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

  Program:   Visualization Toolkit
  Module:    vtkDiscreteFlyingEdgesClipper2D.cxx

  Copyright (c) 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 "vtkDiscreteFlyingEdgesClipper2D.h"

#include "vtkImageData.h"
#include "vtkCellArray.h"
#include "vtkImageTransform.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkCellData.h"
#include "vtkPolyData.h"
#include "vtkFloatArray.h"
#include "vtkStreamingDemandDrivenPipeline.h"
#include "vtkSMPTools.h"

#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <limits>

vtkStandardNewMacro(vtkDiscreteFlyingEdgesClipper2D);

//============================================================================
namespace { //anonymous

// Determine whether an image label/value is a specified contour
// value. Different data structures are used depending on the
// number of contour values. A cache is used for the common case
// of repeated queries for the same contour value.
template <typename T>
struct ContourMap
{
  T CachedValue;
  T CachedOutValue;
  bool CachedOutValueInitialized;

  ContourMap(double *values, int vtkNotUsed(numValues))
  {
    this->CachedValue = static_cast<T>(values[0]);
    this->CachedOutValue = static_cast<T>(values[0]);
    this->CachedOutValueInitialized = false;
  }
  virtual ~ContourMap() {}
  virtual bool IsContourValue(T label) = 0;
  bool IsContourValueInCache(T label, bool& inContourSet)
  {
    if ( label == this->CachedValue )
    {
      inContourSet = true;
      return true;
    }
    else if ( this->CachedOutValueInitialized &&
              label == this->CachedOutValue )
    {
      inContourSet = false;
      return true;
    }
    else
    {
      return false;
    }
  }
};

// Cache a single contour value
template <typename T>
struct SingleContourValue : public ContourMap<T>
{
  SingleContourValue(double *values) :
    ContourMap<T>(values, 1) {}
  bool IsContourValue(T label) override
  {
    return ( label == this->CachedValue ? true : false );
  }
};

// Represent a few contour values
template <typename T>
struct ContourVector : public ContourMap<T>
{
  std::vector<T> Map;

  ContourVector(double *values, int numValues) :
    ContourMap<T>(values, numValues)
  {
    for (int vidx = 0; vidx < numValues; vidx++)
    {
      Map.push_back(static_cast<T>(values[vidx]));
    }
  }
  bool IsContourValue(T label) override
  {
    bool inContourSet;
    if ( this->IsContourValueInCache(label, inContourSet) )
    {
      return inContourSet;
    }

    else
    {
      if ( std::find(this->Map.begin(), this->Map.end(), label) != this->Map.end() )
      {
        this->CachedValue = label;
        return true;
      }
      else
      {
        this->CachedOutValue = label;
        this->CachedOutValueInitialized = true;
        return false;
      }
    }
  }
};

// Represent many contour values
template <typename T>
struct ContourSet : public ContourMap<T>
{
  std::set<T> Map;

  ContourSet(double *values, int numValues) :
    ContourMap<T>(values, numValues)
  {
    for (int vidx = 0; vidx < numValues; vidx++)
    {
      Map.insert(static_cast<T>(values[vidx]));
    }
  }
  bool IsContourValue(T label) override
  {
    bool inContourSet;
    if ( this->IsContourValueInCache(label, inContourSet) )
    {
      return inContourSet;
    }

    else
    {
      if ( this->Map.find(label) != this->Map.end() )
      {
        this->CachedValue = label;
        return true;
      }
      else
      {
        this->CachedOutValue = label;
        this->CachedOutValueInitialized = true;
        return false;
      }
    }
  }
};

// This templated class is the heart of the algorithm. Templated across
// scalar type T. vtkDiscreteFlyingEdgesClipper2D populates the information
// in this class and then invokes ContourImage() to actually initiate
// executions.
template <class T>
class vtkDiscreteClipperAlgorithm
{
public:
  // Used to classify the flying edges 2D dyad
  enum DyadClass {
    Outside = 0,        // dyad origin outside
    Inside = 1,         // dyad origin inside
    XIntersection = 2,  // dyad x-axis intersects
    YIntersection = 4,  // dyad y-axis intersects
    InteriorPoint = 8,  // dyad requires interior point
  };

  // Edges to generate output polygonal primitives (aka case table). The table is
  // generated from an external program. This is a special cases table based on
  // the potential nine vertices that are necessary to tessellate the cell.
  static const unsigned char VertCases[256][23];

  // This table is used to accelerate the generation of output primitives.
  // The VertUses array, a function of the case number, indicates which pixel
  // vertices, edges, and center point intersect with the contour (i.e.,
  // require interpolation).
  unsigned char VertUses[256][9];

  // Algorithm-derived data
  unsigned char *DyadCases;
  vtkIdType *EdgeMetaData;

  // Internal variables used by the various algorithm methods. Interfaces VTK
  // image data in a form more convenient to the algorithm.
  vtkIdType Dims[2];
  int K;
  int Axis0;
  int Min0;
  int Max0;
  int Inc0;
  int Axis1;
  int Min1;
  int Max1;
  int Inc1;
  int Axis2;
  ContourMap<T> *CMap;

  // Output data. Threads write to partitioned memory.
  T         *Scalars;
  vtkIdType *NewPolys;
  float     *NewPoints;
  T         *NewScalars; //cell scalars if requested

  // Instantiate and initialize key data members.
  vtkDiscreteClipperAlgorithm();

  // The three threaded passes of the algorithm.
  void ClassifyXEdges(T* inPtr, vtkIdType row); //PASS 1
  void ClassifyYEdges(T* inPtr, vtkIdType row); //PASS 2
  void GenerateOutput(T* inPtr, vtkIdType row); //PASS 4

  // Place holder for now in case fancy bit fiddling is needed later.
  void SetDyadClassification(unsigned char *dPtr, unsigned char vertCase)
    {*dPtr = vertCase;}

  // Given the four dyads required to define a case, return the case number.
  unsigned char GetDyadCase(unsigned char d0, unsigned char d1,
                            unsigned char d2, unsigned char d3)
  {
    unsigned char dCase = d0 & 0x1;
    dCase |= (d1 & 0x1) << 1;
    dCase |= (d2 & 0x1) << 2;
    dCase |= (d3 & 0x1) << 3;
    dCase |= (d0 & 0x2) << 3;
    dCase |= (d2 & 0x2) << 4;
    dCase |= (d0 & 0x4) << 4;
    dCase |= (d1 & 0x4) << 5;

    return dCase;
  }

  // Return number of contouring primitives (polygons) for a particular case.
  unsigned char GetNumberOfPrimitives(unsigned char caseNum)
    { return this->VertCases[caseNum][0]; }

  // Return the polygon connectivity length for a particular case.
  unsigned char GetConnectivityLength(unsigned char caseNum)
    { return this->VertCases[caseNum][1]; }

  // Return whether an interior vertex is required for a particular case.
  unsigned char GetInteriorVertex(unsigned char caseNum)
    { return this->VertCases[caseNum][2]; }

  // Return an array indicating which pixel vert intersect the contour.
  unsigned char *GetVertUses(unsigned char dCase)
    { return this->VertUses[dCase]; }

  // Produce the primitives for this pixel cell.
  void GeneratePolys(unsigned char dCase, unsigned char numPolys,
                     vtkIdType ptIds[9], vtkIdType &rowConnLen)
  {
    vtkIdType *prim, vid;
    unsigned char connLen = this->VertCases[dCase][1];
    const unsigned char *verts = this->VertCases[dCase] + 3;
    prim = this->NewPolys + rowConnLen;
    for (int i=0; i < numPolys; ++i)
    {
      prim[0] = *verts++;
      for (int j=1; j <= prim[0]; ++j)
      {
        vid = *verts++;
        vid = (vid <= 3 ? vid : (vid <= 13 ? (vid-6) : 8) );
        prim[j] = ptIds[vid];
      }
      prim += (prim[0] + 1);
    }
    rowConnLen += connLen;
  }

  // Produce the output points on the dyad. Special cases exist on the
  // boundary. The eids[9] array is the point ids on the pixel associated with
  // the dyad.
  void GenerateDyadPoints(int ijk[3], unsigned char vCase, vtkIdType *eIds);
  void GenerateXDyadPoints(int ijk[3], unsigned char vCase, vtkIdType *eIds);
  void GenerateYDyadPoints(int ijk[3], unsigned char vCase, vtkIdType *eIds);
  void GenerateOriginDyadPoint(int ijk[3], unsigned char vCase, vtkIdType *eIds);

  // Generate cell scalar vaues if requested
  void GenerateScalars(T *s, unsigned char dCase, vtkIdType &polyNum);

  // Helper function to set up the point ids on pixel vertices including the
  // mid-edge vertices and possible interior vertex.
  unsigned char InitPixelIds(unsigned char *dPtr0, unsigned char *dPtr0x,
                             unsigned char *dPtr1, unsigned char *dPtr1x,
                             vtkIdType *eMD0, vtkIdType *eMD1, vtkIdType *ids)
  {
    unsigned char dCase = GetDyadCase(*dPtr0,*dPtr0x,*dPtr1,*dPtr1x);
    ids[0] = eMD0[0];
    ids[1] = ids[0] + this->VertUses[dCase][0] + this->VertUses[dCase][4];
    ids[2] = eMD1[0];
    ids[3] = ids[2] + this->VertUses[dCase][2] + this->VertUses[dCase][5];
    ids[4] = ids[0] + this->VertUses[dCase][0];
    ids[5] = ids[2] + this->VertUses[dCase][2];
    ids[6] = eMD0[1];
    ids[7] = ids[6] + this->VertUses[dCase][6] + this->VertUses[dCase][8];
    ids[8] = ids[6] + this->VertUses[dCase][6];
    return dCase;
  }

  // Helper function to advance the point ids along pixel rows.
  void AdvancePixelIds(unsigned char dCase, vtkIdType *ids)
  {
    ids[0] = ids[1];
    ids[1] = ids[0] + this->VertUses[dCase][0] + this->VertUses[dCase][4];
    ids[2] = ids[3];
    ids[3] = ids[2] + this->VertUses[dCase][2] + this->VertUses[dCase][5];
    ids[4] = ids[0] + this->VertUses[dCase][0];
    ids[5] = ids[2] + this->VertUses[dCase][2];
    ids[6] = ids[7];
    ids[7] = ids[6] + this->VertUses[dCase][6] + this->VertUses[dCase][8];
    ids[8] = ids[6] + this->VertUses[dCase][6];
  }

  // Threading integration via SMPTools
  template <class TT> class Pass1
  {
    public:
      Pass1(vtkDiscreteClipperAlgorithm<TT> *algo)
        { this->Algo = algo;}
      vtkDiscreteClipperAlgorithm<TT> *Algo;
      void  operator()(vtkIdType row, vtkIdType end)
      {
        TT *rowPtr = this->Algo->Scalars + row*this->Algo->Inc1;
        for ( ; row < end; ++row)
        {
          this->Algo->ClassifyXEdges(rowPtr, row);
          rowPtr += this->Algo->Inc1;
        }//for all rows in this batch
      }
  };
  template <class TT> class Pass2
  {
    public:
      Pass2(vtkDiscreteClipperAlgorithm<TT> *algo)
        { this->Algo = algo;}
      vtkDiscreteClipperAlgorithm<TT> *Algo;
      void  operator()(vtkIdType row, vtkIdType end)
      {
        TT *rowPtr = this->Algo->Scalars + row*this->Algo->Inc1;
        for ( ; row < end; ++row)
        {
          this->Algo->ClassifyYEdges(rowPtr, row);
          rowPtr += this->Algo->Inc1;
        }//for all rows in this batch
      }
  };
  template <class TT> class Pass4
  {
    public:
      Pass4(vtkDiscreteClipperAlgorithm<TT> *algo)
        { this->Algo = algo; }
      vtkDiscreteClipperAlgorithm<TT> *Algo;
      void  operator()(vtkIdType row, vtkIdType end)
      {
        T *rowPtr = this->Algo->Scalars + row*this->Algo->Inc1;
        for ( ; row < end; ++row)
        {
          this->Algo->GenerateOutput(rowPtr, row);
          rowPtr += this->Algo->Inc1;
        }//for all rows in this batch
      }
  };

  // Interface between VTK and templated functions
  static void ContourImage(vtkDiscreteFlyingEdgesClipper2D *self, T *scalars, vtkPoints *newPts,
                           vtkDataArray *newScalars, vtkCellArray *newPolys,
                           vtkImageData *input, int *updateExt);
};

// The case table is formatted: (numPolys, connectityLen, centerPoint,
// vi,vj,vk, vi,vj,vk, ...) referring to the pixel corner points [0,3];
// points generated on pixel edges [10,13]; and possibly the pixel center
// point (100) to define polygons. The case number is determined by combining
// the DyadClass classifications of the dyads forming a pixel. Note because
// we are generating manifold cases, the non-manifold cases are empty. THIS
// IS NOT A MARCHING CUBES-TYPE CASE TABLE. Note also that for every polygon,
// the first point is always an image corner point (which is useful for obtaining
// the cell data for the polygon).
template <class T> const unsigned char vtkDiscreteClipperAlgorithm<T>::
  VertCases[256][23] = {
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 0 (0,0,0,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 1 (1,0,0,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 2 (0,1,0,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 3 (1,1,0,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 4 (0,0,1,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 5 (1,0,1,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 6 (0,1,1,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 7 (1,1,1,0) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 8 (0,0,0,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 9 (1,0,0,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 10 (0,1,0,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 11 (1,1,0,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 12 (0,0,1,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 13 (1,0,1,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 14 (0,1,1,1) (0,0,0,0)
    {1,5,0, 4,0,1,3,2, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 15 (1,1,1,1) (0,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 16 (0,0,0,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 17 (1,0,0,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 18 (0,1,0,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 19 (1,1,0,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 20 (0,0,1,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 21 (1,0,1,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 22 (0,1,1,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 23 (1,1,1,0) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 24 (0,0,0,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 25 (1,0,0,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 26 (0,1,0,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 27 (1,1,0,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 28 (0,0,1,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 29 (1,0,1,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 30 (0,1,1,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 31 (1,1,1,1) (1,0,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 32 (0,0,0,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 33 (1,0,0,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 34 (0,1,0,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 35 (1,1,0,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 36 (0,0,1,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 37 (1,0,1,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 38 (0,1,1,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 39 (1,1,1,0) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 40 (0,0,0,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 41 (1,0,0,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 42 (0,1,0,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 43 (1,1,0,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 44 (0,0,1,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 45 (1,0,1,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 46 (0,1,1,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 47 (1,1,1,1) (0,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 48 (0,0,0,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 49 (1,0,0,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 50 (0,1,0,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 51 (1,1,0,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 52 (0,0,1,0) (1,1,0,0)
    {1,5,0, 4,0,10,11,2, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 53 (1,0,1,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 54 (0,1,1,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 55 (1,1,1,0) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 56 (0,0,0,1) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 57 (1,0,0,1) (1,1,0,0)
    {1,5,0, 4,1,3,11,10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 58 (0,1,0,1) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 59 (1,1,0,1) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 60 (0,0,1,1) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 61 (1,0,1,1) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 62 (0,1,1,1) (1,1,0,0)
    {2,10,0, 4,0,10,11,2, 4,1,3,11,10, 0,0,0,0,0,0,0,0,0,0}, //case 63 (1,1,1,1) (1,1,0,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 64 (0,0,0,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 65 (1,0,0,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 66 (0,1,0,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 67 (1,1,0,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 68 (0,0,1,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 69 (1,0,1,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 70 (0,1,1,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 71 (1,1,1,0) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 72 (0,0,0,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 73 (1,0,0,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 74 (0,1,0,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 75 (1,1,0,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 76 (0,0,1,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 77 (1,0,1,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 78 (0,1,1,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 79 (1,1,1,1) (0,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 80 (0,0,0,0) (1,0,1,0)
    {1,4,0, 3,0,10,12, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 81 (1,0,0,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 82 (0,1,0,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 83 (1,1,0,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 84 (0,0,1,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 85 (1,0,1,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 86 (0,1,1,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 87 (1,1,1,0) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 88 (0,0,0,1) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 89 (1,0,0,1) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 90 (0,1,0,1) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 91 (1,1,0,1) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 92 (0,0,1,1) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 93 (1,0,1,1) (1,0,1,0)
    {1,6,0, 5,3,2,12,10,1, 0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 94 (0,1,1,1) (1,0,1,0)
    {2,10,0, 5,3,2,12,10,1, 3,0,10,12, 0,0,0,0,0,0,0,0,0,0}, //case 95 (1,1,1,1) (1,0,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 96 (0,0,0,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 97 (1,0,0,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 98 (0,1,0,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 99 (1,1,0,0) (0,1,1,0)
    {1,4,0, 3,2,12,11, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 100 (0,0,1,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 101 (1,0,1,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 102 (0,1,1,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 103 (1,1,1,0) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 104 (0,0,0,1) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 105 (1,0,0,1) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 106 (0,1,0,1) (0,1,1,0)
    {1,6,0, 5,1,3,11,12,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 107 (1,1,0,1) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 108 (0,0,1,1) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 109 (1,0,1,1) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 110 (0,1,1,1) (0,1,1,0)
    {2,10,0, 5,1,3,11,12,0, 3,2,12,11, 0,0,0,0,0,0,0,0,0,0}, //case 111 (1,1,1,1) (0,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 112 (0,0,0,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 113 (1,0,0,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 114 (0,1,0,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 115 (1,1,0,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 116 (0,0,1,0) (1,1,1,0)
    {2,10,1, 4,2,12,100,13, 4,0,10,100,12, 0,0,0,0,0,0,0,0,0,0}, //case 117 (1,0,1,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 118 (0,1,1,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 119 (1,1,1,0) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 120 (0,0,0,1) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 121 (1,0,0,1) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 122 (0,1,0,1) (1,1,1,0)
    {2,11,1, 5,1,3,11,100,10, 4,0,10,100,12, 0,0,0,0,0,0,0,0,0}, //case 123 (1,1,0,1) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 124 (0,0,1,1) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 125 (1,0,1,1) (1,1,1,0)
    {2,11,1, 5,1,3,11,100,10, 4,2,12,100,11, 0,0,0,0,0,0,0,0,0}, //case 126 (0,1,1,1) (1,1,1,0)
    {3,16,1, 5,1,3,11,100,10, 4,0,10,100,12, 4,2,12,100,11, 0,0,0,0}, //case 127 (1,1,1,1) (1,1,1,0)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 128 (0,0,0,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 129 (1,0,0,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 130 (0,1,0,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 131 (1,1,0,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 132 (0,0,1,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 133 (1,0,1,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 134 (0,1,1,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 135 (1,1,1,0) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 136 (0,0,0,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 137 (1,0,0,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 138 (0,1,0,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 139 (1,1,0,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 140 (0,0,1,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 141 (1,0,1,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 142 (0,1,1,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 143 (1,1,1,1) (0,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 144 (0,0,0,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 145 (1,0,0,0) (1,0,0,1)
    {1,4,0, 3,1,13,10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 146 (0,1,0,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 147 (1,1,0,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 148 (0,0,1,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 149 (1,0,1,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 150 (0,1,1,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 151 (1,1,1,0) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 152 (0,0,0,1) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 153 (1,0,0,1) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 154 (0,1,0,1) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 155 (1,1,0,1) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 156 (0,0,1,1) (1,0,0,1)
    {1,6,0, 5,2,0,10,13,3, 0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 157 (1,0,1,1) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 158 (0,1,1,1) (1,0,0,1)
    {2,10,0, 5,2,0,10,13,3, 3,1,13,10, 0,0,0,0,0,0,0,0,0,0}, //case 159 (1,1,1,1) (1,0,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 160 (0,0,0,0) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 161 (1,0,0,0) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 162 (0,1,0,0) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 163 (1,1,0,0) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 164 (0,0,1,0) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 165 (1,0,1,0) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 166 (0,1,1,0) (0,1,0,1)
    {1,6,0, 5,0,1,13,11,2, 0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 167 (1,1,1,0) (0,1,0,1)
    {1,4,0, 3,3,11,13, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 168 (0,0,0,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 169 (1,0,0,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 170 (0,1,0,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 171 (1,1,0,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 172 (0,0,1,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 173 (1,0,1,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 174 (0,1,1,1) (0,1,0,1)
    {2,10,0, 5,0,1,13,11,2, 3,3,11,13, 0,0,0,0,0,0,0,0,0,0}, //case 175 (1,1,1,1) (0,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 176 (0,0,0,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 177 (1,0,0,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 178 (0,1,0,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 179 (1,1,0,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 180 (0,0,1,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 181 (1,0,1,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 182 (0,1,1,0) (1,1,0,1)
    {2,11,1, 5,2,0,10,100,11, 4,1,13,100,10, 0,0,0,0,0,0,0,0,0}, //case 183 (1,1,1,0) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 184 (0,0,0,1) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 185 (1,0,0,1) (1,1,0,1)
    {2,10,1, 4,1,13,100,10, 4,3,11,100,13, 0,0,0,0,0,0,0,0,0,0}, //case 186 (0,1,0,1) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 187 (1,1,0,1) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 188 (0,0,1,1) (1,1,0,1)
    {2,11,1, 5,2,0,10,100,11, 4,3,11,100,13, 0,0,0,0,0,0,0,0,0}, //case 189 (1,0,1,1) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 190 (0,1,1,1) (1,1,0,1)
    {2,10,1, 4,1,13,100,10, 4,3,11,100,13, 0,0,0,0,0,0,0,0,0,0}, //case 191 (1,1,1,1) (1,1,0,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 192 (0,0,0,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 193 (1,0,0,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 194 (0,1,0,0) (0,0,1,1)
    {1,5,0, 4,0,1,13,12, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 195 (1,1,0,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 196 (0,0,1,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 197 (1,0,1,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 198 (0,1,1,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 199 (1,1,1,0) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 200 (0,0,0,1) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 201 (1,0,0,1) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 202 (0,1,0,1) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 203 (1,1,0,1) (0,0,1,1)
    {1,5,0, 4,2,12,13,3, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 204 (0,0,1,1) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 205 (1,0,1,1) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 206 (0,1,1,1) (0,0,1,1)
    {2,10,0, 4,0,1,13,12, 4,2,12,13,3, 0,0,0,0,0,0,0,0,0,0}, //case 207 (1,1,1,1) (0,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 208 (0,0,0,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 209 (1,0,0,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 210 (0,1,0,0) (1,0,1,1)
    {2,10,1, 4,0,10,100,12, 4,1,13,100,10, 0,0,0,0,0,0,0,0,0,0}, //case 211 (1,1,0,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 212 (0,0,1,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 213 (1,0,1,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 214 (0,1,1,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 215 (1,1,1,0) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 216 (0,0,0,1) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 217 (1,0,0,1) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 218 (0,1,0,1) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 219 (1,1,0,1) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 220 (0,0,1,1) (1,0,1,1)
    {2,11,1, 5,3,2,12,100,13, 4,0,10,100,12, 0,0,0,0,0,0,0,0,0}, //case 221 (1,0,1,1) (1,0,1,1)
    {2,11,1, 5,3,2,12,100,13, 4,1,13,100,10, 0,0,0,0,0,0,0,0,0}, //case 222 (0,1,1,1) (1,0,1,1)
    {2,10,1, 4,0,10,100,12, 4,1,13,100,10, 0,0,0,0,0,0,0,0,0,0}, //case 223 (1,1,1,1) (1,0,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 224 (0,0,0,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 225 (1,0,0,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 226 (0,1,0,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 227 (1,1,0,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 228 (0,0,1,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 229 (1,0,1,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 230 (0,1,1,0) (0,1,1,1)
    {2,11,1, 5,0,1,13,100,12, 4,2,12,100,11, 0,0,0,0,0,0,0,0,0}, //case 231 (1,1,1,0) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 232 (0,0,0,1) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 233 (1,0,0,1) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 234 (0,1,0,1) (0,1,1,1)
    {2,11,1, 5,0,1,13,100,12, 4,3,11,100,13, 0,0,0,0,0,0,0,0,0}, //case 235 (1,1,0,1) (0,1,1,1)
    {2,10,1, 4,2,12,100,11, 4,3,11,100,13, 0,0,0,0,0,0,0,0,0,0}, //case 236 (0,0,1,1) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 237 (1,0,1,1) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 238 (0,1,1,1) (0,1,1,1)
    {3,16,1, 5,0,1,13,100,12, 4,2,12,100,11, 4,3,11,100,13, 0,0,0,0}, //case 239 (1,1,1,1) (0,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 240 (0,0,0,0) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 241 (1,0,0,0) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 242 (0,1,0,0) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 243 (1,1,0,0) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 244 (0,0,1,0) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 245 (1,0,1,0) (1,1,1,1)
    {2,10,1, 4,1,13,100,10, 4,2,12,100,11, 0,0,0,0,0,0,0,0,0,0}, //case 246 (0,1,1,0) (1,1,1,1)
    {3,15,1, 4,0,10,100,12, 4,1,13,100,10, 4,2,12,100,11, 0,0,0,0,0}, //case 247 (1,1,1,0) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 248 (0,0,0,1) (1,1,1,1)
    {2,10,1, 4,0,10,100,12, 4,3,11,100,13, 0,0,0,0,0,0,0,0,0,0}, //case 249 (1,0,0,1) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 250 (0,1,0,1) (1,1,1,1)
    {3,15,1, 4,0,10,100,12, 4,1,13,100,10, 4,3,11,100,13, 0,0,0,0,0}, //case 251 (1,1,0,1) (1,1,1,1)
    {0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, //case 252 (0,0,1,1) (1,1,1,1)
    {3,15,1, 4,0,10,100,12, 4,3,11,100,13, 4,2,12,100,11, 0,0,0,0,0}, //case 253 (1,0,1,1) (1,1,1,1)
    {3,15,1, 4,1,13,100,10, 4,3,11,100,13, 4,2,12,100,11, 0,0,0,0,0}, //case 254 (0,1,1,1) (1,1,1,1)
    {4,20,1, 4,0,10,100,12, 4,1,13,100,10, 4,3,11,100,13, 4,2,12,100,11} //case 255 (1,1,1,1) (1,1,1,1)
  };

//----------------------------------------------------------------------------
// Instantiate and initialize key data members. Mostly we build some
// acceleration structures from the case table.
template <class T> vtkDiscreteClipperAlgorithm<T>::
vtkDiscreteClipperAlgorithm():DyadCases(nullptr),EdgeMetaData(nullptr),Scalars(nullptr),
                              NewPolys(nullptr),NewPoints(nullptr),NewScalars(nullptr)
{
  int j, v, dCase, numPolys, centerPoint, numVerts;
  const unsigned char *vertCase;

  // Initialize over all the cases
  for (dCase=0; dCase<256; ++dCase)
  {
    for (j=0; j<9; ++j)
    {
      this->VertUses[dCase][j] = 0;
    }
  }

  // Populate the derived case table information.
  for (dCase=0; dCase<256; ++dCase)
  {
    vertCase = this->VertCases[dCase];
    numPolys = *vertCase++;
    vertCase++; //skip connectivity length
    centerPoint = *vertCase++;

    // Mark verts and edges and maybe interior point that are used by this
    // case. Thus the case table refers to a mix of different types of
    // generated vertices.
    for (j=0; j < numPolys; ++j) //just loop over all edges
    {
      numVerts = *vertCase++;
      for (v=0; v < numVerts; ++v) //just loop over all vertices
      {
        if ( vertCase[v] <= 3 ) //pixel points
        {
          this->VertUses[dCase][vertCase[v]] = 1;
        }
        else if ( vertCase[v] >= 10 && vertCase[v] <= 13 ) //edges
        {
          this->VertUses[dCase][4+(vertCase[v]-10)] = 1;
        }
      }
      vertCase += numVerts;
    }//for all primitives in this case

    if ( centerPoint ) //possible center point
    {
      this->VertUses[dCase][8] = 1;
    }
  }
}

//----------------------------------------------------------------------------
// Generate the output points
template <class T> void vtkDiscreteClipperAlgorithm<T>::
GenerateDyadPoints(int ijk[3], unsigned char vertCase, vtkIdType *ids)
{
  if ( vertCase == 0 )
  {
    return;
  }

  // Generate points from the dyad. This may include the origin point;
  // intersection points along the x & y edges; and possibly an interior center
  // pixel point.
  float *xo;
  if ( (vertCase & vtkDiscreteClipperAlgorithm::Inside) ) //dyad origin
  {
    xo = this->NewPoints + 3*ids[0];
    xo[0] = ijk[0];
    xo[1] = ijk[1];
    xo[2] = ijk[2];
  }

  if ( (vertCase & vtkDiscreteClipperAlgorithm::XIntersection) ) //x axes edge
  {
    xo = this->NewPoints + 3*ids[4];
    xo[0] = ijk[0] + 0.5;
    xo[1] = ijk[1];
    xo[2] = ijk[2];
  }

  if ( (vertCase & vtkDiscreteClipperAlgorithm::YIntersection) ) //y axes edge
  {
    xo = this->NewPoints + 3*ids[6];
    xo[0] = ijk[0];
    xo[1] = ijk[1] + 0.5;
    xo[2] = ijk[2];
  }

  if ( (vertCase & vtkDiscreteClipperAlgorithm::InteriorPoint) ) //pixel center point
  {
    xo = this->NewPoints + 3*ids[8];
    xo[0] = ijk[0] + 0.5;
    xo[1] = ijk[1] + 0.5;
    xo[2] = ijk[2];
  }
}

//----------------------------------------------------------------------------
// Generate the output points along the upper edge of the image boundary.
template <class T> void vtkDiscreteClipperAlgorithm<T>::
GenerateXDyadPoints(int ijk[3], unsigned char vertCase, vtkIdType *ids)
{
  if ( vertCase == 0 )
  {
    return;
  }

  // Generate points from the dyad along the boundary of the image. This may
  // include the origin point; and an intersection points along the x dyad
  // edge. Note that the ids[9] array comes from the pixel "below" this dyad
  // x edge.
  float *xo;
  if ( (vertCase & vtkDiscreteClipperAlgorithm::Inside) ) //dyad origin
  {
    xo = this->NewPoints + 3*ids[2];
    xo[0] = ijk[0];
    xo[1] = ijk[1] + 1;
    xo[2] = ijk[2];
  }

  if ( (vertCase & vtkDiscreteClipperAlgorithm::XIntersection) ) //x axes edge
  {
    xo = this->NewPoints + 3*ids[5];
    xo[0] = ijk[0] + 0.5;
    xo[1] = ijk[1] + 1;
    xo[2] = ijk[2];
  }
}

//----------------------------------------------------------------------------
// Generate the output points along the right edge of the image boundary.
template <class T> void vtkDiscreteClipperAlgorithm<T>::
GenerateYDyadPoints(int ijk[3], unsigned char vertCase, vtkIdType *ids)
{
  if ( vertCase == 0 )
  {
    return;
  }

  // Generate points from the dyad along the right boundary of the
  // image. This may include the origin point; and an intersection points
  // along the y dyad edge. Note that the ids[9] array comes from the pixel
  // "to the left of" this dyad y edge.
  float *xo;
  if ( (vertCase & vtkDiscreteClipperAlgorithm::Inside) ) //dyad origin
  {
    xo = this->NewPoints + 3*ids[1];
    xo[0] = ijk[0] + 1;
    xo[1] = ijk[1];
    xo[2] = ijk[2];
  }

  if ( (vertCase & vtkDiscreteClipperAlgorithm::YIntersection) ) //y axes edge
  {
    xo = this->NewPoints + 3*ids[7];
    xo[0] = ijk[0] + 1;
    xo[1] = ijk[1] + 0.5;
    xo[2] = ijk[2];
  }
}

//----------------------------------------------------------------------------
// Generate the output point at the origin of the dyad. This method may be
// invoked once per execution, and it is invoked by a pixel below and to the
// left.
template <class T> void vtkDiscreteClipperAlgorithm<T>::
GenerateOriginDyadPoint(int ijk[3], unsigned char vertCase, vtkIdType *ids)
{
  // Generate points from the dyad at the upper right corner of the image.
  if ( (vertCase & vtkDiscreteClipperAlgorithm::Inside) ) //dyad origin
  {
    float *xo = this->NewPoints + 3*ids[3];
    xo[0] = ijk[0] + 1;
    xo[1] = ijk[1] + 1;
    xo[2] = ijk[2];
  }
}

//----------------------------------------------------------------------------
// Cell scalars are produced. The pointer to the scalar field s is positioned
// at the lower left corner of a pixel. The number of scalars to produce is
// indicated by numPolys; the cellScalars
template <class T> void vtkDiscreteClipperAlgorithm<T>::
GenerateScalars(T *sPtr, unsigned char dCase, vtkIdType &polyNum)
{
  unsigned char numPolys = this->VertCases[dCase][0];
  const unsigned char *verts = this->VertCases[dCase] + 3;
  unsigned char nVerts, id;
  T *s;

  // Remember the first id is guaranteed to be on an image pixel
  for (int i=0; i < numPolys; ++i)
  {
    nVerts = verts[0];
    id = verts[1];

    if ( id == 0 )
    {
      s = sPtr; // use s
    }
    else if ( id == 1 )
    {
      s = sPtr + 1;
    }
    else if ( id == 2 )
    {
      s = sPtr + this->Dims[0];
    }
    else //( id == 3 )
    {
      s = sPtr + 1 + this->Dims[0];
    }

    this->NewScalars[polyNum++] = *s;
    verts += (nVerts + 1);
  }
}

//----------------------------------------------------------------------------
// PASS 1: Process a single x-row and associated dyads for each pixel. Start
// building cell contour case table, determine the number of intersections,
// and trim intersections along the row. Note that dyads at the +x,y
// boundaries are partial and must be treated appropriately.
template <class T> void vtkDiscreteClipperAlgorithm<T>::
ClassifyXEdges(T* inPtr, vtkIdType row)
{
  vtkIdType nxcells=this->Dims[0];
  vtkIdType minInt=nxcells, maxInt = 0;
  unsigned char vertCase=vtkDiscreteClipperAlgorithm::Outside;
  vtkIdType *eMD=this->EdgeMetaData+row*6;
  unsigned char *dPtr=this->DyadCases + row*nxcells;
  T s0, sx=(*inPtr);
  bool isCV0, isCVx=this->CMap->IsContourValue(sx);

  // run along the entire x-edge classifying dyad x and y axes
  std::fill_n(eMD, 6, 0);
  for (vtkIdType i=0; i < nxcells; ++i, ++dPtr)
  {
    // At volume boundaries we have to be careful since the dyads are partial
    s0 = sx;
    isCV0 = isCVx;
    if ( i == (nxcells - 1) )
      {//dummy x-edge on image boundary
      sx = s0;
      isCVx = isCV0;
    }
    else
    {
      sx = static_cast<T>(*(inPtr + (i+1)*this->Inc0));
      isCVx = this->CMap->IsContourValue(sx);
    }

    // Is the current vertex a contour value?
    if ( isCV0 )
    {
      vertCase = vtkDiscreteClipperAlgorithm::Inside;
      eMD[0]++; //increment number of points along x-edges
    }
    else
    {
      vertCase = vtkDiscreteClipperAlgorithm::Outside;
    }

    // Does the current x-edge need dividing?
    if ( (isCV0 || isCVx) && s0 != sx )
    {
      vertCase |= vtkDiscreteClipperAlgorithm::XIntersection;
      eMD[0]++; //increment number of points along x-edges
    }

    this->SetDyadClassification(dPtr, vertCase);

    // If either x- or y-dyad edge intersects contour, or the pixel is inside
    // the region, then the pixels will have to be processed.
    if ( vertCase > vtkDiscreteClipperAlgorithm::Outside )
    {
      minInt = ( i < minInt ? i : minInt);
      maxInt = i + 1;
    }//if contour interacts with this dyad
  }//for all dyad-x-edges along this image x-edge

  // The beginning and ending of intersections along the edge is used for
  // computational trimming.
  eMD[4] = minInt;
  eMD[5] = ( maxInt < nxcells ? maxInt : nxcells-1 );
}

//----------------------------------------------------------------------------
// PASS 2: Classify the y-axis portion of the dyads along a single x-row.
// Determine whether an interior point is needed for the tessellation.
template <class T> void vtkDiscreteClipperAlgorithm<T>::
ClassifyYEdges(T* inPtr0, vtkIdType row)
{
  // Edge metadata
  vtkIdType *eMD0 = this->EdgeMetaData + row*6;
  vtkIdType *eMD1 = this->EdgeMetaData + (row+1)*6;

  // Determine whether this row of pixels needs processing. If there are no
  // x-axis dyad intersections or corner points (dyad origin), then no y-axis
  // pixel classification is required.
  if ( (eMD0[0] == 0) && //any x-axis dyad ints from bottom row?
       (eMD1[0] == 0) ) //any x-axis dyad ints from top row?
  {
    return; //there are no y-dyad-ints or interior points, thus no
            //classification required
  }

  // Okay need to do more work.
  // Current row pointer from the row above

  // The trim edges may need adjustment; check both top and bottom x-edges
  // to process the maximal extent.
  vtkIdType xL = ( (eMD0[4] < eMD1[4]) ? eMD0[4] : eMD1[4]);
  vtkIdType xR = ( (eMD0[5] > eMD1[5]) ? eMD0[5] : eMD1[5]);

  // Grab the dyad cases bounding this pixel. Remember this is trimmed.
  inPtr0 += xL;
  T *inPtr1 = inPtr0 + this->Inc1;;
  T *inPtr0x = inPtr0 + 1;
  T *inPtr1x = inPtr0x + this->Inc1;

  // The dyad cases surrounding this pixel
  unsigned char *dPtr0 = this->DyadCases + row*this->Dims[0] + xL;
  unsigned char *dPtr1 = dPtr0 + this->Dims[0];
  unsigned char *dPtr0x = dPtr0 + 1;
  unsigned char *dPtr1x = dPtr1 + 1;

  // Check if dyad y-axis should be split or not. If the two points are
  // different values, or both inside but different values, then splitting is
  // required. This is initially done to the left side of the pixel, in the
  // loop that follows we classify the right side of the pixel.
  if ( ((*dPtr0 & 0x1) != (*dPtr1 & 0x1)) || (*inPtr0 != *inPtr1 ) )
  {
    *dPtr0 |= vtkDiscreteClipperAlgorithm::YIntersection;
    eMD0[1]++; //an dyad y-axis intersection
  }

  // Okay run along the trimmed dyads to classify y-axis edges,
  // as well as whether interior pixel points are needed.
  unsigned char dCase, numPolys;
  vtkIdType i;
  for (i=xL; i < xR; ++i) //run along the trimmed x-pixels
  {
    if ( ((*dPtr0x & 0x1) != (*dPtr1x & 0x1)) || (*inPtr0x != *inPtr1x ) )
    {
      *dPtr0x |= vtkDiscreteClipperAlgorithm::YIntersection;
      eMD0[1]++; //an dyad y-axis intersection
    }

    dCase = this->GetDyadCase(*dPtr0,*dPtr0x,*dPtr1,*dPtr1x);

    if ( (numPolys=this->GetNumberOfPrimitives(dCase)) > 0 )
    {
      // Now determine if interior point is required. Add this to the
      // number of y-points required.
      if ( this->GetInteriorVertex(dCase) )
      {
        *dPtr0 |= vtkDiscreteClipperAlgorithm::InteriorPoint;
      }
      eMD0[1] += this->GetInteriorVertex(dCase);

      // Okay let's increment the primitive count.
      eMD0[2] += numPolys;

      // Okay let's increment the connectivity list.
      eMD0[3] += this->GetConnectivityLength(dCase);
    }//if cell contains contour

    // advance the pointers along pixel rows
    dPtr0++; dPtr0x++; dPtr1++; dPtr1x++;
    inPtr0x++; inPtr1x++;
  }//for all pixels along this x-edge
}

//----------------------------------------------------------------------------
// PASS 4: Process the x-row dyads to generate output primitives, including
// point coordinates and polygon primitives. This is the fourth pass of the
// algorithm.
template <class T> void vtkDiscreteClipperAlgorithm<T>::
GenerateOutput(T* rowPtr, vtkIdType row)
{
  vtkIdType *eMD0 = this->EdgeMetaData + row*6;
  vtkIdType *eMD1 = this->EdgeMetaData + (row+1)*6;
  // Return if there is nothing to do (i.e., no points to generate)
  if ( eMD0[0] == eMD1[0] )
  {
    return;
  }

  // Get the trim edges and prepare to generate
  vtkIdType i;
  vtkIdType rightPixels=(this->Dims[0]-2), topPixels=(this->Dims[1]-2);
  vtkIdType xL = ( (eMD0[4] < eMD1[4]) ? eMD0[4] : eMD1[4]);
  vtkIdType xR = ( (eMD0[5] > eMD1[5]) ? eMD0[5] : eMD1[5]);

  // Grab the dyads bounding the pixels along this x-row. Begin at left trim edge.
  unsigned char *dPtr0 = this->DyadCases + row*this->Dims[0] + xL;
  unsigned char *dPtr1 = dPtr0 + this->Dims[0];
  unsigned char *dPtr0x = dPtr0 + 1;
  unsigned char *dPtr1x = dPtr1 + 1;

  // Traverse all pixels in this row, those containing output primitives
  // further identified for processing, meaning generating points and
  // polygons. Begin by setting up point ids on pixel edges.
  vtkIdType polyNum = eMD0[2];
  vtkIdType rowConnLen = eMD0[3];
  vtkIdType ids[9]; //the ids of generated points
  unsigned char numPolys;

  // Process the dyads as necessary to generate point intersections.
  dPtr0 = this->DyadCases + row*this->Dims[0] + xL;
  int ijk[3];
  ijk[1] = row + this->Min1;
  ijk[2] = this->K;
  unsigned char dCase = this->InitPixelIds(dPtr0,dPtr0x,dPtr1,dPtr1x,eMD0,eMD1,ids);

  // Run along pixels in x-row direction and generate output primitives and points.
  // The left and right boundaries of the image confuse everything as the dyads are
  // not "complete" on the boundaries.
  for (i=xL; i < xR; ++i)
  {
    // Advance point ids as necessary (if not first pixel). The reason this
    // increment is not just done at the end of this loop is that it would
    // advance into undefined memory etc.
    if ( i != xL )
    {
      // Advance dyads along pixel row and get the case of the next pixel
      dPtr0++; dPtr0x++; dPtr1++; dPtr1x++;
      dCase = GetDyadCase(*dPtr0,*dPtr0x,*dPtr1,*dPtr1x);
      this->AdvancePixelIds(dCase,ids);
    }

    // See whether any polygonal primitives need to be generated
    if ( (numPolys=this->GetNumberOfPrimitives(dCase)) > 0 )
    {
      // Now produce point(s) along the dyad if needed. Watch the boundaries.
      ijk[0] = i + this->Min0;
      this->GenerateDyadPoints(ijk, *dPtr0, ids);

      // If end of row, generate partial dyad from right side of pixel
      if ( i == rightPixels )
      {
        this->GenerateYDyadPoints(ijk, *dPtr0x, ids);
      }

      // If top of image, generate partial dyad from top of pixel
      if ( row == topPixels )
      {
        this->GenerateXDyadPoints(ijk, *dPtr1, ids);
        // If top right pixel, then the origin of the dyad may contribute a point
        if ( i == rightPixels )
        {
          this->GenerateOriginDyadPoint(ijk, *dPtr1x, ids);
        }
      }

      // Generate polygons for this case
      this->GeneratePolys(dCase,numPolys,ids,rowConnLen);

      // If requested, generate cell scalars for the polygons in this case
      if ( this->NewScalars )
      {
        this->GenerateScalars(rowPtr+i, dCase, polyNum);
      }
    }//if anything to be generated

  } //for all non-trimmed pixels along this x-edge
}


//----------------------------------------------------------------------------
// Contouring filter specialized for images. This templated function interfaces the
// vtkDiscreteFlyingEdgesClipper2D class with the templated algorithm class. It also invokes
// the three passes of the Flying Edges algorithm.
//
template <class T> void vtkDiscreteClipperAlgorithm<T>::
ContourImage(vtkDiscreteFlyingEdgesClipper2D *self, T *scalars, vtkPoints *newPts,
             vtkDataArray *newScalars, vtkCellArray *newPolys,
             vtkImageData *input, int *updateExt)
{
  double *values=self->GetValues();
  vtkIdType numContours = self->GetNumberOfContours();
  vtkIdType row, *eMD;

  // The update extent may be different than the extent of the image.
  // The only problem with using the update extent is that one or two
  // sources enlarge the update extent.  This behavior is slated to be
  // eliminated.
  vtkIdType incs[3];
  input->GetIncrements(incs);
  int *ext = input->GetExtent();

  // Figure out which 2D plane the image lies in. Capture information for
  // subsequent processing.
  vtkDiscreteClipperAlgorithm<T> algo;
  if (updateExt[4] == updateExt[5])
  { // z collapsed
    algo.Axis0 = 0;
    algo.Min0 = updateExt[0];
    algo.Max0 = updateExt[1];
    algo.Inc0 = incs[0];
    algo.Axis1 = 1;
    algo.Min1 = updateExt[2];
    algo.Max1 = updateExt[3];
    algo.Inc1 = incs[1];
    algo.K = updateExt[4];
    algo.Axis2 = 2;
  }
  else if (updateExt[2] == updateExt[3])
  { // y collapsed
    algo.Axis0 = 0;
    algo.Min0 = updateExt[0];
    algo.Max0 = updateExt[1];
    algo.Inc0 = incs[0];
    algo.Axis1 = 2;
    algo.Min1 = updateExt[4];
    algo.Max1 = updateExt[5];
    algo.Inc1 = incs[2];
    algo.K = updateExt[2];
    algo.Axis2 = 1;
  }
  else if (updateExt[0] == updateExt[1])
  { // x collapsed
    algo.Axis0 = 1;
    algo.Min0 = updateExt[2];
    algo.Max0 = updateExt[3];
    algo.Inc0 = incs[1];
    algo.Axis1 = 2;
    algo.Min1 = updateExt[4];
    algo.Max1 = updateExt[5];
    algo.Inc1 = incs[2];
    algo.K = updateExt[0];
    algo.Axis2 = 0;
  }
  else
  {
    vtkGenericWarningMacro("Expecting 2D data.");
    return;
  }

  // Now allocate working arrays. The DyadCases array tracks case# for each pixel dyad.
  algo.Dims[0] = algo.Max0 - algo.Min0 + 1;
  algo.Dims[1] = algo.Max1 - algo.Min1 + 1;
  algo.DyadCases = new unsigned char [algo.Dims[0]*algo.Dims[1]];

  // Also allocate the characterization (metadata) array for the x edges.
  // This array tracks the number of intersections along each x-row, y-row;
  // as well as the number of polygon primitives and connectivity length, and
  // the xMin_i and xMax_i (minimum index of first intersection, maximum
  // index of intersection for row i, so-called trim edges used for
  // computational trimming).
  algo.EdgeMetaData = new vtkIdType [algo.Dims[1]*6];

  // Compute the starting location for scalar data.  We may be operating
  // on a part of the image.
  algo.Scalars = scalars + incs[0]*(updateExt[0]-ext[0]) +
    incs[1]*(updateExt[2]-ext[2]) + incs[2]*(updateExt[4]-ext[4]) +
    self->GetArrayComponent();

  // This algorithm executes just once no matter how many contour values,
  // requiring a fast lookup as to whether a data value is a contour value.
  // Depending on the number of contours, different lookup strategies are
  // used.
  if ( numContours == 1 )
  {
    algo.CMap = new SingleContourValue<T>(values);
  }
  else if ( numContours < 10 )
  {
    algo.CMap = new ContourVector<T>(values,numContours);
  }
  else
  {
    algo.CMap = new ContourSet<T>(values,numContours);
  }

  // The algorithm is separated into multiple passes. The first pass detects
  // intersections on row edges, counting the number of intersected edges as
  // it progresses. It also keeps track of the generated edge cases and other
  // incidental information about intersections along rows. The second pass
  // classifies y-edges and identifies intersection information.  A prefix
  // sum is used in the third pass to allocate memory for output. In the
  // fourth and final pass, intersection points (including interior points)
  // and polygonal primitives are generated.

  // PASS 1: Traverse all rows identifying intersections and classifying the
  // dyads. Also accumulate information necessary for later allocation.  For
  // example the number of output points is computed.
  Pass1<T> pass1(&algo);
  vtkSMPTools::For(0,algo.Dims[1], pass1);

  // PASS 2: Traverse all rows and process interior information. Continue building
  // dyad case table from this information.
  Pass2<T> pass2(&algo);
  vtkSMPTools::For(0,algo.Dims[1]-1, pass2);

  // PASS 3: Now allocate output. First we have to update the x-Edge meta
  // data to partition the output into separate pieces so independent threads
  // can write into separate memory partititions. Once allocation is
  // complete, process on a row by row basis and produce output points and
  // polygon primitives, (if necessary).
  vtkIdType numXPts, numYPts, numPolys, connLen;
  vtkIdType numOutXPts, numOutYPts, numOutPolys, outConnLen;

  numOutXPts = 0;
  numOutYPts = 0;
  numOutPolys = 0;
  outConnLen = 0;
  for (row=0; row < algo.Dims[1]; ++row)
  {
    eMD = algo.EdgeMetaData + row*6;
    numXPts = eMD[0];
    numYPts = eMD[1];
    numPolys = eMD[2];
    connLen = eMD[3];

    eMD[0] = numOutXPts + numOutYPts;
    eMD[1] = eMD[0] + numXPts;
    eMD[2] = numOutPolys;
    eMD[3] = outConnLen;

    numOutXPts += numXPts;
    numOutYPts += numYPts;
    numOutPolys += numPolys;
    outConnLen += connLen;
  }

  // Output can now be allocated.
  vtkIdType totalPts = numOutXPts + numOutYPts;
  if ( totalPts > 0 )
  {
    newPts->GetData()->WriteVoidPointer(0,3*totalPts);
    algo.NewPoints = static_cast<float*>(newPts->GetVoidPointer(0));
    newPolys->WritePointer(numOutPolys,outConnLen);
    algo.NewPolys = static_cast<vtkIdType*>(newPolys->GetPointer());
    if (newScalars)
    {
      newScalars->WriteVoidPointer(0,numOutPolys);
      algo.NewScalars = static_cast<T*>(newScalars->GetVoidPointer(0));
    }

    // PASS 4: Now process each x-pixel-row and produce the output
    // primitives.
    Pass4<T> pass4(&algo);
    vtkSMPTools::For(0,algo.Dims[1]-1, pass4);
  }//if output generated

  // Clean up and return
  delete [] algo.DyadCases;
  delete [] algo.EdgeMetaData;
  delete algo.CMap;
}

} //anonymous namespace

//============================================================================
//----------------------------------------------------------------------------
// Here is the VTK class proper.
vtkDiscreteFlyingEdgesClipper2D::vtkDiscreteFlyingEdgesClipper2D()
{
  this->ContourValues = vtkContourValues::New();

  this->ComputeScalars = 1;
  this->ArrayComponent = 0;

  // by default process active point scalars
  this->SetInputArrayToProcess(0,0,0,vtkDataObject::FIELD_ASSOCIATION_POINTS,
                               vtkDataSetAttributes::SCALARS);
}

//----------------------------------------------------------------------------
vtkDiscreteFlyingEdgesClipper2D::~vtkDiscreteFlyingEdgesClipper2D()
{
  this->ContourValues->Delete();
}

//----------------------------------------------------------------------------
// Description:
// Overload standard modified time function. If contour values are modified,
// then this object is modified as well.
vtkMTimeType vtkDiscreteFlyingEdgesClipper2D::GetMTime()
{
  vtkMTimeType mTime=this->Superclass::GetMTime();
  vtkMTimeType mTime2=this->ContourValues->GetMTime();

  return ( mTime2 > mTime ? mTime2 : mTime );
}

//----------------------------------------------------------------------------
// Contouring filter specialized for images (or slices from images)
//
int vtkDiscreteFlyingEdgesClipper2D::RequestData( vtkInformation *vtkNotUsed(request),
  vtkInformationVector **inputVector, vtkInformationVector *outputVector)
{
  // get the info objects
  vtkInformation *inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation *outInfo = outputVector->GetInformationObject(0);

  // get the input and output
  vtkImageData *input = vtkImageData::SafeDownCast(
    inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData *output = vtkPolyData::SafeDownCast(
    outInfo->Get(vtkDataObject::DATA_OBJECT()));

  vtkDebugMacro(<< "Executing discrete 2D clipping");

  if ( this->GetNumberOfContours() < 1 )
  {
    return 1;
  }

  int *ext =
    inInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT());
  vtkDataArray *inScalars = this->GetInputArrayToProcess(0,inputVector);
  if ( inScalars == nullptr )
  {
    vtkErrorMacro(<<"Scalars must be defined for contouring");
    return 1;
  }

  int numComps = inScalars->GetNumberOfComponents();
  if (this->ArrayComponent >= numComps)
  {
    vtkErrorMacro("Scalars have " << numComps << " components. "
                  "ArrayComponent must be smaller than " << numComps);
    return 1;
  }

  // Create necessary objects to hold output. We will defer the
  // actual allocation to a later point.
  vtkCellArray *newPolys = vtkCellArray::New();
  vtkPoints *newPts = vtkPoints::New();
  newPts->SetDataTypeToFloat();
  vtkDataArray *newScalars = nullptr;

  if (this->ComputeScalars)
  {
    newScalars = inScalars->NewInstance();
    newScalars->SetNumberOfComponents(1);
    newScalars->SetName(inScalars->GetName());
  }

  // Check data type and execute appropriate function
  void *scalars = inScalars->GetVoidPointer(0);
  switch (inScalars->GetDataType())
  {
    vtkTemplateMacro(vtkDiscreteClipperAlgorithm<VTK_TT>::
                     ContourImage(this,(VTK_TT *)scalars, newPts,
                      newScalars, newPolys, input, ext));
  }//switch

  vtkDebugMacro(<<"Created: "
                << newPts->GetNumberOfPoints() << " points, "
                << newPolys->GetNumberOfCells() << " polygons");

  // Update ourselves.
  output->SetPoints(newPts);
  newPts->Delete();

  output->SetPolys(newPolys);
  newPolys->Delete();

  if (newScalars)
  {
    int idx = output->GetCellData()->AddArray(newScalars);
    output->GetCellData()->SetActiveAttribute(idx, vtkDataSetAttributes::SCALARS);
    newScalars->Delete();
  }

  vtkImageTransform::TransformPointSet(input, output);

  return 1;
}

//----------------------------------------------------------------------------
int vtkDiscreteFlyingEdgesClipper2D::FillInputPortInformation(int, vtkInformation *info)
{
  info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkImageData");
  return 1;
}

//----------------------------------------------------------------------------
void vtkDiscreteFlyingEdgesClipper2D::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  this->ContourValues->PrintSelf(os,indent.GetNextIndent());

  os << indent << "Compute Scalars: " << (this->ComputeScalars ? "On\n" : "Off\n");
  os << indent << "ArrayComponent: " << this->ArrayComponent << endl;
}
