Integrate with nixGl

[tobiasBora]

First, thanks for this great program.

When running a program using openGl (e.g. blender) you get an error:

$ nix run github:thiagokokada/nix-alien -- blender
/tmp/blender-3.2.2-linux-x64/blender: error while loading shared libraries: libGL.so.1: cannot open shared object file: No such file or directory

As far as I see the best solution is to use nixGl:

$ nix run --impure github:guibou/nixGL --override-input nixpkgs nixpkgs/nixos-21.11 -- nix run github:thiagokokada/nix-alien -- blender

This does work but it is definitely not super easy to run... It would be great if nix-alien could directly handle openGl correctly.

[thiagokokada]

We probably can integrate it in the generated flake.nix file, adding nixGL as the input.

However I have zero experience with nixGL, and I also don't run non-NixOS Linux systems with Nix, so I would be open for a PR here.

[soleera]

nixGL is essentially just a wrapper script that sets a few system-specific environment variables ( e.g. LIBGL_DRIVERS_PATH) before calling a GUI program. One option would be to change the last line of the templates to something like ${__wrapper__} ${__program__} "$@" and then add an optional argument to nix-alien (e.g. nix-alien --wrapper nixGL blender), or we could add an optional argument that allows you to specify the exec command independently (e.g. nix-alien --exec "nixGL blender" blender).

[thiagokokada]

nixGL is essentially just a wrapper script that sets a few system-specific environment variables ( e.g. LIBGL_DRIVERS_PATH) before calling a GUI program. One option would be to change the last line of the templates to something like ${__wrapper__} ${__program__} "$@" and then add an optional argument to nix-alien (e.g. nix-alien --wrapper nixGL blender), or we could add an optional argument that allows you to specify the exec command independently (e.g. nix-alien --exec "nixGL blender" blender).

This looks easy to add, but it would assume that the user installed nixGL in a user accessible PATH and that this nixGL matches the current nixpkgs version of the one used by nix-alien right? From what I understood reading the README, this can cause GLIBC errors.

Ideally the integration with nixGL runs deeper. A --nixgl flag could add nixgl to the flake.nix inputs and also properly override it. Not sure what to do with the shell.nix version though, I can either not add this to the non-flake version or just add it and hope for the best.

[thiagokokada]

@soleera @tobiasBora Can either of you provide a binary that works with nix-alien+nixGL but doesn't work without it? Like the blender example from OP? The link for download is fine.