GMCL on Linux: Bugs, Nuances, and Important Information


3D Modeler
Staff member
This thread exists to provide support to those on Linux distributions who may want to play GMod Cruise Line. As with most other GMod experiences, Linux is not generally the most pleasant way to play, but since I play on Ubuntu sometimes, I can provide some insight and advice to those who also want to play on Linux operating systems.

Common Bugs, and How to Avoid or Fix Them

Screen Tearing Fix:

Status: Not a bug; Fix below

Description: Screen tearing can be annoying and is a big problem in Linux games relying on OpenGL, as well as in video playback and other such things. To resolve this on AMD GPUs, follow the directions here (AMD). To fix this on Intel or Nvidia iGPU/GPUs, follow the directions here (Intel) and/or here (Nvidia).

Note: These fixes, unlike enabling Vsync, do not limit your in-game frame rates. If for some reason these fixes do not work for you, keep the game in full screen mode and enable Vsync.

BASS/MP3 Support:

Status: Fixed! (Use 64-bit build)
Note: Not yet supported in Ubuntu 19.04 and derivatives thereof
No more need for the workaround below

Bug Description: The module intended to provide support for MP3 playback on Garry's Mod requires your operating system to have proper MP3 decoders available for it to hook into. You will not have this by default, and I've yet to find one which works. I thought mpg123 was the way to go but it did not work for me. Instead, you can replace the included with Garry's Mod with the one found here.

Rainbow Reflections:
Status: Fixed!

Bug Description: Reflections are sometimes rendered as a rainbow-y cube. I have a feeling this is because cubemaps have not been properly built for the ship map yet and should hopefully be fixed once they are. In the meantime, if this bug really bothers you, you can disable specular mapping (essentially disabling reflections on map brushes) using the console command "mat_specular 0" while in the game. This command will have to be run every time you join the game to work properly, unless you add it to your autoexec.cfg.

In-Game Settings Not Saving:
Status: Fixed! (Use 64-bit build)

Bug Description: Settings may not save when you quit the game while connected to the server; to prevent this, disconnect from the server before clicking "Quit" in the Garry's Mod menu. This seems to happen because Garry's Mod on Linux might crash when quitting the game while connected; leaving the server first seems to prevent this from happening.

Fonts Not Displaying Correctly:
Status: Fixed as of May 14, 2019. If you still experience problems, manually install fonts following the instructions below.

Update May, 2019: Emojis in chat should now work on distros that support Emoji. (Use 64-bit build)

Bug Description: This is not a GMCL problem, but a problem with how Linux handles fonts in general. This has not been addressed yet in a GMod update. Without a fix in place from server developers, all fonts must be manually installed to properly display in game. To fix this download "" (Note: Updated May 14, 2019 to only include fonts used by us and a few stock GMod fonts; if you wish to install all stock GMod fonts, they're in garrysmod/resource/fonts)" and extract it in your Downloads directory, then open a Terminal window using CTRL+ALT+T and run the following commands to install the fonts and rebuild the font cache. We use mv (move) to install the fonts so we won't have to delete leftover files later.
sudo mkdir /usr/share/fonts/truetype/gmod/
sudo mv ~/Downloads/*.ttf /usr/share/fonts/truetype/gmod/
sudo fc-cache
sudo dpkg-reconfigure fontconfig will be updated when/if new fonts are added to GMCL.

Black Line in the Horizon:
Status: Identified. Will keep updated.

Bug Description: I'm unsure of what causes this bug currently. I will report back with more information when it's available.

Miscolored Water/Water Reflections:
Status: Identified. Will keep updated.

Bug Description: I'm unsure of what causes this bug currently. I will report back with more information when it's available.

Lua-based Particles Duplicating Infinitely:
Status: Identified. Will keep updated.

Update Jul, 2018: Snow particles no longer rendered via Lua code and thus are no long affected by this bug.

Update May, 2019: Cube Particle Effect is still affected by this in 64-bit build.

Bug Description: Lua code will need to be updated at some point to prevent this. The currently affected particles are the Cubes particles.

If you find any problems I have missed, please report them in the proper Bug Report section of the forums and I will see if there is any way to fix them. I am also willing to help resolve problems with my fixes provided above. Thank you for reading. This will be updated as time goes on and new bugs, features, and fixes are discovered or released. Stay tuned.

Update May, 2019: Many of these bugs are no longer applicable on the latest 64-bit build of GMod. The Status of bugs has been updated accordingly.
Last edited:
I've now updated the thread and am happy to announce the Rainbow Reflections bug is no longer applicable! This was fixed in the new version of the Ship map since cubemaps were properly built before the map shipped.
Updated the thread with more current information. Enjoy. The game is becoming massively more pleasant and playable on Linux distributions, so look out for more updates in the coming weeks/months.