How to use SDL2 and SDL_image with cmake

Question

I'm looking for the simplest way to compile a c++ program using SDL2 and SDL_image with cmake.

Here is my best attempt, after hours of searching:

CMakeLists.txt

project(shooter-cmake2)

cmake_minimum_required(VERSION 2.8)

set(SOURCES
shooter.cpp
classes.cpp
utils.cpp
)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")

add_executable(${PROJECT_NAME} ${SOURCES})

INCLUDE(FindPkgConfig)
PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
PKG_SEARCH_MODULE(SDL2_image REQUIRED sdl2_image)
INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIRS} ${SDL2IMAGE_INCLUDE_DIR})
TARGET_LINK_LIBRARIES(${PROJECT_NAME} ${SDL2_LIBRARIES} ${SDL2IMAGE_LIBRARY})

I get these errors:

In function `loadTexture(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, SDL_Renderer*)':
undefined reference to `IMG_LoadTexture'
collect2: ld returned 1 exit status

Here is the function call:

#include "SDL.h"
#include "SDL_image.h"

SDL_Texture* loadTexture(const std::string &file, SDL_Renderer *ren){
    SDL_Texture *texture = IMG_LoadTexture(ren, file.c_str());
    texture != nullptr or die("LoadTexture");
    return texture;
}

I am desperate. Please help me! Thanks! :)

Remember that SDL is a C library, and not a C++ library. So using C++ classes like std::string as arguments will most likely not work. — Some programmer dude
Also, since you're new here on SO, if you have a question regarding build (compiler or linker) errors, please include the complete and unedited error log in your question, including the code that causes the error (preferably a Minimal, Complete, and Verifiable example). In your case please edit your question to include the code where you call IMG_LoadTexture together with enough context to understand the code (like variable declarations etc.). — Some programmer dude
Don't know any cmake specifics, but shouldn't you add ${SDL2_IMAGE_LIBRARIES} as well? — keltar

wojciii wojciii · Accepted Answer · 2014-05-25T17:35:48

I think that the following will work, as it finds the libraries on my ubuntu system and the example function you provided can link:

project(shooter-cmake2)

cmake_minimum_required(VERSION 2.8)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")

add_executable(${PROJECT_NAME} src/test.cpp)

INCLUDE(FindPkgConfig)

PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
PKG_SEARCH_MODULE(SDL2IMAGE REQUIRED SDL2_image>=2.0.0)

INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIRS} ${SDL2IMAGE_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(${PROJECT_NAME} ${SDL2_LIBRARIES} ${SDL2IMAGE_LIBRARIES})

If cmake is executed with --debug-output it outputs:

-- Found PkgConfig: /usr/bin/pkg-config (found version "0.26") 
Called from: [2]    /usr/share/cmake-2.8/Modules/FindPkgConfig.cmake
            [1] $USER/stack-overflow/cmake-sdl2-image/CMakeLists.txt
-- checking for one of the modules 'sdl2'
Called from: [1]    $USER/stack-overflow/cmake-sdl2-image/CMakeLists.txt
-- checking for one of the modules 'SDL2_image>=2.0.0'
Called from: [1]    $USER/stack-overflow/cmake-sdl2-image/CMakeLists.txt

This made me check the contents of

/usr/lib/x86_64-linux-gnu/pkgconfig/sdl2.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/SDL2_image.pc

I noticed that SDL2_image.pc contains Name: SDL2_image which I assumed should match the third parameter to PKG_SEARCH_MODULE for this library.

How to use SDL2 and SDL_image with cmake

5 Answers