Video Setup > FOV and Viewmodels > Legs, off by default. In first person the player's own body, which the game animates as everyone else sees it but does not draw for its own player, is drawn from the waist down: looking down, your legs walk, run, strafe and crouch as the body's animation moves them. How it is drawn (port/linux/game/first_person_legs.c): - A copy of the body's pose as drawn: everything but the hips and legs (by node name: pelvis, thigh, calf, foot, toe) folded into a lid over the waist, the root kept. - The body set back behind the eye, each frame, as far as keeps the waist's open rim beyond the bottom plane of the view (the way Halo 2's fp_body keeps its open top out of sight): looking ahead, 4 cm; straight down at 105 degrees, about 67 cm. The legs are seen as they swing forward. - Drawn with the world's camera, so it keeps its place and size at any FOV; not in mirrors, not in the shadow pass, without what it carries. The waist's rim is found from the model's own triangles: object_mesh.c reads an object's drawn mesh (its most detailed geometry, in the permutations it shows) from the vertex and index buffers the game draws it from, as powerup_render_bounds.c reads them; its cache is forgotten on a new map (objects_initialize_for_new_map). Only the drawing changes: the body, its hit boxes, markers, the camera and everything sent between machines are the game's. Checked by compiling the changed units; the fold and set-back were checked against a capture of the cyborg's mesh and pose and played on Windows. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015jtk9vPUKbWd48oBMzXuzd
Halo: Combat Evolved for Linux, Windows and Android
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.
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.
- Start the game.
- At the first start, the game asks for the disc image. Select it.
- 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:
- Install Python and ninja.
- Install the tools for your platform. Refer to the README for the platform.
- In the root folder of the repository, enter
python configure.py. - Enter
ninjawith 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.profdatafor Linux and Android.pgo/halo_windows.profdatafor Windows.
The profiles need clang 22 or later. With an older clang, the builds do not use the profiles.
To record a new profile:
- Delete the profile.
- Enter
python configure.py --pgo=train. - Enter
ninja linuxorninja 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.
- Enter
python configure.py --profile, then build as usual. - Start a recording. Enter
profile_recordin the console (or the telnet console), or setdebug.profile_record = trueinconfig.toml. To record each game of a session, also setdebug.profile_record_when = "game". - 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.