Re: [Flightgear-devel] Segfault with OSG multi threading

[ThorstenB <br...@gm...>]

On 30.05.2011 19:25, Stefan Seifert wrote:
> The segfault happens when the main loop thread tries to
> access GL information. I know next to nothing about openGL programming but I
> seem to recall that it's not allowed to access the same GL context in different
> threads. So how is this supposed to work?

Well, wouldn't surprise me to find more related multi-threading issues. 
Not sure how long OSG itself supports it, but I guess it wasn't a major 
priority at the time when FG was adapted to OSG. And I'm sure more fixes 
will be necessary to safely support it.
The particular source lines also have an "//OSGFIXME" comment - another 
hint that work was left behind.
Try replacing the calls to SGIsOpenGLExtensionSupported - they provide 
constant information anyway. It'd be enough to check 
version/capabilities once during init and then use constant data at 
run-time. Try if that helps. Patches welcome :).

cheers,
Thorsten