[Qt-interest] Performance issues with Graphics View Framework

[Simone Artesino]

I've got a terrible performance degradation when switch Viewport from
QWidget to QGLWidget. The same qt code (no opengl calls in it) that make a
simple animation, it runs 10 times slower (from 40 fps to 4 fps). On the
same hand, when I move to qglwidget I can see a relevant increase in cpu
usage.

 QGraphicsView view(&scene);

// view.setViewport(new QGLWidget()); //slower

// view.setViewport(new QWidget()); //faster

Basically i start a timer that activate an animation.

int frameRate=40;
m_timer=new QTimer(1000/frameRate);
connect(m_timer, SIGNAL(timeout()), this, SLOT(animate()));

The animation moves on the screen few QPixmaps and QImages.

My hardware is an embedded solution based on intell ATOM 1.1 Ghz, GMA 500 as
VideoCard , 512 MB ram. But i get similar results by running the same
application on my desktop(dual core 3G Ram NVIDIAcard).

Any idea?

Simone
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