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, Direct3D 12, Metal) or OpenGL 3.3 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, Direct3D 12, Metal) reproducing the Direct3D 7 fixed-function pipeline in shaders, and an OpenGL 3.3 renderer with the same shaders for GPUs without Vulkan or Direct3D 12 (Linux and Windows)
- 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
- In-race HUD scaled with the screen and kept at its edges on wide screens, with a configurable size
- 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, CountrySpecific
and SetupRep, and does not start when one of them is missing.
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. The Screen page of the
graphics options sets hud_scale, menu_scale, vsync and fullscreen in
the game.
| 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 |
[video] car_detail |
1 |
Every car with the model and textures of the player's car (1), or the original's lower detail for the other cars (0); applies with Car Detail set to High |
[video] hud_scale |
100 |
Size of the in-race HUD in percent of the original's at the screen's height; 0 keeps the original's layout in pixels |
[video] hud_aspect |
16:9 |
Widest shape the HUD spreads over, centred on wider screens: an aspect ratio such as 16:9 or 21:9, or full for the whole screen |
[video] menu_scale |
100 |
Size of the menus in percent of the original's at the screen's height; 0 keeps the original's layout in pixels |
[video] outline_fonts |
1 |
Draw the text from outlines, sharp at any size (1), or from the original's bitmaps (0) |
[video] vsync |
1 |
Wait for the display's refresh (1) or draw frames as soon as they are ready (0) |
[video] graphics_api |
auto |
Renderer: sdl_gpu (Vulkan, Direct3D 12, Metal), opengl (OpenGL 3.3, Linux and Windows), or auto for SDL GPU when the GPU has a Vulkan, Direct3D 12 or Metal driver (not a software one) and OpenGL otherwise |
[video] window_scale |
1 |
Size of the window in multiples of the game's resolution, applied when leaving fullscreen |
[video] smooth_scaling |
1 |
Smooth the picture when it is scaled to the window or screen (1), or keep sharp pixels (0) |
[video] anisotropy |
1 |
Anisotropic texture filtering, 2 to 16; 1 is off, as in the original |
[video] stretch_movies |
0 |
Stretch the movies over the whole window (1) instead of keeping their 4:3 proportions |
[input] key_repeat_delay |
750 |
Milliseconds before a key held in the menus repeats |
[input] key_repeat_interval |
100 |
Milliseconds between the repeats of a held key |
[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 OpenCMR2Linux
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-devThen 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, and the OpenGL renderer on Linux and Windows GLSL
330 ones, so the build fetches SPIRV-Cross to translate them (or uses
spirv-cross from the PATH). -DOPENCMR2_RENDERER_GL=OFF leaves the OpenGL
renderer out.
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 assembleReleaseThe 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.