[linux-audio-dev] Two or more monitors) Re: Project: modularsynth editor

David Olofson david at olofson.net
Tue Jan 20 03:59:05 UTC 2004


On Tuesday 20 January 2004 00.34, Martijn Sipkema wrote:
> [...]
>
> > I just remembered; the Matrox G100/200/400 drivers and/or
> > hardware has problems with multiple OpenGL contexts. Matrox have
> > known about it for ages, but seem to ignore the problem. This is
> > part of the reason why I gave up on my G400.
>
> Most likely a driver problem (or elsewhere in the software). I
> don't think there's
> _that_ much "context" on a G400 anyway...

That's probably the problem. Maintaining multiple contexts without 
actual h/w support means the driver has lots of stuff to move around. 
Still a serious bug if the driver doesn't implement it...


> > That said, IIRC, you *can* still get multiple windows (different
> > processes) accelerated. If so, why not windows on different
> > desktops...?
>
> It should not be a problem as far as I can tell really...
> I'm not an export though...

I can't see why it would make a difference from the h/w POV, but it 
could be a big difference to the driver. Still, if the driver can 
manage multiple contexts *at all*, it must be some obscure bug that 
causes it to break in the special case where some of the contexts 
belong to the same process.

Actually, IIRC it works with *some* applications, so it's not a matter 
of multiple contexts per process, but rather a bug that's triggered 
by some unfortunate applications for reasons unknown so far.

It *could* just be that the "working" applications actually use only 
one context, though... That would make sense for applications with 
custom OpenGL toolkits and OpenGL based child windows. They could 
still look pretty much like ordinary Windoze/GTK+/Qt/whatever apps, 
depending on the theme of the OpenGL toolkit.


> I do think we should use OpenGL more. That way the problems that
> may exist will eventually get fixed :)
> And besides, it _is_ a very nice graphics API.

Yes. If M$ weren't punishing their users for trying to use OpenGL 
apps, and OpenGL support was more widely available, there wouldn't be 
any reason to use anything else for serious graphics - 2D or 3D. It's 
hard to find a card without 3D acceleration these days, though there 
seem to be a few Windoze-only chipets that don't have OpenGL 
support...


//David Olofson - Programmer, Composer, Open Source Advocate

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