Minecraft terrain in Garry's Mod — offline prototype

This is an early local prototype for the approved idea: control the Garry's Mod player in terrain imported from Minecraft Java Edition.

What's in this slice

• A read-only Python importer for Minecraft's region/chunk NBT and installed client jar.
• A local development export of the nearest 25 chunks from the selected Minecraft save.
• A compact top-surface terrain file that GMod can render and use as a static collision surface.
• A native GMod Lua addon that draws a colored, top-down terrain surface and places the player near the imported save's height in offline single-player.

The importer writes only to its output folder. It never writes to a Minecraft save. local-data/ contains derived data from the local test save and is ignored by Git; do not distribute it.

Development export

Run from the project directory with Python 3:

python work/minecraft-gmod-mashup/tools/export_dev_slice.py `
  "$env:APPDATA\.minecraft\saves\Demo_World" `
  "$env:APPDATA\.minecraft\versions\26.2\26.2.jar" `
  work/minecraft-gmod-mashup/local-data --radius 2

This creates world.json for local inspection and the smaller terrain.json for the addon. Both are local test outputs and include information from the selected save.

Offline GMod test setup

1. Copy addon/mc_gmod_mashup to Garry's Mod's garrysmod/addons/ folder.
2. Copy the generated terrain.json to garrysmod/data/mc_gmod_mashup/terrain.json.
3. Start Garry's Mod in offline single-player on a map. The addon loads the imported terrain automatically when the map finishes loading.

The addon does not request or use a server. Keep all testing in offline single-player.

Current limits

This is a terrain proof of concept, not a complete Minecraft/Garry's Mod mashup yet. It renders only the highest solid block in each imported X/Z column as a colored tile. It does not yet render block sides or source textures, mine/place blocks, load adjacent chunks while walking, simulate Minecraft mobs, add Minecraft items, or provide automatic Melty setup. A real offline GMod launch and visual/collision check are still required before treating the addon as playable or packaging it for release.

Minecraft and Garry's Mod assets, world saves, and extracted textures are not included in the addon.