CMake ===== .. warning:: The CMake scripts do not have feature parity with the SCons ones at this stage and are still a work in progress. There are a number of people who have been working on alternative CMake solutions that are frequently referenced in the discord chats: Ivan's cmake-rewrite_ branch and Vorlac's godot-roguelite_ Project .. _cmake-rewrite: https://github.com/IvanInventor/godot-cpp/tree/cmake-rewrite .. _godot-roguelite: https://github.com/vorlac/godot-roguelite Introduction ------------ Compiling godot-cpp independently of an extension project is mainly for godot-cpp developers, package maintainers, and CI/CD. Look to the godot-cpp-template_ for a practical example on how to consume the godot-cpp library as part of a Godot extension. Configuration examples are listed at the bottom of the page. .. _godot-cpp-template: https://github.com/godotengine/godot-cpp-template Debug vs template_debug ----------------------- Something I've seen come up many times is the conflation of a compilation of c++ source code with debug symbols enabled, and compiling a Godot extension with debug features enabled. The two concepts are not mutually inclusive. - debug_features Enables a pre-processor definition to selectively compile code to help users of a Godot extension with their own project. debug features are enabled in editor and template_debug builds, which can be specified during the configure phase like so ``cmake -S . -B cmake-build -DGODOTCPP_TARGET=`` - Debug Sets compiler flags so that debug symbols are generated to help godot extension developers debug their extension. ``Debug`` is the default build type for CMake projects, to select another it depends on the generator used For single configuration generators, add to the configure command: ``-DCMAKE_BUILD_TYPE=`` For multi-config generators add to the build command: ``--config `` where ```` is one of ``Debug``, ``Release``, ``RelWithDebInfo``, ``MinSizeRel`` SCons Deviations ---------------- Not everything from SCons can be perfectly representable in CMake, here are the notable differences. - debug_symbols No longer has an explicit option, and is enabled via Debug-like CMake build configurations; ``Debug``, ``RelWithDebInfo``. - dev_build Does not define ``NDEBUG`` when disabled, ``NDEBUG`` is set via Release-like CMake build configurations; ``Release``, ``MinSizeRel``. - arch CMake sets the architecture via the toolchain files, macos universal is controlled vua the ``CMAKE_OSX_ARCHITECTURES`` property which is copied to targets when they are defined. - debug_crt CMake controls linking to windows runtime libraries by copying the value of ``CMAKE_MSVC_RUNTIME_LIBRARIES`` to targets as they are defined. godot-cpp will set this variable if it isn't already set. so include it before other dependencies to have the value propagate across the projects. Testing Integration ------------------- The testing target ``godot-cpp-test`` is guarded by ``GODOTCPP_ENABLE_TESTING`` which is off by default. To configure and build the godot-cpp project to enable the integration testing targets the command will look something like: .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build -DGODOTCPP_ENABLE_TESTING=YES cmake --build cmake-build --target godot-cpp-test Basic walkthrough ----------------- .. topic:: Clone the git repository .. code-block:: git clone https://github.com/godotengine/godot-cpp.git Cloning into 'godot-cpp'... ... cd godot-cpp .. topic:: Options To list the available options CMake use the ``-L[AH]`` option. ``A`` is for advanced, and ``H`` is for help strings. .. code-block:: cmake .. -LH Options are specified on the command line when configuring eg. .. code-block:: cmake .. -DGODOTCPP_USE_HOT_RELOAD:BOOL=ON \ -DGODOTCPP_PRECISION:STRING=double \ -DCMAKE_BUILD_TYPE:STRING=Debug Review setting-build-variables_ and build-configurations_ for more information. .. _setting-build-variables: https://cmake.org/cmake/help/latest/guide/user-interaction/index.html#setting-build-variables .. _build-configurations: https://cmake.org/cmake/help/latest/manual/cmake-buildsystem.7.html#build-configurations A non-exhaustive list of options: .. code-block:: // Path to a custom GDExtension API JSON file (takes precedence over `GODOTCPP_GDEXTENSION_DIR`) ( /path/to/custom_api_file ) `GODOTCPP_CUSTOM_API_FILE:FILEPATH=` // Force disabling exception handling code (ON|OFF) GODOTCPP_DISABLE_EXCEPTIONS:BOOL=ON // Path to a custom directory containing GDExtension interface header and API JSON file ( /path/to/gdextension_dir ) GODOTCPP_GDEXTENSION_DIR:PATH=gdextension // Set the floating-point precision level (single|double) GODOTCPP_PRECISION:STRING=single // Enable the extra accounting required to support hot reload. (ON|OFF) GODOTCPP_USE_HOT_RELOAD:BOOL= .. topic:: Configure the build .. code-block:: cmake -S . -B cmake-build -G Ninja ``-S .`` Specifies the source directory ``-B cmake-build`` Specifies the build directory ``-G Ninja`` Specifies the Generator The source directory in this example is the source code for godot-cpp. The build directory is so that generated files do not clutter up the source tree. CMake doesn't build the code, it generates the files that another tool uses to build the code, in this case Ninja. To see the list of generators run ``cmake --help``. .. topic:: Compiling Tell cmake to invoke the build system it generated in the specified directory. The default target is template_debug and the default build configuration is Debug. .. code-block:: cmake --build cmake-build Examples -------- Windows and MSVC - Release ~~~~~~~~~~~~~~~~~~~~~~~~~~ So long as CMake is installed from the `CMake Downloads`_ page and in the PATH, and Microsoft Visual Studio is installed with c++ support, CMake will detect the MSVC compiler. Note that Visual Studio is a Multi-Config Generator so the build configuration needs to be specified at build time ie ``--config Release`` .. _CMake downloads: https://cmake.org/download/ .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build -DGODOTCPP_ENABLE_TESTING=YES cmake --build cmake-build -t godot-cpp-test --config Release MSys2/clang64, "Ninja" - Debug ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Assumes the ming-w64-clang-x86_64-toolchain is installed Note that Ninja is a Single-Config Generator so the build type needs to be specified at Configure time. Using the msys2/clang64 shell .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build -G"Ninja" -DGODOTCPP_ENABLE_TESTING=YES -DCMAKE_BUILD_TYPE=Release cmake --build cmake-build -t godot-cpp-test MSys2/clang64, "Ninja Multi-Config" - dev_build, Debug Symbols ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Assumes the ming-w64-clang-x86_64-toolchain is installed This time we are choosing the 'Ninja Multi-Config' generator, so the build type is specified at build time. Using the msys2/clang64 shell .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build -G"Ninja Multi-Config" -DGODOTCPP_ENABLE_TESTING=YES -DGODOTCPP_DEV_BUILD:BOOL=ON cmake --build cmake-build -t godot-cpp-test --config Debug Emscripten for web platform ~~~~~~~~~~~~~~~~~~~~~~~~~~~ I've only tested this on windows so far. I cloned and installed the latest Emscripten tools to ``c:\emsdk`` At the time of writing that was v3.1.69 I've been using ``C:\emsdk\emsdk.ps1 activate latest`` to enable the environment from powershell in the current shell. The ``emcmake.bat`` utility adds the emscripten toolchain to the CMake command It can also be added manually, the location is listed inside the emcmake.bat file .. code-block:: # Assuming our current directory is the godot-cpp source root C:\emsdk\emsdk.ps1 activate latest emcmake.bat cmake -S . -B cmake-build-web -DCMAKE_BUILD_TYPE=Release cmake --build cmake-build-web Android Cross Compile from Windows ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There are two separate paths you can choose when configuring for android. Use the ``CMAKE_ANDROID_*`` variables specified on the commandline or in your own toolchain file as listed in the cmake-toolchains_ documentation .. _cmake-toolchains: https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html#cross-compiling-for-android-with-the-ndk Or use the toolchain and scripts provided by the Android SDK and make changes using the ``ANDROID_*`` variables listed there. Where ```` is whatever ndk version you have installed (tested with `23.2.8568313`) and ```` is for android sdk platform, (tested with ``android-29``) .. warning:: The Android SDK website explicitly states that they do not support using the CMake built-in method, and recommends you stick with their toolchain files. .. topic:: Using your own toolchain file as described in the CMake documentation .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build --toolchain my_toolchain.cmake cmake --build cmake-build -t template_release Doing the equivalent on just using the command line .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build \ -DCMAKE_SYSTEM_NAME=Android \ -DCMAKE_SYSTEM_VERSION= \ -DCMAKE_ANDROID_ARCH_ABI= \ -DCMAKE_ANDROID_NDK=/path/to/android-ndk cmake --build cmake-build .. topic:: Using the toolchain file from the Android SDK Defaults to minimum supported version( android-16 in my case) and armv7-a. .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build --toolchain $ANDROID_HOME/ndk//build/cmake/android.toolchain.cmake cmake --build cmake-build Specify Android platform and ABI .. code-block:: # Assuming our current directory is the godot-cpp source root cmake -S . -B cmake-build --toolchain $ANDROID_HOME/ndk//build/cmake/android.toolchain.cmake \ -DANDROID_PLATFORM:STRING=android-29 \ -DANDROID_ABI:STRING=armeabi-v7a cmake --build cmake-build Toolchains ---------- This section attempts to list the host and target combinations that have been at tested. Linux Host ~~~~~~~~~~ Macos Host ~~~~~~~~~~ :System: Mac Mini :OS Name: Sequoia 15.0.1 :Processor: Apple M2 * AppleClang Windows Host ~~~~~~~~~~~~ :OS Name: Windows 11 :Processor: AMD Ryzen 7 6800HS Creator Edition * `Microsoft Visual Studio 17 2022 `_ * `LLVM `_ * `LLVM-MinGW `_ * aarch64-w64-mingw32 * armv7-w64-mingw32 * i686-w64-mingw32 * x86_64-w64-mingw32 * `AndroidSDK `_ * `Emscripten `_ * `MinGW-W64-builds `_ * `Jetbrains-CLion `_ Jetbrains builtin compiler is just the MingW64 above. * `MSYS2 `_ Necessary reading about MSYS2 `environments `_ * ucrt64 * clang64 * mingw32 * mingw64 * clangarm64