iocod

iocod is an experimental standalone engine fork of ioquake3 aimed at reconstructing enough of the original Call of Duty (2003) engine behavior to work with CoD1-style assets, UI, scripts, and networking.

This is not stock ioquake3, and it is not an official Call of Duty source release. If you want upstream Quake III engine work, use ioquake3 directly. If you want to understand or extend this fork's Call of Duty compatibility work, this repository is the right place.

What This Repository Is

Call of Duty 1 compatibility and replacement effort

The default standalone build is branded as iocod, uses main/ as its base game directory, and produces:

• iocod for the client
• iocod-ded for the dedicated server
• main/ game modules built from this source tree

Current Status

This fork already contains substantial CoD-oriented work, but it is still an in-progress engine port rather than a finished drop-in replacement.

• Multiplayer is the current focus.
• Single-player launch paths are intentionally not implemented in the current standalone UI.
• The standalone path is currently English-focused.
• Compatibility is incomplete; expect rough edges, missing features, and behavior that still differs from the original binaries.
• No proprietary game data is bundled here.

Building

This fork keeps ioquake3's CMake-based build system. The commands below assume the default standalone configuration.

On Linux or other Unix-like systems, a typical build is:

cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build

On Debian/Ubuntu, install at least:

sudo apt install cmake ninja-build libsdl2-dev

On Windows, use a generator that fits your toolchain, for example:

cmake -S . -B build -G "Visual Studio 17 2022"
cmake --build build --config Release

Build outputs are written under build/<config>/, for example:

• build/Release/iocod
• build/Release/iocod-ded
• build/Release/main/

The repository's CI currently builds this code on Linux, Windows, macOS, Emscripten, FreeBSD, and OpenBSD.

Game Data

You must supply your own retail Call of Duty data. This repository does not include main/pak*.pk3, localized packs, or any other proprietary game content.

The engine expects a CoD-style main/ directory. The simplest approach is to point fs_basepath at an existing Call of Duty installation:

./build/Release/iocod +set fs_basepath "/path/to/Call of Duty"
./build/Release/iocod-ded +set fs_basepath "/path/to/Call of Duty"

On Linux standalone builds, the engine also probes the default Steam/Proton location at ~/.steam/steam/steamapps/common/Call of Duty.

If you are targeting the web build, the expected main/ asset layout is listed in code/web/client-config.json.

Credits And Provenance

• id Software for the Quake III Arena GPL source release that made ioquake3, and therefore this fork, possible.
• The ioquake3 project and contributors for the cross-platform engine base this repository extends: https://github.com/ioquake/ioq3
• Infinity Ward and Activision for the original Call of Duty whose data formats, assets, scripting conventions, and game behavior this project targets for compatibility.

This repository is an independent fork. It does not include or relicense the original Call of Duty game assets.

License

The core engine code in this repository is derived from Quake III Arena and ioquake3 and is distributed under the GNU GPL. See COPYING.txt.

Bundled or third-party components may carry additional license terms. Those notices are kept alongside the relevant material, especially under code/thirdparty/.

Original Call of Duty game assets, packs, and other proprietary content are not included and remain the property of their respective rightsholders.