opencod2

A reconstruction of the Call of Duty 2 engine

The reconstruction is incomplete. It may crash, omit subsystems, or only partially implement behavior that exists in the original game.

Older Call of Duty titles and game engines from this era have a history of security-sensitive bugs, especially around networking, file parsing, content-loading paths, and memory safety. This project should not currently be treated as a hardened or production-safe engine.

One long-term goal of the reconstruction is to make those risks easier to audit and fix: preserve compatibility where practical, but replace unsafe behavior and close vulnerabilities as they are found. Until then, run it only with data you trust and avoid exposing test servers to untrusted networks.

All targets are driven by CMake (≥ 3.16), each an out-of-source build into its own directory.

The engine is a 32-bit x86 binary; you need a multilib toolchain and 32-bit libs (Debian/Ubuntu names shown):

sudo apt install build-essential gcc-multilib g++-multilib cmake \
     libsdl2-dev:i386 libgl1-mesa-dev:i386 libx11-dev:i386 \
     libcurl4-openssl-dev:i386 zlib1g-dev:i386 libstdc++6:i386

cmake -S . -B build-native
cmake --build build-native -j
# -> build-native/cod2_linux    (client)
# -> build-native/cod2_lnxded   (dedicated server)

cmake -S . -B build-win32 -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-mingw32.cmake
cmake --build build-win32 -j
# -> build-win32/cod2_win32_ded.exe   (dedicated server)

Add -DCOD2_WIN32_CLIENT=ON for the SDL2/GL client (supply SDL2 dev libs under src/win32/sdl2/lib/; the dedicated server needs none).

The renderer can be built as a separate swap-in DLL — it exports GetRefAPI and talks to the engine only through the ri/re tables. With the client configured, run the gfxdll target:

cmake --build build-win32 --target gfxdll
# -> build-win32/gfx_d3d_mp_x86_s.dll   (renderer DLL)
# -> build-win32/cod2_win32_gfxdll.exe  (engine that loads it at runtime)

The renderer↔engine bridge is pre-generated and committed under build/gfxdll/; the build is pure compile+link. Experimental — not exhaustively tested.

A native Windows build of the full SDL2/GL client with the Microsoft C/C++ compiler (cl.exe) — no cross-compiler required. It is additive: it does not touch the MinGW path above (everything MSVC-specific is gated behind the COD2_WIN_MSVC CMake option).

Requires Visual Studio 2022 or newer with the x86 MSVC toolset. The binary is 32-bit, so configure and build from an "x86 Native Tools for VS" command prompt (or run call "<VS_INSTALL_DIR>\VC\Auxiliary\Build\vcvars32.bat" to put the x86 cl, CMake, and Ninja on PATH):

Debug build:

cmake --preset msvc-client
cmake --build build/msvc --target cod2_win32
:: -> build/msvc/cod2_win32.exe   (full client, ~2.7 MB)

Optimized Release build (/O2):

cmake --preset msvc-client-release
cmake --build build/msvc-release --target cod2_win32
:: -> build/msvc-release/cod2_win32.exe   (~1.9 MB)

SDL2 is user-supplied (never committed). Drop the 32-bit MSVC SDL2 dev package under third_party/SDL2-<version>/ (or the legacy src/win32/sdl2/); the build finds the headers and lib/x86 automatically.

• Default — dynamic. Uses the import SDL2.lib; copy the 32-bit SDL2.dll next to the built exe in build/msvc/ (or build/msvc-release/).

• Optional — fully static / standalone (-DCOD2_SDL2_STATIC=ON, on either preset). Produces a single self-contained exe that imports only Windows system DLLs — no SDL2.dll, no VC runtime DLLs. This one flag statically links both SDL2 and the CRT (/MTd Debug, /MT Release). You supply a static SDL2-static.lib you build yourself from the SDL2 source, in the same config as the engine:

  :: match the engine: -DCMAKE_BUILD_TYPE=Debug for msvc-client, =Release for -release
  cmake -S SDL2-2.32.10 -B sdl2-build -DCMAKE_BUILD_TYPE=Debug ^
        -DSDL_STATIC=ON -DSDL_SHARED=OFF -DSDL_RENDER=OFF -DSDL_FORCE_STATIC_VCRT=ON
  cmake --build sdl2-build
  :: copy the resulting SDL2-static*.lib -> third_party/SDL2-*/lib/x86/SDL2-static.lib

  • Config must match — a /MTd (Debug) SDL2 lib against a /MT (Release) engine, or vice-versa, fails with LNK4098. SDL_FORCE_STATIC_VCRT=ON gives the static CRT; the SDL2 build's CMAKE_BUILD_TYPE picks /MTd vs /MT.
  • SDL_RENDER=OFF — the engine uses SDL only for window/GL/input, and SDL's render backend exports a MatrixMultiply that otherwise collides with the engine's own.

  The extra system deps (uuid, dinput8) are linked for you. Most people won't need this.

With no SDL2 lib at all, the link falls back to a stub and no window opens.

This target compiles all TUs, links with no unresolved or duplicate symbols, boots, renders the menu, and can load maps — but the same work-in-progress caveats above apply.

This reconstructs the engine, not the content. Point it at data from a copy of the game you legally own:

./build-native/cod2_linux +set fs_basepath /path/to/your/game

On Windows (native MSVC client):

:: Debug
build\msvc\cod2_win32.exe +set fs_basepath "C:\path\to\your\game"

:: Release
build\msvc-release\cod2_win32.exe +set fs_basepath "C:\path\to\your\game"

Without legally-obtained data the build runs but has nothing to load.

This is an independent, source-level reconstruction of the Call of Duty 2 engine. It is not affiliated with, authorized by, sponsored by, or endorsed by Activision Publishing, Inc., Infinity Ward, or any of their affiliates.

"Call of Duty" and "Call of Duty 2" are trademarks of Activision Publishing, Inc. They are used in this repository only for identification and interoperability, to describe what the code reconstructs. No claim is made to those marks.

This project does not provide or help obtain copyrighted game data. To use it with real game content, you must supply data files from a copy of Call of Duty 2 that you legally own.

The reconstructed engine source is a derivative work created for the purposes of preservation, interoperability, research, and education. It is provided as-is, without warranty of any kind, express or implied. The original port, build system, and platform glue are separable original work.

If you are a rights holder and believe something here should not be distributed, please open an issue or contact the maintainer and it will be addressed promptly.