[Mesa-dev] [PATCH] glsl: allow ForceGLSLVersion to override #version directives

[Ilia Mirkin]

On Fri, Mar 27, 2015 at 3:00 PM, Brian Paul <brianp at vmware.com> wrote:
> On 03/27/2015 12:49 PM, Ilia Mirkin wrote:
>>
>> On Fri, Mar 27, 2015 at 2:44 PM, Brian Paul <brianp at vmware.com> wrote:
>>>
>>>
>>> The Geeks3d GpuTest GiMark test for Windows has several shaders with
>>> #version 330 that don't actually use any 3.30 features.  Other shaders in
>>> the test use #version 130.  Furthermore, when a context is created, only
>>> a
>>> 3.0 context is requested.  We don't support GL 3.0 w/ 3.30 shaders but if
>>> I
>>> override the #version 330 with 130 then everything works fine.
>>
>>
>> That's incredibly annoying. Well your patch looks like it'll work as
>> advertised, so
>>
>> Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
>>
>> But perhaps leave it on the list for a bit in case there are
>> dissenting opinions on the actual functionality?
>
>
> Sure, no problem.
>
> The sad reality is that Windows OpenGL apps are pretty sloppy/buggy when it
> comes to choosing the right OpenGL context version/profile and shader
> versions.  We have quite a few work-arounds in our in-house code to allow
> these apps to run.  If we don't do that, we get bug reports and negative
> comments from product reviewers.

Yeah, you can't really hold end users hostage over buggy applications,
esp when they work with other (less discerning) drivers.

> The problem is the Windows nvidia/amd/intel drivers are often more lax than
> Mesa about version/extension checking.  Also, the nvidia/amd/intel drivers
> support compat profile with OpenGL 3.2+ so a lot of those apps don't have
> any consideration of core vs. compat profile issues.  It's an ongoing
> headache.

Right. I think that will keep on being a headache until Mesa starts
supporting higher GL compat versions, especially for Windows-targeted
software (I guess OSX also doesn't do compat beyond GL2.1 or 3.0). But
I'm not well enough versed in the details to be able to suggest a path
forward, nor am I going to personally be able to do the work...

  -ilia