[Interest] Performance comparison of painting methods

Gunnar Roth gunnar.roth at gmx.de
Mon Nov 20 17:00:24 CET 2017



>On 13.11.2017 17:12, Jean-Michaël Celerier wrote:

>> http://kgronholm.blogspot.fr/2017/11/qt-510-qml-shape-testing.html
>>
>> An interesting blog post which compares QPainter, the upcoming QML
>> Shapes and QNanoPainter. I'm surprised to see QML Shapes perform so
>> much slower than good old QPainter.
>>
>>
>Doesn't QML Shapes depend on the NVIDIA only GL-extension for shapes? I
>am assuming it is just falling back to raster QPainter instead of FBO
>QPainter when not present.
 
No, only when Quick2DRenderer is used.
http://blog.qt.io/blog/2017/07/07/let-there-be-shapes/
There are multiple implementations under the hood, with the front Qt Quick item API staying the same. The default, generic solution is to reuse the triangulator from QPainter’s OpenGL backend in QtGui. For NVIDIA GPUs there is an alternative path using the GL_NV_path_rendering OpenGL extension. When using the software renderer of Qt Quick, a simple backend falling back to QPainter will be used.

Regards,
Gunnar



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