IF(WITH_DRIVER_OPENGL)
  ADD_SUBDIRECTORY(opengl)
ENDIF()

IF(WITH_DRIVER_OPENGLES)
  ADD_SUBDIRECTORY(opengles)
ENDIF()

IF(WIN32)
  IF(WITH_DRIVER_DIRECT3D)
    ADD_SUBDIRECTORY(direct3d)
  ENDIF()
ENDIF()