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

  Program:   Visualization Toolkit
  Module:    vtkProbeFilter.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.

=========================================================================*/
// .NAME vtkProbeFilter - sample data values at specified point locations
// .SECTION Description
// vtkProbeFilter is a filter that computes point attributes (e.g., scalars,
// vectors, etc.) at specified point positions. The filter has two inputs:
// the Input and Source. The Input geometric structure is passed through the
// filter. The point attributes are computed at the Input point positions
// by interpolating into the source data. For example, we can compute data
// values on a plane (plane specified as Input) from a volume (Source).
// The cell data of the source data is copied to the output based on in
// which source cell each input point is. If an array of the same name exists
// both in source's point and cell data, only the one from the point data is
// probed.
//
// This filter can be used to resample data, or convert one dataset form into
// another. For example, an unstructured grid (vtkUnstructuredGrid) can be
// probed with a volume (three-dimensional vtkImageData), and then volume
// rendering techniques can be used to visualize the results. Another example:
// a line or curve can be used to probe data to produce x-y plots along
// that line or curve.

#ifndef __vtkProbeFilter_h
#define __vtkProbeFilter_h

#include "vtkDataSetAlgorithm.h"

class vtkIdTypeArray;

class VTK_GRAPHICS_EXPORT vtkProbeFilter : public vtkDataSetAlgorithm
{
public:
  static vtkProbeFilter *New();
  vtkTypeRevisionMacro(vtkProbeFilter,vtkDataSetAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Specify the point locations used to probe input. Any geometry
  // can be used. Old style. Do not use unless for backwards compatibility.
  void SetSource(vtkDataObject *source);
  vtkDataObject *GetSource();

  // Description:
  // Specify the point locations used to probe input. Any geometry
  // can be used. New style. Equivalent to SetInputConnection(1, algOutput).
  void SetSourceConnection(vtkAlgorithmOutput* algOutput);

  // Description:
  // This flag is used only when a piece is requested to update.  By default
  // the flag is off.  Because no spatial correspondence between input pieces
  // and source pieces is known, all of the source has to be requested no
  // matter what piece of the output is requested.  When there is a spatial 
  // correspondence, the user/application can set this flag.  This hint allows
  // the breakup of the probe operation to be much more efficient.  When piece
  // m of n is requested for update by the user, then only n of m needs to
  // be requested of the source. 
  vtkSetMacro(SpatialMatch, int);
  vtkGetMacro(SpatialMatch, int);
  vtkBooleanMacro(SpatialMatch, int);

  // Description:
  // Get the list of point ids in the output that contain attribute data
  // interpolated from the source.
  vtkGetObjectMacro(ValidPoints, vtkIdTypeArray);
  
protected:
  vtkProbeFilter();
  ~vtkProbeFilter();

  int SpatialMatch;

  virtual int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
  virtual int RequestInformation(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
  virtual int RequestUpdateExtent(vtkInformation *, vtkInformationVector **, vtkInformationVector *);

  void Probe(vtkDataSet *input, vtkDataSet *source, vtkDataSet *output);

  vtkIdTypeArray *ValidPoints;
private:
  vtkProbeFilter(const vtkProbeFilter&);  // Not implemented.
  void operator=(const vtkProbeFilter&);  // Not implemented.
};

#endif
