/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkGeometryFilter.cxx,v $
  Language:  C++
  Date:      $Date: 2003/09/23 15:02:08 $
  Version:   $Revision: 1.92 $

  Copyright (c) 1993-2002 Ken Martin, Will Schroeder, Bill Lorensen 
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "vtkGeometryFilter.h"

#include "vtkCellArray.h"
#include "vtkCellData.h"
#include "vtkGenericCell.h"
#include "vtkHexahedron.h"
#include "vtkMergePoints.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"
#include "vtkPyramid.h"
#include "vtkStructuredGrid.h"
#include "vtkTetra.h"
#include "vtkUnsignedCharArray.h"
#include "vtkUnstructuredGrid.h"
#include "vtkVoxel.h"
#include "vtkWedge.h"

vtkCxxRevisionMacro(vtkGeometryFilter, "$Revision: 1.92 $");
vtkStandardNewMacro(vtkGeometryFilter);

// Construct with all types of clipping turned off.
vtkGeometryFilter::vtkGeometryFilter()
{
  this->PointMinimum = 0;
  this->PointMaximum = VTK_LARGE_ID;

  this->CellMinimum = 0;
  this->CellMaximum = VTK_LARGE_ID;

  this->Extent[0] = -VTK_LARGE_FLOAT;
  this->Extent[1] = VTK_LARGE_FLOAT;
  this->Extent[2] = -VTK_LARGE_FLOAT;
  this->Extent[3] = VTK_LARGE_FLOAT;
  this->Extent[4] = -VTK_LARGE_FLOAT;
  this->Extent[5] = VTK_LARGE_FLOAT;

  this->PointClipping = 0;
  this->CellClipping = 0;
  this->ExtentClipping = 0;

  this->Merging = 1;
  this->Locator = NULL;
}

vtkGeometryFilter::~vtkGeometryFilter()
{
  if ( this->Locator )
    {
    this->Locator->UnRegister(this);
    this->Locator = NULL;
    }
}

// Specify a (xmin,xmax, ymin,ymax, zmin,zmax) bounding box to clip data.
void vtkGeometryFilter::SetExtent(float xMin, float xMax, float yMin,
                                     float yMax, float zMin, float zMax)
{
  float extent[6];

  extent[0] = xMin;
  extent[1] = xMax;
  extent[2] = yMin;
  extent[3] = yMax;
  extent[4] = zMin;
  extent[5] = zMax;

  this->SetExtent(extent);
}

// Specify a (xmin,xmax, ymin,ymax, zmin,zmax) bounding box to clip data.
void vtkGeometryFilter::SetExtent(float extent[6])
{
  int i;

  if ( extent[0] != this->Extent[0] || extent[1] != this->Extent[1] ||
       extent[2] != this->Extent[2] || extent[3] != this->Extent[3] ||
       extent[4] != this->Extent[4] || extent[5] != this->Extent[5] )
    {
    this->Modified();
    for (i=0; i<3; i++)
      {
      if ( extent[2*i+1] < extent[2*i] )
        {
        extent[2*i+1] = extent[2*i];
        }
      this->Extent[2*i] = extent[2*i];
      this->Extent[2*i+1] = extent[2*i+1];
      }
    }
}

void vtkGeometryFilter::Execute()
{
  vtkIdType cellId, newCellId;
  int i, j;
  vtkDataSet *input= this->GetInput();
  vtkIdType numPts=input->GetNumberOfPoints();
  vtkIdType numCells=input->GetNumberOfCells();
  char *cellVis;
  vtkGenericCell *cell;
  vtkCell *face;
  float *x;
  vtkIdList *ptIds;
  vtkIdList *cellIds;
  vtkIdList *pts;
  vtkPoints *newPts;
  vtkIdType ptId;
  int npts;
  vtkIdType pt=0;
  vtkPointData *pd = input->GetPointData();
  vtkCellData *cd = input->GetCellData();
  int allVisible;
  vtkPolyData *output = this->GetOutput();
  vtkPointData *outputPD = output->GetPointData();
  vtkCellData *outputCD = output->GetCellData();
  // ghost cell stuff
  unsigned char  updateLevel = (unsigned char)(output->GetUpdateGhostLevel());
  unsigned char  *cellGhostLevels = NULL;
  
  if (numCells == 0)
    {
    return;
    }

  switch (input->GetDataObjectType())
    {
    case  VTK_POLY_DATA:
      this->PolyDataExecute();
      return;
    case  VTK_UNSTRUCTURED_GRID:
      this->UnstructuredGridExecute();
      return;
    case VTK_STRUCTURED_GRID:      
      this->StructuredGridExecute();
      return;
    }

  vtkDataArray* temp = 0;
  if (cd)
    {
    temp = cd->GetArray("vtkGhostLevels");
    }
  if ( (!temp) || (temp->GetDataType() != VTK_UNSIGNED_CHAR)
    || (temp->GetNumberOfComponents() != 1))
    {
    vtkDebugMacro("No appropriate ghost levels field available.");
    }
  else
    {
    cellGhostLevels = ((vtkUnsignedCharArray*)temp)->GetPointer(0);
    }
  
  cellIds = vtkIdList::New();
  pts = vtkIdList::New();

  vtkDebugMacro(<<"Executing geometry filter");

  cell = vtkGenericCell::New();

  if ( (!this->CellClipping) && (!this->PointClipping) && 
  (!this->ExtentClipping) )
    {
    allVisible = 1;
    cellVis = NULL;
    }
  else
    {
    allVisible = 0;
    cellVis = new char[numCells];
    }

  // Mark cells as being visible or not
  //
  if ( ! allVisible )
    {
    for(cellId=0; cellId < numCells; cellId++)
      {
      if ( this->CellClipping && cellId < this->CellMinimum ||
      cellId > this->CellMaximum )
        {
        cellVis[cellId] = 0;
        }
      else
        {
        input->GetCell(cellId,cell);
        ptIds = cell->GetPointIds();
        for (i=0; i < ptIds->GetNumberOfIds(); i++) 
          {
          ptId = ptIds->GetId(i);
          x = input->GetPoint(ptId);

          if ( (this->PointClipping && (ptId < this->PointMinimum ||
          ptId > this->PointMaximum) ) ||
          (this->ExtentClipping && 
          (x[0] < this->Extent[0] || x[0] > this->Extent[1] ||
          x[1] < this->Extent[2] || x[1] > this->Extent[3] ||
          x[2] < this->Extent[4] || x[2] > this->Extent[5] )) )
            {
            cellVis[cellId] = 0;
            break;
            }
          }
        if ( i >= ptIds->GetNumberOfIds() )
          {
          cellVis[cellId] = 1;
          }
        }
      }
    }

  // Allocate
  //
  newPts = vtkPoints::New();
  newPts->Allocate(numPts,numPts/2);
  output->Allocate(4*numCells,numCells/2);
  outputPD->CopyAllocate(pd,numPts,numPts/2);
  outputCD->CopyAllocate(cd,numCells,numCells/2);

  if ( this->Merging )
    {
    if ( this->Locator == NULL )
      {
      this->CreateDefaultLocator();
      }
    this->Locator->InitPointInsertion (newPts, input->GetBounds());
    }

  // Traverse cells to extract geometry
  //
  int abort=0;
  vtkIdType progressInterval = numCells/20 + 1;
  for(cellId=0; cellId < numCells && !abort; cellId++)
    {
    //Progress and abort method support
    if ( !(cellId % progressInterval) )
      {
      vtkDebugMacro(<<"Process cell #" << cellId);
      this->UpdateProgress ((float)cellId/numCells);
      abort = this->GetAbortExecute();
      }

    // Handle ghost cells here.  Another option was used cellVis array.
    if (cellGhostLevels && cellGhostLevels[cellId] > updateLevel)
      { // Do not create surfaces in outer ghost cells.
      continue;
      }
    
    if ( allVisible || cellVis[cellId] )
      {
      input->GetCell(cellId,cell);
      switch (cell->GetCellDimension())
        {
        // create new points and then cell
        case 0: case 1: case 2:
          
          npts = cell->GetNumberOfPoints();
          pts->Reset();
          for ( i=0; i < npts; i++)
            {
            ptId = cell->GetPointId(i);
            x = input->GetPoint(ptId);

            if ( this->Merging && this->Locator->InsertUniquePoint(x, pt) )
              {
              outputPD->CopyData(pd,ptId,pt);
              }
            else if (!this->Merging)
              {
              pt = newPts->InsertNextPoint(x);
              outputPD->CopyData(pd,ptId,pt);
              }
            pts->InsertId(i,pt);
            }
          newCellId = output->InsertNextCell(cell->GetCellType(), pts);
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case 3:
          int numFaces = cell->GetNumberOfFaces();
          for (j=0; j < numFaces; j++)
            {
            face = cell->GetFace(j);
            input->GetCellNeighbors(cellId, face->PointIds, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
            (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              npts = face->GetNumberOfPoints();
              pts->Reset();
              for ( i=0; i < npts; i++)
                {
                ptId = face->GetPointId(i);
                x = input->GetPoint(ptId);
                if (this->Merging && this->Locator->InsertUniquePoint(x, pt) )
                  {
                  outputPD->CopyData(pd,ptId,pt);
                  }
                else if (!this->Merging)
                  {
                  pt = newPts->InsertNextPoint(x);
                  outputPD->CopyData(pd,ptId,pt);
                  }
                pts->InsertId(i,pt);
                }
              newCellId = output->InsertNextCell(face->GetCellType(), pts);
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        } //switch
      } //if visible
    } //for all cells

  vtkDebugMacro(<<"Extracted " << newPts->GetNumberOfPoints() << " points,"
                << output->GetNumberOfCells() << " cells.");

  // Update ourselves and release memory
  //
  cell->Delete();
  output->SetPoints(newPts);
  newPts->Delete();

  //free storage
  if (!this->Merging && this->Locator)
    {
    this->Locator->Initialize(); 
    }
  output->Squeeze();

  cellIds->Delete();
  pts->Delete();
  if ( cellVis )
    {
    delete [] cellVis;
    }
}

// Specify a spatial locator for merging points. By
// default an instance of vtkMergePoints is used.
void vtkGeometryFilter::SetLocator(vtkPointLocator *locator)
{
  if ( this->Locator == locator ) 
    {
    return;
    }
  if ( this->Locator )
    {
    this->Locator->UnRegister(this);
    this->Locator = NULL;
    }    
  if ( locator )
    {
    locator->Register(this);
    }
  this->Locator = locator;
  this->Modified();
}

void vtkGeometryFilter::CreateDefaultLocator()
{
  if ( this->Locator == NULL )
    {
    this->Locator = vtkMergePoints::New();
    }
}

void vtkGeometryFilter::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  os << indent << "Point Minimum : " << this->PointMinimum << "\n";
  os << indent << "Point Maximum : " << this->PointMaximum << "\n";

  os << indent << "Cell Minimum : " << this->CellMinimum << "\n";
  os << indent << "Cell Maximum : " << this->CellMaximum << "\n";

  os << indent << "Extent: \n";
  os << indent << "  Xmin,Xmax: (" << this->Extent[0] << ", " << this->Extent[1] << ")\n";
  os << indent << "  Ymin,Ymax: (" << this->Extent[2] << ", " << this->Extent[3] << ")\n";
  os << indent << "  Zmin,Zmax: (" << this->Extent[4] << ", " << this->Extent[5] << ")\n";

  os << indent << "PointClipping: " << (this->PointClipping ? "On\n" : "Off\n");
  os << indent << "CellClipping: " << (this->CellClipping ? "On\n" : "Off\n");
  os << indent << "ExtentClipping: " << (this->ExtentClipping ? "On\n" : "Off\n");

  os << indent << "Merging: " << (this->Merging ? "On\n" : "Off\n");
  if ( this->Locator )
    {
    os << indent << "Locator: " << this->Locator << "\n";
    }
  else
    {
    os << indent << "Locator: (none)\n";
    }
}

unsigned long int vtkGeometryFilter::GetMTime()
{
  unsigned long mTime=this-> vtkDataSetToPolyDataFilter::GetMTime();
  unsigned long time;

  if ( this->Locator != NULL )
    {
    time = this->Locator->GetMTime();
    mTime = ( time > mTime ? time : mTime );
    }
  return mTime;
}


void vtkGeometryFilter::PolyDataExecute()
{
  vtkPolyData *input= (vtkPolyData *)this->GetInput();
  vtkIdType cellId;
  int i;
  int allVisible;
  vtkIdType npts;
  vtkIdType *pts;
  vtkPoints *p = input->GetPoints();
  vtkIdType numCells=input->GetNumberOfCells();
  vtkPointData *pd = input->GetPointData();
  vtkCellData *cd = input->GetCellData();
  vtkPolyData *output = this->GetOutput();
  vtkPointData *outputPD = output->GetPointData();
  vtkCellData *outputCD = output->GetCellData();
  vtkIdType newCellId, ptId;
  int visible, type;
  float *x;
  // ghost cell stuff
  unsigned char  updateLevel = (unsigned char)(output->GetUpdateGhostLevel());
  unsigned char  *cellGhostLevels = 0;
  
  vtkDebugMacro(<<"Executing geometry filter for poly data input");

  vtkDataArray* temp = 0;
  if (cd)
    {
    temp = cd->GetArray("vtkGhostLevels");
    }
  if ( (!temp) || (temp->GetDataType() != VTK_UNSIGNED_CHAR)
    || (temp->GetNumberOfComponents() != 1))
    {
    vtkDebugMacro("No appropriate ghost levels field available.");
    }
  else
    {
    cellGhostLevels = ((vtkUnsignedCharArray*)temp)->GetPointer(0);
    }
  
  if ( (!this->CellClipping) && (!this->PointClipping) &&
       (!this->ExtentClipping) )
    {
    allVisible = 1;
    }
  else
    {
    allVisible = 0;
    }

  if ( allVisible ) //just pass input to output
    {
    output->CopyStructure(input);
    outputPD->PassData(pd);
    outputCD->PassData(cd);
    return;
    }

  // Always pass point data
  output->SetPoints(p);
  outputPD->PassData(pd);

  // Allocate
  //
  output->Allocate(numCells);
  outputCD->CopyAllocate(cd,numCells,numCells/2);
  input->BuildCells(); //needed for GetCellPoints()
  
  vtkIdType progressInterval = numCells/20 + 1;
  for(cellId=0; cellId < numCells; cellId++)
    {
    //Progress and abort method support
    if ( !(cellId % progressInterval) )
      {
      vtkDebugMacro(<<"Process cell #" << cellId);
      this->UpdateProgress ((float)cellId/numCells);
      }

    // Handle ghost cells here.  Another option was used cellVis array.
    if (cellGhostLevels && cellGhostLevels[cellId] > updateLevel)
      { // Do not create surfaces in outer ghost cells.
      continue;
      }
    
    input->GetCellPoints(cellId,npts,pts);
    visible = 1;
    if ( !allVisible )
      {
      if ( this->CellClipping && cellId < this->CellMinimum ||
      cellId > this->CellMaximum )
        {
        visible = 0;
        }
      else
        {
        for (i=0; i < npts; i++) 
          {
          ptId = pts[i];
          x = input->GetPoint(ptId);

          if ( (this->PointClipping && (ptId < this->PointMinimum ||
                                        ptId > this->PointMaximum) ) ||
               (this->ExtentClipping && 
                (x[0] < this->Extent[0] || x[0] > this->Extent[1] ||
                 x[1] < this->Extent[2] || x[1] > this->Extent[3] ||
                 x[2] < this->Extent[4] || x[2] > this->Extent[5] )) )
            {
            visible = 0;
            break;
            }
          }
        }
      }
    
    // now if visible extract geometry
    if (allVisible || visible)
      {
      type = input->GetCellType(cellId);
      newCellId = output->InsertNextCell(type,npts,pts);
      outputCD->CopyData(cd,cellId,newCellId);
      } //if visible
    } //for all cells
  
  // Update ourselves and release memory
  //
  output->Squeeze();

  vtkDebugMacro(<<"Extracted " << output->GetNumberOfPoints() << " points,"
                << output->GetNumberOfCells() << " cells.");
}

void vtkGeometryFilter::UnstructuredGridExecute()
{
  vtkUnstructuredGrid *input= (vtkUnstructuredGrid *)this->GetInput();
  vtkCellArray *Connectivity = input->GetCells();
  if (Connectivity == NULL) {return;}
  vtkIdType cellId;
  int i;
  int allVisible;
  vtkIdType npts = 0;
  vtkIdType *pts = 0;
  vtkPoints *p = input->GetPoints();
  vtkIdType numCells=input->GetNumberOfCells();
  vtkPointData *pd = input->GetPointData();
  vtkCellData *cd = input->GetCellData();
  vtkPolyData *output = this->GetOutput();
  vtkPointData *outputPD = output->GetPointData();
  vtkCellData *outputCD = output->GetCellData();
  vtkCellArray *Verts, *Lines, *Polys, *Strips;
  vtkIdList *cellIds, *faceIds;
  char *cellVis;
  vtkIdType newCellId;
  int faceId, *faceVerts, numFacePts;
  float *x;
  int PixelConvert[4];
  // ghost cell stuff
  unsigned char  updateLevel = (unsigned char)(output->GetUpdateGhostLevel());
  unsigned char  *cellGhostLevels = 0;  
  
  PixelConvert[0] = 0;
  PixelConvert[1] = 1;
  PixelConvert[2] = 3;
  PixelConvert[3] = 2;
  
  vtkDebugMacro(<<"Executing geometry filter for unstructured grid input");

  vtkDataArray* temp = 0;
  if (cd)
    {
    temp = cd->GetArray("vtkGhostLevels");
    }
  if ( (!temp) || (temp->GetDataType() != VTK_UNSIGNED_CHAR)
    || (temp->GetNumberOfComponents() != 1))
    {
    vtkDebugMacro("No appropriate ghost levels field available.");
    }
  else
    {
    cellGhostLevels = ((vtkUnsignedCharArray*)temp)->GetPointer(0);
    }
  
  // Check input
  if ( Connectivity == NULL )
    {
    vtkDebugMacro(<<"Nothing to extract");
    return;
    }

  // Determine nature of what we have to do
  cellIds = vtkIdList::New();
  faceIds = vtkIdList::New();
  if ( (!this->CellClipping) && (!this->PointClipping) &&
       (!this->ExtentClipping) )
    {
    allVisible = 1;
    cellVis = NULL;
    }
  else
    {
    allVisible = 0;
    cellVis = new char[numCells];
    }

  // Just pass points through, never merge
  output->SetPoints(input->GetPoints());
  outputPD->PassData(pd);

  outputCD->CopyAllocate(cd,numCells,numCells/2);

  Verts = vtkCellArray::New();
  Verts->Allocate(numCells/4+1,numCells);
  Lines = vtkCellArray::New();
  Lines->Allocate(numCells/4+1,numCells);
  Polys = vtkCellArray::New();
  Polys->Allocate(numCells/4+1,numCells);
  Strips = vtkCellArray::New();
  Strips->Allocate(numCells/4+1,numCells);
  
  // Loop over the cells determining what's visible
  if (!allVisible)
    {
    for (cellId=0, Connectivity->InitTraversal(); 
         Connectivity->GetNextCell(npts,pts); 
         cellId++)
      {
      cellVis[cellId] = 1;
      if ( this->CellClipping && cellId < this->CellMinimum ||
           cellId > this->CellMaximum )
        {
        cellVis[cellId] = 0;
        }
      else
        {
        for (i=0; i < npts; i++) 
          {
          x = p->GetPoint(pts[i]);
          if ( (this->PointClipping && (pts[i] < this->PointMinimum ||
                                        pts[i] > this->PointMaximum) ) ||
               (this->ExtentClipping && 
                (x[0] < this->Extent[0] || x[0] > this->Extent[1] ||
                 x[1] < this->Extent[2] || x[1] > this->Extent[3] ||
                 x[2] < this->Extent[4] || x[2] > this->Extent[5] )) )
            {
            cellVis[cellId] = 0;
            break;
            }//point/extent clipping
          }//for each point
        }//if point clipping needs checking
      }//for all cells
    }//if not all visible
  
  // Loop over all cells now that visibility is known
  // (Have to compute visibility first for 3D cell boundarys)
  int progressInterval = numCells/20 + 1;
  for (cellId=0, Connectivity->InitTraversal(); 
       Connectivity->GetNextCell(npts,pts); 
       cellId++)
    {
    //Progress and abort method support
    if ( !(cellId % progressInterval) )
      {
      vtkDebugMacro(<<"Process cell #" << cellId);
      this->UpdateProgress ((float)cellId/numCells);
      }

    // Handle ghost cells here.  Another option was used cellVis array.
    if (cellGhostLevels && cellGhostLevels[cellId] > updateLevel)
      { // Do not create surfaces in outer ghost cells.
      continue;
      }
    
    if (allVisible || cellVis[cellId])  //now if visible extract geometry
      {
      //special code for nonlinear cells - rarely occurs, so right now it
      //is slow.
      switch (input->GetCellType(cellId))
        {
        case VTK_EMPTY_CELL:
          break;

        case VTK_VERTEX:
        case VTK_POLY_VERTEX:
          newCellId = Verts->InsertNextCell(npts,pts);
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case VTK_LINE: 
        case VTK_POLY_LINE:
          newCellId = Lines->InsertNextCell(npts,pts);
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case VTK_TRIANGLE:
        case VTK_QUAD:
        case VTK_POLYGON:
          newCellId = Polys->InsertNextCell(npts,pts);
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case VTK_TRIANGLE_STRIP:
          newCellId = Strips->InsertNextCell(npts,pts);
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case VTK_PIXEL:
          newCellId = Polys->InsertNextCell(npts);
          for ( i=0; i < npts; i++)
            {
            Polys->InsertCellPoint(pts[PixelConvert[i]]);
            }
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case VTK_TETRA:
          for (faceId = 0; faceId < 4; faceId++)
            {
            faceIds->Reset();
            faceVerts = vtkTetra::GetFaceArray(faceId);
            faceIds->InsertNextId(pts[faceVerts[0]]);
            faceIds->InsertNextId(pts[faceVerts[1]]);
            faceIds->InsertNextId(pts[faceVerts[2]]);
            numFacePts = 3;
            input->GetCellNeighbors(cellId, faceIds, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
                 (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              newCellId = Polys->InsertNextCell(numFacePts);
              for ( i=0; i < numFacePts; i++)
                {
                Polys->InsertCellPoint(pts[faceVerts[i]]);
                }
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        case VTK_VOXEL:
          for (faceId = 0; faceId < 6; faceId++)
            {
            faceIds->Reset();
            faceVerts = vtkVoxel::GetFaceArray(faceId);
            faceIds->InsertNextId(pts[faceVerts[0]]);
            faceIds->InsertNextId(pts[faceVerts[1]]);
            faceIds->InsertNextId(pts[faceVerts[2]]);
            faceIds->InsertNextId(pts[faceVerts[3]]);
            numFacePts = 4;
            input->GetCellNeighbors(cellId, faceIds, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
                 (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              newCellId = Polys->InsertNextCell(numFacePts);
              for ( i=0; i < numFacePts; i++)
                {
                Polys->InsertCellPoint(pts[faceVerts[PixelConvert[i]]]);
                }
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        case VTK_HEXAHEDRON:
          for (faceId = 0; faceId < 6; faceId++)
            {
            faceIds->Reset();
            faceVerts = vtkHexahedron::GetFaceArray(faceId);
            faceIds->InsertNextId(pts[faceVerts[0]]);
            faceIds->InsertNextId(pts[faceVerts[1]]);
            faceIds->InsertNextId(pts[faceVerts[2]]);
            faceIds->InsertNextId(pts[faceVerts[3]]);
            numFacePts = 4;
            input->GetCellNeighbors(cellId, faceIds, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
                 (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              newCellId = Polys->InsertNextCell(numFacePts);
              for ( i=0; i < numFacePts; i++)
                {
                Polys->InsertCellPoint(pts[faceVerts[i]]);
                }
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        case VTK_WEDGE:
          for (faceId = 0; faceId < 5; faceId++)
            {
            faceIds->Reset();
            faceVerts = vtkWedge::GetFaceArray(faceId);
            faceIds->InsertNextId(pts[faceVerts[0]]);
            faceIds->InsertNextId(pts[faceVerts[1]]);
            faceIds->InsertNextId(pts[faceVerts[2]]);
            numFacePts = 3;
            if (faceVerts[3] >= 0)
              {
              faceIds->InsertNextId(pts[faceVerts[3]]);
              numFacePts = 4;
              }
            input->GetCellNeighbors(cellId, faceIds, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
                 (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              newCellId = Polys->InsertNextCell(numFacePts);
              for ( i=0; i < numFacePts; i++)
                {
                Polys->InsertCellPoint(pts[faceVerts[i]]);
                }
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        case VTK_PYRAMID:
          for (faceId = 0; faceId < 5; faceId++)
            {
            faceIds->Reset();
            faceVerts = vtkPyramid::GetFaceArray(faceId);
            faceIds->InsertNextId(pts[faceVerts[0]]);
            faceIds->InsertNextId(pts[faceVerts[1]]);
            faceIds->InsertNextId(pts[faceVerts[2]]);
            numFacePts = 3;
            if (faceVerts[3] >= 0)
              {
              faceIds->InsertNextId(pts[faceVerts[3]]);
              numFacePts = 4;
              }
            input->GetCellNeighbors(cellId, faceIds, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
                 (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              newCellId = Polys->InsertNextCell(numFacePts);
              for ( i=0; i < numFacePts; i++)
                {
                Polys->InsertCellPoint(pts[faceVerts[i]]);
                }
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        //Quadratic cells
        case VTK_QUADRATIC_EDGE:
        case VTK_QUADRATIC_TRIANGLE:
        case VTK_QUADRATIC_QUAD:
        case VTK_QUADRATIC_TETRA:
        case VTK_QUADRATIC_HEXAHEDRON:
          {
          vtkGenericCell *cell = vtkGenericCell::New();
          input->GetCell(cellId,cell);
          vtkIdList *ipts = vtkIdList::New();  
          vtkPoints *coords = vtkPoints::New();
          vtkIdList *icellIds = vtkIdList::New();
          vtkIdType inewCellId;

          if ( cell->GetCellDimension() == 1 )
            {
            cell->Triangulate(0,ipts,coords);
            for (i=0; i < ipts->GetNumberOfIds(); i+=2)
              {
              inewCellId = Lines->InsertNextCell(2);
              Lines->InsertCellPoint(ipts->GetId(i));
              Lines->InsertCellPoint(ipts->GetId(i+1));
              outputCD->CopyData(cd,cellId,inewCellId);
              }
            }
          else if ( cell->GetCellDimension() == 2 )
            {
            cell->Triangulate(0,ipts,coords);
            for (i=0; i < ipts->GetNumberOfIds(); i+=3)
              {
              inewCellId = Lines->InsertNextCell(2);
              Polys->InsertCellPoint(ipts->GetId(i));
              Polys->InsertCellPoint(ipts->GetId(i+1));
              Polys->InsertCellPoint(ipts->GetId(i+2));
              outputCD->CopyData(cd,cellId,inewCellId);
              }
            } 
          else //3D nonlinear cell
            {
            vtkCell *face;
            for (int j=0; j < cell->GetNumberOfFaces(); j++)
              {
              face = cell->GetFace(j);
              input->GetCellNeighbors(cellId, face->PointIds, icellIds);
              if ( icellIds->GetNumberOfIds() <= 0)
                {
                face->Triangulate(0,ipts,coords);
                for (i=0; i < ipts->GetNumberOfIds(); i+=3)
                  {
                  inewCellId = Lines->InsertNextCell(2);
                  Polys->InsertCellPoint(ipts->GetId(i));
                  Polys->InsertCellPoint(ipts->GetId(i+1));
                  Polys->InsertCellPoint(ipts->GetId(i+2));
                  outputCD->CopyData(cd,cellId,inewCellId);
                  }
                }
              }
            } //3d cell
          icellIds->Delete();
          coords->Delete();
          ipts->Delete();
          cell->Delete();
          }
          break; //done with quadratic cells
          
        } //switch
      } //if visible
    } //for all cells
  
  // Update ourselves and release memory
  //
  output->SetVerts(Verts);
  Verts->Delete();
  output->SetLines(Lines);
  Lines->Delete();
  output->SetPolys(Polys);
  Polys->Delete();
  output->SetStrips(Strips);
  Strips->Delete();
  
  output->Squeeze();

  vtkDebugMacro(<<"Extracted " << input->GetNumberOfPoints() << " points,"
  << output->GetNumberOfCells() << " cells.");

  cellIds->Delete();
  faceIds->Delete();
  if ( cellVis )
    {
    delete [] cellVis;
    }
}

void vtkGeometryFilter::StructuredGridExecute()
{
  vtkIdType cellId, newCellId;
  int i;
  vtkStructuredGrid *input=(vtkStructuredGrid *)this->GetInput();
  vtkIdType numCells=input->GetNumberOfCells();
  char *cellVis;
  vtkGenericCell *cell;
  float *x;
  vtkIdList *ptIds;
  vtkIdList *cellIds;
  vtkIdList *pts;
  vtkIdType ptId;
  int *faceVerts, faceId, numFacePts;
  vtkIdType *facePts;
  vtkPointData *pd = input->GetPointData();
  vtkCellData *cd = input->GetCellData();
  int allVisible;
  vtkPolyData *output = this->GetOutput();
  vtkPointData *outputPD = output->GetPointData();
  vtkCellData *outputCD = output->GetCellData();
  vtkCellArray *cells;
  // ghost cell stuff
  unsigned char  updateLevel = (unsigned char)(output->GetUpdateGhostLevel());
  unsigned char  *cellGhostLevels = 0;
  
  cellIds = vtkIdList::New();
  pts = vtkIdList::New();

  vtkDebugMacro(<<"Executing geometry filter with structured grid input");

  cell = vtkGenericCell::New();

  vtkDataArray* temp = 0;
  if (cd)
    {
    temp = cd->GetArray("vtkGhostLevels");
    }
  if ( (!temp) || (temp->GetDataType() != VTK_UNSIGNED_CHAR)
    || (temp->GetNumberOfComponents() != 1))
    {
    vtkDebugMacro("No appropriate ghost levels field available.");
    }
  else
    {
    cellGhostLevels = ((vtkUnsignedCharArray*)temp)->GetPointer(0);
    }
  
  if ( (!this->CellClipping) && (!this->PointClipping) && 
  (!this->ExtentClipping) )
    {
    allVisible = 1;
    cellVis = NULL;
    }
  else
    {
    allVisible = 0;
    cellVis = new char[numCells];
    }

  // Mark cells as being visible or not
  //
  if ( ! allVisible )
    {
    for(cellId=0; cellId < numCells; cellId++)
      {
      cellVis[cellId] = 1;
      if ( this->CellClipping && cellId < this->CellMinimum ||
      cellId > this->CellMaximum )
        {
        cellVis[cellId] = 0;
        }
      else
        {
        input->GetCell(cellId,cell);
        ptIds = cell->GetPointIds();
        for (i=0; i < ptIds->GetNumberOfIds(); i++) 
          {
          ptId = ptIds->GetId(i);
          x = input->GetPoint(ptId);

          if ( (this->PointClipping && (ptId < this->PointMinimum ||
          ptId > this->PointMaximum) ) ||
          (this->ExtentClipping && 
          (x[0] < this->Extent[0] || x[0] > this->Extent[1] ||
          x[1] < this->Extent[2] || x[1] > this->Extent[3] ||
          x[2] < this->Extent[4] || x[2] > this->Extent[5] )) )
            {
            cellVis[cellId] = 0;
            break;
            }
          }
        }
      }
    }

  // Allocate - points are never merged
  //
  output->SetPoints(input->GetPoints());
  outputPD->PassData(pd);
  outputCD->CopyAllocate(cd,numCells,numCells/2);

  cells = vtkCellArray::New();
  cells->Allocate(numCells,numCells/2);
  
  // Traverse cells to extract geometry
  //
  vtkIdType progressInterval = numCells/20 + 1;
  for(cellId=0; cellId < numCells; cellId++)
    {
    //Progress and abort method support
    if ( !(cellId % progressInterval) )
      {
      vtkDebugMacro(<<"Process cell #" << cellId);
      this->UpdateProgress ((float)cellId/numCells);
      }

    // Handle ghost cells here.  Another option was used cellVis array.
    if (cellGhostLevels && cellGhostLevels[cellId] > updateLevel)
      { // Do not create surfaces in outer ghost cells.
      continue;
      }
    
    if ( (allVisible || cellVis[cellId]))
      {
      input->GetCell(cellId,cell);
      switch (cell->GetCellDimension())
        {
        // create new points and then cell
        case 0: case 1: case 2:
          newCellId = cells->InsertNextCell(cell);
          outputCD->CopyData(cd,cellId,newCellId);
          break;

        case 3: //must be hexahedron
          facePts = cell->GetPointIds()->GetPointer(0);
          for (faceId = 0; faceId < 6; faceId++)
            {
            pts->Reset();
            faceVerts = vtkHexahedron::GetFaceArray(faceId);
            pts->InsertNextId(facePts[faceVerts[0]]);
            pts->InsertNextId(facePts[faceVerts[1]]);
            pts->InsertNextId(facePts[faceVerts[2]]);
            pts->InsertNextId(facePts[faceVerts[3]]);
            numFacePts = 4;
            input->GetCellNeighbors(cellId, pts, cellIds);
            if ( cellIds->GetNumberOfIds() <= 0 || 
                 (!allVisible && !cellVis[cellIds->GetId(0)]) )
              {
              newCellId = cells->InsertNextCell(numFacePts);
              for ( i=0; i < numFacePts; i++)
                {
                cells->InsertCellPoint(facePts[faceVerts[i]]);
                }
              outputCD->CopyData(cd,cellId,newCellId);
              }
            }
          break;

        } //switch
      } //if visible
    } //for all cells

  switch (input->GetDataDimension())
    {
    case 0: 
      output->SetVerts(cells);
      break;
    case 1: 
      output->SetLines(cells);
      break;
    case 2: case 3:
      output->SetPolys(cells);
    }
  
  vtkDebugMacro(<<"Extracted " << output->GetNumberOfPoints() << " points,"
                << output->GetNumberOfCells() << " cells.");

  // Update ourselves and release memory
  //
  cells->Delete();
  cell->Delete();
  output->Squeeze();
  cellIds->Delete();
  pts->Delete();
  if ( cellVis )
    {
    delete [] cellVis;
    }
}


void vtkGeometryFilter::ComputeInputUpdateExtents(vtkDataObject *output)
{
  int piece, numPieces, ghostLevels;
  
  if (this->GetInput() == NULL)
    {
    vtkErrorMacro("No Input");
    return;
    }
  piece = output->GetUpdatePiece();
  numPieces = output->GetUpdateNumberOfPieces();
  ghostLevels = output->GetUpdateGhostLevel();
  
  if (numPieces > 1)
    {
    ++ghostLevels;
    }

  this->GetInput()->SetUpdateExtent(piece, numPieces, ghostLevels);

  this->GetInput()->RequestExactExtentOn();
}

void vtkGeometryFilter::ExecuteInformation()
{
  if (this->GetInput() == NULL)
    {
    vtkErrorMacro("No Input");
    return;
    }
}
