Hi,

I'm doing some experiments on using OpenGL with Qt. My app is a small image viewer, that allows for browsing images by pressing the cursor keys. For the transition from the overview to the single image view I'd like to realize a zooming animation in OpenGL.

According to Trolltechs "Overpainting" example you can mix QPainter commands and OpenGL commands in one class (using paintEvent instead of paintGL). So I started to replace QWidget by QGLWidget, nothing more. Unfortunately the application reacts much slower (same paint method, no OpenGL commands yet). I took a bunch of images and pressed a cursor until I reached the end. The GLWidget took about 30 % more time. So my question is, if there is some kind of overhead that prevents QGLWidget from being as fast as a normal QWidget? I really like to mix OpenGL and normal drawing in one widget!

By the way, this behavior is the same on several machines. And having a look at Trolltech's Overpainting example where they compare a QGLWidget and an QWidget that use the same paint method code, I have the impression that the QWidget variant runs smoother that that GL one.

Regards,
André