diff options
Diffstat (limited to 'src/widgets/kernel/qopenglwidget.cpp')
| -rw-r--r-- | src/widgets/kernel/qopenglwidget.cpp | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/src/widgets/kernel/qopenglwidget.cpp b/src/widgets/kernel/qopenglwidget.cpp index d8f31bfcc83..757cac8cea5 100644 --- a/src/widgets/kernel/qopenglwidget.cpp +++ b/src/widgets/kernel/qopenglwidget.cpp @@ -228,6 +228,22 @@ QT_BEGIN_NAMESPACE regarding stacking orders for example. QOpenGLWidget avoids this by not creating a separate native window. + Due to being backed by a framebuffer object, the behavior of QOpenGLWidget is + very similar to QOpenGLWindow with the update behavior set to \c + PartialUpdateBlit or \c PartialUpdateBlend. This means that the contents are + preserved between paintGL() calls so that incremental rendering is + possible. With QGLWidget (and naturally QOpenGLWindow with the default update + behavior) this is usually not the case because swapping the buffers leaves the + back buffer with undefined contents. + + \note Most applications do not need incremental rendering because they will + render everything in the view on every paint call. In this case it is + important to call glClear() as early as possible in paintGL(). This helps + mobile GPUs that use a tile-based architecture to recognize that the tile + buffer does not need to be reloaded with the framebuffer's previous + contents. Omitting the clear call can lead to significant performance drops on + such systems. + \section1 Multisampling To enable multisampling, set the number of requested samples on the @@ -372,7 +388,7 @@ QT_BEGIN_NAMESPACE \e{OpenGL is a trademark of Silicon Graphics, Inc. in the United States and other countries.} - \sa QOpenGLFunctions + \sa QOpenGLFunctions, QOpenGLWindow */ /*! |