BFME 2 Source Code

Goal: Source code that rebuilds BFME 2's engine binary (game.dat) byte-for-byte, and game modernization improvements that you've only seen in your dreams.

Join our Discord to participate!

What?

• If you take a part of the BFME 2 binary, recreate the exact source code that would make that part of the binary, then compile the source code and inject it into the binary, you get the same binary
• Doing this piece by piece will eventually give you a full, open source recreation of BFME 2, and enable some (insane) mods
• The target is game.dat — the real engine PE; lotrbfme2.exe is only a launcher stub
• Sister project of Open-BFME-1: same engine family, same MSVC 7.1 toolchain, same workflow — and BFME 1's converted source rides in as a submodule reference

Status

0.59% of the game rebuilds from what we hold — 146 byte-verified functions on day one (zlib 1.1.4, EAC codecs, LZHCompress, md5). Flag calibration is proven: 756 Open-BFME-1 bodies transfer to game.dat verbatim, so the reference sweeps are wide open.

Roadmap

• BFME 2 Source Code (0.59%)
• 60/120 FPS
• Memory fix
• Better crash logs
• Multi CPU
• World builder Source Code
• Bigger maps
• RotWK support

Off-host delay is already fixed by the community (BFME 2 patch 1.09v3, RotWK 2.02 v9), so it is deliberately not on this roadmap.

How You Can Help

Clone the repo and give your AI agent this exact prompt — measured on six agent sessions, a vaguer prompt reliably produces zero progress:

Read AGENTS.md and follow it. Loop: take the served candidate's whole file, convert bodies to byte-exact C++, bank each verified body as its own commit, and before stopping run python3 tools/progress.py origin/master — if C++ exact is +0 bytes, keep going. Make a PR when you have a few landed bodies.

Each commit in the PR is one verified function, and I will be able to merge it.

!! All such AI-generated PRs are appreciated !!

Build

The baseline executables are committed directly; the MSVC 7.1 toolchain and the Zero Hour reference source live in the Open-BFME-1 submodule, so clone with submodules:

git clone --recurse-submodules https://github.com/Open-BFME/Open-BFME-2.git
cd Open-BFME-2
./tools/setup_hooks.sh   # enable the pre-commit byte-check (git won't do this from a clone)
./build.sh               # verify every tracked function against retail   (.\build.ps1 on Windows)

To check a single function while iterating, pass its file or name — a few seconds instead of the full run:

./build.sh Code/Libraries/Source/Compression/ZLib/trees.c