Using SDL2 with CMake | 易学教程

问题

I'm trying to use CLion to create a SDL2 project. The problem is that the SDL headers can't be found when using #include's.

My CMakeLists.txt file:

cmake_minimum_required(VERSION 2.8.4)
project(ChickenShooter)

set(SDL2_INCLUDE_DIR C:/SDL/SDL2-2.0.3/include)
set(SDL2_LIBRARY C:/SDL/SDL2-2.0.3/lib/x64)

include_directories(${SDL2_INCLUDE_DIR})
set(SOURCE_FILES main.cpp)

add_executable(ChickenShooter ${SOURCE_FILES})
target_link_libraries(ChickenShooter ${SDL2_LIBRARY})

My test main.cpp:

#include <iostream>
#include "SDL.h" /* This one can't be found */

int main(){
    if (SDL_Init(SDL_INIT_VIDEO) != 0){
        std::cout << "SDL_Init Error: " << SDL_GetError() << std::endl;
        return 1;
    }
    SDL_Quit();
    return 0;
}

Thank you for any help you could give me.

Edit: I'm using Windows and CLion is configured to use cygwin64.

回答1:

Don't set the path to SDL2 by hand. Use the proper find command which uses FindSDL. Should look like:

find_file(SDL2_INCLUDE_DIR NAME SDL.h HINTS SDL2)
find_library(SDL2_LIBRARY NAME SDL2)
add_executable(ChickenShooter main.cpp)
target_include_directories(ChickenShooter ${SDL2_INCLUDE_DIR})
target_link_libraries(ChickenShooter ${SDL2_LIBRARY})

If SDL2 is not found, you have to add the path to SDL2 to CMAKE_PREFIX_PATH, that's the place where CMake looks for installed software.

If you can use Pkg-config, its use might be easier, see How to use SDL2 and SDL_image with cmake

If you feel more comfortable to use a FindSDL2.cmake file similar to FindSDL.cmake provided by CMake, see https://brendanwhitfield.wordpress.com/2015/02/26/using-cmake-with-sdl2/

回答2:

This blog post shows how you can do it: Using SDL2 with CMake

On Linux you can use a recent CMake (e.g. version 3.7) and using SDL2 works out of the box.

cmake_minimum_required(VERSION 3.7)
project(SDL2Test)

find_package(SDL2 REQUIRED)
include_directories(SDL2Test ${SDL2_INCLUDE_DIRS})

add_executable(SDL2Test Main.cpp)
target_link_libraries(SDL2Test ${SDL2_LIBRARIES})

Under Windows you can download the SDL2 development package, extract it somewhere and then create a sdl-config.cmake file in the extracted location with the following content:

set(SDL2_INCLUDE_DIRS "${CMAKE_CURRENT_LIST_DIR}/include")

# Support both 32 and 64 bit builds
if (${CMAKE_SIZEOF_VOID_P} MATCHES 8)
  set(SDL2_LIBRARIES "${CMAKE_CURRENT_LIST_DIR}/lib/x64/SDL2.lib;${CMAKE_CURRENT_LIST_DIR}/lib/x64/SDL2main.lib")
else ()
  set(SDL2_LIBRARIES "${CMAKE_CURRENT_LIST_DIR}/lib/x86/SDL2.lib;${CMAKE_CURRENT_LIST_DIR}/lib/x86/SDL2main.lib")
endif ()

string(STRIP "${SDL2_LIBRARIES}" SDL2_LIBRARIES)

When you now configure inside the CMake-GUI application there will be a SDL2_DIR variable. You have to point it to the SDL2 directory where you extracted the dev package and reconfigure then everything should work.

You can then include SDL2 headers by just writing #include "SDL.h".

回答3:

You can also pull in the SDL source repository as a submodule and build/link it statically along with your main program via add_subdirectory() and target_link_libraries():

cmake_minimum_required( VERSION 3.7.0 )
project( sdl2-demo )

set( SDL_STATIC ON CACHE BOOL "" FORCE )
set( SDL_SHARED OFF CACHE BOOL "" FORCE )
add_subdirectory( external/sdl )

add_executable(
    sdl2-demo
    "src/main.cpp"
    )
target_link_libraries( sdl2-demo SDL2main SDL2-static )

(At least as of the release-2.0.9 tag, possibly earlier.)

回答4:

You don't seems to have a CMake error whike generating your make file. But I think your problem is, the SDL Header are located in a subfolder named "SDL2".

Change your CMakeLists.txt to include

C:/SDL/SDL2-2.0.3/include/SDL2

Instead of

C:/SDL/SDL2-2.0.3/include

回答5:

cmake_minimum_required(VERSION 2.8.4)

project(ChickenShooter)

set(SDL2_INCLUDE_DIR C:/SDL/SDL2-2.0.3/include/SDL2)
set(SDL2_LIB_DIR C:/SDL/SDL2-2.0.3/lib/x64)

include_directories(${SDL2_INCLUDE_DIR})
link_directories(${SDL2_LIB_DIR})

set(SOURCE_FILES main.cpp)

add_executable(${PROJECT_NAME} ${SOURCE_FILES})
target_link_libraries(${PROJECT_NAME} SDL2main SDL2)

回答6:

Using the SDL2 CMake module that I developed, you can integrate the SDL2 library easily in a modern and portable approach.

You should just copy the module in cmake/sdl2 (Or just clone the modules repo) in your project:

git clone https://github.com/aminosbh/sdl2-cmake-modules cmake/sdl2

Then add the following lines in your CMakeLists.txt:

list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/sdl2)
find_package(SDL2 REQUIRED)
target_link_libraries(${PROJECT_NAME} SDL2::Main)

Note: If CMake didn't find the SDL2 library (in Windows), we can specify the CMake option SDL2_PATH as follows:

cmake .. -DSDL2_PATH="/path/to/sdl2"

For more details, please read the README.md file.

The SDL2 CMake modules support other related libraries : SDL2_image, SDL2_ttf, SDL2_mixer, SDL2_net and SDL2_gfx.

You can find a list of examples/samples and projects that uses these modules here : https://github.com/aminosbh/sdl-samples-and-projects

回答7:

With the compiled version of SDL2-2.0.9 with MinGW-w64 in Windows, the following configuration works for me:

find_package(SDL2 REQUIRED)

add_executable(sdl-test ${SOURCES})

target_link_libraries(sdl-test
  mingw32
  SDL2::SDL2main
  SDL2::SDL2
)

A longer explanation

By reading SDL2Targets.cmake file, I've learned that SDL2 is providing several targets:

SDL2::SDL2main (lib/libSDL2main.a)
SDL2::SDL2 (lib/libSDL2.dll.a)
SDL2::SDL2-static (lib/libSDL2-static.a)

Each of them has INTERFACE_INCLUDE_DIRECTORIES defined, which means we don't need to manually specify include_directories for SDL2.

But by only adding SDL2::SDL2main and SDL2::SDL2 as target_link_libraries is not enough. The g++ compiler might be complaining about "undefined reference to `WinMain'".

By inspecting the compiler options, I found that the SDL2 libraries are added before -lmingw32 option. In order to make the -lmingw32 option comes before SDL2 libraries, we have to also specify mingw32 as the first target_link_libraries. Which will make this configuration working.

The command that I have used for building it is:

$ mkdir build && cd build && cmake .. -G"MinGW Makefiles" && cmake --build .

The only small problem here is in the finally generated compiler options, the -lmingw32 option is duplicated. But since it doesn't affect the linking process, I've ignored it for now.

回答8:

by the time of my answer, SDL2 is provided with sdl2-config executable (as I understand, developers call him "experimental"). After "make install" of SDL2 you can try calling it from terminal with sdl2-config --cflags --libs to see what it outputs.

And then you can add call to it in your makefile:

set(PROJECT_NAME SomeProject)

project(${PROJECT_NAME})

execute_process(COMMAND /usr/local/bin/sdl2-config --libs RESULT_VARIABLE CMD_RES OUTPUT_VARIABLE SDL2_CFLAGS_LIBS ERROR_VARIABLE ERR_VAR OUTPUT_STRIP_TRAILING_WHITESPACE)
message("SDL2_CFLAGS_LIBS=${SDL2_CFLAGS_LIBS}; CMD_RES=${CMD_RES}; ERR_VAR=${ERR_VAR}")

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 ${SDL2_CFLAGS_LIBS}")

set(SOURCE_FILES main.cpp)
add_executable(${PROJECT_NAME} ${SOURCE_FILES})

Here I have a problem - if I only put an executable name without path like

execute_process(COMMAND sdl2-config --libs <...>

I get error "No such file", i.e. cmake does not search in current path and I don't know how to write it properly by now.

One more notice: in my makefile I do not user --cflags option, because cmake finds includes correctly and I do not need to specify them explicitly.

回答9:

I had the same problem and none of the other solutions worked. But I finally got it working by following this solution : How to properly link libraries with cmake?

In a nutshell, the problem was that the SDL2 library was not linked properly in my CMakeLists.txt. And by writing this into the file, it worked (more explainations in the other thread) :

project (MyProgramExecBlaBla)  #not sure whether this should be the same name of the executable, but I always see that "convention"
cmake_minimum_required(VERSION 2.8)

ADD_LIBRARY(LibsModule 
    file1.cpp
    file2.cpp
)

target_link_libraries(LibsModule -lpthread)
target_link_libraries(LibsModule liblapack.a)
target_link_libraries(LibsModule -L/home/user/libs/somelibpath/)
ADD_EXECUTABLE(MyProgramExecBlaBla main.cpp)
target_link_libraries(MyProgramExecBlaBla LibsModule)

回答10:

Highlighting the steps of how I was able to eventually accomplish this using the FindSDL2.cmake module:

Download SDL2-devel-2.0.9-VC.zip (or whatever version is out after this answer is posted) under the Development Libraries section of the downloads page.
Extract the zip folder and you should see a folder similar to "SDL2-2.0.9". Paste this folder in your C:\Program Files(x86)\ directory.
Copy the FindSDL2.cmake module and place it in a new "cmake" directory within your project. I found a FindSDL2.cmake file in the answer referenced in the Accepted Answer: https://brendanwhitfield.wordpress.com/2015/02/26/using-cmake-with-sdl2/
Find the SET(SDL2_SEARCH_PATHS line in the FindSDL2.cmake and add your copied development directory for SDL2 as a new line: "/Program Files (x86)/SDL2-2.0.9" # Windows
Within my CMakeLists.txt, add this line: set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

After this, running CMake worked for me. I'm including the rest of my CMakeLists just in case it further clarifies anything I may have left out:

cmake_minimum_required(VERSION 2.8.4)
project(Test_Project)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

# includes cmake/FindSDL2.cmake
set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

set(SOURCE_FILES src/main.cpp src/test.cpp)
add_executable(test ${SOURCE_FILES})

# The two lines below have been removed to run on my Windows machine
#INCLUDE(FindPkgConfig)
#PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
find_package(SDL2 REQUIRED)

INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIR})
TARGET_LINK_LIBRARIES(chip8 ${SDL2_LIBRARY})

Hope this helps somebody in the near future.

来源：https://stackoverflow.com/questions/28395833/using-sdl2-with-cmake

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