reimplemented and fixed edge mesh split

vcg/complex/algorithms/clean.h

@@ -436,32 +436,50 @@ public:
     return count_removed;
   }
 
+
 	static int SplitSelectedVertexOnEdgeMesh(MeshType& m)
 	{
 		tri::RequireCompactness(m);
-    tri::UpdateFlags<MeshType>::VertexClearV(m);
+
-    int count_split = 0;
+		// count selected vertices references
+		std::unordered_map<size_t,size_t> refCount; // selected vertex index -> reference count
+		size_t countSplit = 0;
 		for (size_t i=0; i<m.edge.size(); ++i)
 		{
 			for (int j=0; j<2; ++j)
 			{
-        VertexPointer vp = m.edge[i].V(j);
+				const VertexPointer vp = m.edge[i].V(j);
 				if (vp->IsS())
 				{
-          if(!vp->IsV())
+					const size_t refs = ++refCount[Index(m, m.edge[i].V(j))];
+					if (refs > 1) {
+						countSplit++;
+					}
+				}
+			}
+		}
+		// actual split
+		if (countSplit > 0)
 		{
-            m.edge[i].V(j) = &*(tri::Allocator<MeshType>::AddVertex(m,vp->P()));
+			auto newVertIt = tri::Allocator<MeshType>::AddVertices(m, countSplit);
-	    ++count_split;
+			for (size_t i=0; i<m.edge.size(); ++i)
-	    }
-          else 
 			{
-	      vp->SetV();
+				for (int j=0; j<2; ++j)
-	    }
+				{
-	  
+					const VertexPointer vp = m.edge[i].V(j);
+					const size_t vIdx = Index(m, vp);
+					if (vp->IsS())
+					{
+						if (--refCount[vIdx] > 0)
+						{
+							newVertIt->ImportData(*vp);
+							m.edge[i].V(j) = &*(newVertIt++);
 						}
 					}
 				}
-    return count_split;
+			}
+		}
+		return int(countSplit);
 	}
 
 
@@ -485,6 +503,7 @@ public:
     tri::RequireCompactness(m);
     tri::RequireVEAdjacency(m);
     tri::UpdateTopology<MeshType>::VertexEdge(m);
+	tri::UpdateSelection<MeshType>::VertexClear(m);
     for(size_t i=0;i<m.vert.size();++i)
     {
       std::vector<VertexPointer> VVStarVec;