[Development] OpenGL drivers

[Sletta Gunnar]

Hi,

As many of you might already have noticed, OpenGL drivers are not always working as well as would like. This has always been a problem, but since Qt Creator 3.0 is using Qt Quick 2.0 and Qt Quick 2.0 is also being used in more and more places, the problem is becoming more mainstream. We are aware of several issues and patched Qt to tackle them, but we expect we will need more. To figure out what needs to be done, we need a broader picture.

Long term, the solution for Qt might be that we bundle a software GL implementation (llvmpipe for instance) and switch to that if a driver is too problematic for us. Hopefully, we can get by with applying workarounds in Qt though.

So, I'm asking that if you encounter issues with flickering, crashes, bad rendering and similar, help us track which things are problematic by filing a bugreport on bugreports.qt-project.org and use the label "driverissue" in the task. Please  include OS, windowing system, graphics hardware and driver version. And since most of the workarounds have been applied to Qt 5.2, do test against the 5.2 RC1 or later.

Some other things that might help while identifying the problem is:
- Does upgrading driver or installing latest vendor supplied driver help?
- QSG_RENDER_LOOP=basic -> switch Qt Quick to use the GUI thread for rendering
- QSG_INFO=1 -> make Qt Quick output SG and GL information.
- LIBGL_ALWAYS_SOFTWARE=1 -> for Linux/Mesa based only, forces use of software Mesa rendering
- How does other GL applications in the system fare and what about Qt's OpenGL examples?
- vsynced or not?

thanks,
Gunnar

Please don't reply to this mail to report issues :)