dox/Hybrid/vtkGreedyTerrainDecimation.h

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

  Program:   Visualization Toolkit
  Module:    vtkGreedyTerrainDecimation.h

  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.

=========================================================================*/
#ifndef __vtkGreedyTerrainDecimation_h
#define __vtkGreedyTerrainDecimation_h

#include "vtkPolyDataAlgorithm.h"

class vtkPriorityQueue;
class vtkDataArray;
class vtkPointData;
class vtkIdList;
class vtkDoubleArray;
class vtkFloatArray;

//PIMPL Encapsulation for STL containers
class vtkGreedyTerrainDecimationTerrainInfoType;
class vtkGreedyTerrainDecimationPointInfoType;

#define VTK_ERROR_NUMBER_OF_TRIANGLES 0
#define VTK_ERROR_SPECIFIED_REDUCTION 1
#define VTK_ERROR_ABSOLUTE            2
#define VTK_ERROR_RELATIVE            3

class VTK_HYBRID_EXPORT vtkGreedyTerrainDecimation : public vtkPolyDataAlgorithm
{
public:
  vtkTypeMacro(vtkGreedyTerrainDecimation,vtkPolyDataAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent);

  static vtkGreedyTerrainDecimation* New();


  vtkSetClampMacro(ErrorMeasure,int,VTK_ERROR_NUMBER_OF_TRIANGLES,VTK_ERROR_RELATIVE);
  vtkGetMacro(ErrorMeasure,int);
  void SetErrorMeasureToNumberOfTriangles() 
    {this->SetErrorMeasure(VTK_ERROR_NUMBER_OF_TRIANGLES);}
  void SetErrorMeasureToSpecifiedReduction() 
    {this->SetErrorMeasure(VTK_ERROR_SPECIFIED_REDUCTION);}
  void SetErrorMeasureToAbsoluteError() 
    {this->SetErrorMeasure(VTK_ERROR_ABSOLUTE);}
  void SetErrorMeasureToRelativeError() 
    {this->SetErrorMeasure(VTK_ERROR_RELATIVE);}


  vtkSetClampMacro(NumberOfTriangles,vtkIdType,2,VTK_LARGE_ID);
  vtkGetMacro(NumberOfTriangles,vtkIdType);


  vtkSetClampMacro(Reduction,double,0.0,1.0);
  vtkGetMacro(Reduction,double);


  vtkSetClampMacro(AbsoluteError,double,0.0,VTK_DOUBLE_MAX);
  vtkGetMacro(AbsoluteError,double);


  vtkSetClampMacro(RelativeError,double,0.0,VTK_DOUBLE_MAX);
  vtkGetMacro(RelativeError,double);


  vtkSetMacro(BoundaryVertexDeletion,int);
  vtkGetMacro(BoundaryVertexDeletion,int);
  vtkBooleanMacro(BoundaryVertexDeletion,int);


  vtkSetMacro(ComputeNormals, int);
  vtkGetMacro(ComputeNormals, int);
  vtkBooleanMacro(ComputeNormals, int);

protected:
  vtkGreedyTerrainDecimation();
  ~vtkGreedyTerrainDecimation();

  virtual int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
  virtual int FillInputPortInformation(int port, vtkInformation *info);

  int ComputeNormals;
  vtkFloatArray* Normals;
  void ComputePointNormal(int i, int j, float n[3]);

  //ivars that the API addresses
  int       ErrorMeasure;
  vtkIdType NumberOfTriangles;
  double    Reduction;
  double    AbsoluteError;
  double    RelativeError;
  int       BoundaryVertexDeletion; //Can we delete boundary vertices?

  //Used for convenience
  vtkPolyData    *Mesh;
  vtkPointData   *InputPD;
  vtkPointData   *OutputPD;
  vtkDoubleArray *Points;
  vtkDataArray   *Heights;
  vtkIdType      CurrentPointId;
  double         Tolerance;
  vtkIdList      *Neighbors;
  int            Dimensions[3];
  double         Origin[3];
  double         Spacing[3];
  vtkIdType      MaximumNumberOfTriangles;
  double         Length;

  //Bookeeping arrays
  vtkPriorityQueue                          *TerrainError; //errors for each pt in height field
  vtkGreedyTerrainDecimationTerrainInfoType *TerrainInfo;  //owning triangle for each pt
  vtkGreedyTerrainDecimationPointInfoType   *PointInfo;    //map mesh pt id to input pt id
  
  //Make a guess at initial allocation
  void EstimateOutputSize(const vtkIdType numInputPts, vtkIdType &numPts, vtkIdType &numTris);
  
  //Returns non-zero if the error measure is satisfied.
  virtual int SatisfiesErrorMeasure(double error);

  //Insert all the boundary vertices into the TIN
  void InsertBoundaryVertices();
    
  //Insert a point into the triangulation; get a point from the triangulation
  vtkIdType AddPointToTriangulation(vtkIdType inputPtId);
  vtkIdType InsertNextPoint(vtkIdType inputPtId, double x[3]);
  double *GetPoint(vtkIdType id);
  void GetPoint(vtkIdType id, double x[3]);

  //Helper functions
  void GetTerrainPoint(int i, int j, double x[3]);
  void ComputeImageCoordinates(vtkIdType inputPtId, int ij[2]);
  int InCircle (double x[3], double x1[3], double x2[3], double x3[3]);
  vtkIdType FindTriangle(double x[3], vtkIdType ptIds[3], vtkIdType tri,
                         double tol, vtkIdType nei[3], vtkIdList *neighbors, int& status);
  void CheckEdge(vtkIdType ptId, double x[3], vtkIdType p1, vtkIdType p2,
                 vtkIdType tri, int depth);

  void UpdateTriangles(vtkIdType meshPtId); //update all points connected to this point
  void UpdateTriangle(vtkIdType triId, vtkIdType p1, vtkIdType p2, vtkIdType p3);
  void UpdateTriangle(vtkIdType triId, int ij1[2], int ij2[2], int ij3[2], double h[4]);

  int CharacterizeTriangle(int ij1[2], int ij2[2], int ij[3],
                           int* &min, int* &max, int* &midL, int* &midR,
                           int* &mid, int mid2[2], double h[3], double &hMin, double &hMax, 
                           double &hL, double &hR);

private:
  vtkGreedyTerrainDecimation(const vtkGreedyTerrainDecimation&);  // Not implemented.
  void operator=(const vtkGreedyTerrainDecimation&);  // Not implemented.

};

#endif

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