private static float GetSmallestAdjacentAngleOnEdge(HalfEdge edge, HashSet<EdgeID> deleteSet, List<Vector2> vertes)
 {
     float em = GetSmallestAdjacentAngleOnHalfEdge(edge, deleteSet, vertes);
     float pm = GetSmallestAdjacentAngleOnHalfEdge(edge.mPartner, deleteSet, vertes);
     return Mathf.Max(em, pm);
 }
 private static EdgeID GetEdgeId(HalfEdge edge)
 {
     return GetEdgeId(edge.mIndex, edge.mNext.mIndex);
 }