Hi, I think I have understood the osgviewerQT sample. This creates a QGLWidget overloads its paintGL() function and calls into osgviewer::frame() to let OSG do the rendering and all is good - i.e. we see the OSG scene displayed inside a window managed by QT.
I am now trying to do something more advanced and let QT render semi-transparent widgets on top of the openGL scene. In the relevant QT examples this is done by assigning a QGraphicsScene to the QGLWidget instead of overloading the QGLWidget's paintGL() function. The relevant QT examples are called "boxes" (in the demos folder of QT) as well as "openglcanvas" sample ( see the article http://doc.trolltech.com/qq/qq26-openglcanvas.html ) The QGraphicsScene has a drawBackground() function where we are inside an openGL context created and maintained by QT. Trolltech (Nokia) say that you can do your own OpenGL 3D rendering here, but you're supposed to revert all changes you make to the OpenGL state when you're done rendering, so that QT can draw its widgets on top successfully (also using OpenGL, mind you). Apparently simply calling osgviewer::frame() here is doomed to failure as the openGL states of OSG and those maintained of QT will clash seriously. Unfortunately my experience with OSG's state management is poor. How would I achieve to save all OpenGL state, then make OSG set up its needed OpenGL state from scratch, render its frame, and then restore QT's previous OpenGL state? Would it be easier to let OSG render everything to texture using a separate OpenGL context and just render this texture inside drawBackground()? Any help with this will be greatly appreciated. _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
