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The QGLPixelBuffer class encapsulates an OpenGL pbuffer. More...
#include <QGLPixelBuffer>
Inherits QPaintDevice.
This class was introduced in Qt 4.1.
The 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:
Pbuffers are provided by the OpenGL pbuffer extension; call hasOpenGLPbuffer() to find out if the system provides pbuffers.
See also Pbuffers Example.
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).
Destroys the pbuffer and frees any allocated resources.
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().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Generates and binds a 2D GL texture based on pixmap.
Equivalent to calling QGLContext::bindTexture().
See also deleteTexture().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Reads the DirectDrawSurface (DDS) compressed file fileName and generates a 2D GL texture from it.
Equivalent to calling QGLContext::bindTexture().
See also deleteTexture().
Binds the texture specified by texture_id to this pbuffer. Returns true on success; otherwise returns 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.
Example:
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().
Removes the texture identified by texture_id from the texture cache.
Equivalent to calling QGLContext::deleteTexture().
Makes no context the current OpenGL context. Returns true on success; otherwise returns false.
Returns the format of the pbuffer. The format may be different from the one that was requested.
Generates 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().
See also size().
Returns the native pbuffer handle.
Returns true if the OpenGL pbuffer extension is present on this system; otherwise returns false.
Returns true if this pbuffer is valid; otherwise returns false.
Makes this pbuffer the current OpenGL rendering context. Returns true on success; otherwise returns false.
See also QGLContext::makeCurrent() and doneCurrent().
Releases the pbuffer from any previously bound texture. Returns true on success; otherwise returns false.
See also bindToDynamicTexture().
Returns the size of the pbuffer.
Returns the contents of the pbuffer as a QImage.
Copies the pbuffer contents into the texture specified with texture_id.
The texture must be of the same size and format as the pbuffer.
Example:
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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