`ImportError: Library "GL" not found.` when running game

[claymorwan]

Whenever i try running my game i get this error message (using uv)

$ uv run snake
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/mnt/media/Programmation/Python/Snake/snake/__main__.py", line 1, in <module>
    import arcade
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/arcade/__init__.py", line 96, in <module>
    from .application import MOUSE_BUTTON_LEFT
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/arcade/application.py", line 15, in <module>
    import pyglet.gl as gl
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/pyglet/gl/__init__.py", line 53, in <module>
    from pyglet.gl.gl import *  # Must always be imported before gl_info or bad things happen.  # noqa: F403
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/pyglet/gl/gl.py", line 10, in <module>
    from pyglet.gl.lib import link_GL as _link_function
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/pyglet/gl/lib.py", line 102, in <module>
    from pyglet.gl.lib_glx import link_GL, link_GLX
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/pyglet/gl/lib_glx.py", line 12, in <module>
    gl_lib = pyglet.lib.load_library('GL')
  File "/mnt/media/Programmation/Python/Snake/.venv/lib/python3.13/site-packages/pyglet/lib.py", line 138, in load_library
    raise ImportError(msg)
ImportError: Library "GL" not found.

[Cleptomania]

Can you share information about your hardware/operating system? This is generally what happens if you don't have an OpenGL driver available. Arcade requires OpenGL 3.3+

[claymorwan]

I'm running NixOS 26.05, i got mesa drivers installed so i should have OpenGL drivers
also i have another project that uses python arcade which works for some reasons (same arcade version than the one that breaks)

[Cleptomania]

Ah I believe nix does some level of sandboxing/moving around the library files in a way that Pyglet can't find them without special cases for nix that it can't know without information from nix at install time? I'm not that well-versed with Nix, but I know there's usually problems loading things like the GL library if something is installed not through nix's package manager.

Nix has a special pyglet package that fixes it here: https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/pyglet/default.nix

I'm not sure how to use that in combination with Arcade, or how we could potentially make it work without needing that special package. It might be worthwhile to raise an issue on Pyglet's repo to investigate a potential solution in Pyglet that will work with nix, but I'm not sure to what extent the nix patches could work in Pyglet directly: https://github.com/pyglet/pyglet

[claymorwan]

aw man, i'll see what i can do, but it's really weird that it works on one project but not on the other

[Cleptomania]

is the other project maybe somehow using the nix package for pyglet instead of a version from pypi?

[claymorwan]

is the other project maybe somehow using the nix package for pyglet instead of a version from pypi?

Nope, installed the same way it's installed for the broken one (aka uv venv, source then uv add arcade)