[Mesa-dev] KWin and Mesa

[Jerome Glisse]

On Wed, Apr 20, 2011 at 9:43 AM, Martin Gräßlin <mgraesslin at kde.org> wrote:
> 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 ;-)
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>

Then why do you need hack ? To me it seems you are trying to enable
feature just on some specific driver version, that's wrong, my point
is define what mesa you want, then from that deduce the feature set
that is safe to use then from that define what are the default
feature, absolutely no hack in code needed here and you can still
provide option for people to enable new feature if they want to try
them with their driver.

Cheers,
Jerome