa attachment()
*/
void QOpenGLFramebufferObjectFormat::setAttachment(QOpenGLFramebufferObject::Attachment attachment)
{
    detach();
    d->attachment = attachment;
}

/*!
    Returns the configuration of the depth and stencil buffers attached to
    a framebuffer object.  The default is QOpenGLFramebufferObject::NoAttachment.

    \sa setAttachment()
*/
QOpenGLFramebufferObject::Attachment QOpenGLFramebufferObjectFormat::attachment() const
{
    return d->attachment;
}

/*!
    Sets the texture target of the texture attached to a framebuffer object to
    \a target. Ignored for multisample framebuffer objects.

    \sa textureTarget(), samples()
*/
void QOpenGLFramebufferObjectFormat::setTextureTarget(GLenum target)
{
    detach();
    d->target = target;
}

/*!
    Returns the texture target of the texture attached to a framebuffer object.
    Ignored for multisample framebuffer objects.  The default is
    \c GL_TEXTURE_2D.

    \sa setTextureTarget(), samples()
*/
GLenum QOpenGLFramebufferObjectFormat::textureTarget() const
{
    return d->target;
}

/*!
    Sets the internal format of a framebuffer object's texture or
    multisample framebuffer object's color buffer to
    \a internalTextureFormat.

    \sa internalTextureFormat()
*/
void QOpenGLFramebufferObjectFormat::setInternalTextureFormat(GLenum internalTextureFormat)
{
    detach();
    d->internal_format = internalTextureFormat;
}

/*!
    Returns the internal format of a framebuffer object's texture or
    multisample framebuffer object's color buffer.  The default is
    \c GL_RGBA8 on desktop OpenGL systems, and \c GL_RGBA on
    OpenGL/ES systems.

    \sa setInternalTextureFormat()
*/
GLenum QOpenGLFramebufferObjectFormat::internalTextureFormat() const
{
    return d->internal_format;
}

/*!
    Returns \c true if all the options of this framebuffer object format
    are the same as \a other; otherwise returns \c false.
*/
bool QOpenGLFramebufferObjectFormat::operator==(const QOpenGLFramebufferObjectFormat& other) const
{
    if (d == other.d)
        return true;
    else
        return d->equals(other.d);
}

/*!
    Returns \c false if all the options of this framebuffer object format
    are the same as \a other; otherwise returns \c true.
*/
bool QOpenGLFramebufferObjectFormat::operator!=(const QOpenGLFramebufferObjectFormat& other) const
{
    return !(*this == other);
}

bool QOpenGLFramebufferObjectPrivate::checkFramebufferStatus(QOpenGLContext *ctx) const
{
    if (!ctx)
        return false;   // Context no longer exists.
    GLenum status = ctx->functions()->glCheckFramebufferStatus(GL_FRAMEBUFFER);
    switch(status) {
    case GL_NO_ERROR:
    case GL_FRAMEBUFFER_COMPLETE:
        return true;
    case GL_FRAMEBUFFER_UNSUPPORTED:
        qDebug("QOpenGLFramebufferObject: Unsupported framebuffer format.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete attachment.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, missing attachment.");
        break;
#ifdef GL_FRAMEBUFFER_INCOMPLETE_DUPLICATE_ATTACHMENT
    case GL_FRAMEBUFFER_INCOMPLETE_DUPLICATE_ATTACHMENT:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, duplicate attachment.");
        break;
#endif
#ifdef GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS
    case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, attached images must have same dimensions.");
        break;
#endif
#ifdef GL_FRAMEBUFFER_INCOMPLETE_FORMATS
    case GL_FRAMEBUFFER_INCOMPLETE_FORMATS:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, attached images must have same format.");
        break;
#endif
#ifdef GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER
    case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, missing draw buffer.");
        break;
#endif
#ifdef GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER
    case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, missing read buffer.");
        break;
#endif
#ifdef GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE
    case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
        qDebug("QOpenGLFramebufferObject: Framebuffer incomplete, attachments must have same number of samples per pixel.");
        break;
#endif
    default:
        qDebug() <<"QOpenGLFramebufferObject: An undefined error has occurred: "<< status;
        break;
    }
    return false;
}

namespace
{
    void freeFramebufferFunc(QOpenGLFunctions *funcs, GLuint id)
    {
        funcs->glDeleteFramebuffers(1, &id);
    }

    void freeRenderbufferFunc(QOpenGLFunctions *funcs, GLuint id)
    {
        funcs->glDeleteRenderbuffers(1, &id);
    }

    void freeTextureFunc(QOpenGLFunctions *funcs, GLuint id)
    {
        funcs->glDeleteTextures(1, &id);
    }
}

void QOpenGLFramebufferObjectPrivate::init(QOpenGLFramebufferObject *, const QSize &sz,
                                       QOpenGLFramebufferObject::Attachment attachment,
                                       GLenum texture_target, GLenum internal_format,
                                       GLint samples, bool mipmap)
{
    QOpenGLContext *ctx = QOpenGLContext::currentContext();

    funcs.initializeOpenGLFunctions();

    if (!funcs.hasOpenGLFeature(QOpenGLFunctions::Framebuffers))
        return;


    // Fall back to using a normal non-msaa FBO if we don't have support for MSAA
    if (!funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)
            || !funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit)) {
        samples = 0;
    }

#ifndef QT_OPENGL_ES_2
    GLint maxSamples;
    funcs.glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);
    samples = qBound(0, int(samples), int(maxSamples));
#endif

    size = sz;
    target = texture_target;
    // texture dimensions

    QT_RESET_GLERROR(); // reset error state
    GLuint fbo = 0;

    funcs.glGenFramebuffers(1, &fbo);
    funcs.glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLuint color_buffer = 0;

    QT_CHECK_GLERROR();
    // init texture
    if (samples == 0) {
        initTexture(texture_target, internal_format, size, mipmap);
    } else {
        mipmap = false;
        funcs.glGenRenderbuffers(1, &color_buffer);
        funcs.glBindRenderbuffer(GL_RENDERBUFFER, color_buffer);
        funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, internal_format, size.width(), size.height());
        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_RENDERBUFFER, color_buffer);
        QT_CHECK_GLERROR();
        valid = checkFramebufferStatus(ctx);

        if (valid) {
            funcs.glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_SAMPLES, &samples);
            color_buffer_guard = new QOpenGLSharedResourceGuard(ctx, color_buffer, freeRenderbufferFunc);
        }
    }

    format.setTextureTarget(target);
    format.setSamples(int(samples));
    format.setInternalTextureFormat(internal_format);
    format.setMipmap(mipmap);

    initAttachments(ctx, attachment);

    if (valid) {
        fbo_guard = new QOpenGLSharedResourceGuard(ctx, fbo, freeFramebufferFunc);
    } else {
        if (color_buffer_guard) {
            color_buffer_guard->free();
            color_buffer_guard = 0;
        } else if (texture_guard) {
            texture_guard->free();
            texture_guard = 0;
        }
        funcs.glDeleteFramebuffers(1, &fbo);
    }
    QT_CHECK_GLERROR();
}

void QOpenGLFramebufferObjectPrivate::initTexture(GLenum target, GLenum internal_format,
                                                  const QSize &size, bool mipmap)
{
    QOpenGLContext *ctx = QOpenGLContext::currentContext();
    GLuint texture = 0;

    funcs.glGenTextures(1, &texture);
    funcs.glBindTexture(target, texture);

    funcs.glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    funcs.glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    funcs.glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    funcs.glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    funcs.glTexImage2D(target, 0, internal_format, size.width(), size.height(), 0,
                       GL_RGBA, GL_UNSIGNED_BYTE, NULL);
    if (mipmap) {
        int width = size.width();
        int height = size.height();
        int level = 0;
        while (width > 1 || height > 1) {
            width = qMax(1, width >> 1);
            height = qMax(1, height >> 1);
            ++level;
            funcs.glTexImage2D(target, level, internal_format, width, height, 0,
                               GL_RGBA, GL_UNSIGNED_BYTE, NULL);
        }
    }
    funcs.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                 target, texture, 0);

    QT_CHECK_GLERROR();
    funcs.glBindTexture(target, 0);
    valid = checkFramebufferStatus(ctx);
    if (valid)
        texture_guard = new QOpenGLSharedResourceGuard(ctx, texture, freeTextureFunc);
    else
        funcs.glDeleteTextures(1, &texture);
}

void QOpenGLFramebufferObjectPrivate::initAttachments(QOpenGLContext *ctx, QOpenGLFramebufferObject::Attachment attachment)
{
    int samples = format.samples();

    // free existing attachments
    if (depth_buffer_guard) {
        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, 0);
        depth_buffer_guard->free();
    }
    if (stencil_buffer_guard) {
        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, 0);
        if (stencil_buffer_guard != depth_buffer_guard)
            stencil_buffer_guard->free();
    }

    depth_buffer_guard = 0;
    stencil_buffer_guard = 0;

    GLuint depth_buffer = 0;
    GLuint stencil_buffer = 0;

    // In practice, a combined depth-stencil buffer is supported by all desktop platforms, while a
    // separate stencil buffer is not. On embedded devices however, a combined depth-stencil buffer
    // might not be supported while separate buffers are, according to QTBUG-12861.

    if (attachment == QOpenGLFramebufferObject::CombinedDepthStencil
        && funcs.hasOpenGLExtension(QOpenGLExtensions::PackedDepthStencil))
    {
        // depth and stencil buffer needs another extension
        funcs.glGenRenderbuffers(1, &depth_buffer);
        funcs.glBindRenderbuffer(GL_RENDERBUFFER, depth_buffer);
        Q_ASSERT(funcs.glIsRenderbuffer(depth_buffer));
        if (samples != 0 && funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample))
            funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples,
                GL_DEPTH24_STENCIL8, size.width(), size.height());
        else
            funcs.glRenderbufferStorage(GL_RENDERBUFFER,
                GL_DEPTH24_STENCIL8, size.width(), size.height());

        stencil_buffer = depth_buffer;
        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                     GL_RENDERBUFFER, depth_buffer);
        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
                                     GL_RENDERBUFFER, stencil_buffer);

        valid = checkFramebufferStatus(ctx);
        if (!valid) {
            funcs.glDeleteRenderbuffers(1, &depth_buffer);
            stencil_buffer = depth_buffer = 0;
        }
    }

    if (depth_buffer == 0 && (attachment == QOpenGLFramebufferObject::CombinedDepthStencil
        || (attachment == QOpenGLFramebufferObject::Depth)))
    {
        funcs.glGenRenderbuffers(1, &depth_buffer);
        funcs.glBindRenderbuffer(GL_RENDERBUFFER, depth_buffer);
        Q_ASSERT(funcs.glIsRenderbuffer(depth_buffer));
        if (samples != 0 && funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
            if (ctx->isOpenGLES()) {
                if (funcs.hasOpenGLExtension(QOpenGLExtensions::Depth24))
                    funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples,
                                                           GL_DEPTH_COMPONENT24, size.width(), size.height());
                else
                    funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples,
                                                           GL_DEPTH_COMPONENT16, size.width(), size.height());
            } else {
                funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples,
                                                       GL_DEPTH_COMPONENT, size.width(), size.height());
            }
        } else {
            if (ctx->isOpenGLES()) {
                if (funcs.hasOpenGLExtension(QOpenGLExtensions::Depth24)) {
                    funcs.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24,
                                                size.width(), size.height());
                } else {
                    funcs.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16,
                                                size.width(), size.height());
                }
            } else {
                funcs.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, size.width(), size.height());
            }
        }
        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                     GL_RENDERBUFFER, depth_buffer);
        valid = checkFramebufferStatus(ctx);
        if (!valid) {
            funcs.glDeleteRenderbuffers(1, &depth_buffer);
            depth_buffer = 0;
        }
    }

    if (stencil_buffer == 0 && (attachment == QOpenGLFramebufferObject::CombinedDepthStencil)) {
        funcs.glGenRenderbuffers(1, &stencil_buffer);
        funcs.glBindRenderbuffer(GL_RENDERBUFFER, stencil_buffer);
        Q_ASSERT(funcs.glIsRenderbuffer(stencil_buffer));

#ifdef QT_OPENGL_ES
        GLenum storage = GL_STENCIL_INDEX8;
#else
        GLenum storage = ctx->isOpenGLES() ? GL_STENCIL_INDEX8 : GL_STENCIL_INDEX;
#endif

        if (samples != 0 && funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample))
            funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, storage, size.width(), size.height());
        else
            funcs.glRenderbufferStorage(GL_RENDERBUFFER, storage, size.width(), size.height());

        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
                                  GL_RENDERBUFFER, stencil_buffer);
        valid = checkFramebufferStatus(ctx);
        if (!valid) {
            funcs.glDeleteRenderbuffers(1, &stencil_buffer);
            stencil_buffer = 0;
        }
    }

    // The FBO might have become valid after removing the depth or stencil buffer.
    valid = checkFramebufferStatus(ctx);

    if (depth_buffer && stencil_buffer) {
        fbo_attachment = QOpenGLFramebufferObject::CombinedDepthStencil;
    } else if (depth_buffer) {
        fbo_attachment = QOpenGLFramebufferObject::Depth;
    } else {
        fbo_attachment = QOpenGLFramebufferObject::NoAttachment;
    }

    if (valid) {
        if (depth_buffer)
            depth_buffer_guard = new QOpenGLSharedResourceGuard(ctx, depth_buffer, freeRenderbufferFunc);
        if (stencil_buffer) {
            if (stencil_buffer == depth_buffer)
                stencil_buffer_guard = depth_buffer_guard;
            else
                stencil_buffer_guard = new QOpenGLSharedResourceGuard(ctx, stencil_buffer, freeRenderbufferFunc);
        }
    } else {
        if (depth_buffer)
            funcs.glDeleteRenderbuffers(1, &depth_buffer);
        if (stencil_buffer && depth_buffer != stencil_buffer)
            funcs.glDeleteRenderbuffers(1, &stencil_buffer);
    }
    QT_CHECK_GLERROR();

    format.setAttachment(fbo_attachment);
}

/*!
    \class QOpenGLFramebufferObject
    \brief The QOpenGLFramebufferObject class encapsulates an OpenGL framebuffer object.
    \since 5.0
    \inmodule QtGui

    \ingroup painting-3D

    The QOpenGLFramebufferObject class encapsulates an OpenGL framebuffer
    object, defined by the \c{GL_EXT_framebuffer_object} extension. It provides
    a rendering surface that can be painted on with a QPainter with the help of
    QOpenGLPaintDevice, or rendered to using native OpenGL calls. This surface
    can be bound and used as a regular texture in your own OpenGL drawing code.
    By default, the QOpenGLFramebufferObject class generates a 2D OpenGL
    texture (using the \c{GL_TEXTURE_2D} target), which is used as the internal
    rendering target.

    \b{It is important to have a current OpenGL context when creating a
    QOpenGLFramebufferObject, otherwise initialization will fail.}

    Create the QOpenGLFrameBufferObject instance with the CombinedDepthStencil
    attachment if you want QPainter to render correctly. Note that you need to
    create a QOpenGLFramebufferObject with more than one sample per pixel for
    primitives to be antialiased when drawing using a QPainter. To create a
    multisample framebuffer object you should use one of the constructors that
    take a QOpenGLFramebufferObjectFormat parameter, and set the
    QOpenGLFramebufferObjectFormat::samples() property to a non-zero value.

    For multisample framebuffer objects a color render buffer is created,
    otherwise a texture with the specified texture target is created.
    The color render buffer or texture will have the specified internal
    format, and will be bound to the \c GL_COLOR_ATTACHMENT0
    attachment in the framebuffer object.

    If you want to use a framebuffer object with multisampling enabled
    as a texture, you first need to copy from it to a regular framebuffer
    object using QOpenGLContext::blitFramebuffer().

    It is possible to draw into a QOpenGLFramebufferObject using QPainter and
    QOpenGLPaintDevice in a separate thread.
*/


/*!
    \enum QOpenGLFramebufferObject::Attachment

    This enum type is used to configure the depth and stencil buffers
    attached to the framebuffer object when it is created.

    \value NoAttachment         No attachment is added to the framebuffer object. Note that the
                                OpenGL depth and stencil tests won't work when rendering to a
                                framebuffer object without any depth or stencil buffers.
                                This is the default value.

    \value CombinedDepthStencil If the \c GL_EXT_packed_depth_stencil extension is present,
                                a combined depth and stencil buffer is attached.
                                If the extension is not present, only a depth buffer is attached.

    \value Depth                A depth buffer is attached to the framebuffer object.

    \sa attachment()
*/


/*! \fn QOpenGLFramebufferObject::QOpenGLFramebufferObject(const QSize &size, GLenum target)

    Constructs an OpenGL framebuffer object and binds a 2D OpenGL texture
    to the buffer of the size \a size. The texture is bound to the
    \c GL_COLOR_ATTACHMENT0 target in the framebuffer object.

    The \a target parameter is used to specify the OpenGL texture
    target. The default target is \c GL_TEXTURE_2D. Keep in mind that
    \c GL_TEXTURE_2D textures must have a power of 2 width and height
    (e.g. 256x512), unless you are using OpenGL 2.0 or higher.

    By default, no depth and stencil buffers are attached. This behavior
    can be toggled using one of the overloaded constructors.

    The default internal texture format is \c GL_RGBA8 for desktop
    OpenGL, and \c GL_RGBA for OpenGL/ES.

    It is important that you have a current OpenGL context set when
    creating the QOpenGLFramebufferObject, otherwise the initialization
    will fail.

    \sa size(), texture(), attachment()
*/

QOpenGLFramebufferObject::QOpenGLFramebufferObject(const QSize &size, GLenum target)
    : d_ptr(new QOpenGLFramebufferObjectPrivate)
{
    Q_D(QOpenGLFramebufferObject);
    d->init(this, size, NoAttachment, target,
#ifndef QT_OPENGL_ES_2
            QOpenGLContext::currentContext()->isOpenGLES() ? GL_RGBA : GL_RGBA8
#else
            GL_RGBA
#endif
        );
}

/*! \overload

    Constructs an OpenGL framebuffer object and binds a 2D OpenGL texture
    to the buffer of the given \a width and \a height.

    \sa size(), texture()
*/
QOpenGLFramebufferObject::QOpenGLFramebufferObject(int width, int height, GLenum target)
    : d_ptr(new QOpenGLFramebufferObjectPrivate)
{
    Q_D(QOpenGLFramebufferObject);
    d->init(this, QSize(width, height), NoAttachment, target,
#ifndef QT_OPENGL_ES_2
            QOpenGLContext::currentContext()->isOpenGLES() ? GL_RGBA : GL_RGBA8
#else
            GL_RGBA
#endif
        );
}

/*! \overload

    Constructs an OpenGL framebuffer object of the given \a size based on the
    supplied \a format.
*/

QOpenGLFramebufferObject::QOpenGLFramebufferObject(const QSize &size, const QOpenGLFramebufferObjectFormat &format)
    : d_ptr(new QOpenGLFramebufferObjectPrivate)
{
    Q_D(QOpenGLFramebufferObject);
    d->init(this, size, format.attachment(), format.textureTarget(), format.internalTextureFormat(),
            format.samples(), format.mipmap());
}

/*! \overload

    Constructs an OpenGL framebuffer object of the given \a width and \a height
    based on the supplied \a format.
*/

QOpenGLFramebufferObject::QOpenGLFramebufferObject(int width, int height, const QOpenGLFramebufferObjectFormat &format)
    : d_ptr(new QOpenGLFramebufferObjectPrivate)
{
    Q_D(QOpenGLFramebufferObject);
    d->init(this, QSize(width, height), format.attachment(), format.textureTarget(),
            format.internalTextureFormat(), format.samples(), format.mipmap());
}

/*! \overload

    Constructs an OpenGL framebuffer object and binds a texture to the
    buffer of the given \a width and \a height.

    The \a attachment parameter describes the depth/stencil buffer
    configuration, \a target the texture target and \a internal_format
    the internal texture format. The default texture target is \c
    GL_TEXTURE_2D, while the default internal format is \c GL_RGBA8
    for desktop OpenGL and \c GL_RGBA for OpenGL/ES.

    \sa size(), texture(), attachment()
*/
QOpenGLFramebufferObject::QOpenGLFramebufferObject(int width, int height, Attachment attachment,
                                           GLenum target, GLenum internal_format)
    : d_ptr(new QOpenGLFramebufferObjectPrivate)
{
    Q_D(QOpenGLFramebufferObject);
    if (!internal_format)
#ifdef QT_OPENGL_ES_2
        internal_format = GL_RGBA;
#else
        internal_format = QOpenGLContext::currentContext()->isOpenGLES() ? GL_RGBA : GL_RGBA8;
#endif
    d->init(this, QSize(width, height), attachment, target, internal_format);
}

/*! \overload

    Constructs an OpenGL framebuffer object and binds a texture to the
    buffer of the given \a size.

    The \a attachment parameter describes the depth/stencil buffer
    configuration, \a target the texture target and \a internal_format
    the internal texture format. The default texture target is \c
    GL_TEXTURE_2D, while the default internal format is \c GL_RGBA8
    for desktop OpenGL and \c GL_RGBA for OpenGL/ES.

    \sa size(), texture(), attachment()
*/
QOpenGLFramebufferObject::QOpenGLFramebufferObject(const QSize &size, Attachment attachment,
                                           GLenum target, GLenum internal_format)
    : d_ptr(new QOpenGLFramebufferObjectPrivate)
{
    Q_D(QOpenGLFramebufferObject);
    if (!internal_format)
#ifdef QT_OPENGL_ES_2
        internal_format = GL_RGBA;
#else
        internal_format = QOpenGLContext::currentContext()->isOpenGLES() ? GL_RGBA : GL_RGBA8;
#endif
    d->init(this, size, attachment, target, internal_format);
}

/*!
    \fn QOpenGLFramebufferObject::~QOpenGLFramebufferObject()

    Destroys the framebuffer object and frees any allocated resources.
*/
QOpenGLFramebufferObject::~QOpenGLFramebufferObject()
{
    Q_D(QOpenGLFramebufferObject);
    if (isBound())
        release();

    if (d->texture_guard)
        d->texture_guard->free();
    if (d->color_buffer_guard)
        d->color_buffer_guard->free();
    if (d->depth_buffer_guard)
        d->depth_buffer_guard->free();
    if (d->stencil_buffer_guard && d->stencil_buffer_guard != d->depth_buffer_guard)
        d->stencil_buffer_guard->free();
    if (d->fbo_guard)
        d->fbo_guard->free();
}

/*!
    \fn bool QOpenGLFramebufferObject::isValid() const

    Returns \c true if the framebuffer object is valid.

    The framebuffer can become invalid if the initialization process
    fails, the user attaches an invalid buffer to the framebuffer
    object, or a non-power of two width/height is specified as the
    texture size if the texture target is \c{GL_TEXTURE_2D}.
    The non-power of two limitation does not apply if the OpenGL version
    is 2.0 or higher, or if the GL_ARB_texture_non_power_of_two extension
    is present.

    The framebuffer can also become invalid if the QOpenGLContext that
    the framebuffer was created within is destroyed and there are
    no other shared contexts that can take over ownership of the
    framebuffer.
*/
bool QOpenGLFramebufferObject::isValid() const
{
    Q_D(const QOpenGLFramebufferObject);
    return d->valid && d->fbo_guard && d->fbo_guard->id();
}

/*!
    \fn bool QOpenGLFramebufferObject::bind()

    Switches rendering from the default, windowing system provided
    framebuffer to this framebuffer object.
    Returns \c true upon success, false otherwise.

    \note If takeTexture() was called, a new texture is created and associated
    with the framebuffer object. This is potentially expensive and changes the
    context state (the currently bound texture).

    \sa release()
*/
bool QOpenGLFramebufferObject::bind()
{
    if (!isValid())
        return false;
    Q_D(QOpenGLFramebufferObject);
    QOpenGLContext *current = QOpenGLContext::currentContext();
    if (!current)
        return false;
#ifdef QT_DEBUG
    if (current->shareGroup() != d->fbo_guard->group())
        qWarning("QOpenGLFramebufferObject::bind() called from incompatible context");
#endif
    d->funcs.glBindFramebuffer(GL_FRAMEBUFFER, d->fbo());
    if (d->texture_guard || d->format.samples() != 0)
        d->valid = d->checkFramebufferStatus(current);
    else
        d->initTexture(d->format.textureTarget(), d->format.internalTextureFormat(), d->size, d->format.mipmap());
    return d->valid;
}

/*!
    \fn bool QOpenGLFramebufferObject::release()

    Switches rendering back to the default, windowing system provided
    framebuffer.
    Returns \c true upon success, false otherwise.

    \sa bind()
*/
bool QOpenGLFramebufferObject::release()
{
    if (!isValid())
        return false;

    QOpenGLContext *current = QOpenGLContext::currentContext();
    if (!current)
        return false;

    Q_D(QOpenGLFramebufferObject);
#ifdef QT_DEBUG
    if (current->shareGroup() != d->fbo_guard->group())
        qWarning("QOpenGLFramebufferObject::release() called from incompatible context");
#endif

    if (current)
        d->funcs.glBindFramebuffer(GL_FRAMEBUFFER, current->defaultFramebufferObject());

    return true;
}

/*!
    \fn GLuint QOpenGLFramebufferObject::texture() const

    Returns the texture id for the texture attached as the default
    rendering target in this framebuffer object. This texture id can
    be bound as a normal texture in your own OpenGL code.

    If a multisample framebuffer object is used then the value returned
    from this function will be invalid.

    \sa takeTexture()
*/
GLuint QOpenGLFramebufferObject::texture() const
{
    Q_D(const QOpenGLFramebufferObject);
    return d->texture_guard ? d->texture_guard->id() : 0;
}

/*!
   \fn GLuint QOpenGLFramebufferObject::takeTexture()

   Returns the texture id for the texture attached to this framebuffer
   object. The ownership of the texture is transferred to the caller.

   If the framebuffer object is currently bound, an implicit release()
   will be done. During the next call to bind() a new texture will be
   created.

   If a multisample framebuffer object is used, then there is no
   texture and the return value from this function will be invalid.
   Similarly, incomplete framebuffer objects will also return 0.

   \since 5.3

   \sa texture(), bind(), release()
 */
GLuint QOpenGLFramebufferObject::takeTexture()
{
    Q_D(QOpenGLFramebufferObject);
    GLuint id = 0;
    if (isValid() && d->texture_guard) {
        QOpenGLContext *current = QOpenGLContext::currentContext();
        if (current && current->shareGroup() == d->fbo_guard->group() && isBound())
            release();
        id = d->texture_guard->id();
        // Do not call free() on texture_guard, just null it out.
        // This way the texture will not be deleted when the guard is destroyed.
        d->texture_guard = 0;
    }
    return id;
}

/*!
    \fn QSize QOpenGLFramebufferObject::size() const

    Returns the size of the texture attached to this framebuffer
    object.
*/
QSize QOpenGLFramebufferObject::size() const
{
    Q_D(const QOpenGLFramebufferObject);
    return d->size;
}

/*!
    \fn int QOpenGLFramebufferObject::width() const

    Returns the width of the framebuffer object attachments.
*/

/*!
    \fn int QOpenGLFramebufferObject::height() const

    Returns the height of the framebuffer object attachments.
*/

/*!
    Returns the format of this framebuffer object.
*/
QOpenGLFramebufferObjectFormat QOpenGLFramebufferObject::format() const
{
    Q_D(const QOpenGLFramebufferObject);
    return d->format;
}

Q_GUI_EXPORT QImage qt_gl_read_framebuffer(const QSize &size, bool alpha_format, bool include_alpha)
{
    int w = size.width();
    int h = size.height();

    QOpenGLFunctions *funcs = QOpenGLContext::currentContext()->functions();
    while (funcs->glGetError());

#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
    QImage img(size, (alpha_format && include_alpha) ? QImage::Format_ARGB32_Premultiplied
                                                     : QImage::Format_RGB32);
#ifdef QT_OPENGL_ES
    GLint fmt = GL_BGRA_EXT;
#else
    GLint fmt = GL_BGRA;
#endif
    funcs->glReadPixels(0, 0, w, h, fmt, GL_UNSIGNED_BYTE, img.bits());
    if (!funcs->glGetError())
        return img.mirrored();
#endif

    QImage rgbaImage(size, (alpha_format && include_alpha) ? QImage::Format_RGBA8888_Premultiplied
                                                           : QImage::Format_RGBX8888);
    funcs->glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, rgbaImage.bits());
    return rgbaImage.mirrored();
}

/*!
    \fn QImage QOpenGLFramebufferObject::toImage() const

    Returns the contents of this framebuffer object as a QImage.

    Will try to return a premultiplied ARBG32 or RGB32 image. Since 5.2 it will fall back to
    a premultiplied RGBA8888 or RGBx8888 image when reading to ARGB32 is not supported.
*/
QImage QOpenGLFramebufferObject::toImage() const
{
    Q_D(const QOpenGLFramebufferObject);
    if (!d->valid)
        return QImage();

    // qt_gl_read_framebuffer doesn't work on a multisample FBO
    if (format().samples() != 0) {
        QOpenGLFramebufferObject temp(size(), QOpenGLFramebufferObjectFormat());

        QRect rect(QPoint(0, 0), size());
        blitFramebuffer(&temp, rect, const_cast<QOpenGLFramebufferObject *>(this), rect);

        return temp.toImage();
    }

    bool wasBound = isBound();
    if (!wasBound)
        const_cast<QOpenGLFramebufferObject *>(this)->bind();
    QImage image = qt_gl_read_framebuffer(d->size, format().internalTextureFormat() != GL_RGB, true);
    if (!wasBound)
        const_cast<QOpenGLFramebufferObject *>(this)->release();

    return image;
}

/*!
    \fn bool QOpenGLFramebufferObject::bindDefault()

    Switches rendering back to the default, windowing system provided
    framebuffer.
    Returns \c true upon success, false otherwise.

    \sa bind(), release()
*/
bool QOpenGLFramebufferObject::bindDefault()
{
    QOpenGLContext *ctx = const_cast<QOpenGLContext *>(QOpenGLContext::currentContext());

    if (ctx)
        ctx->functions()->glBindFramebuffer(GL_FRAMEBUFFER, ctx->defaultFramebufferObject());
#ifdef QT_DEBUG
    else
        qWarning("QOpenGLFramebufferObject::bindDefault() called without current context.");
#endif

    return ctx != 0;
}

/*!
    \fn bool QOpenGLFramebufferObject::hasOpenGLFramebufferObjects()

    Returns \c true if the OpenGL \c{GL_EXT_framebuffer_object} extension
    is present on this system; otherwise returns \c false.
*/
bool QOpenGLFramebufferObject::hasOpenGLFramebufferObjects()
{
    return QOpenGLContext::currentContext()->functions()->hasOpenGLFeature(QOpenGLFunctions::Framebuffers);
}

/*!
    \fn GLuint QOpenGLFramebufferObject::handle() const

    Returns the OpenGL framebuffer object handle for this framebuffer
    object (returned by the \c{glGenFrameBuffersEXT()} function). This
    handle can be used to attach new images or buffers to the
    framebuffer. The user is responsible for cleaning up and
    destroying these objects.
*/
GLuint QOpenGLFramebufferObject::handle() const
{
    Q_D(const QOpenGLFramebufferObject);
    return d->fbo();
}

/*!
    Returns the status of the depth and stencil buffers attached to
    this framebuffer object.
*/

QOpenGLFramebufferObject::Attachment QOpenGLFramebufferObject::attachment() const
{
    Q_D(const QOpenGLFramebufferObject);
    if (d->valid)
        return d->fbo_attachment;
    return NoAttachment;
}

/*!
    Sets the attachments of the framebuffer object to \a attachment.

    This can be used to free or reattach the depth and stencil buffer
    attachments as needed.
 */
void QOpenGLFramebufferObject::setAttachment(QOpenGLFramebufferObject::Attachment attachment)
{
    Q_D(QOpenGLFramebufferObject);
    if (attachment == d->fbo_attachment || !isValid())
        return;
    QOpenGLContext *current = QOpenGLContext::currentContext();
    if (!current)
        return;
#ifdef QT_DEBUG
    if (current->shareGroup() != d->fbo_guard->group())
        qWarning("QOpenGLFramebufferObject::setAttachment() called from incompatible context");
#endif
    d->funcs.glBindFramebuffer(GL_FRAMEBUFFER, d->fbo());
    d->initAttachments(current, attachment);
}

/*!
    Returns \c true if the framebuffer object is currently bound to the current context,
    otherwise false is returned.
*/
bool QOpenGLFramebufferObject::isBound() const
{
    Q_D(const QOpenGLFramebufferObject);
    QOpenGLContext *ctx = QOpenGLContext::currentContext();
    if (!ctx)
        return false;
    GLint fbo = 0;
    ctx->functions()->glGetIntegerv(GL_FRAMEBUFFER_BINDING, &fbo);
    return GLuint(fbo) == d->fbo();
}

/*!
    \fn bool QOpenGLFramebufferObject::hasOpenGLFramebufferBlit()

    Returns \c true if the OpenGL \c{GL_EXT_framebuffer_blit} extension
    is present on this system; otherwise returns \c false.

    \sa blitFramebuffer()
*/
bool QOpenGLFramebufferObject::hasOpenGLFramebufferBlit()
{
    return QOpenGLExtensions(QOpenGLContext::currentContext()).hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit);
}


/*!
    \overload

    Convenience overload to blit between two framebuffer objects.
*/
void QOpenGLFramebufferObject::blitFramebuffer(QOpenGLFramebufferObject *target,
                                               QOpenGLFramebufferObject *source,
                                               GLbitfield buffers, GLenum filter)
{
    if (!target && !source)
        return;

    QSize targetSize;
    QSize sourceSize;

    if (target)
        targetSize = target->size();
    if (source)
        sourceSize = source->size();

    if (targetSize.isEmpty())
        targetSize = sourceSize;
    else if (sourceSize.isEmpty())
        sourceSize = targetSize;

    blitFramebuffer(target, QRect(QPoint(0, 0), targetSize),
                    source, QRect(QPoint(0, 0), sourceSize),
                    buffers, filter);
}

/*!
    Blits from the \a sourceRect rectangle in the \a source framebuffer
    object to the \a targetRect rectangle in the \a target framebuffer object.

    If \a source or \a target is 0, the default framebuffer will be used
    instead of a framebuffer object as source or target respectively.

    The \a buffers parameter should be a mask consisting of any combination of
    \c GL_COLOR_BUFFER_BIT, \c GL_DEPTH_BUFFER_BIT, and
    \c GL_STENCIL_BUFFER_BIT.  Any buffer type that is not present both
    in the source and target buffers is ignored.

    The \a sourceRect and \a targetRect rectangles may have different sizes;
    in this case \a buffers should not contain \c GL_DEPTH_BUFFER_BIT or
    \c GL_STENCIL_BUFFER_BIT. The \a filter parameter should be set to
    \c GL_LINEAR or \c GL_NEAREST, and specifies whether linear or nearest
    interpolation should be used when scaling is performed.

    If \a source equals \a target a copy is performed within the same buffer.
    Results are undefined if the source and target rectangles overlap and
    have different sizes. The sizes must also be the same if any of the
    framebuffer objects are multisample framebuffers.

    Note that the scissor test will restrict the blit area if enabled.

    This function will have no effect unless hasOpenGLFramebufferBlit() returns
    true.

    \sa hasOpenGLFramebufferBlit()
*/
void QOpenGLFramebufferObject::blitFramebuffer(QOpenGLFramebufferObject *target, const QRect &targetRect,
                                           QOpenGLFramebufferObject *source, const QRect &sourceRect,
                                           GLbitfield buffers,
                                           GLenum filter)
{
    QOpenGLContext *ctx = QOpenGLContext::currentContext();
    if (!ctx)
        return;

    QOpenGLExtensions extensions(ctx);
    if (!extensions.hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit))
        return;

    const int sx0 = sourceRect.left();
    const int sx1 = sourceRect.left() + sourceRect.width();
    const int sy0 = sourceRect.top();
    const int sy1 = sourceRect.top() + sourceRect.height();

    const int tx0 = targetRect.left();
    const int tx1 = targetRect.left() + targetRect.width();
    const int ty0 = targetRect.top();
    const int ty1 = targetRect.top() + targetRect.height();

    extensions.glBindFramebuffer(GL_READ_FRAMEBUFFER, source ? source->handle() : 0);
    extensions.glBindFramebuffer(GL_DRAW_FRAMEBUFFER, target ? target->handle() : 0);

    extensions.glBlitFramebuffer(sx0, sy0, sx1, sy1,
                                 tx0, ty0, tx1, ty1,
                                 buffers, filter);
}

QT_END_NAMESPACE