Index: vtkQuadricDecimation.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/Graphics/vtkQuadricDecimation.cxx,v
retrieving revision 1.39.50.1
diff -u -r1.39.50.1 vtkQuadricDecimation.cxx
--- vtkQuadricDecimation.cxx	17 Jul 2008 20:29:18 -0000	1.39.50.1
+++ vtkQuadricDecimation.cxx	11 May 2009 15:42:15 -0000
@@ -12,7 +12,7 @@
      PURPOSE.  See the above copyright notice for more information.
 
 =========================================================================*/
-// Comments from Brad---
+// Comments from Brad->-
 // FIXME: I do not have a very good method for detecting the stability of a
 // matrix
 
@@ -59,7 +59,7 @@
 vtkStandardNewMacro(vtkQuadricDecimation);
 
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 vtkQuadricDecimation::vtkQuadricDecimation()
 {
   this->Edges = vtkEdgeTable::New();
@@ -68,7 +68,7 @@
   this->EndPoint2List = vtkIdList::New();
   this->ErrorQuadrics = NULL;
   this->TargetPoints = vtkDoubleArray::New();
-  
+
   this->TargetReduction = 0.9;
   this->NumberOfEdgeCollapses = 0;
   this->NumberOfComponents = 0;
@@ -89,7 +89,7 @@
   this->ActualReduction = 0.0;
 }
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 vtkQuadricDecimation::~vtkQuadricDecimation()
 {
   this->Edges->Delete();
@@ -170,7 +170,7 @@
     }
 }
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 int vtkQuadricDecimation::RequestData(
   vtkInformation *vtkNotUsed(request),
   vtkInformationVector **inputVector,
@@ -337,6 +337,18 @@
       continue;
       }
     
+    // check for a non-collapsible edges -- AWT
+    if ( !this->IsEdgeCollapsible( endPtIds[0], endPtIds[1] ) )
+    {
+         vtkDebugMacro(<<"Pyramid detected " << edgeId << " " <<  cost);
+         // return the point to the queue but with the max cost so that 
+         // when it is recomputed it will be reconsidered
+         this->EdgeCosts->Insert(VTK_DOUBLE_MAX, edgeId);
+
+         edgeId = this->EdgeCosts->Pop(0, cost);
+         continue;
+    }
+
     this->NumberOfEdgeCollapses++;
         
     // Set the new coordinates of point0.
@@ -371,7 +383,7 @@
   delete [] this->TempB;
   delete [] this->TempA;
   delete [] this->TempData;
-  
+
   // copy the simplified mesh from the working mesh to the output mesh
   for (i = 0; i < this->Mesh->GetNumberOfCells(); i++) 
     {
@@ -406,7 +418,86 @@
   return 1;
 }
 
-//----------------------------------------------------------------------------
+int vtkQuadricDecimation::IsEdgeCollapsible( vtkIdType pt0Id, vtkIdType pt1Id )
+{
+   bool isPyramid = false;
+
+   vtkIdType i, j, k, m;
+   vtkIdType npts, *pts;
+
+   vtkIdList* uniqueVertices = vtkIdList::New( );
+   vtkIdList* neighbourCells = vtkIdList::New( );
+
+   // Look for the cells which use this edge
+   this->Mesh->GetPointCells(pt0Id, this->CollapseCellIds);
+   for (i = 0; i < this->CollapseCellIds->GetNumberOfIds(); i++) 
+   {
+      const vtkIdType cellId = this->CollapseCellIds->GetId(i);
+      this->Mesh->GetCellPoints(cellId, npts, pts);
+      for (j = 0; j < 3 && !isPyramid; j++) 
+      {
+         if (pts[j] == pt1Id) 
+         {
+            vtkIdType thisTriangleVerts[] = { pt0Id, pt1Id, 
+               GetThirdVertexId( cellId, pt0Id, pt1Id ) };
+
+            uniqueVertices->SetNumberOfIds( 0 );
+            uniqueVertices->Allocate( neighbourCells->GetNumberOfIds( ) );
+
+            for ( k = 0; k < 3; ++k )
+            {
+               this->Mesh->GetCellEdgeNeighbors( cellId, thisTriangleVerts[k], thisTriangleVerts[(k+1)%3], neighbourCells );
+
+               for ( m = 0; m < neighbourCells->GetNumberOfIds( ); ++m )
+               {
+                  vtkIdType farVertex = GetThirdVertexId( neighbourCells->GetId( m ), thisTriangleVerts[k], thisTriangleVerts[(k+1)%3] );
+
+                  if ( farVertex == VTK_INT_MAX )
+                     continue;
+
+                  if ( -1 == uniqueVertices->IsId( farVertex ) )
+                  {
+                     uniqueVertices->InsertNextId( farVertex );
+                  }
+                  else
+                  {
+                     isPyramid = true;
+                  }
+               }
+            }
+         }
+      }
+   }
+
+   uniqueVertices->Delete( );
+   neighbourCells->Delete( );
+
+   return ( isPyramid ) ? 0 : 1;
+}
+
+int vtkQuadricDecimation::GetThirdVertexId( vtkIdType cellId, vtkIdType pt0Id, vtkIdType pt1Id )
+{
+   // Should only be 3 at most... because there is a check to make
+   // sure only done only done on triangle meshes
+   vtkIdList* pts = vtkIdList::New( );
+
+   this->Mesh->GetCellPoints( cellId, pts );
+
+   for ( int i = 0; i < 3; ++i )
+   {
+      const int id = pts->GetId( i );
+      if ( id != pt0Id && id != pt1Id )
+      {
+         pts->Delete( );
+         return id;
+      }
+   }
+
+   pts->Delete( );
+   return VTK_INT_MAX;
+}
+
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 void vtkQuadricDecimation::InitializeQuadrics(vtkIdType numPts)
 {
   vtkPolyData *input = this->Mesh;
@@ -651,7 +742,7 @@
   delete [] QEM;
 }
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 void vtkQuadricDecimation::AddQuadric(vtkIdType oldPtId, vtkIdType newPtId)
 {
   int i;
@@ -663,7 +754,7 @@
     }
 }
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 void vtkQuadricDecimation::FindAffectedEdges(vtkIdType p1Id, vtkIdType p2Id,
                                               vtkIdList *edges)
 {
@@ -788,7 +879,7 @@
   return; 
 }
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 double vtkQuadricDecimation::ComputeCost(vtkIdType edgeId, double *x)
 {
   static const double errorNumber = 1e-10;
@@ -887,7 +978,7 @@
 }
 
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 double vtkQuadricDecimation::ComputeCost2(vtkIdType edgeId, double *x)
 {
   // this function is so ugly because the functionality of converting an QEM
@@ -1086,53 +1177,52 @@
   return cost;
 }
 
-
 int vtkQuadricDecimation::CollapseEdge(vtkIdType pt0Id, vtkIdType pt1Id) 
 {
-  int j, numDeleted=0;
-  vtkIdType i, npts, *pts, cellId;
+   int j, numDeleted=0;
+   vtkIdType i, npts, *pts, cellId;
 
-  this->Mesh->GetPointCells(pt0Id, this->CollapseCellIds);
-  for (i = 0; i < this->CollapseCellIds->GetNumberOfIds(); i++) 
-    {
-    cellId = this->CollapseCellIds->GetId(i);
-    this->Mesh->GetCellPoints(cellId, npts, pts);
-    for (j = 0; j < 3; j++) 
-      {
-      if (pts[j] == pt1Id) 
-        {
-        this->Mesh->RemoveCellReference(cellId);
-        this->Mesh->DeleteCell(cellId);       
-        numDeleted++;
-        }
-      }
-    }
-
-  this->Mesh->GetPointCells(pt1Id, this->CollapseCellIds);
-  this->Mesh->ResizeCellList(pt0Id, this->CollapseCellIds->GetNumberOfIds());
-  for (i=0; i < this->CollapseCellIds->GetNumberOfIds(); i++)
-    {
-    cellId = this->CollapseCellIds->GetId(i);
-    this->Mesh->GetCellPoints(cellId, npts, pts);
-    // making sure we don't already have the triangle we're about to
-    // change this one to
-    if ((pts[0] == pt1Id && this->Mesh->IsTriangle(pt0Id, pts[1], pts[2])) ||
-        (pts[1] == pt1Id && this->Mesh->IsTriangle(pts[0], pt0Id, pts[2])) ||
-        (pts[2] == pt1Id && this->Mesh->IsTriangle(pts[0], pts[1], pt0Id)))
-      {
-      this->Mesh->RemoveCellReference(cellId);
-      this->Mesh->DeleteCell(cellId);
-      numDeleted++;
+   this->Mesh->GetPointCells(pt0Id, this->CollapseCellIds);
+   for (i = 0; i < this->CollapseCellIds->GetNumberOfIds(); i++) 
+   {
+      cellId = this->CollapseCellIds->GetId(i);
+      this->Mesh->GetCellPoints(cellId, npts, pts);
+      for (j = 0; j < 3; j++) 
+      {
+         if (pts[j] == pt1Id) 
+         {
+            this->Mesh->RemoveCellReference(cellId);
+            this->Mesh->DeleteCell(cellId);       
+            numDeleted++;
+         }
+      }
+   }
+
+   this->Mesh->GetPointCells(pt1Id, this->CollapseCellIds);
+   this->Mesh->ResizeCellList(pt0Id, this->CollapseCellIds->GetNumberOfIds());
+   for (i=0; i < this->CollapseCellIds->GetNumberOfIds(); i++)
+   {
+      cellId = this->CollapseCellIds->GetId(i);
+      this->Mesh->GetCellPoints(cellId, npts, pts);
+      // making sure we don't already have the triangle we're about to
+      // change this one to
+      if ((pts[0] == pt1Id && this->Mesh->IsTriangle(pt0Id, pts[1], pts[2])) ||
+         (pts[1] == pt1Id && this->Mesh->IsTriangle(pts[0], pt0Id, pts[2])) ||
+         (pts[2] == pt1Id && this->Mesh->IsTriangle(pts[0], pts[1], pt0Id)))
+      {
+         this->Mesh->RemoveCellReference(cellId);
+         this->Mesh->DeleteCell(cellId);
+         numDeleted++;
       }
-    else
+      else
       {
-      this->Mesh->AddReferenceToCell(pt0Id, cellId);
-      this->Mesh->ReplaceCellPoint(cellId, pt1Id, pt0Id);
+         this->Mesh->AddReferenceToCell(pt0Id, cellId);
+         this->Mesh->ReplaceCellPoint(cellId, pt1Id, pt0Id);
       }
-    }
-  this->Mesh->DeletePoint(pt1Id);
-  
-  return numDeleted;
+   }
+   this->Mesh->DeletePoint(pt1Id);
+
+   return numDeleted;
 }
 
 
@@ -1293,7 +1383,7 @@
     }
   this->AttributeComponents[1] = this->NumberOfComponents;
 
-  // Normals attributes -- normals are assumed normalized
+  // Normals attributes -> normals are assumed normalized
   if (pd->GetNormals() != NULL && this->NormalsAttribute) 
     {
     this->NumberOfComponents += 3;
@@ -1348,7 +1438,7 @@
   vtkDebugMacro("Number of components: " << this->NumberOfComponents);
 }
 
-//----------------------------------------------------------------------------
+//->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->->
 void vtkQuadricDecimation::PrintSelf(ostream& os, vtkIndent indent)
 {
   this->Superclass::PrintSelf(os,indent);
Index: vtkQuadricDecimation.h
===================================================================
RCS file: /cvsroot/VTK/VTK/Graphics/vtkQuadricDecimation.h,v
retrieving revision 1.22
diff -u -r1.22 vtkQuadricDecimation.h
--- vtkQuadricDecimation.h	29 Nov 2004 18:41:29 -0000	1.22
+++ vtkQuadricDecimation.h	11 May 2009 15:42:01 -0000
@@ -169,6 +169,9 @@
   vtkIdType GetEdgeCellId(vtkIdType p1Id, vtkIdType p2Id);
 
   int IsGoodPlacement(vtkIdType pt0Id, vtkIdType pt1Id, const double *x);
+  int IsEdgeCollapsible( vtkIdType pt0Id, vtkIdType pt1Id );
+  int GetThirdVertexId( vtkIdType cellId, vtkIdType pt0Id, vtkIdType pt1Id );
+
   int TrianglePlaneCheck(const double t0[3], const double t1[3], 
                          const double t2[3],  const double *x);
   void ComputeNumberOfComponents(void);