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

  Program:   Visualization Toolkit
  Module:    vtkClipVolume.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 vtkClipVolume - clip volume data with user-specified implicit function or input scalar data
// .SECTION Description
// vtkClipVolume is a filter that clips volume data (i.e., vtkImageData)
// using either: any subclass of vtkImplicitFunction or the input scalar
// data. The clipping operation cuts through the cells of the
// dataset--converting 3D image data into a 3D unstructured grid--returning
// everything inside of the specified implicit function (or greater than the
// scalar value). During the clipping the filter will produce pieces of a
// cell. (Compare this with vtkExtractGeometry or vtkGeometryFilter, which
// produces entire, uncut cells.) The output of this filter is a 3D
// unstructured grid (e.g., tetrahedra or other 3D cell types).
//
// To use this filter, you must decide if you will be clipping with an
// implicit function, or whether you will be using the input scalar data.  If
// you want to clip with an implicit function, you must first define and then
// set the implicit function with the SetClipFunction() method. Otherwise,
// you must make sure input scalar data is available. You can also specify a
// scalar value, which is used to decide what is inside and outside of the
// implicit function. You can also reverse the sense of what inside/outside
// is by setting the InsideOut instance variable. (The cutting algorithm
// proceeds by computing an implicit function value or using the input scalar
// data for each point in the dataset. This is compared to the scalar value
// to determine inside/outside.)
//
// This filter can be configured to compute a second output. The
// second output is the portion of the volume that is clipped away. Set the
// GenerateClippedData boolean on if you wish to access this output data.
//
// The filter will produce an unstructured grid of entirely tetrahedra or a
// mixed grid of tetrahedra and other 3D cell types (e.g., wedges). Control
// this behavior by setting the Mixed3DCellGeneration. By default the
// Mixed3DCellGeneration is on and a combination of cell types will be
// produced. Note that producing mixed cell types is a faster than producing
// only tetrahedra.

// .SECTION Caveats
// This filter is designed to function with 3D structured points. Clipping
// 2D images should be done by converting the image to polygonal data
// and using vtkClipPolyData,

// .SECTION See Also
// vtkImplicitFunction vtkClipPolyData vtkGeometryFilter vtkExtractGeometry

#ifndef __vtkClipVolume_h
#define __vtkClipVolume_h

#include "vtkUnstructuredGridAlgorithm.h"

class vtkCellData;
class vtkDataArray;
class vtkIdList;
class vtkImplicitFunction;
class vtkMergePoints;
class vtkOrderedTriangulator;
class vtkPointData;
class vtkIncrementalPointLocator;
class vtkPoints;
class vtkUnstructuredGrid;
class vtkCell;
class vtkTetra;
class vtkCellArray;
class vtkIdTypeArray;
class vtkUnsignedCharArray;

class VTK_GRAPHICS_EXPORT vtkClipVolume : public vtkUnstructuredGridAlgorithm
{
public:
  vtkTypeMacro(vtkClipVolume,vtkUnstructuredGridAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Construct with user-specified implicit function; InsideOut turned off;
  // value set to 0.0; and generate clip scalars turned off.
  static vtkClipVolume *New();

  // Description:
  // Set the clipping value of the implicit function (if clipping with
  // implicit function) or scalar value (if clipping with scalars). The
  // default value is 0.0.
  vtkSetMacro(Value,double);
  vtkGetMacro(Value,double);
  
  // Description:
  // Set/Get the InsideOut flag. When off, a vertex is considered inside the
  // implicit function if its value is greater than the Value ivar. When
  // InsideOutside is turned on, a vertex is considered inside the implicit
  // function if its implicit function value is less than or equal to the
  // Value ivar.  InsideOut is off by default.
  vtkSetMacro(InsideOut,int);
  vtkGetMacro(InsideOut,int);
  vtkBooleanMacro(InsideOut,int);

  // Description
  // Specify the implicit function with which to perform the clipping. If you
  // do not define an implicit function, then the input scalar data will be
  // used for clipping.
  virtual void SetClipFunction(vtkImplicitFunction*);
  vtkGetObjectMacro(ClipFunction,vtkImplicitFunction);

  // Description:
  // If this flag is enabled, then the output scalar values will be 
  // interpolated from the implicit function values, and not the 
  // input scalar data. If you enable this flag but do not provide an
  // implicit function an error will be reported.
  vtkSetMacro(GenerateClipScalars,int);
  vtkGetMacro(GenerateClipScalars,int);
  vtkBooleanMacro(GenerateClipScalars,int);

  // Description:
  // Control whether a second output is generated. The second output
  // contains the unstructured grid that's been clipped away.
  vtkSetMacro(GenerateClippedOutput,int);
  vtkGetMacro(GenerateClippedOutput,int);
  vtkBooleanMacro(GenerateClippedOutput,int);

  // Description:
  // Return the clipped output.
  vtkUnstructuredGrid *GetClippedOutput();

  // Description:
  // Control whether the filter produces a mix of 3D cell types on output, or
  // whether the output cells are all tetrahedra. By default, a mixed set of
  // cells (e.g., tetrahedra and wedges) is produced. (Note: mixed type
  // generation is faster and less overall data is generated.)
  vtkSetMacro(Mixed3DCellGeneration,int);
  vtkGetMacro(Mixed3DCellGeneration,int);
  vtkBooleanMacro(Mixed3DCellGeneration,int);

  // Description:
  // Set the tolerance for merging clip intersection points that are near
  // the corners of voxels. This tolerance is used to prevent the generation
  // of degenerate tetrahedra.
  vtkSetClampMacro(MergeTolerance,double,0.0001,0.25);
  vtkGetMacro(MergeTolerance,double);
  
  // Description:
  // Set / Get a spatial locator for merging points. By default, 
  // an instance of vtkMergePoints is used.
  void SetLocator(vtkIncrementalPointLocator *locator);
  vtkGetObjectMacro(Locator,vtkIncrementalPointLocator);

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

  // Description:
  // Return the mtime also considering the locator and clip function.
  unsigned long int GetMTime();

protected:
  vtkClipVolume(vtkImplicitFunction *cf=NULL);
  ~vtkClipVolume();

  virtual void ReportReferences(vtkGarbageCollector*);

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

  void ClipTets(double value, vtkTetra *clipTetra, vtkDataArray *clipScalars, 
                vtkDataArray *cellScalars, vtkIdList *tetraIds, 
                vtkPoints *tetraPts, vtkPointData *inPD, vtkPointData *outPD, 
                vtkCellData *inCD, vtkIdType cellId, vtkCellData *outCD, 
                vtkCellData *clippedCD, int insideOut);
  void ClipVoxel(double value, vtkDataArray *cellScalars, int flip,
                 double origin[3], double spacing[3], vtkIdList *cellIds,
                 vtkPoints *cellPts, vtkPointData *inPD, vtkPointData *outPD, 
                 vtkCellData *inCD, vtkIdType cellId, vtkCellData *outCD, 
                 vtkCellData *clippedCD);

  vtkImplicitFunction *ClipFunction;
  vtkIncrementalPointLocator     *Locator;
  int                  InsideOut;
  double                Value;
  int                  GenerateClipScalars;
  double                MergeTolerance;
  int                  Mixed3DCellGeneration;
  int                  GenerateClippedOutput;
  vtkUnstructuredGrid *ClippedOutput;
  
private:
  vtkOrderedTriangulator *Triangulator;
  
  // Used temporarily to pass data around
  vtkIdType             NumberOfCells;
  vtkCellArray          *Connectivity;
  vtkUnsignedCharArray  *Types;
  vtkIdTypeArray        *Locations;
  vtkIdType             NumberOfClippedCells;
  vtkCellArray          *ClippedConnectivity;
  vtkUnsignedCharArray  *ClippedTypes;
  vtkIdTypeArray        *ClippedLocations;

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

#endif
