[Qt-interest] Overlay in conflict to QPainter?

[Oliver.Knoll at comit.ch]

Malyushytsky, Alex wrote on Thursday, July 22, 2010 11:13 PM:

> I am not an expert at this topic but I think it is not only ( or not
> at all) hardware issues. 
> System and Opengl implementation may provide or don't provide opengl
> overlay support. 

Well that's exactly what I said ;) GL overlay support is - or was - only supported on "high end" graphics card used for CAD applications, where the OpenGL driver was not just "optimised for games", but rather for line rendering "precision" (or "nice anti-aliasing") and features mostly needed in CAD applications (for example "textures" are not as important for CAD applications, whereas the rendering quality of 3D primitives is more important). 

Only for these cards the manufacturers actually made/make the effort to provide "proper OpenGL drivers", but most consumer cards - such as those I ever had, and I guess even the one on my iMac at home - provide only "basic OpenGL drivers" which provide enough support for games and "all-day 3D apps", but don't implement every possible feature such as GL overlays.

As I said, I never got the "overlay" examples (and I just checked, they were really only part of the Qt 3.x examples) to run due to lack of support.

Why do you say that on Vista it is an obsolete feature? It is the OpenGL driver implementation in the end which decides which features are supported and which not, no?

Cheers, Oliver
-- 
Oliver Knoll
Dipl. Informatik-Ing. ETH
COMIT AG - ++41 79 520 95 22