ImGui Sincerely

"Give someone state and they'll have a bug one day, but teach them how to represent state in two separate locations that have to be kept in sync and they'll have bugs for a lifetime." - ryg

Current State

Subsystems	Stage
Fonts(ttf)	Completed, syncing with main
Fonts(otf)	Hasn't started yet, not planned
Viewports	Currently only one is supported
Windows	WIP
Widgets	WIP
Backends	Currently only have GMod backend

How to Try it in GMOD?

1. Clone this project into your GMod addons folder
2. Create a singleplayer game
3. Run imgui_test command in engine console
4. You can also write your own test scripts and run locally

My Development Platform

GMod x86-64 branch (2026.1.21) with LuaJIT 2.1.0-beta3, Lua 5.1. Recording this is actually necessary, since who knows how GMod Lua APIs will change in the future!

The core code(code except backend ones) in lua/ don't and shouldn't use anything that is exclusive in GMod Lua.

Primary Goal

Try to make an Immediate Mode UI library for Garry's Mod.

In other words, currently I'm implementing an ImGui clone in pure Lua.

Originally I just wanted to make some contributions to RiceLib, and it wasn't the first time that I got terrified by the messy and bloat codebase of it. So I set out to remove all the non-UI related features added by RiceLib author RiceMCUT and to make UI creation for GMod in general easier.

Credits

Thanks to Dear ImGui!

References:

• Garry's Mod Wiki
• Jaffies's paint lib
• Valve Developer Wiki
• handsomematt's 3d2d-vgui
• TomDotBat's ui3d2d

Previous Attempts at immediate-mode UIs in GMod:

• wyozi's imgui
• Fun Project GMod's imgui

AIs:

• DeepSeek
• KIMI K2 Thinking
• TRAE

for helping me avoid those areas involving a lot of repeatitive work!