1// Copyright (C) 2016 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#include "qplatformgraphicsbuffer.h"
5#include <QtGui/QOpenGLContext>
6#include <QtGui/QOpenGLFunctions>
7#include <QtGui/qopengl.h>
8#include <QtCore/QDebug>
9
10QT_BEGIN_NAMESPACE
11/*!
12 \class QPlatformGraphicsBuffer
13 \inmodule QtGui
14 \since 5.5
15 \brief The QPlatformGraphicsBuffer is a windowsystem abstraction for native graphics buffers
16
17 Different platforms have different ways of representing graphics buffers. On
18 some platforms, it is possible to create one graphics buffer that you can bind
19 to a texture and also get main memory access to the image bits. On the
20 other hand, on some platforms all graphics buffer abstraction is completely
21 hidden.
22
23 QPlatformGraphicsBuffer is an abstraction of a single Graphics Buffer.
24
25 There is no public constructor nor any public factory function.
26
27 \internal
28*/
29
30/*!
31 \enum QPlatformGraphicsBuffer::AccessType
32
33 This enum describes the access that is desired or granted for the graphics
34 buffer.
35
36 \value None
37 \value SWReadAccess
38 \value SWWriteAccess
39 \value TextureAccess
40 \value HWCompositor
41*/
42
43/*!
44 \enum QPlatformGraphicsBuffer::Origin
45
46 This enum describes the origin of the content of the buffer.
47
48 \value OriginTopLeft
49 \value OriginBottomLeft
50*/
51
52/*!
53 Protected constructor to initialize the private members.
54
55 \a size is the size of the buffer.
56 \a format is the format of the buffer.
57
58 \sa size() format()
59*/
60QPlatformGraphicsBuffer::QPlatformGraphicsBuffer(const QSize &size, const QPixelFormat &format)
61 : m_size(size)
62 , m_format(format)
63{
64}
65
66
67/*!
68 Virtual destructor.
69*/
70QPlatformGraphicsBuffer::~QPlatformGraphicsBuffer()
71{
72}
73
74/*!
75 Binds the content of this graphics buffer into the currently bound texture.
76
77 This function should fail for buffers not capable of locking to TextureAccess.
78
79 \a rect is the subrect which is desired to be bounded to the texture. This
80 argument has a no less than semantic, meaning more (if not all) of the buffer
81 can be bounded to the texture. An empty QRect is interpreted as entire buffer
82 should be bound.
83
84 This function only supports binding buffers to the GL_TEXTURE_2D texture
85 target.
86
87 Returns true on success, otherwise false.
88*/
89bool QPlatformGraphicsBuffer::bindToTexture(const QRect &rect) const
90{
91 Q_UNUSED(rect);
92 return false;
93}
94
95/*!
96 \fn QPlatformGraphicsBuffer::AccessTypes QPlatformGraphicsBuffer::isLocked() const
97 Function to check if the buffer is locked.
98
99 \sa lock()
100*/
101
102/*!
103 Before the data can be retrieved or before a buffer can be bound to a
104 texture it needs to be locked. This is a separate function call since this
105 operation might be time consuming, and it would not be satisfactory to do
106 it per function call.
107
108 \a access is the access type wanted.
109
110 \a rect is the subrect which is desired to be locked. This
111 argument has a no less than semantic, meaning more (if not all) of the buffer
112 can be locked. An empty QRect is interpreted as entire buffer should be locked.
113
114 Return true on successfully locking all AccessTypes specified \a access
115 otherwise returns false and no locks have been granted.
116*/
117bool QPlatformGraphicsBuffer::lock(AccessTypes access, const QRect &rect)
118{
119 bool locked = doLock(access, rect);
120 if (locked)
121 m_lock_access |= access;
122
123 return locked;
124}
125
126/*!
127 Unlocks the current buffer lock.
128
129 This function calls doUnlock, and then emits the unlocked signal with the
130 AccessTypes from before doUnlock was called.
131*/
132void QPlatformGraphicsBuffer::unlock()
133{
134 if (m_lock_access == None)
135 return;
136 AccessTypes previous = m_lock_access;
137 doUnlock();
138 m_lock_access = None;
139 emit unlocked(previousAccessTypes: previous);
140}
141
142
143/*!
144 \fn QPlatformGraphicsBuffer::doLock(AccessTypes access, const QRect &rect = QRect())
145
146 This function should be reimplemented by subclasses. If one of the \a
147 access types specified cannot be locked, then all should fail and this
148 function should return false.
149
150 \a rect is the subrect which is desired to be locked. This
151 argument has a no less than semantic, meaning more (if not all) of the
152 buffer can be locked. An empty QRect should be interpreted as the entire buffer
153 should be locked.
154
155 It is safe to call isLocked() to verify the current lock state.
156*/
157
158/*!
159 \fn QPlatformGraphicsBuffer::doUnlock()
160
161 This function should remove all locks set on the buffer.
162
163 It is safe to call isLocked() to verify the current lock state.
164*/
165
166/*!
167 \fn QPlatformGraphicsBuffer::unlocked(AccessTypes previousAccessTypes)
168
169 Signal that is emitted after unlocked has been called.
170
171 \a previousAccessTypes is the access types locked before unlock was called.
172*/
173
174/*!
175 Accessor for the bytes of the buffer. This function needs to be called on a
176 buffer with SWReadAccess access lock. Behavior is undefined for modifying
177 the memory returned when not having a SWWriteAccess.
178*/
179const uchar *QPlatformGraphicsBuffer::data() const
180{ return nullptr; }
181
182/*!
183 Accessor for the bytes of the buffer. This function needs to be called on a
184 buffer with SWReadAccess access lock. Behavior is undefined for modifying
185 the memory returned when not having a SWWriteAccess.
186*/
187uchar *QPlatformGraphicsBuffer::data()
188{
189 return nullptr;
190}
191
192/*!
193 Accessor for the length of the data buffer. This function is a convenience
194 function multiplying height of buffer with bytesPerLine().
195
196 \sa data() bytesPerLine() size()
197*/
198int QPlatformGraphicsBuffer::byteCount() const
199{
200 return size().height() * bytesPerLine();
201}
202
203/*!
204 Accessor for bytes per line in the graphics buffer.
205*/
206int QPlatformGraphicsBuffer::bytesPerLine() const
207{
208 return 0;
209}
210
211
212/*!
213 In origin of the content of the graphics buffer.
214
215 Default implementation is OriginTopLeft, as this is the coordinate
216 system default for Qt. However, for most regular OpenGL textures
217 this will be OriginBottomLeft.
218*/
219QPlatformGraphicsBuffer::Origin QPlatformGraphicsBuffer::origin() const
220{
221 return OriginTopLeft;
222}
223
224/*!
225 \fn QPlatformGraphicsBuffer::size() const
226
227 Accessor for content size.
228*/
229
230/*!
231 \fn QPlatformGraphicsBuffer::format() const
232
233 Accessor for the pixel format of the buffer.
234*/
235
236QT_END_NAMESPACE
237
238#include "moc_qplatformgraphicsbuffer.cpp"
239

source code of qtbase/src/gui/kernel/qplatformgraphicsbuffer.cpp