164 lines
6.0 KiB
Markdown
164 lines
6.0 KiB
Markdown
# CMake
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(www.cmake.org)
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SDL's build system was traditionally based on autotools. Over time, this
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approach has suffered from several issues across the different supported
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platforms.
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To solve these problems, a new build system based on CMake was introduced.
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It is developed in parallel to the legacy autotools build system, so users
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can experiment with it without complication.
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The CMake build system is supported on the following platforms:
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* FreeBSD
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* Linux
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* Microsoft Visual C
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* MinGW and Msys
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* macOS, iOS, and tvOS, with support for XCode
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* Android
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* Emscripten
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* RiscOS
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* Playstation Vita
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## Building SDL
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Assuming the source for SDL is located at `~/sdl`
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```sh
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cd ~
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mkdir build
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cd build
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cmake ~/sdl
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cmake --build .
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```
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This will build the static and dynamic versions of SDL in the `~/build` directory.
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Installation can be done using:
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```sh
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cmake --install . # '--install' requires CMake 3.15, or newer
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```
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## Including SDL in your project
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SDL can be included in your project in 2 major ways:
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- using a system SDL library, provided by your (*nix) distribution or a package manager
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- using a vendored SDL library: this is SDL copied or symlinked in a subfolder.
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The following CMake script supports both, depending on the value of `MYGAME_VENDORED`.
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```cmake
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cmake_minimum_required(VERSION 3.0)
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project(mygame)
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# Create an option to switch between a system sdl library and a vendored sdl library
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option(MYGAME_VENDORED "Use vendored libraries" OFF)
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if(MYGAME_VENDORED)
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add_subdirectory(vendored/sdl EXCLUDE_FROM_ALL)
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else()
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# 1. Look for a SDL2 package, 2. look for the SDL2 component and 3. fail if none can be found
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find_package(SDL2 REQUIRED CONFIG REQUIRED COMPONENTS SDL2)
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# 1. Look for a SDL2 package, 2. Look for the SDL2maincomponent and 3. DO NOT fail when SDL2main is not available
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find_package(SDL2 REQUIRED CONFIG COMPONENTS SDL2main)
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endif()
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# Create your game executable target as usual
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add_executable(mygame WIN32 mygame.c)
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# SDL2::SDL2main may or may not be available. It is e.g. required by Windows GUI applications
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if(TARGET SDL2::SDL2main)
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# It has an implicit dependency on SDL2 functions, so it MUST be added before SDL2::SDL2 (or SDL2::SDL2-static)
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target_link_libraries(mygame PRIVATE SDL2::SDL2main)
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endif()
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# Link to the actual SDL2 library. SDL2::SDL2 is the shared SDL library, SDL2::SDL2-static is the static SDL libarary.
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target_link_libraries(mygame PRIVATE SDL2::SDL2)
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```
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### A system SDL library
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For CMake to find SDL, it must be installed in [a default location CMake is looking for](https://cmake.org/cmake/help/latest/command/find_package.html#config-mode-search-procedure).
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The following components are available, to be used as an argument of `find_package`.
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| Component name | Description |
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|----------------|--------------------------------------------------------------------------------------------|
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| SDL2 | The SDL2 shared library, available through the `SDL2::SDL2` target [^SDL_TARGET_EXCEPTION] |
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| SDL2-static | The SDL2 static library, available through the `SDL2::SDL2-static` target |
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| SDL2main | The SDL2main static library, available through the `SDL2::SDL2main` target |
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| SDL2test | The SDL2test static library, available through the `SDL2::SDL2test` target |
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### Using a vendored SDL
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This only requires a copy of SDL in a subdirectory.
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## CMake configuration options for platforms
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### iOS/tvOS
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CMake 3.14+ natively includes support for iOS and tvOS. SDL binaries may be built
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using Xcode or Make, possibly among other build-systems.
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When using a recent version of CMake (3.14+), it should be possible to:
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- build SDL for iOS, both static and dynamic
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- build SDL test apps (as iOS/tvOS .app bundles)
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- generate a working SDL_config.h for iOS (using SDL_config.h.cmake as a basis)
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To use, set the following CMake variables when running CMake's configuration stage:
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- `CMAKE_SYSTEM_NAME=<OS>` (either `iOS` or `tvOS`)
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- `CMAKE_OSX_SYSROOT=<SDK>` (examples: `iphoneos`, `iphonesimulator`, `iphoneos12.4`, `/full/path/to/iPhoneOS.sdk`,
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`appletvos`, `appletvsimulator`, `appletvos12.4`, `/full/path/to/AppleTVOS.sdk`, etc.)
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- `CMAKE_OSX_ARCHITECTURES=<semicolon-separated list of CPU architectures>` (example: "arm64;armv7s;x86_64")
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#### Examples
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- for iOS-Simulator, using the latest, installed SDK:
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```bash
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cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphonesimulator -DCMAKE_OSX_ARCHITECTURES=x86_64
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```
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- for iOS-Device, using the latest, installed SDK, 64-bit only
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```bash
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cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos -DCMAKE_OSX_ARCHITECTURES=arm64
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```
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- for iOS-Device, using the latest, installed SDK, mixed 32/64 bit
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```cmake
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cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos -DCMAKE_OSX_ARCHITECTURES="arm64;armv7s"
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```
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- for iOS-Device, using a specific SDK revision (iOS 12.4, in this example):
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```cmake
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cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos12.4 -DCMAKE_OSX_ARCHITECTURES=arm64
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```
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- for iOS-Simulator, using the latest, installed SDK, and building SDL test apps (as .app bundles):
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```cmake
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cmake ~/sdl -DSDL_TESTS=1 -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphonesimulator -DCMAKE_OSX_ARCHITECTURES=x86_64
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```
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- for tvOS-Simulator, using the latest, installed SDK:
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```cmake
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cmake ~/sdl -DCMAKE_SYSTEM_NAME=tvOS -DCMAKE_OSX_SYSROOT=appletvsimulator -DCMAKE_OSX_ARCHITECTURES=x86_64
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```
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- for tvOS-Device, using the latest, installed SDK:
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```cmake
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cmake ~/sdl -DCMAKE_SYSTEM_NAME=tvOS -DCMAKE_OSX_SYSROOT=appletvos -DCMAKE_OSX_ARCHITECTURES=arm64`
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```
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[^SDL_TARGET_EXCEPTION]: `SDL2::SDL2` can be an ALIAS to a static `SDL2::SDL2-static` target for multiple reasons.
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