QGLPixelBuffer Class ReferenceThe QGLPixelBuffer class encapsulates an OpenGL pbuffer. Далее... #include <QGLPixelBuffer> Inherits: QPaintDevice. This class was introduced in Qt 4.1. Открытые функции
Переопределённые открытые функции
Статические открытые члены
Переопределённые защищённые функции
Подробное описаниеThe QGLPixelBuffer class encapsulates an OpenGL pbuffer. Rendering into a pbuffer is normally done using full hardware acceleration. This can be significantly faster than rendering into a QPixmap. There are three approaches to using this class:
ПотокиAs of Qt 4.8, it's possible to render into a QGLPixelBuffer using a QPainter in a separate thread. Note that OpenGL 2.0 or OpenGL ES 2.0 is required for this to work. Also, under X11, it's necessary to set the Qt::AA_X11InitThreads application attribute. Pbuffers are provided by the OpenGL pbuffer extension; call hasOpenGLPbuffer() to find out if the system provides pbuffers. See also Pbuffers Example. Описание функций-членовQGLPixelBuffer::QGLPixelBuffer ( const QSize & size, const QGLFormat & format = QGLFormat::defaultFormat(), QGLWidget * shareWidget = 0 )Constructs an OpenGL pbuffer of the given size. If no format is specified, the default format is used. If the shareWidget parameter points to a valid QGLWidget, the pbuffer will share its context with shareWidget. If you intend to bind this pbuffer as a dynamic texture, the width and height components of size must be powers of two (e.g., 512 x 128). QGLPixelBuffer::QGLPixelBuffer ( int width, int height, const QGLFormat & format = QGLFormat::defaultFormat(), QGLWidget * shareWidget = 0 )Это перегруженная функция. Constructs an OpenGL pbuffer with the width and height. If no format is specified, the default format is used. If the shareWidget parameter points to a valid QGLWidget, the pbuffer will share its context with shareWidget. If you intend to bind this pbuffer as a dynamic texture, the width and height components of size must be powers of two (e.g., 512 x 128). QGLPixelBuffer::~QGLPixelBuffer () [virtual]Destroys the pbuffer and frees any allocated resources. GLuint QGLPixelBuffer::bindTexture ( const QImage & image, GLenum target = GL_TEXTURE_2D )Generates and binds a 2D GL texture to the current context, based on image. The generated texture id is returned and can be used in later glBindTexture() calls. The target parameter specifies the texture target. Equivalent to calling QGLContext::bindTexture(). See also deleteTexture(). GLuint QGLPixelBuffer::bindTexture ( const QPixmap & pixmap, GLenum target = GL_TEXTURE_2D )Это перегруженная функция. Generates and binds a 2D GL texture based on pixmap. Equivalent to calling QGLContext::bindTexture(). See also deleteTexture(). GLuint QGLPixelBuffer::bindTexture ( const QString & fileName )Это перегруженная функция. Reads the DirectDrawSurface (DDS) compressed file fileName and generates a 2D GL texture from it. Equivalent to calling QGLContext::bindTexture(). See also deleteTexture(). bool QGLPixelBuffer::bindToDynamicTexture ( GLuint texture_id )Binds the texture specified by texture_id to this pbuffer. Возвращает true, если всё прошло успешно; в противном случае возвращает false. The texture must be of the same size and format as the pbuffer. To unbind the texture, call releaseFromDynamicTexture(). While the texture is bound, it is updated automatically when the pbuffer contents change, eliminating the need for additional copy operations. Пример: QGLPixelBuffer pbuffer(...); ... pbuffer.makeCurrent(); GLuint dynamicTexture = pbuffer.generateDynamicTexture(); pbuffer.bindToDynamicTexture(dynamicTexture); ... pbuffer.releaseFromDynamicTexture(); Warning: This function uses the render_texture extension, which is currently not supported under X11. An alternative that works on all systems (including X11) is to manually copy the pbuffer contents to a texture using updateDynamicTexture(). Warning: For the bindToDynamicTexture() call to succeed on the Mac OS X, the pbuffer needs a shared context, i.e. the QGLPixelBuffer must be created with a share widget. See also generateDynamicTexture() and releaseFromDynamicTexture(). void QGLPixelBuffer::deleteTexture ( GLuint texture_id )Removes the texture identified by texture_id from the texture cache. Equivalent to calling QGLContext::deleteTexture(). bool QGLPixelBuffer::doneCurrent ()Makes no context the current OpenGL context. Возвращает true, если всё прошло успешно; в противном случае возвращает false. void QGLPixelBuffer::drawTexture ( const QRectF & target, GLuint textureId, GLenum textureTarget = GL_TEXTURE_2D )Draws the given texture, textureId, to the given target rectangle, target, in OpenGL model space. The textureTarget should be a 2D texture target. Equivalent to the corresponding QGLContext::drawTexture(). Эта функция была введена в Qt 4.4. void QGLPixelBuffer::drawTexture ( const QPointF & point, GLuint textureId, GLenum textureTarget = GL_TEXTURE_2D )Draws the given texture, textureId, at the given point in OpenGL model space. The textureTarget parameter should be a 2D texture target. Equivalent to the corresponding QGLContext::drawTexture(). Эта функция была введена в Qt 4.4. QGLFormat QGLPixelBuffer::format () constReturns the format of the pbuffer. The format may be different from the one that was requested. GLuint QGLPixelBuffer::generateDynamicTexture () constGenerates and binds a 2D GL texture that is the same size as the pbuffer, and returns the texture's ID. This can be used in conjunction with bindToDynamicTexture() and updateDynamicTexture(). Смотрите также size(). Qt::HANDLE QGLPixelBuffer::handle () constReturns the native pbuffer handle. bool QGLPixelBuffer::hasOpenGLPbuffers () [static]Returns true if the OpenGL pbuffer extension is present on this system; otherwise returns false. bool QGLPixelBuffer::isValid () constReturns true if this pbuffer is valid; otherwise returns false. bool QGLPixelBuffer::makeCurrent ()Makes this pbuffer the current OpenGL rendering context. Возвращает true, если всё прошло успешно; в противном случае возвращает false. See also QGLContext::makeCurrent() and doneCurrent(). int QGLPixelBuffer::metric ( PaintDeviceMetric metric ) const [virtual protected]Reimplemented from QPaintDevice::metric(). QPaintEngine * QGLPixelBuffer::paintEngine () const [virtual]Reimplemented from QPaintDevice::paintEngine(). void QGLPixelBuffer::releaseFromDynamicTexture ()Releases the pbuffer from any previously bound texture. See also bindToDynamicTexture(). QSize QGLPixelBuffer::size () constReturns the size of the pbuffer. QImage QGLPixelBuffer::toImage () constReturns the contents of the pbuffer as a QImage. void QGLPixelBuffer::updateDynamicTexture ( GLuint texture_id ) constCopies the pbuffer contents into the texture specified with texture_id. The texture must be of the same size and format as the pbuffer. Пример: QGLPixelBuffer pbuffer(...); ... pbuffer.makeCurrent(); GLuint dynamicTexture = pbuffer.generateDynamicTexture(); ... pbuffer.updateDynamicTexture(dynamicTexture); An alternative on Windows and Mac OS X systems that support the render_texture extension is to use bindToDynamicTexture() to get dynamic updates of the texture. See also generateDynamicTexture() and bindToDynamicTexture(). |
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