Udon Decompiler

Usage

This document was translated from Chinese by an LLM.

After installing this project, you can decompile Udon programs in a world.

Obtain the world file

This project does not provide guidance on this. You should have a .vrcw.vrcw file.

Extract Udon programs

  1. Use the UdonProgramDumperUdonProgramDumper program downloaded in the Installation section to extract program files from .vrcw.vrcw. Specifically:

  • Use the command line

    UdonProgramDumper dump <world.vrcw>
    UdonProgramDumper dump <world.vrcw>

    You should get output like this

    $ UdonProgramDumper dump example.vrcw
    [example.vrcw] dumped 8 program(s), 8 public var file(s) to /path/to/example-dumped
    $ UdonProgramDumper dump example.vrcw
    [example.vrcw] dumped 8 program(s), 8 public var file(s) to /path/to/example-dumped
  • Drag and drop a .vrcw.vrcw file directly onto UdonProgramDumperUdonProgramDumper. This is effectively equivalent to the previous method.

You can then find the generated example-dumpedexample-dumped folder in the same directory as the .vrcw.vrcw file, containing:

  • programs/programs/: extracted .hex.hex program files
  • vars/vars/: extracted .b64.b64 public var files
  • program-var-map.jsonprogram-var-map.json: mapping from programs to GameObjects and public var files

Decompile

Run

udon-decompiler dc example-dumped/programs --info UdonModuleInfo.json
udon-decompiler dc example-dumped/programs --info UdonModuleInfo.json

You need to replace example-dumped/programsexample-dumped/programs and UdonModuleInfo.jsonUdonModuleInfo.json with their actual paths.

The console should show logs like

2026-03-18T03:15:38.832775Z  INFO udon_decompiler: logging initialized level=info
2026-03-18T03:15:38.832843Z  INFO udon_decompiler: start command mode=Dc input=example-dumped/programs output=None template=None
2026-03-18T03:15:38.837946Z  INFO udon_decompiler: processing directory mode=Dc input_dir=example-dumped/programs output=None template=None
2026-03-18T03:15:38.842021Z  INFO udon_decompiler: processing "example-dumped/programs/27d9de9b1e2d2424cadf167f75a47d24.hex"
2026-03-18T03:15:38.845832Z  INFO udon_decompiler::decompiler::context: class name inferred: Sonic853.Udon.Keypad.UdonVRCheckerObjects
2026-03-18T03:15:38.845873Z  INFO udon_decompiler::decompiler::context: decompile context loaded bytecode_len=468 instruction_count=60 entry_points=1 symbols=15 heap_entries=23
2026-03-18T03:15:38.846975Z  INFO udon_decompiler::decompiler::variable: 23 variables identified from heap
2026-03-18T03:15:39.018584Z  INFO udon_decompiler::decompiler::module_info: successfully loaded module info
2026-03-18T03:15:39.019550Z  INFO udon_decompiler::decompiler::basic_block: 7 basic blocks identified
2026-03-18T03:15:39.019791Z  INFO udon_decompiler::decompiler::cfg: 1 functions discovered with their cfgs built
2026-03-18T03:15:39.019884Z  INFO udon_decompiler::decompiler::ir::builder: 1 IrFunctions built
2026-03-18T03:15:39.020321Z  INFO udon_decompiler::decompiler::transform::pipeline: IR transformed.
2026-03-18T03:15:39.020411Z  INFO udon_decompiler::decompiler::codegen: c# code for UdonVRCheckerObjects generated!
2026-03-18T03:15:39.073924Z  INFO udon_decompiler: example-dumped/programs/27d9de9b1e2d2424cadf167f75a47d24.hex -> example-dumped/programs-decompiled/Sonic853_Udon_Keypad_UdonVRCheckerObjects.cs
...
2026-03-18T03:15:39.710051Z  INFO udon_decompiler: done!
2026-03-18T03:15:38.832775Z  INFO udon_decompiler: logging initialized level=info
2026-03-18T03:15:38.832843Z  INFO udon_decompiler: start command mode=Dc input=example-dumped/programs output=None template=None
2026-03-18T03:15:38.837946Z  INFO udon_decompiler: processing directory mode=Dc input_dir=example-dumped/programs output=None template=None
2026-03-18T03:15:38.842021Z  INFO udon_decompiler: processing "example-dumped/programs/27d9de9b1e2d2424cadf167f75a47d24.hex"
2026-03-18T03:15:38.845832Z  INFO udon_decompiler::decompiler::context: class name inferred: Sonic853.Udon.Keypad.UdonVRCheckerObjects
2026-03-18T03:15:38.845873Z  INFO udon_decompiler::decompiler::context: decompile context loaded bytecode_len=468 instruction_count=60 entry_points=1 symbols=15 heap_entries=23
2026-03-18T03:15:38.846975Z  INFO udon_decompiler::decompiler::variable: 23 variables identified from heap
2026-03-18T03:15:39.018584Z  INFO udon_decompiler::decompiler::module_info: successfully loaded module info
2026-03-18T03:15:39.019550Z  INFO udon_decompiler::decompiler::basic_block: 7 basic blocks identified
2026-03-18T03:15:39.019791Z  INFO udon_decompiler::decompiler::cfg: 1 functions discovered with their cfgs built
2026-03-18T03:15:39.019884Z  INFO udon_decompiler::decompiler::ir::builder: 1 IrFunctions built
2026-03-18T03:15:39.020321Z  INFO udon_decompiler::decompiler::transform::pipeline: IR transformed.
2026-03-18T03:15:39.020411Z  INFO udon_decompiler::decompiler::codegen: c# code for UdonVRCheckerObjects generated!
2026-03-18T03:15:39.073924Z  INFO udon_decompiler: example-dumped/programs/27d9de9b1e2d2424cadf167f75a47d24.hex -> example-dumped/programs-decompiled/Sonic853_Udon_Keypad_UdonVRCheckerObjects.cs
...
2026-03-18T03:15:39.710051Z  INFO udon_decompiler: done!

You can then find all decompilation results, that is, .cs.cs pseudocode files, in the example-dumped/programs-decompiledexample-dumped/programs-decompiled directory.