The FAQ has a pretty anemic paragraph about overlay planes and how to use them in WGL. I’ve searched every bookstore I know of and I can’t find anything that cares to cover overlay planes. They all act like overlay planes are outdated, but I can think of plenty of uses.
Can anyone help me out? Some examples or some better documentation?
Yes, perhaps it’s better to forget about overlay/underlay planes. These can be emulated by rendering your overlays/underlays to offscreen buffers/textures and a composition with your main scene using blending.
Once FBO multisampling is a reality, this composition technique will generalize very nicely, and be totally platform independent.
The whole idea of overlay plane is that you do not damage the main plane with your second plane drawings… saving you losts of unessary redraws… but I guess that this concept of simple and basic separation of the drawing plane are only applicable for serious graphics apps. I dont agree!
As for code, you could also look at the green book in the OpenGL series… That’s the one focusing on X Windows, but the code is mostly applicable.
Then, you’ve got the Qt4 APi from Trolltech that has a very neat set of features for there QGLWidget.
Overlay’s are style used in professional software in the CAD/CAM, Fx, CG and the likes…