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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkCellLocator.h,v $
  Language:  C++
  Date:      $Date: 2000/12/10 20:08:31 $
  Version:   $Revision: 1.48 $


Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
// .NAME vtkCellLocator - octree-based spatial search object to quickly locate cells
// .SECTION Description
// vtkCellLocator is a spatial search object to quickly locate cells in 3D.
// vtkCellLocator uses a uniform-level octree subdivision, where each octant
// (an octant is also referred to as a bucket) carries an indication of
// whether it is empty or not, and each leaf octant carries a list of the
// cells inside of it. (An octant is not empty if it has one or more cells
// inside of it.)  Typical operations are intersection with a line to return
// candidate cells, or intersection with another vtkCellLocator to return
// candidate cells.

// .SECTION Caveats
// Many other types of spatial locators have been developed, such as 
// variable depth octrees and kd-trees. These are often more efficient 
// for the operations described here. vtkCellLocator has been designed
// for subclassing; so these locators can be derived if necessary.

// .SECTION See Also
// vtkLocator vtkPointLocator vtkOBBTree

#ifndef __vtkCellLocator_h
#define __vtkCellLocator_h

#include "vtkLocator.h"

class vtkNeighborCells;

class VTK_EXPORT vtkCellLocator : public vtkLocator
{
public:
  vtkTypeMacro(vtkCellLocator,vtkLocator);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Construct with automatic computation of divisions, averaging
  // 25 cells per bucket.
  static vtkCellLocator *New();

  // Description:
  // Specify the average number of cells in each octant.
  vtkSetClampMacro(NumberOfCellsPerBucket,int,1,VTK_LARGE_INTEGER);
  vtkGetMacro(NumberOfCellsPerBucket,int);

  // Description:
  // 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 FindCl.oestPoint routines and the extra memory
  // won't cause disk caching (24 extra bytes per cell are required to
  // save the bounds).
  vtkSetMacro(CacheCellBounds,int);
  vtkGetMacro(CacheCellBounds,int);
  vtkBooleanMacro(CacheCellBounds,int);

  // Description:
  // Return intersection point (if any) of finite line with cells contained
  // in cell locator.
  virtual int IntersectWithLine(float a0[3], float a1[3], float tol,
				float& t, float x[3], float pcoords[3],
				int &subId);

  // Description:
  // Return intersection point (if any) AND the cell which was intersected by
  // the finite line.
  virtual int IntersectWithLine(float a0[3], float a1[3], float tol,
				float& t, float x[3], float pcoords[3],
				int &subId, int &cellId);

  // Description:
  // 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(float a0[3], float a1[3], float tol,
				float& t, float x[3], float pcoords[3],
				int &subId, int &cellId, vtkGenericCell *cell);

  // Description:
  // 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.
  void FindClosestPoint(float x[3], float closestPoint[3], int &cellId,
			int &subId, float& dist2);
  
  // Description:
  // 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.
  void FindClosestPoint(float x[3], float closestPoint[3],
			vtkGenericCell *cell, int &cellId, int &subId,
			float& dist2);
  
  // Description:
  // 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.
  int FindClosestPointWithinRadius(float x[3], float radius,
				   float closestPoint[3], int &cellId,
				   int &subId, float& dist2);
 
  // Description:
  // 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.
  int FindClosestPointWithinRadius(float x[3], float radius,
				   float closestPoint[3],
				   vtkGenericCell *cell, int &cellId,
				   int &subId, float& dist2);

  // Description:
  // 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).
  int FindClosestPointWithinRadius(float x[3], float radius,
				   float closestPoint[3],
				   vtkGenericCell *cell, int &cellId,
				   int &subId, float& dist2, int &inside);
  
  // Description:
  // Get the cells in a particular bucket.
  virtual vtkIdList *GetCells(int bucket);

  // Description:
  // Return number of buckets available : Ensure Locator has been built
  // before attempting to access (octants)buckets
  virtual int GetNumberOfBuckets(void);

  // Description:
  // Satisfy vtkLocator abstract interface
  void FreeSearchStructure();
  void BuildLocator();
  void GenerateRepresentation(int level, vtkPolyData *pd);
  
protected:
  vtkCellLocator();
  ~vtkCellLocator();
  vtkCellLocator(const vtkCellLocator&) {};
  void operator=(const vtkCellLocator&) {};

  void GetBucketNeighbors(int ijk[3], int ndivs, int level);
  void GetOverlappingBuckets(float x[3], int ijk[3], float dist, 
                             int prevMinLevel[3], int prevMaxLevel[3]);

  void ClearCellHasBeenVisited();
  void ClearCellHasBeenVisited(int id);

  float Distance2ToBucket(float x[3], int nei[3]);
  float Distance2ToBounds(float x[3], float bounds[6]);
  
  int NumberOfCellsPerBucket; // cells per octant
  int NumberOfOctants; // number of octants in tree
  float Bounds[6]; // bounding box root octant
  int NumberOfParents; // number of parent octants
  float H[3]; // width of leaf octant in x-y-z directions
  int NumberOfDivisions; // number of "leaf" octant sub-divisions
  vtkIdList **Tree; // octree

  void MarkParents(void*, int, int, int, int, int);
  void GetChildren(int idx, int level, int children[8]);
  int GenerateIndex(int offset, int numDivs, int i, int j, int k, int &idx);
  void GenerateFace(int face, int numDivs, int i, int j, int k,
                    vtkPoints *pts, vtkCellArray *polys);

  vtkNeighborCells *Buckets;
  unsigned char *CellHasBeenVisited;
  unsigned char QueryNumber;
  int CacheCellBounds;
//BTX - begin tcl exclude
  float (*CellBounds)[6];
//ETX - end tcl exclude
};

#endif