if(PROJECT_ENABLE_OPENAL)
  if(PROJECT_BUILD)
    find_package(OpenAL ${OPENAL_VERSION} REQUIRED)

    add_definitions(-DPROJECT_ENABLE_OPENAL)

    include_directories(BEFORE SYSTEM
      ${OPENAL_INCLUDE_DIR}
    )

    link_libraries(
      ${OPENAL_LIBRARY}
    )
  elseif(NOT PROJECT_IS_MINGW OR CMAKE_HOST_WIN32)
    ExternalProject_Add(openal_project
      PREFIX external
      URL ${PROJECT_3RD_PARTY_DIR}/openal-${OPENAL_VERSION}.tar.gz
      URL_HASH SHA256=dfddf3a1f61059853c625b7bb03de8433b455f2f79f89548cbcbd5edca3d4a4a
      LIST_SEPARATOR |
      CMAKE_ARGS ${PROJECT_EXTERNAL_CMAKE_FLAGS}
        -DBUILD_SHARED_LIBS=${PROJECT_BUILD_SHARED_LIBS}
        -DBUILD_STATIC_LIBS=ON
    )

    set(PROJECT_DEPENDENCIES 
      ${PROJECT_DEPENDENCIES}
      openal_project
    )
  endif()
endif()