FindSDL2.cmake

# From: https://trenki2.github.io/blog/2017/06/02/using-sdl2-with-cmake/
# This FindScript is used because the one provided by cmake causes the
# following error:
#    "-L/usr/lib/x86_64-linux-gnu -lSDL2 " which has leading or trailing
#    whitespace.  This is now an error according to policy CMP0004.

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#.rst:
# FindSDL2
# -------
#
# Locate SDL2 library
#
# This module defines
#
# ::
#
# SDL2_LIBRARY, the name of the library to link against
# SDL2_FOUND, if false, do not try to link to SDL
# SDL2_INCLUDE_DIR, where to find SDL.h
# SDL2_VERSION_STRING, human-readable string containing the version of SDL
#
#
#
# This module responds to the flag:
#
# ::
#
# SDL2_BUILDING_LIBRARY
# If this is defined, then no SDL2_main will be linked in because
# only applications need main().
# Otherwise, it is assumed you are building an application and this
# module will attempt to locate and set the proper link flags
# as part of the returned SDL2_LIBRARY variable.
#
#
#
# Don't forget to include SDLmain.h and SDLmain.m your project for the
# OS X framework based version. (Other versions link to -lSDLmain which
# this module will try to find on your behalf.) Also for OS X, this
# module will automatically add the -framework Cocoa on your behalf.
#
#
#
# Additional Note: If you see an empty SDL2_LIBRARY_TEMP in your
# configuration and no SDL2_LIBRARY, it means CMake did not find your SDL
# library (SDL.dll, libsdl.so, SDL.framework, etc). Set
# SDL2_LIBRARY_TEMP to point to your SDL library, and configure again.
# Similarly, if you see an empty SDLMAIN_LIBRARY, you should set this
# value as appropriate. These values are used to generate the final
# SDL2_LIBRARY variable, but when these values are unset, SDL2_LIBRARY
# does not get created.
#
#
#
# $SDLDIR is an environment variable that would correspond to the
# ./configure --prefix=$SDLDIR used in building SDL. l.e.galup 9-20-02
#
# Modified by Eric Wing. Added code to assist with automated building
# by using environmental variables and providing a more
# controlled/consistent search behavior. Added new modifications to
# recognize OS X frameworks and additional Unix paths (FreeBSD, etc).
# Also corrected the header search path to follow "proper" SDL
# guidelines. Added a search for SDLmain which is needed by some
# platforms. Added a search for threads which is needed by some
# platforms. Added needed compile switches for MinGW.
#
# On OSX, this will prefer the Framework version (if found) over others.
# People will have to manually change the cache values of SDL2_LIBRARY to
# override this selection or set the CMake environment
# CMAKE_INCLUDE_PATH to modify the search paths.
#
# Note that the header path has changed from SDL/SDL.h to just SDL.h
# This needed to change because "proper" SDL convention is #include
# "SDL.h", not <SDL/SDL.h>. This is done for portability reasons
# because not all systems place things in SDL/ (see FreeBSD).

if(NOT SDL2_DIR)
    set(SDL2_DIR
        ""
        CACHE PATH "SDL2 directory")
endif()

find_path(
    SDL2_INCLUDE_DIR SDL.h
    HINTS ENV SDLDIR ${SDL2_DIR}
    PATH_SUFFIXES
        SDL2
        # path suffixes to search inside ENV{SDLDIR}
        include/SDL2 include)

if(CMAKE_SIZEOF_VOID_P EQUAL 8)
    set(VC_LIB_PATH_SUFFIX lib/x64)
else()
    set(VC_LIB_PATH_SUFFIX lib/x86)
endif()

# SDL-1.1 is the name used by FreeBSD ports...
# don't confuse it for the version number.
find_library(
    SDL2_LIBRARY_TEMP
    NAMES SDL2
    HINTS ENV SDLDIR ${SDL2_DIR}
    PATH_SUFFIXES lib ${VC_LIB_PATH_SUFFIX})

# Hide this cache variable from the user, it's an internal implementation
# detail. The documented library variable for the user is SDL2_LIBRARY
# which is derived from SDL2_LIBRARY_TEMP further below.
set_property(CACHE SDL2_LIBRARY_TEMP PROPERTY TYPE INTERNAL)

if(NOT SDL2_BUILDING_LIBRARY)
    if(NOT SDL2_INCLUDE_DIR MATCHES ".framework")
        # Non-OS X framework versions expect you to also dynamically link to
        # SDLmain. This is mainly for Windows and OS X. Other (Unix) platforms
        # seem to provide SDLmain for compatibility even though they don't
        # necessarily need it.
        find_library(
            SDL2MAIN_LIBRARY
            NAMES SDL2main
            HINTS ENV SDLDIR ${SDL2_DIR}
            PATH_SUFFIXES lib ${VC_LIB_PATH_SUFFIX}
            PATHS /sw /opt/local /opt/csw /opt)
    endif()
endif()

# SDL may require threads on your system.
# The Apple build may not need an explicit flag because one of the
# frameworks may already provide it.
# But for non-OSX systems, I will use the CMake Threads package.
if(NOT APPLE)
    find_package(Threads)
endif()

# MinGW needs an additional link flag, -mwindows
# It's total link flags should look like -lmingw32 -lSDLmain -lSDL -mwindows
if(MINGW)
    set(MINGW32_LIBRARY
        mingw32 "-mwindows"
        CACHE STRING "link flags for MinGW")
endif()

if(SDL2_LIBRARY_TEMP)
    # For SDLmain
    if(SDL2MAIN_LIBRARY AND NOT SDL2_BUILDING_LIBRARY)
        list(FIND SDL2_LIBRARY_TEMP "${SDL2MAIN_LIBRARY}" _SDL2_MAIN_INDEX)
        if(_SDL2_MAIN_INDEX EQUAL -1)
            set(SDL2_LIBRARY_TEMP "${SDL2MAIN_LIBRARY}" ${SDL2_LIBRARY_TEMP})
        endif()
        unset(_SDL2_MAIN_INDEX)
    endif()

    # For OS X, SDL uses Cocoa as a backend so it must link to Cocoa.
    # CMake doesn't display the -framework Cocoa string in the UI even
    # though it actually is there if I modify a pre-used variable.
    # I think it has something to do with the CACHE STRING.
    # So I use a temporary variable until the end so I can set the
    # "real" variable in one-shot.
    if(APPLE)
        set(SDL2_LIBRARY_TEMP ${SDL2_LIBRARY_TEMP} "-framework Cocoa")
    endif()

    # For threads, as mentioned Apple doesn't need this.
    # In fact, there seems to be a problem if I used the Threads package
    # and try using this line, so I'm just skipping it entirely for OS X.
    if(NOT APPLE)
        set(SDL2_LIBRARY_TEMP ${SDL2_LIBRARY_TEMP} ${CMAKE_THREAD_LIBS_INIT})
    endif()

    # For MinGW library
    if(MINGW)
        set(SDL2_LIBRARY_TEMP ${MINGW32_LIBRARY} ${SDL2_LIBRARY_TEMP})
    endif()

    # Set the final string here so the GUI reflects the final state.
    set(SDL2_LIBRARY
        ${SDL2_LIBRARY_TEMP}
        CACHE STRING "Where the SDL Library can be found")
endif()

if(SDL2_INCLUDE_DIR AND EXISTS "${SDL2_INCLUDE_DIR}/SDL2_version.h")
    file(STRINGS "${SDL2_INCLUDE_DIR}/SDL2_version.h" SDL2_VERSION_MAJOR_LINE
         REGEX "^#define[ \t]+SDL2_MAJOR_VERSION[ \t]+[0-9]+$")
    file(STRINGS "${SDL2_INCLUDE_DIR}/SDL2_version.h" SDL2_VERSION_MINOR_LINE
         REGEX "^#define[ \t]+SDL2_MINOR_VERSION[ \t]+[0-9]+$")
    file(STRINGS "${SDL2_INCLUDE_DIR}/SDL2_version.h" SDL2_VERSION_PATCH_LINE
         REGEX "^#define[ \t]+SDL2_PATCHLEVEL[ \t]+[0-9]+$")
    string(REGEX REPLACE "^#define[ \t]+SDL2_MAJOR_VERSION[ \t]+([0-9]+)$" "\\1" SDL2_VERSION_MAJOR
                         "${SDL2_VERSION_MAJOR_LINE}")
    string(REGEX REPLACE "^#define[ \t]+SDL2_MINOR_VERSION[ \t]+([0-9]+)$" "\\1" SDL2_VERSION_MINOR
                         "${SDL2_VERSION_MINOR_LINE}")
    string(REGEX REPLACE "^#define[ \t]+SDL2_PATCHLEVEL[ \t]+([0-9]+)$" "\\1" SDL2_VERSION_PATCH
                         "${SDL2_VERSION_PATCH_LINE}")
    set(SDL2_VERSION_STRING ${SDL2_VERSION_MAJOR}.${SDL2_VERSION_MINOR}.${SDL2_VERSION_PATCH})
    unset(SDL2_VERSION_MAJOR_LINE)
    unset(SDL2_VERSION_MINOR_LINE)
    unset(SDL2_VERSION_PATCH_LINE)
    unset(SDL2_VERSION_MAJOR)
    unset(SDL2_VERSION_MINOR)
    unset(SDL2_VERSION_PATCH)
endif()

set(SDL2_LIBRARIES ${SDL2_LIBRARY})
set(SDL2_INCLUDE_DIRS ${SDL2_INCLUDE_DIR})

find_package_handle_standard_args(
    SDL
    REQUIRED_VARS SDL2_LIBRARIES SDL2_INCLUDE_DIRS
    VERSION_VAR SDL2_VERSION_STRING)

mark_as_advanced(SDL2_LIBRARY SDL2_INCLUDE_DIR)