cmake_modules/FindLIBAV.cmake
author Simon McVittie <smcv@debian.org>
Mon, 12 Sep 2022 10:40:53 -0400
branch1.0.0
changeset 15859 7b1d6dfa3173
parent 9959 1a42d36f346a
permissions -rw-r--r--
Remove FindSDL2 find-module, use sdl2-config.cmake instead This requires SDL >= 2.0.4. Since <https://bugzilla.libsdl.org/show_bug.cgi?id=2464> was fixed in SDL 2.0.4, SDL behaves as a CMake "config-file package", even if it was not itself built using CMake: it installs a sdl2-config.cmake file to ${libdir}/cmake/SDL2, which tells CMake where to find SDL's headers and library, analogous to a pkg-config .pc file. As a result, we no longer need to copy/paste a "find-module package" to be able to find a system copy of SDL >= 2.0.4 with find_package(SDL2). Find-module packages are now discouraged by the CMake developers, in favour of having upstream projects behave as config-file packages. This results in a small API change: FindSDL2 used to set SDL2_INCLUDE_DIR and SDL2_LIBRARY, but the standard behaviour for config-file packages is to set <name>_INCLUDE_DIRS and <name>_LIBRARIES. Use the CONFIG keyword to make sure we search in config-file package mode, and will not find a FindSDL2.cmake in some other directory that implements the old interface. In addition to deleting redundant code, this avoids some assumptions in FindSDL2 about the layout of a SDL installation. The current libsdl2-dev package in Debian breaks those assumptions; this is considered a bug and will hopefully be fixed soon, but it illustrates how fragile these assumptions can be. We can be more robust against different installation layouts by relying on SDL's own CMake integration. When linking to a copy of CMake in a non-standard location, users can now set the SDL2_DIR or CMAKE_PREFIX_PATH environment variable to point to it; previously, these users would have used the SDL2DIR environment variable. This continues to be unnecessary if using matching system-wide installations of CMake and SDL2, for example both from Debian.

# Find ffmpeg/libav libraries (libavcodec, libavformat and libavutil)
# Once done this will define
#
#  LIBAV_FOUND             - system has libavcodec, libavformat, libavutil
#  LIBAV_INCLUDE_DIR       - libav include directories
#  LIBAV_LIBRARIES         - libav libraries (libavcodec, libavformat, libavutil)
#
#  LIBAVCODEC_LIBRARY      - libavcodec library
#  LIBAVCODEC_INCLUDE_DIR  - libavcodec include directory
#  LIBAVFORMAT_LIBRARY     - libavformat library
#  LIBAVUTIL_LIBRARY       - libavutil library
#
#  Copyright (c) 2008 Andreas Schneider <mail@cynapses.org>
#  Modified for other libraries by Lasse Kärkkäinen <tronic>
#  Modified for Hedgewars by Stepik777
#  Copyright (c) 2013 Vittorio Giovara <vittorio.giovara@gmail.com>
#
#  Redistribution and use is allowed according to the terms of the New
#  BSD license.
#

include(FindPackageHandleStandardArgs)


# use pkg-config to get the directories and then use these values
# in the FIND_PATH() and FIND_LIBRARY() calls
find_package(PkgConfig)
if(PKG_CONFIG_FOUND)
    if(NOT LIBAVCODEC_INCLUDE_DIR OR NOT LIBAVCODEC_LIBRARY)
        pkg_check_modules(_LIBAV_AVCODEC libavcodec)
    endif()
    if(NOT LIBAVFORMAT_LIBRARY)
        pkg_check_modules(_LIBAV_AVFORMAT libavformat)
    endif()
    if(NOT LIBAVUTIL_LIBRARY)
        pkg_check_modules(_LIBAV_AVUTIL libavutil)
    endif()
endif(PKG_CONFIG_FOUND)

find_path(LIBAVCODEC_INCLUDE_DIR
    NAMES libavcodec/avcodec.h
    PATHS ${_LIBAV_AVCODEC_INCLUDE_DIRS}     #pkg-config
          /usr/include /usr/local/include    #system level
          /opt/local/include /sw/include     #macports & fink
    PATH_SUFFIXES libav ffmpeg
)

#TODO: add other include paths

find_library(LIBAVCODEC_LIBRARY
    NAMES avcodec
    PATHS ${_LIBAV_AVCODEC_LIBRARY_DIRS}    #pkg-config
          /usr/lib /usr/local/lib           #system level
          /opt/local/lib /sw/lib            #macports & fink
)

find_library(LIBAVFORMAT_LIBRARY
    NAMES avformat
    PATHS ${_LIBAV_AVFORMAT_LIBRARY_DIRS}   #pkg-config
          /usr/lib /usr/local/lib           #system level
          /opt/local/lib /sw/lib            #macports & fink
)

find_library(LIBAVUTIL_LIBRARY
    NAMES avutil
    PATHS ${_LIBAV_AVUTIL_LIBRARY_DIRS}     #pkg-config
          /usr/lib /usr/local/lib           #system level
          /opt/local/lib /sw/lib            #macports & fink
)

find_package_handle_standard_args(LIBAV DEFAULT_MSG LIBAVCODEC_LIBRARY
                                                    LIBAVCODEC_INCLUDE_DIR
                                                    LIBAVFORMAT_LIBRARY
                                                    LIBAVUTIL_LIBRARY
                                                    )
set(LIBAV_INCLUDE_DIR ${LIBAVCODEC_INCLUDE_DIR}
                      #TODO: add other include paths
                      )
set(LIBAV_LIBRARIES ${LIBAVCODEC_LIBRARY}
                    ${LIBAVFORMAT_LIBRARY}
                    ${LIBAVUTIL_LIBRARY}
                    )

mark_as_advanced(LIBAV_INCLUDE_DIR
                 LIBAV_LIBRARIES
                 LIBAVCODEC_LIBRARY
                 LIBAVCODEC_INCLUDE_DIR
                 LIBAVFORMAT_LIBRARY
                 LIBAVUTIL_LIBRARY)