[Development] About inheriting QBlitterPaintEngine from QGL2PaintEngineEx class

[Lind Jorgen]

Hi
On 10 Jul 2014, at 11:48, haithem rahmani <haithem.rahmani at gmail.com<mailto:haithem.rahmani at gmail.com>> wrote:

Hi,

When running Qt-5 on top of the directfb qpa plugin,  some benchmarks are quite slow.
(http://smashcat.org/av/canvas_test)

 I've found that the 2D painting ops are going through the QBlitterPaintEngine class
that is inheriting the QRasterPaintEngine class, which is doing all the painting via CPU.

Qt provides another paintEgine class, QGL2PaintEngineEx, that is doing the same paintings via the GPU.

So I want to know whether is possible to make the QBlitterPaintEngine inherit this QGL2PaintEngineEx
instead of QRasterPaintEngine and got things working correctly or not?

PS: the eglfs qpa plugin is going through the QRasterPaintEngine class too.

Its been a while since I have looked at the DirectFB apis, so I might be wrong, but it used to not be very clear how to interoperate DirectFB and OpenGL.

When that is said, it will be a lot of work to base QBlitterPaintEngine on top of QOpenGL2PaintEngineEx, to give something that gives acceptable performance.

Jørgen
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