[Mesa-dev] [RFC PATCH 1/1] st/dri: add a new driconf option override_glsl_version for ARK games

[Bas Nieuwenhuizen]

On Fri, Feb 3, 2017, at 19:24, Jason Ekstrand wrote:

> On Fri, Feb 3, 2017 at 9:23 AM, Samuel Pitoiset
> <samuel.pitoiset at gmail.com> wrote:
>> This is similar to the MESA_GLSL_VERSION_OVERRIDE envvar (mainly

>> for developers). But this one has the advantage to be configured

>> for specific apps which require a context with an explicit version.

>> 

>> For example, when an app requires a 3.2 core context, RadeonSI

>> will return a 4.5 context but this might fail (eg. ARK games).

> 

> Why is returning a 4.5 context a problem?  It's supposed to be more-or-
> less backwards compatible.
> I'm also a bit concerned about making this driconf option be global
> across drivers without it being just a maximum.  Suppose someone sets
> it to 4.3 for some app that doesn't like 4.5.  What happens if they
> try to run that app on hardware that doesn't support 4.3?  Do they get
> a 4.3 context that just doesn't work?


As far as I can see[1], when the game detects GL 4.3+, the engine
tries to load a different set of shaders from disk, but the game
developers have not enabled the right flag during building, so the
shaders for GL4.3+ are not actually distributed with the game, which
results in a failure to load the game. From my POV this is entirely
the fault of the game.


That said, the bug contains a report from someone else that it works on
intel with GL4.3+. I never got to test that or look deeper into this, so
it could very well be that I overlooked something during this analysis.


- Bas



[1]: https://bugs.freedesktop.org/show_bug.cgi?id=95374
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