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vtkCellLocator Class Reference

octree-based spatial search object to quickly locate cells. More...

#include <vtkCellLocator.h>

Inheritance diagram for vtkCellLocator:

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List of all members.

Public Methods

virtual const char * GetClassName ()
virtual int IsA (const char *type)
void PrintSelf (ostream &os, vtkIndent indent)
virtual void SetNumberOfCellsPerBucket (int)
virtual int GetNumberOfCellsPerBucket ()
virtual void SetCacheCellBounds (int)
virtual int GetCacheCellBounds ()
virtual void CacheCellBoundsOn ()
virtual void CacheCellBoundsOff ()
virtual int IntersectWithLine (float a0[3], float a1[3], float tol, float &t, float x[3], float pcoords[3], int &subId)
virtual int IntersectWithLine (float a0[3], float a1[3], float tol, float &t, float x[3], float pcoords[3], int &subId, int &cellId)
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)
void FindClosestPoint (float x[3], float closestPoint[3], int &cellId, int &subId, float &dist2)
void FindClosestPoint (float x[3], float closestPoint[3], vtkGenericCell *cell, int &cellId, int &subId, float &dist2)
int FindClosestPointWithinRadius (float x[3], float radius, float closestPoint[3], int &cellId, int &subId, float &dist2)
int FindClosestPointWithinRadius (float x[3], float radius, float closestPoint[3], vtkGenericCell *cell, int &cellId, int &subId, float &dist2)
int FindClosestPointWithinRadius (float x[3], float radius, float closestPoint[3], vtkGenericCell *cell, int &cellId, int &subId, float &dist2, int &inside)
virtual vtkIdListGetCells (int bucket)
virtual int GetNumberOfBuckets (void)
void FreeSearchStructure ()
void BuildLocator ()
void GenerateRepresentation (int level, vtkPolyData *pd)

Static Public Methods

int IsTypeOf (const char *type)
vtkCellLocator * SafeDownCast (vtkObject *o)
vtkCellLocator * New ()

Protected Methods

 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])
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)

Protected Attributes

int NumberOfCellsPerBucket
int NumberOfOctants
float Bounds [6]
int NumberOfParents
float H [3]
int NumberOfDivisions
vtkIdList ** Tree
vtkNeighborCells * Buckets
unsigned char * CellHasBeenVisited
unsigned char QueryNumber
int CacheCellBounds
float(* CellBounds )[6]

Detailed Description

octree-based spatial search object to quickly locate cells.

Date:
2000/12/10 20:08:31
Revision:
1.48

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.

Warning:
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.
See also:
vtkLocator vtkPointLocator vtkOBBTree
Examples:
vtkCellLocator (examples)


Member Function Documentation

void vtkCellLocator::BuildLocator   [virtual]
 

Build the locator from the input dataset.

Implements vtkLocator.

Reimplemented in vtkOBBTree.

void vtkCellLocator::FindClosestPoint float    x[3],
float    closestPoint[3],
vtkGenericCell   cell,
int &    cellId,
int &    subId,
float &    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.

void vtkCellLocator::FindClosestPoint float    x[3],
float    closestPoint[3],
int &    cellId,
int &    subId,
float &    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.

int vtkCellLocator::FindClosestPointWithinRadius float    x[3],
float    radius,
float    closestPoint[3],
vtkGenericCell   cell,
int &    cellId,
int &    subId,
float &    dist2,
int &    inside
 

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 vtkCellLocator::FindClosestPointWithinRadius float    x[3],
float    radius,
float    closestPoint[3],
vtkGenericCell   cell,
int &    cellId,
int &    subId,
float &    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.

int vtkCellLocator::FindClosestPointWithinRadius float    x[3],
float    radius,
float    closestPoint[3],
int &    cellId,
int &    subId,
float &    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.

void vtkCellLocator::FreeSearchStructure   [virtual]
 

Satisfy vtkLocator abstract interface

Implements vtkLocator.

Reimplemented in vtkOBBTree.

void vtkCellLocator::GenerateRepresentation int    level,
vtkPolyData   pd
[virtual]
 

Method to build a representation at a particular level. Note that the method GetLevel() returns the maximum number of levels available for the tree. You must provide a vtkPolyData object into which to place the data.

Implements vtkLocator.

Reimplemented in vtkOBBTree.

virtual vtkIdList* vtkCellLocator::GetCells int    bucket [virtual]
 

Get the cells in a particular bucket.

virtual const char* vtkCellLocator::GetClassName   [virtual]
 

Return the class name as a string. This method is defined in all subclasses of vtkObject with the vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkLocator.

Reimplemented in vtkOBBTree.

virtual int vtkCellLocator::GetNumberOfBuckets void    [virtual]
 

Return number of buckets available : Ensure Locator has been built before attempting to access (octants)buckets

virtual int vtkCellLocator::IntersectWithLine float    a0[3],
float    a1[3],
float    tol,
float &    t,
float    x[3],
float    pcoords[3],
int &    subId,
int &    cellId,
vtkGenericCell   cell
[virtual]
 

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.

Reimplemented in vtkOBBTree.

virtual int vtkCellLocator::IntersectWithLine float    a0[3],
float    a1[3],
float    tol,
float &    t,
float    x[3],
float    pcoords[3],
int &    subId,
int &    cellId
[virtual]
 

Return intersection point (if any) AND the cell which was intersected by the finite line.

Reimplemented in vtkOBBTree.

virtual int vtkCellLocator::IntersectWithLine float    a0[3],
float    a1[3],
float    tol,
float &    t,
float    x[3],
float    pcoords[3],
int &    subId
[virtual]
 

Return intersection point (if any) of finite line with cells contained in cell locator.

Reimplemented in vtkOBBTree.

virtual int vtkCellLocator::IsA const char *    type [virtual]
 

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkLocator.

Reimplemented in vtkOBBTree.

int vtkCellLocator::IsTypeOf const char *    type [static]
 

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkLocator.

Reimplemented in vtkOBBTree.

vtkCellLocator* vtkCellLocator::New   [static]
 

Construct with automatic computation of divisions, averaging 25 cells per bucket.

Reimplemented from vtkObject.

Reimplemented in vtkOBBTree.

void vtkCellLocator::PrintSelf ostream &    os,
vtkIndent    indent
[virtual]
 

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkLocator.

vtkCellLocator* vtkCellLocator::SafeDownCast vtkObject   o [static]
 

Will cast the supplied object to vtkObject* is this is a safe operation (i.e., a safe downcast); otherwise NULL is returned. This method is defined in all subclasses of vtkObject with the vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkLocator.

Reimplemented in vtkOBBTree.

virtual void vtkCellLocator::SetCacheCellBounds int    [virtual]
 

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).

virtual void vtkCellLocator::SetNumberOfCellsPerBucket int    [virtual]
 

Specify the average number of cells in each octant.


The documentation for this class was generated from the following file:
Generated on Tue Mar 19 13:24:01 2002 for VTK by doxygen1.2.14 written by Dimitri van Heesch, © 1997-2002