tomato-testing/external/sdl/SDL/docs/README-cmake.md

11 KiB

CMake

www.cmake.org

The CMake build system is supported on the following platforms:

  • FreeBSD
  • Linux
  • Microsoft Visual C
  • MinGW and Msys
  • macOS, iOS, and tvOS, with support for XCode
  • Android
  • Emscripten
  • FreeBSD
  • Haiku
  • Nintendo 3DS
  • Playstation 2
  • Playstation Vita
  • QNX 7.x/8.x
  • RiscOS

Building SDL

Assuming the source tree of SDL is located at ~/sdl, this will configure and build SDL in the ~/build directory:

cmake -S ~/sdl -B ~/build
cmake --build ~/build

Installation can be done using:

cmake --install ~/build --prefix /usr/local        # '--install' requires CMake 3.15, or newer

This will install SDL to /usr/local.

Including SDL in your project

SDL can be included in your project in 2 major ways:

  • using a system SDL library, provided by your (*nix) distribution or a package manager
  • using a vendored SDL library: this is SDL copied or symlinked in a subfolder.

The following CMake script supports both, depending on the value of MYGAME_VENDORED.

cmake_minimum_required(VERSION 3.5)
project(mygame)

# Create an option to switch between a system sdl library and a vendored SDL library
option(MYGAME_VENDORED "Use vendored libraries" OFF)

if(MYGAME_VENDORED)
    # This assumes you have added SDL as a submodule in vendored/SDL
    add_subdirectory(vendored/SDL EXCLUDE_FROM_ALL)
else()
    # 1. Look for a SDL3 package,
    # 2. look for the SDL3-shared component, and
    # 3. fail if the shared component cannot be found.
    find_package(SDL3 REQUIRED CONFIG REQUIRED COMPONENTS SDL3-shared)
endif()

# Create your game executable target as usual
add_executable(mygame WIN32 mygame.c)

# Link to the actual SDL3 library.
target_link_libraries(mygame PRIVATE SDL3::SDL3)

A system SDL library

For CMake to find SDL, it must be installed in a default location CMake is looking for.

The following components are available, to be used as an argument of find_package.

Component name Description
SDL3-shared The SDL3 shared library, available through the SDL3::SDL3-shared target
SDL3-static The SDL3 static library, available through the SDL3::SDL3-static target
SDL3_test The SDL3_test static library, available through the SDL3::SDL3_test target
SDL3 The SDL3 library, available through the SDL3::SDL3 target. This is an alias of SDL3::SDL3-shared or SDL3::SDL3-static. This component is always available.
Headers The SDL3 headers, available through the SDL3::Headers target. This component is always available.

Using a vendored SDL

This only requires a copy of SDL in a subdirectory + add_subdirectory. Alternatively, use FetchContent. Depending on the configuration, the same targets as a system SDL package are available.

CMake configuration options

Build optimized library

By default, CMake provides 4 build types: Debug, Release, RelWithDebInfo and MinSizeRel. The main difference(s) between these are the optimization options and the generation of debug info. To configure SDL as an optimized Release library, configure SDL with:

cmake ~/SDL -DCMAKE_BUILD_TYPE=Release

To build it, run:

cmake --build . --config Release

Shared or static

By default, only a shared SDL library is built and installed. The options -DSDL_SHARED= and -DSDL_STATIC= accept boolean values to change this.

Pass custom compile options to the compiler

Examples

  • build a SDL library optimized for (more) modern x64 microprocessor architectures.

    With gcc or clang:

    cmake ~/sdl -DCMAKE_C_FLAGS="-march=x86-64-v3" -DCMAKE_CXX_FLAGS="-march=x86-64-v3"
    

    With Visual C:

    cmake .. -DCMAKE_C_FLAGS="/ARCH:AVX2" -DCMAKE_CXX_FLAGS="/ARCH:AVX2"
    

iOS/tvOS

CMake 3.14+ natively includes support for iOS and tvOS. SDL binaries may be built using Xcode or Make, possibly among other build-systems.

When using a recent version of CMake (3.14+), it should be possible to:

  • build SDL for iOS, both static and dynamic
  • build SDL test apps (as iOS/tvOS .app bundles)
  • generate a working SDL_build_config.h for iOS (using SDL_build_config.h.cmake as a basis)

To use, set the following CMake variables when running CMake's configuration stage:

  • CMAKE_SYSTEM_NAME=<OS> (either iOS or tvOS)
  • CMAKE_OSX_SYSROOT=<SDK> (examples: iphoneos, iphonesimulator, iphoneos12.4, /full/path/to/iPhoneOS.sdk, appletvos, appletvsimulator, appletvos12.4, /full/path/to/AppleTVOS.sdk, etc.)
  • CMAKE_OSX_ARCHITECTURES=<semicolon-separated list of CPU architectures> (example: "arm64;armv7s;x86_64")

Examples

  • for iOS-Simulator, using the latest, installed SDK:

    cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphonesimulator -DCMAKE_OSX_ARCHITECTURES=x86_64
    
  • for iOS-Device, using the latest, installed SDK, 64-bit only

    cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos -DCMAKE_OSX_ARCHITECTURES=arm64
    
  • for iOS-Device, using the latest, installed SDK, mixed 32/64 bit

    cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos -DCMAKE_OSX_ARCHITECTURES="arm64;armv7s"
    
  • for iOS-Device, using a specific SDK revision (iOS 12.4, in this example):

    cmake ~/sdl -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphoneos12.4 -DCMAKE_OSX_ARCHITECTURES=arm64
    
  • for iOS-Simulator, using the latest, installed SDK, and building SDL test apps (as .app bundles):

    cmake ~/sdl -DSDL_TESTS=1 -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_SYSROOT=iphonesimulator -DCMAKE_OSX_ARCHITECTURES=x86_64
    
  • for tvOS-Simulator, using the latest, installed SDK:

    cmake ~/sdl -DCMAKE_SYSTEM_NAME=tvOS -DCMAKE_OSX_SYSROOT=appletvsimulator -DCMAKE_OSX_ARCHITECTURES=x86_64
    
  • for tvOS-Device, using the latest, installed SDK:

    cmake ~/sdl -DCMAKE_SYSTEM_NAME=tvOS -DCMAKE_OSX_SYSROOT=appletvos -DCMAKE_OSX_ARCHITECTURES=arm64`
    
  • for QNX/aarch64, using the latest, installed SDK:

    cmake ~/sdl -DCMAKE_TOOLCHAIN_FILE=~/sdl/build-scripts/cmake-toolchain-qnx-aarch64le.cmake -DSDL_X11=0
    

Help, it doesn't work!

Below, a SDL3 CMake project can be found that builds 99.9% of time (assuming you have internet connectivity). When you have a problem with building or using SDL, please modify it until it reproduces your issue.

cmake_minimum_required(VERSION 3.16)
project(sdl_issue)

# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
# !!!!!!                                                                            !!!!!!
# !!!!!!     This CMake script is not using "CMake best practices".                 !!!!!!
# !!!!!!                 Don't use it in your project.                              !!!!!!
# !!!!!!                                                                            !!!!!!
# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

# 1. Try system SDL3 package first
find_package(SDL3 QUIET)
if(SDL3_FOUND)
    message(STATUS "Using SDL3 via find_package")
endif()

# 2. Try using a vendored SDL library
if(NOT SDL3_FOUND AND EXISTS "${CMAKE_CURRENT_LIST_DIR}/SDL/CMakeLists.txt")
    add_subdirectory(SDL)
    message(STATUS "Using SDL3 via add_subdirectory")
    set(SDL3_FOUND TRUE)
endif()

# 3. Download SDL, and use that.
if(NOT SDL3_FOUND)
    include(FetchContent)
    set(SDL_SHARED TRUE CACHE BOOL "Build a SDL shared library (if available)")
    set(SDL_STATIC TRUE CACHE BOOL "Build a SDL static library (if available)")
    FetchContent_Declare(
        SDL
        GIT_REPOSITORY https://github.com/libsdl-org/SDL.git
        GIT_TAG main  # Replace this with a particular git tag or git hash
        GIT_SHALLOW TRUE
        GIT_PROGRESS TRUE
    )
    message(STATUS "Using SDL3 via FetchContent")
    FetchContent_MakeAvailable(SDL)
    set_property(DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/_deps/sdl-src" PROPERTY EXCLUDE_FROM_ALL TRUE)
endif()

file(WRITE main.c [===========================================[
/**
 * Modify this source such that it reproduces your problem.
 */

/* START of source modifications */

#include <SDL3/SDL.h>

int main(int argc, char *argv[]) {
    if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
        SDL_Log("SDL_Init failed (%s)", SDL_GetError());
        return 1;
    }

    SDL_Window *window = NULL;
    SDL_Renderer *renderer = NULL;

    if (SDL_CreateWindowAndRenderer(640, 480, 0, &window, &renderer) < 0) {
        SDL_Log("SDL_CreateWindowAndRenderer failed (%s)", SDL_GetError());
        SDL_Quit();
        return 1;
    }
    SDL_SetWindowTitle(window, "SDL issue");

    while (1) {
        int finished = 0;
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_EVENT_QUIT) {
                finished = 1;
                break;
            }
        }
        if (finished) {
            break;
        }

        SDL_SetRenderDrawColor(renderer, 80, 80, 80, SDL_ALPHA_OPAQUE);
        SDL_RenderClear(renderer);
        SDL_RenderPresent(renderer);
    }

    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);

    SDL_Quit();
}

/* END of source modifications */

]===========================================])

add_executable(sdl_issue main.c)

target_link_libraries(sdl_issue PRIVATE SDL3::SDL3)
# target_link_libraries(sdl_issue PRIVATE SDL3::SDL3-shared)
# target_link_libraries(sdl_issue PRIVATE SDL3::SDL3-static)