summaryrefslogtreecommitdiffstats
path: root/src/opengl/qglbuffer.cpp
blob: 322bfb65a1a3facfe159a9e38a528ee7a5be6e0c (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
/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtOpenGL module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** 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, Nokia gives you certain additional
** rights. These rights are described in the Nokia 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.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QtOpenGL/qgl.h>
#include <QtOpenGL/private/qgl_p.h>
#include <QtOpenGL/private/qglextensions_p.h>
#include <QtCore/qatomic.h>
#include "qglbuffer.h"

QT_BEGIN_NAMESPACE

/*!
    \class QGLBuffer
    \brief The QGLBuffer class provides functions for creating and managing GL buffer objects.
    \since 4.7
    \ingroup painting-3D

    Buffer objects are created in the GL server so that the
    client application can avoid uploading vertices, indices,
    texture image data, etc every time they are needed.

    QGLBuffer objects can be copied around as a reference to the
    underlying GL buffer object:

    \code
    QGLBuffer buffer1(QGLBuffer::IndexBuffer);
    buffer1.create();

    QGLBuffer buffer2 = buffer1;
    \endcode

    QGLBuffer performs a shallow copy when objects are copied in this
    manner, but does not implement copy-on-write semantics.  The original
    object will be affected whenever the copy is modified.
*/

/*!
    \enum QGLBuffer::Type
    This enum defines the type of GL buffer object to create with QGLBuffer.

    \value VertexBuffer Vertex buffer object for use when specifying
           vertex arrays.
    \value IndexBuffer Index buffer object for use with \c{glDrawElements()}.
    \value PixelPackBuffer Pixel pack buffer object for reading pixel
           data from the GL server (for example, with \c{glReadPixels()}).
           Not supported under OpenGL/ES.
    \value PixelUnpackBuffer Pixel unpack buffer object for writing pixel
           data to the GL server (for example, with \c{glTexImage2D()}).
           Not supported under OpenGL/ES.
*/

/*!
    \enum QGLBuffer::UsagePattern
    This enum defines the usage pattern of a QGLBuffer object.

    \value StreamDraw The data will be set once and used a few times
           for drawing operations.  Under OpenGL/ES 1.1 this is identical
           to StaticDraw.
    \value StreamRead The data will be set once and used a few times
           for reading data back from the GL server.  Not supported
           under OpenGL/ES.
    \value StreamCopy The data will be set once and used a few times
           for reading data back from the GL server for use in further
           drawing operations.  Not supported under OpenGL/ES.
    \value StaticDraw The data will be set once and used many times
           for drawing operations.
    \value StaticRead The data will be set once and used many times
           for reading data back from the GL server.  Not supported
           under OpenGL/ES.
    \value StaticCopy The data will be set once and used many times
           for reading data back from the GL server for use in further
           drawing operations.  Not supported under OpenGL/ES.
    \value DynamicDraw The data will be modified repeatedly and used
           many times for drawing operations.
    \value DynamicRead The data will be modified repeatedly and used
           many times for reading data back from the GL server.
           Not supported under OpenGL/ES.
    \value DynamicCopy The data will be modified repeatedly and used
           many times for reading data back from the GL server for
           use in further drawing operations.  Not supported under OpenGL/ES.
*/

/*!
    \enum QGLBuffer::Access
    This enum defines the access mode for QGLBuffer::map().

    \value ReadOnly The buffer will be mapped for reading only.
    \value WriteOnly The buffer will be mapped for writing only.
    \value ReadWrite The buffer will be mapped for reading and writing.
*/

class QGLBufferPrivate
{
public:
    QGLBufferPrivate(QGLBuffer::Type t)
        : ref(1),
          type(t),
          guard(0),
          usagePattern(QGLBuffer::StaticDraw),
          actualUsagePattern(QGLBuffer::StaticDraw)
    {
    }

    QAtomicInt ref;
    QGLBuffer::Type type;
    QGLSharedResourceGuard guard;
    QGLBuffer::UsagePattern usagePattern;
    QGLBuffer::UsagePattern actualUsagePattern;
};

/*!
    Constructs a new buffer object of type QGLBuffer::VertexBuffer.

    Note: this constructor just creates the QGLBuffer instance.  The actual
    buffer object in the GL server is not created until create() is called.

    \sa create()
*/
QGLBuffer::QGLBuffer()
    : d_ptr(new QGLBufferPrivate(QGLBuffer::VertexBuffer))
{
}

/*!
    Constructs a new buffer object of \a type.

    Note: this constructor just creates the QGLBuffer instance.  The actual
    buffer object in the GL server is not created until create() is called.

    \sa create()
*/
QGLBuffer::QGLBuffer(QGLBuffer::Type type)
    : d_ptr(new QGLBufferPrivate(type))
{
}

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

    Note: QGLBuffer does not implement copy-on-write semantics,
    so \a other will be affected whenever the copy is modified.
*/
QGLBuffer::QGLBuffer(const QGLBuffer &other)
    : d_ptr(other.d_ptr)
{
    d_ptr->ref.ref();
}

#define ctx d->guard.context()

/*!
    Destroys this buffer object, including the storage being
    used in the GL server.
*/
QGLBuffer::~QGLBuffer()
{
    if (!d_ptr->ref.deref()) {
        destroy();
        delete d_ptr;
    }
}

/*!
    Assigns a shallow copy of \a other to this object.

    Note: QGLBuffer does not implement copy-on-write semantics,
    so \a other will be affected whenever the copy is modified.
*/
QGLBuffer &QGLBuffer::operator=(const QGLBuffer &other)
{
    if (d_ptr != other.d_ptr) {
        other.d_ptr->ref.ref();
        if (!d_ptr->ref.deref())
            destroy();
        d_ptr = other.d_ptr;
    }
    return *this;
}

/*!
    Returns the type of buffer represented by this object.
*/
QGLBuffer::Type QGLBuffer::type() const
{
    Q_D(const QGLBuffer);
    return d->type;
}

/*!
    Returns the usage pattern for this buffer object.
    The default value is StaticDraw.

    \sa setUsagePattern()
*/
QGLBuffer::UsagePattern QGLBuffer::usagePattern() const
{
    Q_D(const QGLBuffer);
    return d->usagePattern;
}

/*!
    Sets the usage pattern for this buffer object to \a value.
    This function must be called before allocate() or write().

    \sa usagePattern(), allocate(), write()
*/
void QGLBuffer::setUsagePattern(QGLBuffer::UsagePattern value)
{
    Q_D(QGLBuffer);
#if defined(QT_OPENGL_ES_1)
    // OpenGL/ES 1.1 does not support GL_STREAM_DRAW, so use GL_STATIC_DRAW.
    // OpenGL/ES 2.0 does support GL_STREAM_DRAW.
    d->usagePattern = value;
    if (value == StreamDraw)
        d->actualUsagePattern = StaticDraw;
    else
        d->actualUsagePattern = value;
#else
    d->usagePattern = d->actualUsagePattern = value;
#endif
}

#undef ctx

/*!
    Creates the buffer object in the GL server.  Returns true if
    the object was created; false otherwise.

    This function must be called with a current QGLContext.
    The buffer will be bound to and can only be used in
    that context (or any other context that is shared with it).

    This function will return false if the GL implementation
    does not support buffers, or there is no current QGLContext.

    \sa isCreated(), allocate(), write(), destroy()
*/
bool QGLBuffer::create()
{
    Q_D(QGLBuffer);
    if (d->guard.id())
        return true;
    const QGLContext *ctx = QGLContext::currentContext();
    if (ctx) {
        if (!qt_resolve_buffer_extensions(const_cast<QGLContext *>(ctx)))
            return false;
        GLuint bufferId = 0;
        glGenBuffers(1, &bufferId);
        if (bufferId) {
            d->guard.setContext(ctx);
            d->guard.setId(bufferId);
            return true;
        }
    }
    return false;
}

#define ctx d->guard.context()

/*!
    Returns true if this buffer has been created; false otherwise.

    \sa create(), destroy()
*/
bool QGLBuffer::isCreated() const
{
    Q_D(const QGLBuffer);
    return d->guard.id() != 0;
}

/*!
    Destroys this buffer object, including the storage being
    used in the GL server.  All references to the buffer will
    become invalid.
*/
void QGLBuffer::destroy()
{
    Q_D(QGLBuffer);
    GLuint bufferId = d->guard.id();
    if (bufferId) {
        // Switch to the original creating context to destroy it.
        QGLShareContextScope scope(d->guard.context());
        glDeleteBuffers(1, &bufferId);
    }
    d->guard.setId(0);
    d->guard.setContext(0);
}

/*!
    Reads the \a count bytes in this buffer starting at \a offset
    into \a data.  Returns true on success; false if reading from
    the buffer is not supported.  Buffer reading is not supported
    under OpenGL/ES.

    It is assumed that this buffer has been bound to the current context.

    \sa write(), bind()
*/
bool QGLBuffer::read(int offset, void *data, int count)
{
#if !defined(QT_OPENGL_ES)
    Q_D(QGLBuffer);
    if (!glGetBufferSubData || !d->guard.id())
        return false;
    while (glGetError() != GL_NO_ERROR) ; // Clear error state.
    glGetBufferSubData(d->type, offset, count, data);
    return glGetError() == GL_NO_ERROR;
#else
    Q_UNUSED(offset);
    Q_UNUSED(data);
    Q_UNUSED(count);
    return false;
#endif
}

/*!
    Replaces the \a count bytes of this buffer starting at \a offset
    with the contents of \a data.  Any other bytes in the buffer
    will be left unmodified.

    It is assumed that create() has been called on this buffer and that
    it has been bound to the current context.

    \sa create(), read(), allocate()
*/
void QGLBuffer::write(int offset, const void *data, int count)
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::allocate(): buffer not created");
#endif
    Q_D(QGLBuffer);
    if (d->guard.id())
        glBufferSubData(d->type, offset, count, data);
}

/*!
    Allocates \a count bytes of space to the buffer, initialized to
    the contents of \a data.  Any previous contents will be removed.

    It is assumed that create() has been called on this buffer and that
    it has been bound to the current context.

    \sa create(), read(), write()
*/
void QGLBuffer::allocate(const void *data, int count)
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::allocate(): buffer not created");
#endif
    Q_D(QGLBuffer);
    if (d->guard.id())
        glBufferData(d->type, count, data, d->actualUsagePattern);
}

/*!
    \fn void QGLBuffer::allocate(int count)
    \overload

    Allocates \a count bytes of space to the buffer.  Any previous
    contents will be removed.

    It is assumed that create() has been called on this buffer and that
    it has been bound to the current context.

    \sa create(), write()
*/

/*!
    Binds the buffer associated with this object to the current
    GL context.  Returns false if binding was not possible, usually because
    type() is not supported on this GL implementation.

    The buffer must be bound to the same QGLContext current when create()
    was called, or to another QGLContext that is sharing with it.
    Otherwise, false will be returned from this function.

    \sa release(), create()
*/
bool QGLBuffer::bind()
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::bind(): buffer not created");
#endif
    Q_D(const QGLBuffer);
    GLuint bufferId = d->guard.id();
    if (bufferId) {
        if (!QGLContext::areSharing(QGLContext::currentContext(),
                                    d->guard.context())) {
#ifndef QT_NO_DEBUG
            qWarning("QGLBuffer::bind: buffer is not valid in the current context");
#endif
            return false;
        }
        glBindBuffer(d->type, bufferId);
        return true;
    } else {
        return false;
    }
}

/*!
    Releases the buffer associated with this object from the
    current GL context.

    This function must be called with the same QGLContext current
    as when bind() was called on the buffer.

    \sa bind()
*/
void QGLBuffer::release()
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::release(): buffer not created");
#endif
    Q_D(const QGLBuffer);
    if (d->guard.id())
        glBindBuffer(d->type, 0);
}

#undef ctx

/*!
    Releases the buffer associated with \a type in the current
    QGLContext.

    This function is a direct call to \c{glBindBuffer(type, 0)}
    for use when the caller does not know which QGLBuffer has
    been bound to the context but wants to make sure that it
    is released.

    \code
    QGLBuffer::release(QGLBuffer::VertexBuffer);
    \endcode
*/
void QGLBuffer::release(QGLBuffer::Type type)
{
    const QGLContext *ctx = QGLContext::currentContext();
    if (ctx && qt_resolve_buffer_extensions(const_cast<QGLContext *>(ctx)))
        glBindBuffer(GLenum(type), 0);
}

#define ctx d->guard.context()

/*!
    Returns the GL identifier associated with this buffer; zero if
    the buffer has not been created.

    \sa isCreated()
*/
GLuint QGLBuffer::bufferId() const
{
    Q_D(const QGLBuffer);
    return d->guard.id();
}

#ifndef GL_BUFFER_SIZE
#define GL_BUFFER_SIZE 0x8764
#endif

/*!
    Returns the size of the data in this buffer, for reading operations.
    Returns -1 if fetching the buffer size is not supported, or the
    buffer has not been created.

    It is assumed that this buffer has been bound to the current context.

    \sa isCreated(), bind()
*/
int QGLBuffer::size() const
{
    Q_D(const QGLBuffer);
    if (!d->guard.id())
        return -1;
    GLint value = -1;
    glGetBufferParameteriv(d->type, GL_BUFFER_SIZE, &value);
    return value;
}

/*!
    Maps the contents of this buffer into the application's memory
    space and returns a pointer to it.  Returns null if memory
    mapping is not possible.  The \a access parameter indicates the
    type of access to be performed.

    It is assumed that create() has been called on this buffer and that
    it has been bound to the current context.

    This function is only supported under OpenGL/ES if the
    \c{GL_OES_mapbuffer} extension is present.

    \sa unmap(), create(), bind()
*/
void *QGLBuffer::map(QGLBuffer::Access access)
{
    Q_D(QGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::map(): buffer not created");
#endif
    if (!d->guard.id())
        return 0;
    if (!glMapBufferARB)
        return 0;
#ifdef QT_OPENGL_ES_2
    if (access != QGLBuffer::WriteOnly)
        return 0;
#endif
    return glMapBufferARB(d->type, access);
}

/*!
    Unmaps the buffer after it was mapped into the application's
    memory space with a previous call to map().  Returns true if
    the unmap succeeded; false otherwise.

    It is assumed that this buffer has been bound to the current context,
    and that it was previously mapped with map().

    This function is only supported under OpenGL/ES if the
    \c{GL_OES_mapbuffer} extension is present.

    \sa map()
*/
bool QGLBuffer::unmap()
{
    Q_D(QGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::unmap(): buffer not created");
#endif
    if (!d->guard.id())
        return false;
    if (!glUnmapBufferARB)
        return false;
    return glUnmapBufferARB(d->type) == GL_TRUE;
}

QT_END_NAMESPACE