Include DXVK on Linux

[WinterPhoenix]

A little bit out of the original scope of this project, but stemming from some discussion on the Discord and in #48.

There's some notable performance gains to be had for GMod on Linux if we make it use DXVK (specifically the Native parts of it in 2.0) instead of the ancient ToGL implementation.

This would require us (probably) shipping the library with GModCEFCodecFix, modifying hl2.sh to add some environment variables, and launching GMod with the -vulkan launch option.

Relevant reading: https://www.reddit.com/r/linux_gaming/comments/xfwoso/the_ultimate_garrys_mod_linux_performance_guide/ https://www.reddit.com/r/linux_gaming/comments/xzzolt/i_got_garrys_mod_native_working_using_dxvknative/

Also this is apparently not working with Nvidia GPUs currently... https://www.reddit.com/r/linux_gaming/comments/xzzolt/i_got_garrys_mod_native_working_using_dxvknative/j4mbl7e

...But @JohnPeel reckons they can write a ToGL library replacement that forwards DirectX commands that would've gone to ToGL, to DXVK, and that should fix that.

[mr-sihc]

Can i ask how far has this come? Because this would be awesome to have! (Because rendering performance sucks, and it will relieve the CPU too to have DXVK)

[JohnPeel]

ToGL isn't an option, and from how they interact with ToGL, using DXVK isn't an option.

[mr-sihc]

oh this is sad.. maybe force load a dxvk.so and dont load togl, and maybe this could work

or this is just another thing that cant work? i think it should

if we can stop togl.so from loading or override it with dxvk

[JohnPeel]

It wouldn't work because ToGL doesn't use the normal DirectX API.

[WinterPhoenix]

Related issue: https://github.com/Facepunch/garrysmod-requests/issues/1905