[Mesa-dev] MESA_EXTENSION_OVERRIDE problem

[Brian Paul]

On 11/19/2015 01:19 PM, Ilia Mirkin wrote:
> On Thu, Nov 19, 2015 at 3:13 PM, Brian Paul <brianp at vmware.com> wrote:
>> Hi Nanley,
>>
>> Maybe you can fix an issue I have with the new extension code.
>>
>> Previously, I could do something like export
>> MESA_EXTENSION_OVERRIDE="-ARB_clear_buffer_object" and I would no longer see
>> it in the GL_EXTENSIONS string, even if it was an "always on" extension.
>
> How sure are you that this worked?

I'm pretty sure it worked that way when I first wrote it.


> AFAIK there was no way to
> enable/disable an always-on ext.

That's not the point.  The point is to change what 
glGetString(GL_EXTENSIONS) (or the glGetStringi() method) returns to the 
application.  I don't care if the underlying functionality is still 
working in Mesa.  We're trying to tell the application to not use a 
feature.  I've found this extremely helpful when debugging some apps.


> That env var never affected the
> extension strings, but only the actual ctx->Extensions struct, which
> would indirectly modify the ext string. If the entry in that ext table
> was a dummy one, it had logic to not futz with it. (But it did so
> silently.)

Yeah, I don't care about the table.  I only care about the return value 
of glGetString(GL_EXTENSIONS).

-Brian