#include <simgear/props/props.hxx>
#include <simgear/structure/SGSharedPtr.hxx>
#include <simgear/scene/util/SGSceneFeatures.hxx>
#include <simgear/props/props.hxx>
#include <simgear/structure/SGSharedPtr.hxx>
#include <simgear/scene/util/SGSceneFeatures.hxx>