Jonas VolmanandClaude Opus 5.5 a845bbf55d List the Custom Edition map folders through a handle of their own
custom_edition_maps_look_for listed custom_maps and the install's maps
folder with find_files_start and find_files_next, which keep their place
in one global (find_files_globals). As the game starts, the menus' thread
for the file system's checks (filesystem_initialization_thread_proc in
ui_widget.c) makes the default gametypes' folders with
directory_create_or_delete_contents, which deletes a folder's files with
the same two functions. A map list looked for meanwhile takes that
listing's place, and the thread then deletes the files of the folder being
listed: the player's Custom Edition maps.

The menus take no input until that thread is done, so it takes a start
that asks for the maps at once. Seen with debug.menu_open set to the
Select Map screen
(main_menu/multiplayer_type_select/mp_map_select/mp_map_select_screen) on
a Windows build of c9e4f13f, with six files in custom_maps: one was left.

Each folder is now listed with FindFirstFileA and FindNextFileA on a
handle of the function's own. The same start, twice, left the six files
and listed the three maps among them. Not run on Linux or Android.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-10 01:37:01 -07:00
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Halo: Combat Evolved for Linux, Windows and Android

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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 game on Linux

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

Download

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

Platform Release Debug
Linux halo-linux-release.zip halo-linux-debug.zip
Windows halo-windows-release.zip halo-windows-debug.zip
Android halo-android-release.zip halo-android-debug.zip

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.

Game data

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.

Platforms

Each platform has its own instructions:

Platform Instructions
Linux (32-bit x86 executable, OpenGL 4.5, SDL3) port/linux/README.md
Windows (32-bit x86 executable, OpenGL 4.5, SDL3) port/windows/README.md
Android (arm64 app, OpenGL ES 3, SDL3) port/android/README.md

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

Multiplayer

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.

Build the game

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:
Target Result
ninja linux build/linux/halo
ninja windows (on Windows) build/windows/halo.exe and SDL3.dll
ninja android_apk port/android/app/build/outputs/apk/debug/app-debug.apk

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.

Build options

Give these options to configure.py:

Option Result
(none) A debug build. A failed assertion stops the game.
--release A release build. The game does not examine assertions, as in the retail game.
--portable The Linux and Windows builds operate on all x86-64 processors. The Linux build also operates on older distributions and on SteamOS: refer to "Portable build" in port/linux/README.md. Use this option for builds that you give to other persons.
--lto=thin, --lto=off Less link-time optimization. The link is faster.
--pgo=off No profile-guided optimization.
--pgo=train Records a new optimization profile. Refer to "Optimization profiles".
--profile A profiling build. It records CPU times. Refer to "Profiling builds".

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.

Optimization profiles

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/.

Profiling builds

A profiling build records where the game spends its time.

  1. Enter python configure.py --profile, then build as usual.
  2. Start a recording. Enter profile_record in the console (or the telnet console), or set debug.profile_record = true in config.toml. To record each game of a session, also set debug.profile_record_when = "game".
  3. Stop the recording. Enter profile_stop, load another map, or quit.

The game writes numbered .part<n>.json files under profiles/ in its data root and logs their paths. Parts are retained after the recording stops. Logs go to standard error; a Windows release build without standard error writes them to halo.log next to halo.exe.

tools/net_report.py is a helper for developers. Enter python tools/net_report.py <recording.part1.json> to read a recording as tables. The command also writes <recording>.summary.txt, a short text file.

Command Result
profile_record [seconds] Starts a recording. With a number of seconds, the recording stops after that time.
profile_stop Stops the recording.

debug.profile_memory sets the memory of a recording in MB (default 256, from 4 to 1024). A recording has no length limit: the game writes a part each time the memory is full. Refer to "Settings" in port/linux/README.md.

On Android, the files are in /sdcard/Android/data/com.halo.decomp/files/profiles/. Enter adb pull to copy the recording parts to a computer.

A profiling build plays with normal builds. It does not use --pgo=train.

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