From b19307fbf0e3efc2132b032d3e8800b7602036e4 Mon Sep 17 00:00:00 2001
From: nicopietroni <nico.pietroni@isti.cnr.it>
Date: Fri, 25 Jun 2004 11:30:25 +0000
Subject: [PATCH] decimation and optimizator of tetrahedral mesh

---
 vcg/complex/tetramesh/decimation/decimation.h | 220 ++++++++++++++++++
 1 file changed, 220 insertions(+)
 create mode 100644 vcg/complex/tetramesh/decimation/decimation.h

diff --git a/vcg/complex/tetramesh/decimation/decimation.h b/vcg/complex/tetramesh/decimation/decimation.h
new file mode 100644
index 00000000..72e0b03b
--- /dev/null
+++ b/vcg/complex/tetramesh/decimation/decimation.h
@@ -0,0 +1,220 @@
+/****************************************************************************
+* VCGLib                                                            o o     *
+* Visual and Computer Graphics Library                            o     o   *
+*                                                                _   O  _   *
+* Copyright(C) 2004                                                \/)\/    *
+* Visual Computing Lab                                            /\/|      *
+* ISTI - Italian National Research Council                           |      *
+*                                                                    \      *
+* All rights reserved.                                                      *
+*                                                                           *
+* This program is free software; you can redistribute it and/or modify      *   
+* it under the terms of the GNU General Public License as published by      *
+* the Free Software Foundation; either version 2 of the License, or         *
+* (at your option) any later version.                                       *
+*                                                                           *
+* This program is distributed in the hope that it will be useful,           *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of            *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
+* GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
+* for more details.                                                         *
+*                                                                           *
+****************************************************************************/
+/****************************************************************************
+  History
+****************************************************************************/
+
+#ifndef __VCG_TETRA_DECIMATION
+#define __VCG_TETRA_DECIMATION
+#include<vector>
+#include<algorithm>
+#include<time.h>
+#include<math.h>
+#include<vcg/complex/tetramesh/decimation/operationsdef.h>
+#include<vcg/complex/tetramesh/decimation/collapse.h>
+
+namespace vcg{
+namespace tetra{
+
+
+template<class TETRA_MESH_TYPE>
+class Decimation
+{
+public:
+ 
+  /// The tetrahedral mesh type
+  typedef	typename TETRA_MESH_TYPE TetraMeshType;
+  // ///the decimator's type
+  //typedef	typename Decimation<TetraMeshType> DecimatorBase;
+  /// The tetrahedron type
+  typedef	typename TetraMeshType::TetraType TetraType;
+	/// The vertex type
+	typedef	typename TetraType::VertexType VertexType;
+  /// The coordinate type
+	typedef	typename TetraType::VertexType::CoordType CoordType;
+  /// The scalar type
+  typedef	typename TetraMeshType::VertexType::ScalarType ScalarType;
+  //local modification type 
+  typedef typename  vcg::tetra::LocalModification<TETRA_MESH_TYPE> LocalModification;
+  /// The pos type
+  //typedef typename vcg::tetra::Pos<TetraType> PosType;
+  typedef typename vcg::tetra::LocalModification<TETRA_MESH_TYPE>::PosType PosType;
+
+  ///the element of the heap
+  struct HeapElem
+  {
+    ///the modifier's type
+    vcg::tetra::ModifiersType Mt;
+    ///the value of priority
+    ScalarType priority;
+    ///the pos where the modifier operate
+    PosType pos;
+    ///pointer to instance of local modifier
+    LocalModification*LM;
+    ///temporary mark for the opration
+    char Imark;
+   
+    HeapElem(vcg::tetra::ModifiersType Mtype,PosType p,char mark)
+    {
+      Mt=Mtype;
+      pos=p;
+      Imark=mark;
+      LM=NULL;
+      Instanciate();
+      priority=LM->ComputePriority();
+      delete(LM);
+    };
+
+    const bool operator <(const HeapElem & h) const 
+    {
+		  return (priority<h.priority);
+	  }
+//this method instaciate each different type of operation
+    void Instanciate()
+    {
+       if (Mt==MTEdgeCollapse)
+        LM=new vcg::tetra::Collapse<TetraMeshType>(pos);
+    }
+ 
+    HeapElem & operator =( const HeapElem & h) 
+    {
+      Mt=h.Mt;
+      priority=priority;
+      pos=h.pos;
+      LM=h.LM;
+      Imark=h.Imark;
+      return (*this);
+	  }
+
+
+    bool IsUpToDate()
+    {
+    	if (!pos.T()->IsD())
+		  {
+        VertexType *v0=pos.T()->V(Tetra::VofE(pos.E(),0));
+			  VertexType *v1=pos.T()->V(Tetra::VofE(pos.E(),1));
+			  
+			return (( (!v0->IsD()) && (!v1->IsD())) &&
+							 Imark>=v0->IMark() &&
+							 Imark>=v1->IMark());
+		  }
+		else
+		return false;
+    }
+
+  };
+
+  /// The heap type
+  typedef typename vector<HeapElem> HeapType;
+
+  ///the pointer to tetramesh
+  TetraMeshType &tm;
+  ///the heap of operations
+  HeapType h;
+
+  /// Default Constructor
+	Decimation(TETRA_MESH_TYPE &_tm):tm(_tm)
+		{
+		};
+
+  ~Decimation()
+		{
+		};
+
+
+ void AddOperation(vcg::tetra::ModifiersType Mt,Pos<TetraType> pos)
+  { 
+     h.push_back(HeapElem(Mt,pos,tm.GetMark()));
+		 push_heap( h.begin(), h.end());
+  }
+
+  void DecimationStep(int nstep)
+  {
+    for (int i=0;i<nstep;i++)
+    {
+      if( ! h.back().IsUpToDate())	
+		    h.pop_back();
+	    else  
+      {	
+        h.back().Instanciate();
+        h.back().LM->ComputeError();
+        LocalModification* LastMod= h.back().LM;
+        h.pop_back();
+		    if (LastMod->PreserveTopology())
+        {
+			    LastMod->Execute();
+          LocalModification::HeapRetType h_ret=LastMod->UpdateHeap();
+          LocalModification::HeapRetType::iterator hi;
+          for (hi=h_ret.begin();hi<h_ret.end();hi++)
+            AddOperation((*hi).first,(*hi).second);
+		    }
+        delete (LastMod);     
+      }	 
+    }
+  }
+
+  void DoDecimation(int Time)
+  {
+    clock_t time0=clock();
+    clock_t difftime=0;
+    while ((difftime<(clock_t)Time)&&(HaveOperations()))
+    {
+      
+      DecimationStep(1);
+      clock_t time1=clock();
+      difftime=time1-time0;
+    }
+  }
+
+///initialize for all vertex the temporary mark must call only at the start of decimation
+  void InitDecimation()
+  {
+    tm.InitIMark();
+  }
+
+///erase from the heap the operation that are not upto date
+  void CleanHeap()
+  {
+    vector<vcg::tetra::HeapElem>::iterator hi;
+	  for(hi=h.begin();hi!=h.end();++hi)
+		if(!(*hi)->LM->IsUpToDate())
+		{
+			*hi=h.back();
+			h.pop_back();
+			if(hi==h.end()) break;
+		}
+		//printf("\nReduced heap from %i to %i",sz,h.size());
+		make_heap(h.begin(),h.end());
+  }
+
+  ///return true if the decimation have some operation to perform
+  bool HaveOperations()
+  {
+    return (h.size()>0);
+  }
+    
+};//end class decimation
+
+}//end namespace
+}//end namespace
+#endif
\ No newline at end of file