This project is a port of the Halo: Combat Evolved decompilation to Linux, Windows and Android. The decompilation is of the Xbox build 2342 (cachebeta.exe, SHA-256 4cc87b45f721270392a96f1674ed2b5cd4a7bb4355faeab4531d1cf1884d9520).

The port starts from the decompilation of bnunu/halo-1. That project is a fork of punpckhdq/halo.

GitHub Actions builds the game for each commit. These links download the builds of the latest release:

Use the release build to play. The debug build stops at the first failed assertion and writes it to the log. Use the debug build to find and report problems.

The game updates itself. At start-up it looks for a newer release, and asks if you want to install it. Refer to "Updates" in port/linux/README.md.

Each build of the main branch that passes on all three platforms is a new release. The Releases page keeps the last five releases. If the latest build has a problem, get an older build from that page.

The port does not include the game data. Download an Xbox disc image (.xiso or .iso) of Halo: Combat Evolved. All versions of the game operate. The maps of the European (PAL) version were made for a slower console. The port changes them to play as the North American (NTSC) maps do, so players of the two versions can play together.

1. Start the game.
2. At the first start, the game asks for the disc image. Select it.
3. The game extracts the maps/ folder. Then the game starts.

On Linux and Windows, the game puts maps/ next to the executable. On Android, copy the disc image to the phone first. The app puts maps/ in its data folder. Refer to port/android/README.md.

Each platform has its own instructions:

The Linux README also gives the controls, the settings and the multiplayer functions. These are almost the same on all platforms.

The game can play system link games on a local network and on the internet:

• A system link game can have up to 128 players on up to 128 machines.
• Linux, Windows and Android machines can play in the same game.
• An invite link lets a machine join a game on the internet. No server of this project is necessary.
• The netcode is new. Each machine moves its own player at once, and the host makes the decisions for the game. Refer to port/linux/NETCODE.md.

The game can load Halo Custom Edition maps (.map) and OpenSauce maps (.yelo). This function is experimental, and it is off by default:

1. Set custom_edition = true in the [game] section of config.toml.
2. Put the map in the maps/ folder, with the bitmaps.map, sounds.map and loc.map of Halo Custom Edition.
3. Start the map from init.txt in the data root.

The Windows build was tested with three maps: bloodgulch.map, beavercreek_halo3.yelo and hugeass.map. Other maps can use functions that the port does not have. Ogg Vorbis sounds do not play. Refer to docs/custom_edition_caches.md.

You do not need the Xbox SDK. The port supplies the SDK declarations that the game uses. Refer to port/include/xdk.

To build the game:

1. Install Python and ninja.
2. Install the tools for your platform. Refer to the README for the platform.
3. In the root folder of the repository, enter python configure.py.
4. Enter ninja with the target for the platform:

If you enter ninja without a target, ninja builds the game for the computer that you use.

tools/ci_build.py makes the same builds as GitHub Actions. For example, enter python tools/ci_build.py linux release.

Give these options to configure.py:

Without --portable, the Linux and Windows builds use all the instructions of the processor that builds them (-march=native). Such a build does not always start on a different computer.

The builds use profiles of the game to optimize the code:

• pgo/halo_linux.profdata for Linux and Android.
• pgo/halo_windows.profdata for Windows.

The profiles need clang 22 or later. With an older clang, the builds do not use the profiles.

To record a new profile:

1. Delete the profile.
2. Enter python configure.py --pgo=train.
3. Enter ninja linux or ninja windows.

The build then plays the main menu and the first minute of each campaign level. This procedure continues for approximately 15 minutes. The game data must be in assets/.