UdonLuau

Write VRChat world behaviours in Luau. UdonLuau compiles .lua scripts (.luau is also accepted) to Udon programs inside the Unity editor. It uses whatever externs, types and events your installed VRChat SDK exposes, so new SDK features work without updating UdonLuau.

• Scripts appear on GameObjects as their own components, like UdonSharp behaviours.
• Public variables show in the inspector, with @header, @tooltip, @range, @space, @hideininspector and @multiline annotations.
• Luau and UdonSharp scripts can hold typed references to each other and call each other’s public functions.
• @networkcallable functions, @sync variables and @syncmode follow VRChat’s rules and are checked when compiling.
• Edits to function bodies are hot-reloaded in play mode.
• Generates a definitions file and VS Code settings for the luau-lsp extension.

Requires Windows, Unity 2022.3 or later, and the VRChat Worlds SDK 3.9.0 or later.

Install

Add the package to your world project through the VRChat Creator Companion, or with Window > Package Manager > + > Add package from disk.

Quick start

1. Assets > Create > VRChat > UdonLuau Script creates NewLuauScript.lua.
2. Drag the script onto a GameObject in the Hierarchy, the Scene view or the Inspector.
3. Enter play mode.

-- @range(0, 360)
export local speed: number = 45

function Update()
    transform:Rotate(Vector3.up, speed * Time.deltaTime)
end

The samples (Package Manager > UdonLuau > Samples) show typed references between scripts, network calls and UdonSharp interop.

Settings are in Project Settings > UdonLuau. Tools > UdonLuau has commands to reload the native compiler and regenerate the editor definitions.

Documentation

The language reference and compiler documentation are at github.com/MagmaVRC/UdonLuau.

License

MIT, see LICENSE.md. Third-party components are listed in Third Party Notices.md.