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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkPointLocator.h,v $
  Language:  C++
  Date:      $Date: 2002/12/26 18:24:21 $
  Version:   $Revision: 1.52 $

  Copyright (c) 1993-2002 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 vtkPointLocator - quickly locate points in 3-space
// .SECTION Description
// vtkPointLocator is a spatial search object to quickly locate points in 3D.
// vtkPointLocator works by dividing a specified region of space into a regular
// array of "rectangular" buckets, and then keeping a list of points that 
// lie in each bucket. Typical operation involves giving a position in 3D 
// and finding the closest point.
//
// vtkPointLocator has two distinct methods of interaction. In the first
// method, you supply it with a dataset, and it operates on the points in 
// the dataset. In the second method, you supply it with an array of points,
// and the object operates on the array.

// .SECTION Caveats
// Many other types of spatial locators have been developed such as 
// octrees and kd-trees. These are often more efficient for the 
// operations described here.

// .SECTION See Also
// vtkCellPicker vtkPointPicker

#ifndef __vtkPointLocator_h
#define __vtkPointLocator_h

#include "vtkLocator.h"

class vtkCellArray;
class vtkIdList;
class vtkNeighborPoints;
class vtkPoints;

class VTK_COMMON_EXPORT vtkPointLocator : public vtkLocator
{
public:
  // Description:
  // Construct with automatic computation of divisions, averaging
  // 25 points per bucket.
  static vtkPointLocator *New();

  vtkTypeRevisionMacro(vtkPointLocator,vtkLocator);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Set the number of divisions in x-y-z directions.
  vtkSetVector3Macro(Divisions,int);
  vtkGetVectorMacro(Divisions,int,3);

  // Description:
  // Specify the average number of points in each bucket.
  vtkSetClampMacro(NumberOfPointsPerBucket,int,1,VTK_LARGE_INTEGER);
  vtkGetMacro(NumberOfPointsPerBucket,int);

  // Description:
  // Given a position x, return the id of the point closest to it. Alternative
  // method requires separate x-y-z values.
  // These methods are thread safe if BuildLocator() is directly or
  // indirectly called from a single thread first.
  virtual vtkIdType FindClosestPoint(const float x[3]);
  vtkIdType FindClosestPoint(float x, float y, float z);

  // Description:
  // Given a position x and a radius r, return the id of the point 
  // closest to the point in that radius.
  // These methods are thread safe if BuildLocator() is directly or
  // indirectly called from a single thread first. dist2 returns the squared
  // distance to the point.
  vtkIdType FindClosestPointWithinRadius(float radius, const float x[3],
                                         float& dist2);
  vtkIdType FindClosestPointWithinRadius(float radius, const float x[3], 
                                         float inputDataLength, float& dist2);

  // Description:
  // Initialize the point insertion process. The newPts is an object
  // representing point coordinates into which incremental insertion methods
  // place their data. Bounds are the box that the points lie in.
  // Not thread safe.
  virtual int InitPointInsertion(vtkPoints *newPts, const float bounds[6]);

  // Description:
  // Initialize the point insertion process. The newPts is an object
  // representing point coordinates into which incremental insertion methods
  // place their data. Bounds are the box that the points lie in.
  // Not thread safe.
  virtual int InitPointInsertion(vtkPoints *newPts, const float bounds[6], 
                                 vtkIdType estSize);

  // Description:
  // Incrementally insert a point into search structure with a particular
  // index value. You should use the method IsInsertedPoint() to see whether 
  // this point has already been inserted (that is, if you desire to prevent
  // duplicate points). Before using this method you must make sure that 
  // newPts have been supplied, the bounds has been set properly, and that 
  // divs are properly set. (See InitPointInsertion().)
  // Not thread safe.
  virtual void InsertPoint(vtkIdType ptId, const float x[3]);

  // Description:
  // Incrementally insert a point into search structure. The method returns
  // the insertion location (i.e., point id). You should use the method 
  // IsInsertedPoint() to see whether this point has already been
  // inserted (that is, if you desire to prevent duplicate points).
  // Before using this method you must make sure that newPts have been
  // supplied, the bounds has been set properly, and that divs are 
  // properly set. (See InitPointInsertion().)
  // Not thread safe.
  virtual vtkIdType InsertNextPoint(const float x[3]);

  // Description:
  // Determine whether point given by x[3] has been inserted into points list.
  // Return id of previously inserted point if this is true, otherwise return
  // -1. This method is thread safe.
  vtkIdType IsInsertedPoint(float x, float  y, float z)
    {
    float xyz[3];
    xyz[0] = x; xyz[1] = y; xyz[2] = z;
    return this->IsInsertedPoint (xyz);
    };
  virtual vtkIdType IsInsertedPoint(const float x[3]);

  // Description:
  // Determine whether point given by x[3] has been inserted into points list.
  // Return 0 if point was already in the list, otherwise return 1. If the
  // point was not in the list, it will be ADDED.  In either case, the id of
  // the point (newly inserted or not) is returned in the ptId argument.
  // Note this combines the functionality of IsInsertedPoint() followed
  // by a call to InsertNextPoint().
  // This method is not thread safe.
  virtual int InsertUniquePoint(const float x[3], vtkIdType &ptId);

  // Description:
  // Given a position x, return the id of the point closest to it. This method
  // is used when performing incremental point insertion. Note that -1 
  // indicates that no point was found.
  // This method is thread safe if  BuildLocator() is directly or
  // indirectly called from a single thread first.
  virtual vtkIdType FindClosestInsertedPoint(const float x[3]);

  // Description:
  // Find the closest N points to a position. This returns the closest
  // N points to a position. A faster method could be created that returned
  // N close points to a position, but necessarily the exact N closest.
  // The returned points are sorted from closest to farthest.
  // These methods are thread safe if BuildLocator() is directly or
  // indirectly called from a single thread first.
  virtual void FindClosestNPoints(int N, const float x[3], vtkIdList *result);
  virtual void FindClosestNPoints(int N, float x, float y, float z,
                                  vtkIdList *result);

  // Description:
  // Find the closest points to a position such that each octant of
  // space around the position contains at least N points. Loosely 
  // limit the search to a maximum number of points evaluated, M. 
  // These methods are thread safe if BuildLocator() is directly or
  // indirectly called from a single thread first.
  virtual void FindDistributedPoints(int N, const float x[3], 
                                     vtkIdList *result, int M);
  virtual void FindDistributedPoints(int N, float x, float y, 
                                     float z, vtkIdList *result, int M);

  // Description:
  // Find all points within a specified radius R of position x.
  // The result is not sorted in any specific manner.
  // These methods are thread safe if BuildLocator() is directly or
  // indirectly called from a single thread first.
  virtual void FindPointsWithinRadius(float R, const float x[3],
                                      vtkIdList *result);
  virtual void FindPointsWithinRadius(float R, float x, float y, float z, 
                                      vtkIdList *result);
  
  // Description:
  // Given a position x, return the list of points in the bucket that
  // contains the point. It is possible that NULL is returned. The user
  // provides an ijk array that is the indices into the locator.
  // This method is thread safe.
  virtual vtkIdList *GetPointsInBucket(const float x[3], int ijk[3]);

  // Description:
  // See vtkLocator interface documentation.
  // These methods are not thread safe.
  void Initialize();
  void FreeSearchStructure();
  void BuildLocator();
  void GenerateRepresentation(int level, vtkPolyData *pd);

protected:
  vtkPointLocator();
  ~vtkPointLocator();

  // place points in appropriate buckets
  void GetBucketNeighbors(vtkNeighborPoints* buckets,
                          const int ijk[3], const int ndivs[3], int level);
  void GetOverlappingBuckets(vtkNeighborPoints* buckets, 
                             const float x[3], const int ijk[3], float dist,
                             int level);
  void GetOverlappingBuckets(vtkNeighborPoints* buckets,
                             const float x[3], float dist,
                             int prevMinLevel[3],
                             int prevMaxLevel[3]);
  void GenerateFace(int face, int i, int j, int k, 
                    vtkPoints *pts, vtkCellArray *polys);
  float Distance2ToBucket(const float x[3], const int nei[3]);
  float Distance2ToBounds(const float x[3], const float bounds[6]);

  vtkPoints *Points; // Used for merging points
  int Divisions[3]; // Number of sub-divisions in x-y-z directions
  int NumberOfPointsPerBucket; //Used with previous boolean to control subdivide
  float Bounds[6]; // bounds of points
  vtkIdList **HashTable; // lists of point ids in buckets
  vtkIdType NumberOfBuckets; // total size of hash table
  float H[3]; // width of each bucket in x-y-z directions

  float InsertionTol2;
  vtkIdType InsertionPointId;

  float InsertionLevel; 
private:
  vtkPointLocator(const vtkPointLocator&);  // Not implemented.
  void operator=(const vtkPointLocator&);  // Not implemented.
};

#endif


