一些相关资源链接如下：
http://www.holmes3d.net/graphics/dcel/
http://sintef.org/upload/IKT/9011/geometri/TTL/ttl_1.1.0_doc/halfedge.html
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/HalfedgeDS/Chapter_main.html
http://www.flipcode.com/archives/The_Half-Edge_Data_Structure.shtml
学习ing....
