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

  Program:   Visualization Toolkit
  Module:    vtkDeformPointSet.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   vtkDeformPointSet
 * @brief   use a control polyhedron to deform an input vtkPointSet
 *
 * vtkDeformPointSet is a filter that uses a control polyhdron to deform an
 * input dataset of type vtkPointSet. The control polyhedron (or mesh) must
 * be a closed, manifold surface.
 *
 * The filter executes as follows. In initial pipeline execution, the control
 * mesh and input vtkPointSet are assumed in undeformed position, and an
 * initial set of interpolation weights are computed for each point in the
 * vtkPointSet (one interpolation weight value for each point in the control
 * mesh). The filter then stores these interpolation weights after filter
 * execution. The next time the filter executes, assuming that the number of
 * points/cells in the control mesh and vtkPointSet have not changed, the
 * points in the vtkPointSet are recomputed based on the original
 * weights. Hence if the control mesh has been deformed, it will in turn
 * cause deformation in the vtkPointSet. This can be used to animate or edit
 * the geometry of the vtkPointSet.
 *
 * @warning
 * Note that a set of interpolation weights per point in the vtkPointSet is
 * maintained. The number of interpolation weights is the number of points
 * in the control mesh. Hence keep the control mesh small in size or a n^2
 * data explostion will occur.
 *
 * @warning
 * The filter maintains interpolation weights between executions (after the
 * initial execution pass computes the interpolation weights). You can
 * explicitly cause the filter to reinitialize by setting the
 * InitializeWeights boolean to true. By default, the filter will execute and
 * then set InitializeWeights to false.
 *
 * @warning
 * This work was motivated by the work of Tao Ju et al in "Mesh Value Coordinates
 * for Closed Triangular Meshes." The MVC algorithm is currently used to generate
 * interpolation weights. However, in the future this filter may be extended to
 * provide other interpolation functions.
 *
 * @warning
 * A final note: point data and cell data are passed from the input to the output.
 * Only the point coordinates of the input vtkPointSet are modified.
 *
 * @sa
 * vtkMeanValueCoordinatesInterpolator vtkProbePolyhedron vtkPolyhedron
*/

#ifndef vtkDeformPointSet_h
#define vtkDeformPointSet_h

#include "vtkFiltersGeneralModule.h" // For export macro
#include "vtkPointSetAlgorithm.h"

#include "vtkSmartPointer.h" // For protected ivars

class vtkDoubleArray;
class vtkPolyData;


class VTKFILTERSGENERAL_EXPORT vtkDeformPointSet : public vtkPointSetAlgorithm
{
public:
  //@{
  /**
   * Standard methods for instantiable (i.e., concrete) class.
   */
  static vtkDeformPointSet *New();
  vtkTypeMacro(vtkDeformPointSet,vtkPointSetAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) override;
  //@}

  //@{
  /**
   * Specify the control mesh to deform the input vtkPointSet. The control
   * mesh must be a closed, non-self-intersecting, manifold mesh.
   */
  void SetControlMeshData(vtkPolyData *controlMesh);
  vtkPolyData *GetControlMeshData();
  //@}

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

  //@{
  /**
   * Specify whether to regenerate interpolation weights or not. Initially
   * the filter will reexecute no matter what this flag is set to (initial
   * weights must be computed). Also, this flag is ignored if the number of
   * input points/cells or the number of control mesh points/cells changes
   * between executions. Thus flag is used to force reexecution and
   * recomputation of weights.
   */
  vtkSetMacro(InitializeWeights, int);
  vtkGetMacro(InitializeWeights, int);
  vtkBooleanMacro(InitializeWeights, int);
  //@}

protected:
  vtkDeformPointSet();
  ~vtkDeformPointSet() override;

  int InitializeWeights;

  // Keep track of information between execution passes
  vtkIdType InitialNumberOfControlMeshPoints;
  vtkIdType InitialNumberOfControlMeshCells;
  vtkIdType InitialNumberOfPointSetPoints;
  vtkIdType InitialNumberOfPointSetCells;
  vtkSmartPointer<vtkDoubleArray> Weights;

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

private:
  vtkDeformPointSet(const vtkDeformPointSet&) = delete;
  void operator=(const vtkDeformPointSet&) = delete;

};

#endif
