[feature request] `source $(nixGL shell)` support

[samuela]

It would be super handy to be able to "install" nixGL into a shell session such that I don't have to worry about wrapping each command in nixGL foo ....

Would maintainers be supportive of including such a feature?

[jim3692]

You can alias nix-shell to nixGL nixVulkanIntel nix-shell

[samuela]

That's certainly an option, but what I'm ideally looking for is a solution to "install" nixGL in the currently running shell instead of spawning a new one.

[jim3692]

That's certainly an option, but what I'm ideally looking for is a solution to "install" nixGL in the currently running shell instead of spawning a new one.

Lately Arch updated its gcc version and now that alias fails with these errors:

nix-shell: /nix/store/bn7pnigb0f8874m6riiw6dngsmdyic1g-gcc-13.3.0-lib/lib/libstdc++.so.6: version `CXXABI_1.3.15' not found (required by /usr/lib/libnixexpr.so)
nix-shell: /nix/store/bn7pnigb0f8874m6riiw6dngsmdyic1g-gcc-13.3.0-lib/lib/libstdc++.so.6: version `CXXABI_1.3.15' not found (required by /usr/lib/libnixmain.so)
nix-shell: /nix/store/bn7pnigb0f8874m6riiw6dngsmdyic1g-gcc-13.3.0-lib/lib/libstdc++.so.6: version `CXXABI_1.3.15' not found (required by /usr/lib/libnixstore.so)
nix-shell: /nix/store/bn7pnigb0f8874m6riiw6dngsmdyic1g-gcc-13.3.0-lib/lib/libstdc++.so.6: version `CXXABI_1.3.15' not found (required by /usr/lib/libnixutil.so)

So, I came up with a more "install" solution:

if [[ ! "$IN_NIX_SHELL" = "" ]] && [[ "$IN_NIXGL" = "" ]]; then
  export IN_NIXGL=1
  source <(
    diff <(env) <(nixGL nixVulkanIntel env) \
      | grep '>' | sed 's/^>/export/g'
  )
fi

It extracts the environment variables that nixGL and nixVulkanIntel set, and adds them to the current shell.

[theVakhovskeIsTaken]

Was looking at the solutions posted before and after, and in cross-repositories, but decided to make it the "NixOS" way, so that I won't boil my mind

Since I'm running an immutable setup, I wanted to keep the "packaging" unhingeness for personal reasons

The thing: https://github.com/immutarch/postcopy_beta/blob/main/usr/bin/ima-nix-mesa-binder

What this does?

1. Runs nixGL env, checks for LIBGL_LIBRARY_PATH entries, where usually both 64-bit and 32-but MESA outputs are located
2. Determines which arch are they, and appropiately symlinks each store to /run/opengl-driver(-32)

Cons:

1. You might have to manually re-add symlinks after each mesa + nixgl update

Other than that, it works very much fine with everything graphically-required installed

[jim3692]

2. Determines which arch are they, and appropiately symlinks each store to /run/opengl-driver(-32)

I can't understand how the games manage to find the OpenGL drivers in that path. Are you exporting the /run/opengl-driver path?

[theVakhovskeIsTaken]

Are you exporting the /run/opengl-driver path?

No, I am not. The base library preload directory is defined by package on it's own, so this entire thing is almost 1:1 with NixOS in terms of how drivers get loaded

[jim3692]

Great. I will check it. Is there any related documentation to that? I want to understand whether something like this is possible for Vulkan.

[theVakhovskeIsTaken]

Great. I will check it. Is there any related documentation to that? I want to understand whether something like this is possible for Vulkan.

No reason to, these directories already include Vulkan drivers and their ICD loaders

[jim3692]

Sorry. My fault. I expected Vulkan to require a different method, as it's exposed with nixVulkanIntel, and not nixGL. Your script seems to work fine on Arch.

[theVakhovskeIsTaken]

#!/bin/bash

mkdir -p /etc/tmpfiles.d
get_dri_info(){
    MESA_DRIVERS_PATH=$(nixGL env | grep LIBGL_DRIVERS_PATH | cut -d '=' -f 2 | sed 's/\/lib\/dri//g' | sed 's/:/ /g')
    for driver in ${MESA_DRIVERS_PATH}
    do
        DRIVER_FILE=$(file ${driver}/lib/libEGL_mesa.so.0.0.0 | cut -d ' ' -f 3)
        if [[ "${DRIVER_FILE}" == "64-bit" ]]; then
            DRIVER_64BIT=${driver}
        else
            DRIVER_32BIT=${driver}
        fi
    done
    echo "64-bit driver path: ${DRIVER_64BIT} | This will be symlinked to /run/opengl-driver"
    echo "L+ /run/opengl-driver - - - - ${DRIVER_64BIT}" > /etc/tmpfiles.d/99-nix-ogl-64b.conf
    echo "32-bit driver path: ${DRIVER_32BIT} | This will be symlinked to /run/opengl-driver-32"
    echo "L+ /run/opengl-driver-32 - - - - ${DRIVER_32BIT}" > /etc/tmpfiles.d/99-nix-ogl-32b.conf
    systemd-tmpfiles --create
}

if [[ "$(which nixGL)" ]]; then
    get_dri_info
else
    echo "nixGL is not installed on this system, please install nixGL"
fi

I've updated my scripts for my distro, so that's why i'm sending an universally working one here

[soupglasses]

There's now also https://github.com/soupglasses/nix-system-graphics which is an alternative approach to do this with, which utilizes the /run/opengl-driver approach instead of environment variable magic as nixGL does.