added a new class Pos based on halfedge

vcg/connectors/halfedge_pos.h

@@ -0,0 +1,149 @@
+#ifndef VCG_HEDGE_POS
+#define VCG_HEDGE_POS
+
+namespace vcg
+{
+    namespace hedge
+    {
+        /*!
+          * \brief Class implementing a Pos using halfedges
+          *
+          */
+        template <class MeshType> class Pos
+        {
+
+        public:
+
+            typedef typename MeshType::VertexPointer VertexPointer;
+            typedef typename MeshType::EdgePointer EdgePointer;
+            typedef typename MeshType::HEdgePointer HEdgePointer;
+            typedef typename MeshType::FacePointer FacePointer;
+
+            /*!
+             * Halfedge used to move in the mesh
+             */
+            HEdgePointer he;
+
+            /*!
+             * Direction of movement:
+             *
+             * 0 = clockwise
+             *
+             * 1 = counter-clockwise
+             */
+            bool direction;
+
+            /*!
+             *
+             */
+            Pos(HEdgePointer hep, bool dir)
+            {
+                he = hep;
+                direction = dir;
+            }
+
+            /*!
+             *
+             */
+            Pos(HEdgePointer hep)
+            {
+                he = hep;
+                direction = 1;
+            }
+
+            /*!
+             * Changes vertex mantaininge the same edge and the same face
+             */
+            void FlipV()
+            {
+                direction = !direction;
+            }
+
+            /*!
+             * Changes edge and hedge mantaining the same vertex and the same face
+             */
+            void FlipE()
+            {
+                if(!direction)
+                    he = he->HNp();
+                else
+                    if(he->HasHPrevAdjacency())
+                        he = he->HPp();
+                    else
+                    {
+                        HEdgePointer aux = he;
+                        while(aux->HNp() != he)
+                            aux = aux->HNp();
+                        he = aux;
+                    }
+
+                direction = !direction;
+            }
+
+            /*!
+             * Changes face mantaininge the same vertex and the same edge
+             */
+            void FlipF()
+            {
+                direction = !direction;
+                he = he->HOp();
+            }
+
+            /*!
+             * Gets pointed vertex
+             */
+            VertexPointer V()
+            {
+                if(direction)
+                    return he->HVp();
+                else
+                    return he->HOp()->HVp();
+            }
+
+            /*!
+             * Gets pointed hedge
+             */
+            HEdgePointer HE()
+            {
+                return he;
+            }
+
+            /*!
+             * Gets pointed edge
+             */
+            EdgePointer E()
+            {
+                return he->HEp();
+            }
+
+            /*!
+             * Gets pointed face
+             */
+            FacePointer F()
+            {
+                return he->HFp();
+            }
+
+            /*!
+             * Operator to check if two Pos are equal
+             */
+            inline bool operator == ( Pos const & p ) const
+            {
+                return (he == p.he && direction == p.direction);
+            }
+
+            /*!
+             * Operator to check if two Pos are different
+             */
+            inline bool operator != ( Pos const & p ) const
+            {
+                return (he != p.he || direction != p.direction);
+            }
+
+        };
+
+    }
+}
+
+#endif // VCG_HEDGE_POS
+