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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkGenericContourFilter.h,v $

  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.

=========================================================================*/
// .NAME vtkGenericContourFilter - generate isocontours from input dataset
// .SECTION Description
// vtkGenericContourFilter is a filter that takes as input any (generic)
// dataset and generates on output isosurfaces and/or isolines. The exact
// form of the output depends upon the dimensionality of the input data.
// Data consisting of 3D cells will generate isosurfaces, data consisting of
// 2D cells will generate isolines, and data with 1D or 0D cells will
// generate isopoints. Combinations of output type are possible if the input
// dimension is mixed.
//
// To use this filter you must specify one or more contour values.
// You can either use the method SetValue() to specify each contour
// value, or use GenerateValues() to generate a series of evenly
// spaced contours. It is also possible to accelerate the operation of
// this filter (at the cost of extra memory) by using a
// vtkScalarTree. A scalar tree is used to quickly locate cells that
// contain a contour surface. This is especially effective if multiple
// contours are being extracted. If you want to use a scalar tree,
// invoke the method UseScalarTreeOn().
//
// This filter has been implemented to operate on generic datasets, rather
// than the typical vtkDataSet (and subclasses). vtkGenericDataSet is a more
// complex cousin of vtkDataSet, typically consisting of nonlinear,
// higher-order cells. To process this type of data, generic cells are
// automatically tessellated into linear cells prior to isocontouring.

// .SECTION Caveats
// For unstructured data or structured grids, normals and gradients
// are not computed. Use vtkPolyDataNormals to compute the surface
// normals.

// .SECTION See Also
// vtkContourFilter vtkGenericDataSet

#ifndef __vtkGenericContourFilter_h
#define __vtkGenericContourFilter_h

#include "vtkPolyDataAlgorithm.h"

class vtkContourValues;
class vtkPointLocator;
class vtkPointData;
class vtkCellData;

class VTK_GENERIC_FILTERING_EXPORT vtkGenericContourFilter : public vtkPolyDataAlgorithm
{
public:
  vtkTypeRevisionMacro(vtkGenericContourFilter,
                       vtkPolyDataAlgorithm);
  
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Construct object with initial range (0,1) and single contour value
  // of 0.0.
  static vtkGenericContourFilter *New();
  
  //BTX
  typedef double PointType[3];  // Arbitrary definition of a point
  //ETX
  
  // Description:
  // Methods to set / get contour values.
  void SetValue(int i, float value);
  double GetValue(int i);
  double *GetValues();
  void GetValues(double *contourValues);
  void SetNumberOfContours(int number);
  int GetNumberOfContours();
  void GenerateValues(int numContours, double range[2]);
  void GenerateValues(int numContours, double rangeStart, double rangeEnd);

  // Description:
  // Modified GetMTime Because we delegate to vtkContourValues
  unsigned long GetMTime();

  // Description:
  // Set/Get the computation of normals. Normal computation is fairly
  // expensive in both time and storage. If the output data will be
  // processed by filters that modify topology or geometry, it may be
  // wise to turn Normals and Gradients off.
  vtkSetMacro(ComputeNormals,int);
  vtkGetMacro(ComputeNormals,int);
  vtkBooleanMacro(ComputeNormals,int);

  // Description:
  // Set/Get the computation of gradients. Gradient computation is
  // fairly expensive in both time and storage. Note that if
  // ComputeNormals is on, gradients will have to be calculated, but
  // will not be stored in the output dataset.  If the output data
  // will be processed by filters that modify topology or geometry, it
  // may be wise to turn Normals and Gradients off.
  vtkSetMacro(ComputeGradients,int);
  vtkGetMacro(ComputeGradients,int);
  vtkBooleanMacro(ComputeGradients,int);

  // Description:
  // Set/Get the computation of scalars.
  vtkSetMacro(ComputeScalars,int);
  vtkGetMacro(ComputeScalars,int);
  vtkBooleanMacro(ComputeScalars,int);

  // Description:
  // Set / get a spatial locator for merging points. By default, 
  // an instance of vtkMergePoints is used.
  void SetLocator(vtkPointLocator *locator);
  vtkGetObjectMacro(Locator,vtkPointLocator);

  // Description:
  // Create default locator. Used to create one when none is
  // specified. The locator is used to merge coincident points.
  void CreateDefaultLocator();

  // Description:
  // If you want to contour by an arbitrary scalar attribute, then set its
  // name here.
  // By default this in NULL and the filter will use the active scalar array.
  vtkGetStringMacro(InputScalarsSelection);
  virtual void SelectInputScalars(const char *fieldName);

protected:
  vtkGenericContourFilter();
  ~vtkGenericContourFilter();

  int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
  
  int FillInputPortInformation(int, vtkInformation*);
  
  vtkContourValues *ContourValues;
  int ComputeNormals;
  int ComputeGradients;
  int ComputeScalars;
  vtkPointLocator *Locator;
  
  char *InputScalarsSelection;
  vtkSetStringMacro(InputScalarsSelection);
  
  // Used internal by vtkGenericAdaptorCell::Contour()
  vtkPointData *internalPD;
  vtkPointData *secondaryPD;
  vtkCellData *secondaryCD;
  
private:
  vtkGenericContourFilter(const vtkGenericContourFilter&);  // Not implemented.
  void operator=(const vtkGenericContourFilter&);  // Not implemented.
};
#endif
