OpenCMR2

OpenCMR2 is a work-in-progress native port of Colin McRae Rally 2.0 (PC, 2000) to modern platforms, built on the CMR2Decomp decompilation. It runs the original game code natively on Linux, Windows, macOS and Android. There is no emulation and no Wine or DirectX wrapper: DirectDraw, Direct3D 7, DirectSound, DirectInput, DirectPlay and Bink are replaced with SDL3, the SDL GPU API (Vulkan, Metal) and the port's own code.

opencmr2-1.0-github.mp4

Colin McRae Rally 2.0 running on Linux with OpenCMR2.

Warning

This repository contains no game assets. You need your own copy of the original PC version of Colin McRae Rally 2.0 to play.

Status

Everything tested so far works: the intro videos, the menus, the stages and network races over LAN. The project is still in development, so you may find bugs. If you do, please report them. The game code follows CMR2Decomp, and its progress is brought into the port as it is made.

Platform	Architecture	Status
Linux	x86-64	Plays stages and matches the original physics
Linux	i686	Plays stages, reference build with the original memory layout
Linux	ARM64	Builds and passes the tests, gameplay not yet tested
Windows	x86-64	Plays stages and matches the original physics (tested under Wine)
macOS	ARM64	Builds and passes the tests, gameplay not yet tested
Android	ARM64, x86-64	Plays stages with on-screen controls (Android 10 or later, Vulkan)

Features

• Native SDL3 platform layer for windowing, input, audio and files, with saves and settings in the user directory
• SDL GPU renderer (Vulkan, Metal) reproducing the Direct3D 7 fixed-function pipeline in shaders
• Fullscreen on the desktop resolution or a resizable window, switched with Alt+Enter
• Keyboard, mouse and gamepads through SDL3, and on-screen controls on Android
• Bink intro and country videos with a built-in decoder
• Multiplayer over LAN and the internet using UDP instead of DirectPlay
• Folder dialog on first launch to locate the game installation
• Fixes for some original bugs, such as German in the language menu loading Spanish

The improvements of SilentPatch are built in as well:

• Widescreen resolutions up to the desktop resolution, with the correct perspective instead of a stretched picture
• Configurable field of view
• High and variable frame rates without changing the game speed or the physics, verified against the original game

Approach

The game code in game/ comes from CMR2Decomp and is kept as close to the original as possible. Every change the port needs is marked with a PORT: comment. The rest of the port (src/) implements the platform APIs the game expects on top of SDL3.

Accuracy is tested against the original executable rather than assumed:

• The fixed-point helpers are compared with the original x87 assembly
• The startup math tables (16,896 entries) are compared with dumps from the original game
• 500 vehicle updates of a Finland stage, driven by recorded input, are compared field by field with the original game + SilentPatch at 30, 60, 120, 144 and 240 FPS and at a variable frame rate. All of them match bit for bit (details).

Graphical enhancements will be added one at a time and kept optional, so the original look stays available.

Running

Download the package for your platform from Releases:

Platform	Package
Windows x64	OpenCMR2-Windows-x64.zip
Linux x86-64	OpenCMR2-Linux-x86_64.tar.gz
Linux ARM64	OpenCMR2-Linux-arm64.tar.gz
Linux 32-bit	OpenCMR2-Linux-i686.tar.gz
macOS (Apple silicon)	OpenCMR2-macOS-arm64.zip
Android	OpenCMR2-Android.apk

Extract it and run opencmr2. On first launch, choose the folder of your PC installation. The installation itself, a folder inside it or a parent folder all work. The location is checked and remembered, and the game files stay where they are.

If you have the CD or an ISO, install the game or extract it first: OpenCMR2 reads the installed folders (Game, FrontEnd, Sounds, ...).

On Android, install the APK and copy the installation folder to the device first. On first launch, choose it in the system's folder picker: the game files are copied into the app once (about 700 MB), as Android gives apps no direct access to other folders. The on-screen controls press the default keyboard keys, so they work in the menus and on the stages, and hide while a gamepad is used, external or built into a handheld. Back pauses the game.

The Linux packages are built on Ubuntu 24.04 and need a distribution of similar age or newer. The macOS package is not signed: after extracting it, run xattr -dr com.apple.quarantine OpenCMR2-macOS-arm64 once.

Command-line options:

Option	Description
--data <dir>	Use this game installation and skip the folder dialog
--user-dir <dir>	Keep saves, settings and logs in this directory

The installation can also be set with the OPENCMR2_DATA environment variable or [paths] data in opencmr2.ini, or copied into a Data folder next to the executable, which is found without asking.

Configuration

Settings are stored in opencmr2.ini in the user directory (~/.local/share/OpenCMR2/ on Linux, %APPDATA%\OpenCMR2\ on Windows; files from the older OpenCMR2/OpenCMR2 folder are moved there). It is created with comments on first launch.

Setting	Default	Description
[video] fullscreen	1	Fullscreen (1) or window (0), changed and saved by Alt+Enter
[video] fov	70	Field of view in degrees, 30 to 150 (70 is the original)
[video] run_in_background	0	Keep running when the window loses focus
[install] language	English	English, American, French, German, Italian, Spanish or Polish
[install] sku	EUROPE	Game edition: EUROPE, AMERICA, POLAND or JAPAN
[install] menu_shortcut	asked	Entry in the applications menu (Linux) or Start menu (Windows): 1 keeps it pointing at this copy, 0 removes it
[net] ...		Network play, see NETWORK.md

Building

OpenCMR2 builds with Clang, CMake 3.24+, Ninja and glslang, using the presets in CMakePresets.json:

Preset	Target
linux	Linux, 64-bit (x86-64 or ARM64)
windows-x64	Windows x64 (clang++ with the MSVC runtime)
macos	macOS, Apple silicon
linux-x86	Linux, 32-bit x86 (reference build for the tests)

OpenCMR2 needs SDL 3.4 or later. An installed SDL3 of that version is used; otherwise CMake downloads and builds it and places it next to the executable (to force this, pass -DOPENCMR2_VENDORED_SDL=ON). Start by cloning the repository:

git clone https://github.com/pablocpas/OpenCMR2.git
cd OpenCMR2

Linux

Install the dependencies.

Fedora (SDL3-devel is used when it is 3.4 or later):

sudo dnf install clang cmake ninja-build glslang SDL3-devel

Ubuntu 24.04 or Debian, where SDL3 is built from source with these development libraries:

sudo apt install clang cmake ninja-build glslang-tools pkg-config \
    libx11-dev libxext-dev libxrandr-dev libxcursor-dev libxi-dev libxss-dev libxtst-dev \
    libxkbcommon-dev libwayland-dev wayland-protocols libegl1-mesa-dev \
    libasound2-dev libpulse-dev libudev-dev libdbus-1-dev

Then build:

cmake --preset linux
cmake --build --preset linux

The executable is build/linux/src/opencmr2.

macOS

brew install cmake ninja glslang sdl3
cmake --preset macos
cmake --build --preset macos

Metal needs MSL shaders, so the build fetches SPIRV-Cross to translate them (or uses spirv-cross from the PATH).

Windows

Install Visual Studio 2022 with its "C++ Clang tools" component (or LLVM), Ninja and glslang. From an "x64 Native Tools" command prompt:

cmake --preset windows-x64
cmake --build --preset windows-x64

clang-cl is not supported, as the build uses GNU-style options. To cross-build from Linux with LLVM-MinGW, see WINDOWS.md.

Android

The Gradle project in android/ builds the same CMake project with the Android NDK. It needs JDK 17 or later, the Android SDK (with ANDROID_HOME set or sdk.dir in android/local.properties) and glslang on the PATH. Gradle downloads SDL's source and fetches the NDK, CMake and SDK platform when the SDK licences are accepted:

cd android
./gradlew assembleRelease

The APK is android/app/build/outputs/apk/release/app-release.apk. It is signed with the release key given by OPENCMR2_KEYSTORE, OPENCMR2_KEYSTORE_PASSWORD, OPENCMR2_KEY_ALIAS and OPENCMR2_KEY_PASSWORD (or the opencmr2.keystore Gradle properties), and with the debug key otherwise.

Tests

ctest --preset linux

The 32-bit linux-x86 build keeps the original data layout and is the reference for the tests against the original game. Its dependencies and the rest of the development workflow are described in DEVELOPMENT.md.

Documentation

Document	Contents
ARCHITECTURE.md	Source layout, platform APIs and renderer design
DEVELOPMENT.md	Tests, syncing with CMR2Decomp, repository conventions
PHYSICS_PARITY.md	Physics and timing comparison with the original game
ORIGINAL_REFERENCE.md	Recording the original game for the comparisons
BASELINE.md	Stage capture, replay and CPU profiling
NETWORK.md	Network play setup and protocol
VIDEO.md	Bink decoder
WINDOWS.md	Release packages and cross-building for Windows
64bit-raw-access.md	64-bit memory access audit

The full index is in docs/README.md.

Credits

• CMR2Decomp, the decompilation this port is built on
• Silent, for SilentPatch, whose improvements are built in and which is the reference for the comparisons with the original game
• The SDL and ENet projects
• Filippo Scognamiglio for RadialGamePad, the on-screen controls on Android
• Konstantin Shishkov, Peter Ross and Daniel Verkamp for FFmpeg's Bink decoder, which src/video/ is adapted from

Licence

OpenCMR2 is licensed under the GPL-3.0. Bundled third-party code keeps its own licence: SDL3 (zlib), ENet (MIT), the Bink decoder (LGPL-2.1) and RadialGamePad (GPL-3.0).

OpenCMR2 is an unofficial project, not affiliated with or endorsed by Codemasters or Electronic Arts. Colin McRae Rally 2.0 is a trademark of its respective owners.