Open Halo 2

Looking to play halo 2? https://github.com/andrewnakas/openhalo2/releases

Please support the halo 2 decompolation project as that's the project that we really want to get behind, and i made this project primarily as a helper vehicle to get us to halo 2 full decompilation, so please if you have tokens burning though your claude wallet please lend a hand, if we decompile it that's what unlocked a lot of potential with mods and better porting abilities.

I'm just scratching the surface but i think this can help us get the project decompiled faster?

https://github.com/kirklandsig/halo2-decompiled

Halo 2 (original Xbox, 2004) running natively on a PC. The game's own program code is translated instruction by instruction into C (a static recompilation) and compiled into a Windows program, beside a model of the Xbox hardware it talks to.

You need your own copy of the game, and the recompilation is made from it. This download contains nothing from Halo 2: no maps, sounds, textures or movies, and none of the game's program code. On first start you point it at your disc image; it copies the game files into a game folder, then translates your copy of the game's program into C and compiles it on your PC.

Getting started (Windows 10/11, 64-bit)

1. Unzip anywhere you can write to (not Program Files). About 10 GB of free space is needed: the game files, the build and the save/cache folder.
2. Run OpenHalo2.exe.
3. When it asks, choose your disc image: a Redump .iso or an XISO, or the default.xbe of a copy you already extracted. The import takes a few minutes and checks that it is the original retail disc (the one version this build runs).
4. It then builds the game program (halo2_recomp.exe) from your copy, once, in a window that shows the progress: about 10-30 minutes on a typical PC. The lifted code is checked against the code this release was tested with before it is compiled.
   • The compiler (LLVM clang) and the lifter come with the download. Compiling also needs Microsoft's C runtime and Windows SDK libraries. If Visual Studio or its free Build Tools (C++ workload) are installed they are used; if not, the build asks you to accept Microsoft's licence and downloads them from Microsoft (about 85 MB) with xwin.
5. The game starts. The first start copies maps into the emulated hard disk; it can take several minutes. Later starts are quick (always start OpenHalo2.exe).

Needs a GPU with OpenGL 3.3 and an internet connection for the one Microsoft download (if Visual Studio is not installed). The finished program needs no other installs.

Building it yourself instead

Everything in the download is made from this repository; nothing from the game is in it. port/xr/build_kit.cmd builds the runtime kit (no game code), tools/byog/build_launcher.cmd the launcher, and tools/make_release.sh packs them with the lifter and compiler. To work on the code, tools/relift.sh lifts your own default.xbe into port/xr/src/recomp/gen/ and port/xr/build_win.cmd builds the full program with Visual Studio 2022.

Controls

Controller (XInput): as on the console. Left bumper = white, right bumper = black.

Keyboard and mouse: W A S D move (Shift walks), mouse looks (click into the window first; F1 or Alt+Tab releases the pointer), left mouse fire, right mouse grenade, middle mouse or Z zoom, Space jump (A), F or Backspace (B), E or R reload/action (X), Tab switch weapon (Y), Q (white), G (black), Ctrl or C crouch, Enter or Esc Start, F2 Back, arrow keys d-pad. F11 or Alt+Enter: fullscreen. F12: screenshot.

Settings: halo2.ini

Create halo2.ini next to the program:

fullscreen = 1       ; start fullscreen
mouse_sens = 1.0     ; mouse look speed
mouse_deadzone = 0.2
volume_db = 0        ; master trim in dB, e.g. -6
log_cap_mb = 64      ; halo2_recomp.log is cut back past this size (0 = never)

Online play (free, peer to peer)

There are no game servers. Players connect directly to each other; a small free relay only introduces them. Add one of these to halo2.ini:

System link over the internet. Everyone who uses the same room name sees each other's games under Multiplayer > System Link, as if on one LAN (up to 10 players in a room):

room = my-friends-room

Open Live. The game's own Xbox Live menus (sign in, friends, invites, parties, matchmaking), run between players instead of on Microsoft's servers:

open_live = 1
gamertag = YourName

Stats and leaderboards are not kept.

Saves and logs

save\ next to the program is the emulated Xbox hard disk (profiles, game saves, map cache). halo2_recomp.log describes the last run; if the game ever stops with an error message, that file says why. Please attach it to bug reports.

Known issues

• The picture is the console's 640x480, scaled.
• Sound effects that the console runs on its audio DSP (reverb in large rooms) are not produced yet.
• Closing the window waits up to 5 seconds for a save in progress to finish, then quits.
• Windows only for now; macOS, Linux and browser builds are planned.

Legal

Halo 2 is a trademark of Microsoft. This project is not affiliated with or endorsed by Microsoft, Bungie or 343 Industries. It ships no game data, and it runs only with a copy of the game you own.

Open Halo 2 does not distribute the game's program code in any form. The recompilation is made on your PC from your own copy of the game and stays there. Open Halo 2's own code, tools and documentation are public domain (CC0 1.0, see LICENSE): decompilation projects and anyone else may reuse any of it freely. NOTICE lists the third-party code it uses and its licences.