Bug#923226: Compiling shader doesn't work - game doesn't work

[Simon McVittie]

On Fri, 08 Mar 2019 at 08:34:06 +0100, Julien Puydt wrote:
> OpenGL version string: 2.1 Mesa 18.3.4
> OpenGL shading language version string: 1.20

OK, so your GLSL version is indeed capped at the one corresponding to
your OpenGL version, even though your version of Mesa is new enough to
understand newer versions of GLSL on other hardware (like mine).

The opengl2 renderer seems to be meant to work on GLSL 1.20, or at least
it has code to deal with GLSL 1.20 and it worked on your machine until
recently, but a GLSL 1.30 requirement seems to have crept in between
the two versions you mentioned.

Please try the attached patch, also available at
<https://salsa.debian.org/games-team/ioquake3/merge_requests/1>. If that
works, I think it or something similar is going to be the best solution.
Test binaries: <https://people.debian.org/~smcv/923226/>

I'm not really in favour of using opengl1 forever, since upstream changed
the default to opengl2 back in 2016; but if we can't get the offending
shader to work on your hardware, going back to opengl1 might be reasonable
as a temporary solution for buster (Debian 10).

By the time bullseye (Debian 11) is released, the affected hardware
generation will be more than 10 years old, at which point it might be
rather less relevant.

    smcv