QGLPixelBuffer Class Reference
[QtOpenGL module]

Detailed Description

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:

1. We can draw into the pbuffer and convert it to a QImage using toImage(). This is normally much faster than calling QGLWidget::renderPixmap().
2. We can draw into the pbuffer and copy the contents into an OpenGL texture using updateDynamicTexture(). This allows us to create dynamic textures and works on all systems with pbuffer support.
3. On systems that support it, we can bind the pbuffer to an OpenGL texture. The texture is then updated automatically when the pbuffer contents change, eliminating the need for additional copy operations. This is supported only on Windows and Mac OS X systems that provide the render_texture extension.

Pbuffers are provided by the OpenGL pbuffer extension; call hasOpenGLPbuffer() to find out if the system provides pbuffers.

See also Pbuffers Example.

Member Function Documentation

 QGLPixelBuffer pbuffer(...);
 ...
 pbuffer.makeCurrent();
 GLuint dynamicTexture = pbuffer.generateDynamicTexture();
 pbuffer.bindToDynamicTexture(dynamicTexture);
 ...
 pbuffer.releaseFromDynamicTexture();

 QGLPixelBuffer pbuffer(...);
 ...
 pbuffer.makeCurrent();
 GLuint dynamicTexture = pbuffer.generateDynamicTexture();
 ...
 pbuffer.updateDynamicTexture(dynamicTexture);