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Using SDL2 in a CMake project: generating package configurat |  |
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giogadi
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Howdy,
It seems that there still doesn't exist an official way for a user to use SDL2 in a CMake project. There's a way to do it using pkg-config [1] but this might not work in a Windows environment without cygwin. Another option is to supply a FindSDL2.cmake file; this could work, but the CMake people actually don't recommend doing this when the package in question is already built using CMake (see top of [2]). An interesting option is to actually have SDL's CMakeLists.txt file generate a "package configuration file" that can be found and used by find_package(SDL2). These files have the form of "<package_name>Config.cmake". This is the recommended option if our package is already being built using CMake. I've taken a stab at doing this, using the tutorial [3] as a guide. I have a fork [4] of SDL demonstrating this functionality. All the changes are in the root directory: *) CMakeLists.txt - and updated version of SDL's CMakeLists.txt file for generation of the package configuration files. Most of the new stuff is at the bottom of the file. *) SDL2Config.cmake.in - a new template file for the final SDL2Config.cmake file. *) SDL2ConfigVersion.cmake.in - a new template file for a script that CMake uses to verify that the version of SDL2 being requested in find_package() can be fulfilled by this version of the code. For your convenience I've also attached an archive with the above files. What's cool about the way this is done is that if the user has "make install"-ed SDL2 to a system directory, then find_package(SDL2) will "just work". If the user has not installed SDL2 to a system directory (useful when doing dev), find_package() will work as long as she has supplied a CMake variable "SDL2_DIR" that points to the directory containing the SDL2Config.cmake file. This works both in the CMake build tree AND the install tree! Of course, we have CAVEATS: *) In order to get OSX to properly link to the SDL2 shared libraries when the libs were not installed to a system directory, I had to set a variable called "CMAKE_MACOSX_RPATH". This feature is super cool [5], but only works for CMake versions 2.8.12 and later. If you're not on a Mac and don't have CMake 2.8.12, you can still try this out by reducing the cmake_minimum_required() version. *) This all assumes that SDL2 gets built/packaged using CMake. If SDL2 was built and installed using configure scripts, the SDL2Config.cmake files won't get generated and CMake users won't be able to use find_package(SDL2). *) I'm not a CMake expert, so the ways I've done things (especially handling SDL2's shared/static libs) might not be optimal. As I said before, I'd love to see feedback on how to make this better/more robust. *) I tested building SDL2 and linking it in a sample program. This works great in OSX and Ubuntu! I've also tested this with Visual Studio with less stellar results. When compiling SDL2, I get an error about a missing library "dxguid.lib". A hack [6] lets SDL2 compile, and then I can run the sample SDL2 program if I copy SDL.dll into the executable directory, which I kind of expected for Windows. Therefore this method needs more work to be perfectly Let me know what y'all think of this approach! Thanks, Luis [1] http://duganchen.ca/building-sdl2-programs-with-cmake-and-pkgconfig/ [2] http://www.cmake.org/Wiki/CMake/Tutorials/Packaging [3] http://www.cmake.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file [4] https://bitbucket.org/giogadi/sdl2/src/9566eb5a463381bc8a3d0a2244dc27ecea22a764/?at=add_cmake_package_config [5] http://www.kitware.com/blog/home/post/510 [6] http://stackoverflow.com/questions/11253383/cannot-open-file-dxguid-lib |
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