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

  Program:   Visualization Toolkit
  Module:    vtkClipHyperOctree.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.

=========================================================================*/
/**
 * @class   vtkClipHyperOctree
 * @brief   clip an hyperoctree with user-specified implicit function or input scalar data
 *
 * vtkClipHyperOctree is a filter that clips an hyperoctree using either
 * any subclass of vtkImplicitFunction, or the input scalar
 * data. Clipping means that it actually "cuts" through the leaves (cells) of
 * the hyperoctree, returning everything inside of the specified implicit
 * function (or greater than the scalar value) including "pieces" of
 * a cell. (Compare this with vtkExtractGeometry, which pulls out
 * entire, uncut cells.) The output of this filter is an unstructured
 * grid.
 *
 * 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:
 * 1) define an implicit function
 * 2) set it with the SetClipFunction method
 * 3) apply the GenerateClipScalarsOn method
 * If a ClipFunction is not specified, or GenerateClipScalars is off
 * (the default), then the input's scalar data will be used to clip
 * the polydata.
 *
 * 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 clipping 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 part of the cell that is clipped away. Set the
 * GenerateClippedData boolean on if you wish to access this output data.
 *
 * @warning
 * vtkClipHyperOctree will triangulate all types of 3D cells (i.e., create
 * tetrahedra). This is true even if the cell is not actually cut. This
 * is necessary to preserve compatibility across face neighbors. 2D cells
 * will only be triangulated if the cutting function passes through them.
 *
 * @sa
 * vtkImplicitFunction vtkCutter vtkClipVolume vtkClipPolyData
*/

#ifndef vtkClipHyperOctree_h
#define vtkClipHyperOctree_h

#include "vtkFiltersHyperTreeModule.h" // For export macro
#include "vtkUnstructuredGridAlgorithm.h"

class vtkImplicitFunction;
class vtkIncrementalPointLocator;
class vtkHyperOctreeCursor;
class vtkHyperOctree;
class vtkUnsignedCharArray;
class vtkIdTypeArray;
class vtkCellArray;
class vtkCellData;
class vtkPointData;
class vtkOrderedTriangulator;
class vtkDoubleArray;
class vtkTetra;
class vtkPoints;
class vtkPolygon;
class vtkHyperOctreeClipCutPointsGrabber;

class VTKFILTERSHYPERTREE_EXPORT vtkClipHyperOctree : public vtkUnstructuredGridAlgorithm
{
public:
  vtkTypeMacro(vtkClipHyperOctree,vtkUnstructuredGridAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) override;

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

  //@{
  /**
   * 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);
  //@}

  //@{
  /**
   * 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);
  //@}

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

  //@{
  /**
   * 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);
  //@}

  //@{
  /**
   * Control whether a second output is generated. The second output
   * contains the polygonal data that's been clipped away.
   */
  vtkSetMacro(GenerateClippedOutput,int);
  vtkGetMacro(GenerateClippedOutput,int);
  vtkBooleanMacro(GenerateClippedOutput,int);
  //@}

  /**
   * Return the Clipped output.
   */
  vtkUnstructuredGrid *GetClippedOutput();

  //@{
  /**
   * Specify a spatial locator for merging points. By default, an
   * instance of vtkMergePoints is used.
   */
  void SetLocator(vtkIncrementalPointLocator *locator);
  vtkGetObjectMacro(Locator,vtkIncrementalPointLocator);
  //@}

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

  /**
   * Return the mtime also considering the locator and clip function.
   */
  vtkMTimeType GetMTime() override;

protected:
  vtkClipHyperOctree(vtkImplicitFunction *cf=nullptr);
  ~vtkClipHyperOctree() override;

  int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *) override;

  /**
   * Clip the sub-hierarchy pointed by cursor.
   * \pre cursor_exists: cursor!=0
   * \pre positive_level: level>=0
   */
  void ClipNode(vtkHyperOctreeCursor *cursor,
                int level,
                double bounds[6]);

  int FillInputPortInformation(int port, vtkInformation *info) override;
  vtkImplicitFunction *ClipFunction;

  vtkIncrementalPointLocator *Locator;
  vtkIncrementalPointLocator *Locator2; // used for the clipped output

  int InsideOut;
  double Value;
  int GenerateClipScalars;

  int GenerateClippedOutput;

  vtkHyperOctree *Input;
  vtkUnstructuredGrid *Output;
  vtkUnstructuredGrid *ClippedOutput;

  vtkUnsignedCharArray *Types[2];
  vtkIdTypeArray *Locs[2];
  vtkCellArray *Conn[2];
  vtkCellData *InCD;
  vtkCellData *OutCD[2];
  vtkPointData *OutPD[2];
  vtkOrderedTriangulator *Triangulator;

  vtkHyperOctreeCursor *Sibling; // to avoid allocation in the loop

  vtkDoubleArray *CellScalars;
  vtkTetra *Tetra;
  vtkDoubleArray *TetScalars;

  vtkPoints *Pts;
  vtkPolygon *Polygon;

  vtkIdType CellTypeCounter[65536]; // up-to-65536 points per octant
  vtkIdType TotalCounter;
  vtkIdType TemplateCounter; // record the number of octants that succceed
  // to use the template triangulator

  vtkHyperOctreeClipCutPointsGrabber *Grabber;

private:
  vtkClipHyperOctree(const vtkClipHyperOctree&) = delete;
  void operator=(const vtkClipHyperOctree&) = delete;
};

#endif
