MACRO(USE_OVR)
  FIND_PACKAGE(OVR)
  IF ((NOT OVR_FOUND) AND (${ARGC} LESS 1))
    USING_MESSAGE("Skipping because of missing Oculus Rift SDK (OVR)")
    RETURN()
  ENDIF((NOT OVR_FOUND) AND (${ARGC} LESS 1))
  IF(NOT OVR_USED AND OVR_FOUND)
    SET(OVR_USED TRUE)
    INCLUDE_DIRECTORIES(SYSTEM ${OVR_INCLUDE_DIR})
    SET(EXTRA_LIBS ${EXTRA_LIBS} ${OVR_LIBRARIES})
	IF (WIN32)
    SET(EXTRA_LIBS ${EXTRA_LIBS} winmm.lib)
	ENDIF(WIN32)
  ENDIF()
ENDMACRO(USE_OVR)