A CMake script for find_package(SDL2)

FindSDL2.cmake

#.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 SDL2
#   SDL2_INCLUDE_DIR, where to find SDL.h
#   SDL2_VERSION_STRING, human-readable string containing the version of SDL2
#
#
#
# This module responds to the flag:
#
# ::
#
#   SDL2_BUILDING_LIBRARY
#     If this is defined, then no SDL_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 SDL2
# library (SDL.dll, libsdl.so, SDL.framework, etc).  Set
# SDL_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
# SDL_LIBRARY variable, but when these values are unset, SDL_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 SDL_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).

#=============================================================================
# CMake - Cross Platform Makefile Generator
# Copyright 2000-2015 Kitware, Inc.
# Copyright 2000-2011 Insight Software Consortium
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
# * Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# 
# * Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# 
# * Neither the names of Kitware, Inc., the Insight Software Consortium,
#   nor the names of their contributors may be used to endorse or promote
#   products derived from this software without specific prior written
#   permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# 
# ------------------------------------------------------------------------------
# 
# The above copyright and license notice applies to distributions of
# CMake in source and binary form.  Some source files contain additional
# notices of original copyright by their contributors; see each source
# for details.  Third-party software packages supplied with CMake under
# compatible licenses provide their own copyright notices documented in
# corresponding subdirectories.
# 
# ------------------------------------------------------------------------------
# 
# CMake was initially developed by Kitware with the following sponsorship:
# 
#  * National Library of Medicine at the National Institutes of Health
#    as part of the Insight Segmentation and Registration Toolkit (ITK).
# 
#  * US National Labs (Los Alamos, Livermore, Sandia) ASC Parallel
#    Visualization Initiative.
# 
#  * National Alliance for Medical Image Computing (NAMIC) is funded by the
#    National Institutes of Health through the NIH Roadmap for Medical Research,
#    Grant U54 EB005149.
# 
#  * Kitware, Inc.
#=============================================================================

if(NOT BUILD_SHARED_LIBRARIES)
  set(CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_STATIC_LIBRARY_SUFFIX})
endif()

find_path(SDL2_INCLUDE_DIR SDL.h
  HINTS
    ENV SDL2DIR # Use SDL2DIR on Windows pointing to the SDL2 root.
  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 SDL-2
  HINTS
    ENV SDL2DIR
  PATH_SUFFIXES lib ${VC_LIB_PATH_SUFFIX}
)

if(NOT SDL2_BUILDING_LIBRARY)
  if(NOT SDL2_INCLUDE_DIR MATCHES ".framework")
    # Non-OS X framework versions expect you to also dynamically link to
    # SDL2main. This is mainly for Windows and OS X. Other (Unix) platforms
    # seem to provide SDL2main for compatibility even though they don't
    # necessarily need it.
    find_library(SDL2MAIN_LIBRARY
      NAMES SDL2main
      HINTS
        ENV SDL2DIR
      PATH_SUFFIXES lib ${VC_LIB_PATH_SUFFIX}
      PATHS
      /sw
      /opt/local
      /opt/csw
      /opt
    )
  endif()
endif()

# SDL2 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 library, mwindows
# It's total link flags should look like -lmingw32 -lSDL2main -lSDL2 -lmwindows
# (Actually on second look, I think it only needs one of the m* libraries.)
if(MINGW)
  set(MINGW32_LIBRARY mingw32 CACHE STRING "mwindows for MinGW")
endif()

if(SDL2_LIBRARY_TEMP)
  # For SDL2main
  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 ${SDL2_LIBRARY_TEMP} CACHE STRING "Where the SDL2 Library can be found")
  # Set the temp variable to INTERNAL so it is not seen in the CMake GUI
  set(SDL2_LIBRARY_TEMP "${SDL2_LIBRARY_TEMP}" CACHE INTERNAL "")
endif()

if(SDL2_INCLUDE_DIR AND EXISTS "${SDL2_INCLUDE_DIR}/SDL_version.h")
  file(STRINGS "${SDL2_INCLUDE_DIR}/SDL_version.h" SDL2_VERSION_MAJOR_LINE REGEX "^#define[ \t]+SDL2_MAJOR_VERSION[ \t]+[0-9]+$")
  file(STRINGS "${SDL2_INCLUDE_DIR}/SDL_version.h" SDL2_VERSION_MINOR_LINE REGEX "^#define[ \t]+SDL2_MINOR_VERSION[ \t]+[0-9]+$")
  file(STRINGS "${SDL2_INCLUDE_DIR}/SDL_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()

include(FindPackageHandleStandardArgs)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(SDL2
                                  REQUIRED_VARS SDL2_LIBRARY SDL2_INCLUDE_DIR
                                  VERSION_VAR SDL2_VERSION_STRING)

this does not work ... if totally fails to find SDL2_LIBRARY_TEMP ... SDL2.lib is in /lib/x64 but it doesn't find it.