vtkAbstractCellLocator.h

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

  Program:   Visualization Toolkit
  Module:    vtkAbstractCellLocator.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   vtkAbstractCellLocator
 * @brief   an abstract base class for locators which find cells
 *
 * vtkAbstractCellLocator is a spatial search object to quickly locate cells in 3D.
 * vtkAbstractCellLocator supplies a basic interface which concrete subclasses
 * should implement.
 *
 * @warning
 * When deriving a class from vtkAbstractCellLocator, one should include the
 * 'hidden' member functions by the following construct in the derived class
 * \verbatim
 *  using vtkAbstractCellLocator::IntersectWithLine;
 *  using vtkAbstractCellLocator::FindClosestPoint;
 *  using vtkAbstractCellLocator::FindClosestPointWithinRadius;
 * \endverbatim
 *
 *
 * @sa
 * vtkLocator vtkPointLocator vtkOBBTree vtkCellLocator
*/

#ifndef vtkAbstractCellLocator_h
#define vtkAbstractCellLocator_h

#include "vtkCommonDataModelModule.h" // For export macro
#include "vtkLocator.h"

class vtkCellArray;
class vtkGenericCell;
class vtkIdList;
class vtkPoints;

class VTKCOMMONDATAMODEL_EXPORT vtkAbstractCellLocator : public vtkLocator
{
public:
  vtkTypeMacro(vtkAbstractCellLocator,vtkLocator);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  //@{
  /**
   * Specify the preferred/maximum number of cells in each node/bucket.
   * Default 32. Locators generally operate by subdividing space into
   * smaller regions until the number of cells in each region (or node)
   * reaches the desired level.
   */
  vtkSetClampMacro(NumberOfCellsPerNode,int,1,VTK_INT_MAX);
  vtkGetMacro(NumberOfCellsPerNode,int);
  //@}

  //@{
  /**
   * Boolean controls whether the bounds of each cell are computed only
   * once and then saved.  Should be 10 to 20% faster if repeatedly
   * calling any of the Intersect/Find routines and the extra memory
   * won't cause disk caching (24 extra bytes per cell are required to
   * save the bounds).
   */
  vtkSetMacro(CacheCellBounds,vtkTypeBool);
  vtkGetMacro(CacheCellBounds,vtkTypeBool);
  vtkBooleanMacro(CacheCellBounds,vtkTypeBool);
  //@}

  //@{
  /**
   * Boolean controls whether to maintain list of cells in each node.
   * not applicable to all implementations, but if the locator is being used
   * as a geometry simplification technique, there is no need to keep them.
   */
  vtkSetMacro(RetainCellLists,vtkTypeBool);
  vtkGetMacro(RetainCellLists,vtkTypeBool);
  vtkBooleanMacro(RetainCellLists,vtkTypeBool);
  //@}

  //@{
  /**
   * Most Locators build their search structures during BuildLocator
   * but some may delay construction until it is actually needed.
   * If LazyEvaluation is supported, this turns on/off the feature.
   * if not supported, it is ignored.
   */
  vtkSetMacro(LazyEvaluation,vtkTypeBool);
  vtkGetMacro(LazyEvaluation,vtkTypeBool);
  vtkBooleanMacro(LazyEvaluation,vtkTypeBool);
  //@}

  //@{
  /**
   * Some locators support querying a new dataset without rebuilding
   * the search structure (typically this may occur when a dataset
   * changes due to a time update, but is actually the same topology)
   * Turning on this flag enables some locators to skip the rebuilding
   * phase
   */
  vtkSetMacro(UseExistingSearchStructure,vtkTypeBool);
  vtkGetMacro(UseExistingSearchStructure,vtkTypeBool);
  vtkBooleanMacro(UseExistingSearchStructure,vtkTypeBool);
  //@}

  /**
   * Return intersection point (if any) of finite line with cells contained
   * in cell locator. See vtkCell.h parameters documentation.
   */
  virtual int IntersectWithLine(const double p1[3], const double p2[3], double tol, double& t, double x[3],
    double pcoords[3], int &subId);

  /**
   * Return intersection point (if any) AND the cell which was intersected by
   * the finite line.
   */
  virtual int IntersectWithLine(const double p1[3], const double p2[3], double tol, double& t, double x[3],
    double pcoords[3], int &subId, vtkIdType &cellId);

  /**
   * Return intersection point (if any) AND the cell which was intersected by
   * the finite line. The cell is returned as a cell id and as a generic
   * cell.
   */
  virtual int IntersectWithLine(const double p1[3], const double p2[3], double tol, double& t, double x[3],
    double pcoords[3], int &subId, vtkIdType &cellId, vtkGenericCell *cell);

  /**
   * Take the passed line segment and intersect it with the data set.
   * This method assumes that the data set is a vtkPolyData that describes
   * a closed surface, and the intersection points that are returned in
   * 'points' alternate between entrance points and exit points.
   * The return value of the function is 0 if no intersections were found,
   * -1 if point 'a0' lies inside the closed surface, or +1 if point 'a0'
   * lies outside the closed surface.
   * Either 'points' or 'cellIds' can be set to nullptr if you don't want
   * to receive that information. This method is currently only implemented
   * in vtkOBBTree.
   */
  virtual int IntersectWithLine(
    const double p1[3], const double p2[3],
    vtkPoints *points, vtkIdList *cellIds);

  /**
   * Return the closest point and the cell which is closest to the point x.
   * The closest point is somewhere on a cell, it need not be one of the
   * vertices of the cell.
   */
  virtual void FindClosestPoint(
    const double x[3], double closestPoint[3],
    vtkIdType &cellId, int &subId, double& dist2);

  /**
   * Return the closest point and the cell which is closest to the point x.
   * The closest point is somewhere on a cell, it need not be one of the
   * vertices of the cell.  This version takes in a vtkGenericCell
   * to avoid allocating and deallocating the cell.  This is much faster than
   * the version which does not take a *cell, especially when this function is
   * called many times in a row such as by a for loop, where the allocation and
   * deallocation can be done only once outside the for loop.  If a cell is
   * found, "cell" contains the points and ptIds for the cell "cellId" upon
   * exit.
   */
  virtual void FindClosestPoint(
    const double x[3], double closestPoint[3],
    vtkGenericCell *cell, vtkIdType &cellId,
    int &subId, double& dist2);

  /**
   * Return the closest point within a specified radius and the cell which is
   * closest to the point x. The closest point is somewhere on a cell, it
   * need not be one of the vertices of the cell. This method returns 1 if
   * a point is found within the specified radius. If there are no cells within
   * the specified radius, the method returns 0 and the values of closestPoint,
   * cellId, subId, and dist2 are undefined.
   */
  virtual vtkIdType FindClosestPointWithinRadius(
    double x[3], double radius,
    double closestPoint[3], vtkIdType &cellId,
    int &subId, double& dist2);

  /**
   * Return the closest point within a specified radius and the cell which is
   * closest to the point x. The closest point is somewhere on a cell, it
   * need not be one of the vertices of the cell. This method returns 1 if a
   * point is found within the specified radius. If there are no cells within
   * the specified radius, the method returns 0 and the values of
   * closestPoint, cellId, subId, and dist2 are undefined. This version takes
   * in a vtkGenericCell to avoid allocating and deallocating the cell.  This
   * is much faster than the version which does not take a *cell, especially
   * when this function is called many times in a row such as by a for loop,
   * where the allocation and deallocation can be done only once outside the
   * for loop.  If a closest point is found, "cell" contains the points and
   * ptIds for the cell "cellId" upon exit.
   */
  virtual vtkIdType FindClosestPointWithinRadius(
    double x[3], double radius,
    double closestPoint[3],
    vtkGenericCell *cell, vtkIdType &cellId,
    int &subId, double& dist2);

  /**
   * Return the closest point within a specified radius and the cell which is
   * closest to the point x. The closest point is somewhere on a cell, it
   * need not be one of the vertices of the cell. This method returns 1 if a
   * point is found within the specified radius. If there are no cells within
   * the specified radius, the method returns 0 and the values of
   * closestPoint, cellId, subId, and dist2 are undefined. This version takes
   * in a vtkGenericCell to avoid allocating and deallocating the cell.  This
   * is much faster than the version which does not take a *cell, especially
   * when this function is called many times in a row such as by a for loop,
   * where the allocation and dealloction can be done only once outside the
   * for loop.  If a closest point is found, "cell" contains the points and
   * ptIds for the cell "cellId" upon exit.  If a closest point is found,
   * inside returns the return value of the EvaluatePosition call to the
   * closest cell; inside(=1) or outside(=0).
   */
  virtual vtkIdType FindClosestPointWithinRadius(
    double x[3], double radius,
    double closestPoint[3],
    vtkGenericCell *cell, vtkIdType &cellId,
    int &subId, double& dist2, int &inside);

  /**
   * Return a list of unique cell ids inside of a given bounding box. The
   * user must provide the vtkIdList to populate. This method returns data
   * only after the locator has been built.
   */
  virtual void FindCellsWithinBounds(double *bbox, vtkIdList *cells);

  /**
   * Given a finite line defined by the two points (p1,p2), return the list
   * of unique cell ids in the buckets containing the line. It is possible
   * that an empty cell list is returned. The user must provide the vtkIdList
   * to populate. This method returns data only after the locator has been
   * built.
   */
  virtual void FindCellsAlongLine(const double p1[3], const double p2[3], double tolerance, vtkIdList *cells);

  /**
   * Returns the Id of the cell containing the point,
   * returns -1 if no cell found. This interface uses a tolerance of zero
   */
  virtual vtkIdType FindCell(double x[3]);

  /**
   * Find the cell containing a given point. returns -1 if no cell found
   * the cell parameters are copied into the supplied variables, a cell must
   * be provided to store the information.
   */
  virtual vtkIdType FindCell(
    double x[3], double tol2, vtkGenericCell *GenCell,
    double pcoords[3], double *weights);

  /**
   * Quickly test if a point is inside the bounds of a particular cell.
   * Some locators cache cell bounds and this function can make use
   * of fast access to the data.
   */
  virtual bool InsideCellBounds(double x[3], vtkIdType cell_ID);

protected:
   vtkAbstractCellLocator();
  ~vtkAbstractCellLocator() override;

  //@{
  /**
   * This command is used internally by the locator to copy
   * all cell Bounds into the internal CellBounds array. Subsequent
   * calls to InsideCellBounds(...) can make use of the data
   * A valid dataset must be present for this to work. Returns true
   * if bounds wre copied, false otherwise.
   */
  virtual bool StoreCellBounds();
  virtual void FreeCellBounds();
  //@}

  int NumberOfCellsPerNode;
  vtkTypeBool RetainCellLists;
  vtkTypeBool CacheCellBounds;
  vtkTypeBool LazyEvaluation;
  vtkTypeBool UseExistingSearchStructure;
  vtkGenericCell *GenericCell;
  double (*CellBounds)[6];

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

#endif