Hi Skylark, I managed to get Qt rendering above OSG in a HUD style. I have created a Delta3D example: http://www.delta3d.org/forum/viewtopic.php?showtopic=18707
The example does not really use any Delta3D functionality, so you should not have any problems understanding it. I had to disable buffer swapping of the OSG Qt window to get OSG and Qt to play together. The example works pretty good with a simple OSG scene, but I had some problems when I did tried to draw something besides simple meshes. Specifically, I added a line geometry to the scene, and that caused the HUD to become heavily distorted. I guess OSG sets some GL states (transformations?) that conflict with Qt. Next I will try to render the Qt hud to a texture and use it as an overlay on the 3d scene, similar to the osgQt examples. I played around with the dtQt example and had pretty bad framerates when I rendered a simple calendar widget onto the HUD. I tried something similar with my example and also had huge framerate drops - the larger the Qt widget the lower the framerate. So I guess Qt simply has some performance issues. I will have to analyse the performance implications of the render to texture approach. On the one hand the cost of copying textures from GPU to CPU and back - and on the other hand the clean separation of Qt and OSG threads. BTW I tried rendering simple images onto the HUD. I managed 10 000 moving semi-transparent images with a stable 60 fps - so there is hope that this will rock. ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=27976#27976 _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
