[Mesa-dev] KWin and Mesa

[Martin Gräßlin]

 On Wed, 20 Apr 2011 09:34:01 -0400, Jerome Glisse <j.glisse at gmail.com> 
 wrote:
> Your issue is right there, gnome-shell have been successful dealing
> with that because they target a particular mesa version and they set 
> a
> lower bar for the GL feature they need. Your issue is that you want 
> to
> enable feature that are using too advanced GL stuff for the 
> opensource
> driver, GLSL wasn't that good before mesa 7.7 (or even 7.8 can't
> remember). What you should do is decide was is the lowest mesa 
> version
> you are ready to support and then use that to decide what gl feature
> you can safely use. If you want to support debian that would more 
> than
> likely mean dropping glsl. Trying to enable feature one by one is a
> real bad idea, again i believe here gnome-shell took the right
> approach.
 GNOME Shell was in a much better situation as they were able to develop 
 against future releases of Mesa. Btw we do not depend on GLSL. Our 
 important GLSL shaders are also reimplemented with an ARB Shader 
 fallback. It should all fallback without problems nowadays. If the 
 driver supports GLSL properly, it gets used, if it supports only ARB 
 Shaders those will be used, if both is not supported it gets disabled. 
 If we know the hardware has limitations we do not use the features 
 unsupported by it. So we do what you actually ask as to do. E.g. with 
 Debian and Mesa 7.7 it works totally fine with the ARB fallbacks (yeah I 
 tested that ;-)