qt-everywhere-src-5.15.1/qtbase/src/gui/kernel/qplatformgraphicsbuffer.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** 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 The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL3 included in the
 ** packaging of this file. Please review the following information to
 ** ensure the GNU Lesser General Public License version 3 requirements
 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 2.0 or (at your option) the GNU General
 ** Public license version 3 or any later version approved by the KDE Free
 ** Qt Foundation. The licenses are as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
 ** included in the packaging of this file. Please review the following
 ** information to ensure the GNU General Public License requirements will
 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
 ** https://www.gnu.org/licenses/gpl-3.0.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "qplatformgraphicsbuffer.h"
 #include <QtGui/QOpenGLContext>
 #include <QtGui/QOpenGLFunctions>
 #include <QtGui/qopengl.h>
 #include <QtCore/QDebug>

 QT_BEGIN_NAMESPACE
 /*!
     \class QPlatformGraphicsBuffer
     \inmodule QtGui
     \since 5.5
     \brief The QPlatformGraphicsBuffer is a windowsystem abstraction for native graphics buffers

     Different platforms have different ways of representing graphics buffers. On
     some platforms, it is possible to create one graphics buffer that you can bind
     to a texture and also get main memory access to the image bits. On the
     other hand, on some platforms all graphics buffer abstraction is completely
     hidden.

     QPlatformGraphicsBuffer is an abstraction of a single Graphics Buffer.

     There is no public constructor nor any public factory function.

     QPlatformGraphicsBuffer is intended to be created by using platform specific
     APIs available from QtPlatformHeaders, or there might be accessor functions
     similar to the accessor function that QPlatformBackingstore has.

     \internal
 */

 /*!
     \enum QPlatformGraphicsBuffer::AccessType

     This enum describes the access that is desired or granted for the graphics
     buffer.

     \value None
     \value SWReadAccess
     \value SWWriteAccess
     \value TextureAccess
     \value HWCompositor
 */

 /*!
     \enum QPlatformGraphicsBuffer::Origin

     This enum describes the origin of the content of the buffer.

     \value OriginTopLeft
     \value OriginBottomLeft
 */

 /*!
     Protected constructor to initialize the private members.

     \a size is the size of the buffer.
     \a format is the format of the buffer.

     \sa size() format()
 */
 QPlatformGraphicsBuffer::QPlatformGraphicsBuffer(const QSize &size, const QPixelFormat &format)
     : m_size(size)
     , m_format(format)
 {
 }


 /*!
     Virtual destructor.
 */
 QPlatformGraphicsBuffer::~QPlatformGraphicsBuffer()
 {
 }

 /*!
     Binds the content of this graphics buffer into the currently bound texture.

     This function should fail for buffers not capable of locking to TextureAccess.

     \a rect is the subrect which is desired to be bounded to the texture. This
     argument has a no less than semantic, meaning more (if not all) of the buffer
     can be bounded to the texture. An empty QRect is interpreted as entire buffer
     should be bound.

     This function only supports binding buffers to the GL_TEXTURE_2D texture
     target.

     Returns true on success, otherwise false.
 */
 bool QPlatformGraphicsBuffer::bindToTexture(const QRect &rect) const
 {
     Q_UNUSED(rect);
     return false;
 }

 /*!
     \fn QPlatformGraphicsBuffer::AccessTypes QPlatformGraphicsBuffer::isLocked() const
     Function to check if the buffer is locked.

     \sa lock()
 */

 /*!
     Before the data can be retrieved or before a buffer can be bound to a
     texture it needs to be locked. This is a separate function call since this
     operation might be time consuming, and it would not be satisfactory to do
     it per function call.

     \a access is the access type wanted.

     \a rect is the subrect which is desired to be locked. This
     argument has a no less than semantic, meaning more (if not all) of the buffer
     can be locked. An empty QRect is interpreted as entire buffer should be locked.

     Return true on successfully locking all AccessTypes specified \a access
     otherwise returns false and no locks have been granted.
 */
 bool QPlatformGraphicsBuffer::lock(AccessTypes access, const QRect &rect)
 {
     bool locked = doLock(access, rect);
     if (locked)
         m_lock_access |= access;

     return locked;
 }

 /*!
     Unlocks the current buffer lock.

     This function calls doUnlock, and then emits the unlocked signal with the
     AccessTypes from before doUnlock was called.
 */
 void QPlatformGraphicsBuffer::unlock()
 {
     if (m_lock_access == None)
         return;
     AccessTypes previous = m_lock_access;
     doUnlock();
     m_lock_access = None;
     emit unlocked(previous);
 }


 /*!
     \fn QPlatformGraphicsBuffer::doLock(AccessTypes access, const QRect &rect = QRect())

     This function should be reimplemented by subclasses. If one of the \a
     access types specified cannot be locked, then all should fail and this
     function should return false.

     \a rect is the subrect which is desired to be locked. This
     argument has a no less than semantic, meaning more (if not all) of the
     buffer can be locked. An empty QRect should be interpreted as the entire buffer
     should be locked.

     It is safe to call isLocked() to verify the current lock state.
 */

 /*!
     \fn QPlatformGraphicsBuffer::doUnlock()

     This function should remove all locks set on the buffer.

     It is safe to call isLocked() to verify the current lock state.
 */

 /*!
     \fn QPlatformGraphicsBuffer::unlocked(AccessTypes previousAccessTypes)

     Signal that is emitted after unlocked has been called.

     \a previousAccessTypes is the access types locked before unlock was called.
 */

 /*!
     Accessor for the bytes of the buffer. This function needs to be called on a
     buffer with SWReadAccess access lock. Behavior is undefined for modifying
     the memory returned when not having a SWWriteAccess.
 */
 const uchar *QPlatformGraphicsBuffer::data() const
 { return nullptr; }

 /*!
     Accessor for the bytes of the buffer. This function needs to be called on a
     buffer with SWReadAccess access lock. Behavior is undefined for modifying
     the memory returned when not having a SWWriteAccess.
 */
 uchar *QPlatformGraphicsBuffer::data()
 {
     return nullptr;
 }

 /*!
     Accessor for the length of the data buffer. This function is a convenience
     function multiplying height of buffer with bytesPerLine().

     \sa data() bytesPerLine() size()
 */
 int QPlatformGraphicsBuffer::byteCount() const
 {
     return size().height() * bytesPerLine();
 }

 /*!
     Accessor for bytes per line in the graphics buffer.
 */
 int QPlatformGraphicsBuffer::bytesPerLine() const
 {
     return 0;
 }


 /*!
     In origin of the content of the graphics buffer.

     Default implementation is OriginTopLeft, as this is the coordinate
     system default for Qt. However, for most regular OpenGL textures
     this will be OriginBottomLeft.
 */
 QPlatformGraphicsBuffer::Origin QPlatformGraphicsBuffer::origin() const
 {
     return OriginTopLeft;
 }

 /*!
     \fn QPlatformGraphicsBuffer::size() const

     Accessor for content size.
 */

 /*!
     \fn QPlatformGraphicsBuffer::format() const

     Accessor for the pixel format of the buffer.
 */

 QT_END_NAMESPACE
	/****************************************************************************
	**
	** Copyright (C) 2016 The Qt Company Ltd.
	** Contact: https://www.qt.io/licensing/
	**
	** 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 The Qt Company. For licensing terms
	** and conditions see https://www.qt.io/terms-conditions. For further
	** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
	** Foundation and appearing in the file LICENSE.LGPL3 included in the
	** packaging of this file. Please review the following information to
	** ensure the GNU Lesser General Public License version 3 requirements
	** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
	**
	** GNU General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU
	** General Public License version 2.0 or (at your option) the GNU General
	** Public license version 3 or any later version approved by the KDE Free
	** Qt Foundation. The licenses are as published by the Free Software
	** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
	** included in the packaging of this file. Please review the following
	** information to ensure the GNU General Public License requirements will
	** be met: https://www.gnu.org/licenses/gpl-2.0.html and
	** https://www.gnu.org/licenses/gpl-3.0.html.
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	#include "qplatformgraphicsbuffer.h"
	#include <QtGui/QOpenGLContext>
	#include <QtGui/QOpenGLFunctions>
	#include <QtGui/qopengl.h>
	#include <QtCore/QDebug>

	QT_BEGIN_NAMESPACE
	/*!
	\class QPlatformGraphicsBuffer
	\inmodule QtGui
	\since 5.5
	\brief The QPlatformGraphicsBuffer is a windowsystem abstraction for native graphics buffers

	Different platforms have different ways of representing graphics buffers. On
	some platforms, it is possible to create one graphics buffer that you can bind
	to a texture and also get main memory access to the image bits. On the
	other hand, on some platforms all graphics buffer abstraction is completely
	hidden.

	QPlatformGraphicsBuffer is an abstraction of a single Graphics Buffer.

	There is no public constructor nor any public factory function.

	QPlatformGraphicsBuffer is intended to be created by using platform specific
	APIs available from QtPlatformHeaders, or there might be accessor functions
	similar to the accessor function that QPlatformBackingstore has.

	\internal
	*/

	/*!
	\enum QPlatformGraphicsBuffer::AccessType

	This enum describes the access that is desired or granted for the graphics
	buffer.

	\value None
	\value SWReadAccess
	\value SWWriteAccess
	\value TextureAccess
	\value HWCompositor
	*/

	/*!
	\enum QPlatformGraphicsBuffer::Origin

	This enum describes the origin of the content of the buffer.

	\value OriginTopLeft
	\value OriginBottomLeft
	*/

	/*!
	Protected constructor to initialize the private members.

	\a size is the size of the buffer.
	\a format is the format of the buffer.

	\sa size() format()
	*/
	QPlatformGraphicsBuffer::QPlatformGraphicsBuffer(const QSize &size, const QPixelFormat &format)
	: m_size(size)
	, m_format(format)
	{
	}


	/*!
	Virtual destructor.
	*/
	QPlatformGraphicsBuffer::~QPlatformGraphicsBuffer()
	{
	}

	/*!
	Binds the content of this graphics buffer into the currently bound texture.

	This function should fail for buffers not capable of locking to TextureAccess.

	\a rect is the subrect which is desired to be bounded to the texture. This
	argument has a no less than semantic, meaning more (if not all) of the buffer
	can be bounded to the texture. An empty QRect is interpreted as entire buffer
	should be bound.

	This function only supports binding buffers to the GL_TEXTURE_2D texture
	target.

	Returns true on success, otherwise false.
	*/
	bool QPlatformGraphicsBuffer::bindToTexture(const QRect &rect) const
	{
	Q_UNUSED(rect);
	return false;
	}

	/*!
	\fn QPlatformGraphicsBuffer::AccessTypes QPlatformGraphicsBuffer::isLocked() const
	Function to check if the buffer is locked.

	\sa lock()
	*/

	/*!
	Before the data can be retrieved or before a buffer can be bound to a
	texture it needs to be locked. This is a separate function call since this
	operation might be time consuming, and it would not be satisfactory to do
	it per function call.

	\a access is the access type wanted.

	\a rect is the subrect which is desired to be locked. This
	argument has a no less than semantic, meaning more (if not all) of the buffer
	can be locked. An empty QRect is interpreted as entire buffer should be locked.

	Return true on successfully locking all AccessTypes specified \a access
	otherwise returns false and no locks have been granted.
	*/
	bool QPlatformGraphicsBuffer::lock(AccessTypes access, const QRect &rect)
	{
	bool locked = doLock(access, rect);
	if (locked)
	m_lock_access \|= access;

	return locked;
	}

	/*!
	Unlocks the current buffer lock.

	This function calls doUnlock, and then emits the unlocked signal with the
	AccessTypes from before doUnlock was called.
	*/
	void QPlatformGraphicsBuffer::unlock()
	{
	if (m_lock_access == None)
	return;
	AccessTypes previous = m_lock_access;
	doUnlock();
	m_lock_access = None;
	emit unlocked(previous);
	}


	/*!
	\fn QPlatformGraphicsBuffer::doLock(AccessTypes access, const QRect &rect = QRect())

	This function should be reimplemented by subclasses. If one of the \a
	access types specified cannot be locked, then all should fail and this
	function should return false.

	\a rect is the subrect which is desired to be locked. This
	argument has a no less than semantic, meaning more (if not all) of the
	buffer can be locked. An empty QRect should be interpreted as the entire buffer
	should be locked.

	It is safe to call isLocked() to verify the current lock state.
	*/

	/*!
	\fn QPlatformGraphicsBuffer::doUnlock()

	This function should remove all locks set on the buffer.

	It is safe to call isLocked() to verify the current lock state.
	*/

	/*!
	\fn QPlatformGraphicsBuffer::unlocked(AccessTypes previousAccessTypes)

	Signal that is emitted after unlocked has been called.

	\a previousAccessTypes is the access types locked before unlock was called.
	*/

	/*!
	Accessor for the bytes of the buffer. This function needs to be called on a
	buffer with SWReadAccess access lock. Behavior is undefined for modifying
	the memory returned when not having a SWWriteAccess.
	*/
	const uchar *QPlatformGraphicsBuffer::data() const
	{ return nullptr; }

	/*!
	Accessor for the bytes of the buffer. This function needs to be called on a
	buffer with SWReadAccess access lock. Behavior is undefined for modifying
	the memory returned when not having a SWWriteAccess.
	*/
	uchar *QPlatformGraphicsBuffer::data()
	{
	return nullptr;
	}

	/*!
	Accessor for the length of the data buffer. This function is a convenience
	function multiplying height of buffer with bytesPerLine().

	\sa data() bytesPerLine() size()
	*/
	int QPlatformGraphicsBuffer::byteCount() const
	{
	return size().height() * bytesPerLine();
	}

	/*!
	Accessor for bytes per line in the graphics buffer.
	*/
	int QPlatformGraphicsBuffer::bytesPerLine() const
	{
	return 0;
	}


	/*!
	In origin of the content of the graphics buffer.

	Default implementation is OriginTopLeft, as this is the coordinate
	system default for Qt. However, for most regular OpenGL textures
	this will be OriginBottomLeft.
	*/
	QPlatformGraphicsBuffer::Origin QPlatformGraphicsBuffer::origin() const
	{
	return OriginTopLeft;
	}

	/*!
	\fn QPlatformGraphicsBuffer::size() const

	Accessor for content size.
	*/

	/*!
	\fn QPlatformGraphicsBuffer::format() const

	Accessor for the pixel format of the buffer.
	*/

	QT_END_NAMESPACE