gregWiki/docs/topics/ffi-and-hooks/overview.md

title, sidebar_label, description

title	sidebar_label	description
FFI, hooks & Lua	FFI, hooks & Lua (hub)	FFI, hook lists, Lua runtime, naming — curated reference for mod and plugin authors.

FFI, hooks & Lua

The framework acts as a hook proxy: Unity / IL2CPP events are surfaced as stable framework events for mods in all supported languages — see System architecture & documentation principles.

Hook & event references

• FMF hooks — generated hook surface
• FMF hooks catalog — strings from core sources
• FMF hook naming — FMF.* vs legacy FFM.*
• greg hooks registry (IL2CPP) — greg_hooks.json, Greg*Hooks Harmony emitters, regeneration script
• Greg hooks & events — GregEventDispatcher, Lua subscriptions, native pipeline

Lua runtime

gregCore embeds a MoonSharp Lua VM (LuaLanguageBridge) that provides the greg.* API to Lua scripts:

API group	Key functions	Purpose
Events	greg.on(hook, fn), greg.off(hook), greg.emit(hook, data)	Subscribe to GregEventDispatcher events
Harmony hooks	greg.hook.before(hook, fn), greg.hook.after(hook, fn)	Prefix/postfix on any Harmony-patched method
Unity objects	greg.unity.find(type), get_component(), instantiate(), destroy()	Handle-based Il2Cpp object manipulation
Properties	greg.unity.get_string(h, m), set_number(), get_handle()	Read/write object members by name
Transform	greg.unity.position(h), set_position(), set_local_scale()	Spatial manipulation
Materials	greg.unity.material_hex(h, prop)	Read hex color from material properties
TMPro / TextMesh	greg.unity.tmpro_set(...), textmesh_set(...)	Configure text labels
Physics	greg.unity.raycast(...), camera_ray()	Raycasting
IMGUI	greg.gui.box(), label(), button(), toggle()	OnGUI drawing
Input	greg.input.key_pressed(key), key_down(), ctrl()	Keyboard via InputSystem
File I/O	greg.io.read_file(), write_file(), list_files()	File system access
Config	greg.config.load(path), save()	Key=value config files
Color	greg.color.to_hex(r,g,b), normalize_hex(), parse()	Hex color utilities

Lua scripts define optional lifecycle functions: on_update(dt), on_scene(name), on_gui().

Full API reference: Language Bridges README

Rust / native FFI

Native mods receive a GameAPITable on init and numeric EventIds via mod_on_event. Full lifecycle (update, scene load, shutdown) is managed by FFIBridge through RustLanguageBridgeAdapter.

Architecture

• Repository architecture — language bridges, handle system, runtime layers
• Modding language support — C#, Lua, Rust policies
• Getting started