#
#--- OPENGL
#
if (NOT OpenGL_FOUND)
  find_package(OpenGL REQUIRED)
endif ()
if (NOT TARGET OpenGL::GL)
  add_library(OpenGL::GL INTERFACE IMPORTED)
  set_target_properties(OpenGL::GL PROPERTIES
    INTERFACE_INCLUDE_DIRECTORIES "${OPENGL_INCLUDE_DIR}"
    INTERFACE_LINK_LIBRARIES "${OPENGL_LIBRARIES}")
endif ()
if (NOT TARGET OpenGL::GLU)
  add_library(OpenGL::GLU INTERFACE IMPORTED)
  set_target_properties(OpenGL::GLU PROPERTIES
    INTERFACE_INCLUDE_DIRECTORIES "${OPENGL_INCLUDE_DIR}"
    INTERFACE_LINK_LIBRARIES "${OPENGL_glu_LIBRARY}")
endif ()
