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# vtkLocator Class Reference

`#include <vtkLocator.h>`

Inheritance diagram for vtkLocator:

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Collaboration diagram for vtkLocator:

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List of all members.

## Detailed Description

abstract base class for objects that accelerate spatial searches

Date:
  2003/01/06 20:36:14

Revision:
  1.49

vtkLocator is an abstract base class for spatial search objects, or locators. The principle behind locators is that they divide 3-space into small pieces (or "buckets") that can be quickly found in response to queries like point location, line intersection, or object-object intersection.

The purpose of this base class is to provide ivars and methods shared by all locators. The GenerateRepresentation() is one such interesting method. This method works in conjunction with vtkLocatorFilter to create polygonal representations for the locator. For example, if the locator is an OBB tree (i.e., vtkOBBTree.h), then the representation is a set of one or more oriented bounding boxes, depending upon the specified level.

Locators typically work as follows. One or more "entities", such as points or cells, are inserted into the tree. These entities are associated with one or more buckets. Then, when performing geometric operations, the operations are performed first on the buckets, and then if the operation tests positive, then on the entities in the bucket. For example, during collision tests, the locators are collided first to identify intersecting buckets. If an intersection is found, more expensive operations are then carried out on the entities in the bucket.

To obtain good performance, locators are often organized in a tree structure. In such a structure, there are frequently multiple "levels" corresponding to different nodes in the tree. So the word level (in the context of the locator) can be used to specify a particular representation in the tree. For example, in an octree (which is a tree with 8 children), level 0 is the bounding box, or root octant, and level 1 consists of its eight children.

See also:
  vtkPointLocator vtkCellLocator vtkOBBTree vtkLocatorFilter

Created by:
  - Schroeder, Will

CVS contributions (if > 5%):
  - Schroeder, Will (92%)

CVS logs (CVSweb):
  - .`cxx` (`/Common/vtkLocator.cxx)`
  - .`h` (`/Common/vtkLocator.h)`

Definition at line 74 of file vtkLocator.h.

## Public Types

typedef vtkObject | Superclass

## Public Methods

virtual const char * | GetClassName ()
virtual int | IsA (const char *type)
void | PrintSelf (ostream &os, vtkIndent indent)
virtual void | Update ()
virtual void | Initialize ()
virtual void | BuildLocator ()=0
virtual void | FreeSearchStructure ()=0
virtual void | GenerateRepresentation (int level, vtkPolyData *pd)=0
virtual void | SetDataSet (vtkDataSet *)
virtual vtkDataSet * | GetDataSet ()
virtual void | SetMaxLevel (int)
virtual int | GetMaxLevel ()
virtual int | GetLevel ()
virtual void | SetAutomatic (int)
virtual int | GetAutomatic ()
virtual void | AutomaticOn ()
virtual void | AutomaticOff ()
virtual void | SetTolerance (float)
virtual float | GetTolerance ()
virtual void | SetRetainCellLists (int)
virtual int | GetRetainCellLists ()
virtual void | RetainCellListsOn ()
virtual void | RetainCellListsOff ()
virtual unsigned long | GetBuildTime ()

## Static Public Methods

int | IsTypeOf (const char *type)
vtkLocator * | SafeDownCast (vtkObject *o)

## Protected Methods

| vtkLocator ()
| ~vtkLocator ()

## Protected Attributes

vtkDataSet * | DataSet
int | Automatic
float | Tolerance
int | MaxLevel
int | Level
int | RetainCellLists
vtkTimeStamp | BuildTime

## Member Typedef Documentation

typedef vtkObject vtkLocator::Superclass

| Reimplemented from vtkObject. Reimplemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, vtkMergePoints, vtkMergePoints2D, and vtkOBBTree. Definition at line 77 of file vtkLocator.h.

## Constructor & Destructor Documentation

vtkLocator::vtkLocator | ( |  | ) | `[protected]`

vtkLocator::~vtkLocator | ( |  | ) | `[protected]`

## Member Function Documentation

virtual const char* vtkLocator::GetClassName | ( |  | ) | `[virtual]`

| Reimplemented from vtkObject. Reimplemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, vtkMergePoints, vtkMergePoints2D, and vtkOBBTree.

int vtkLocator::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 vtkTypeRevisionMacro found in vtkSetGet.h. Reimplemented from vtkObject. Reimplemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, vtkMergePoints, vtkMergePoints2D, and vtkOBBTree.

virtual int vtkLocator::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 vtkTypeRevisionMacro found in vtkSetGet.h. Reimplemented from vtkObject. Reimplemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, vtkMergePoints, vtkMergePoints2D, and vtkOBBTree.

vtkLocator* vtkLocator::SafeDownCast | ( | vtkObject * | o | ) | `[static]`

| Reimplemented from vtkObject. Reimplemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, vtkMergePoints, vtkMergePoints2D, and vtkOBBTree.

void vtkLocator::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 vtkObject. Reimplemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, vtkMergePoints, and vtkMergePoints2D.

virtual void vtkLocator::SetDataSet | ( | vtkDataSet * |  | ) | `[virtual]`

| Build the locator from the points/cells defining this dataset.

virtual vtkDataSet* vtkLocator::GetDataSet | ( |  | ) | `[virtual]`

| Build the locator from the points/cells defining this dataset.

virtual void vtkLocator::SetMaxLevel | ( | int |  | ) | `[virtual]`

| Set the maximum allowable level for the tree. If the Automatic ivar is off, this will be the target depth of the locator.

virtual int vtkLocator::GetMaxLevel | ( |  | ) | `[virtual]`

| Set the maximum allowable level for the tree. If the Automatic ivar is off, this will be the target depth of the locator.

virtual int vtkLocator::GetLevel | ( |  | ) | `[virtual]`

| Get the level of the locator (determined automatically if Automatic is true). The value of this ivar may change each time the locator is built.

virtual void vtkLocator::SetAutomatic | ( | int |  | ) | `[virtual]`

| Boolean controls whether locator depth/resolution of locator is computed automatically from average number of entities in bucket. If not set, there will be an explicit method to control the construction of the locator (found in the subclass).

virtual int vtkLocator::GetAutomatic | ( |  | ) | `[virtual]`

| Boolean controls whether locator depth/resolution of locator is computed automatically from average number of entities in bucket. If not set, there will be an explicit method to control the construction of the locator (found in the subclass).

virtual void vtkLocator::AutomaticOn | ( |  | ) | `[virtual]`

| Boolean controls whether locator depth/resolution of locator is computed automatically from average number of entities in bucket. If not set, there will be an explicit method to control the construction of the locator (found in the subclass).

virtual void vtkLocator::AutomaticOff | ( |  | ) | `[virtual]`

| Boolean controls whether locator depth/resolution of locator is computed automatically from average number of entities in bucket. If not set, there will be an explicit method to control the construction of the locator (found in the subclass).

virtual void vtkLocator::SetTolerance | ( | float |  | ) | `[virtual]`

| Specify absolute tolerance (in world coordinates) for performing geometric operations.

virtual float vtkLocator::GetTolerance | ( |  | ) | `[virtual]`

| Specify absolute tolerance (in world coordinates) for performing geometric operations.

virtual void vtkLocator::SetRetainCellLists | ( | int |  | ) | `[virtual]`

| Boolean controls whether to maintain list of entities in each bucket. Normally the lists are maintained, but if the locator is being used as a geometry simplification technique, there is no need to keep them.

virtual int vtkLocator::GetRetainCellLists | ( |  | ) | `[virtual]`

| Boolean controls whether to maintain list of entities in each bucket. Normally the lists are maintained, but if the locator is being used as a geometry simplification technique, there is no need to keep them.

virtual void vtkLocator::RetainCellListsOn | ( |  | ) | `[virtual]`

| Boolean controls whether to maintain list of entities in each bucket. Normally the lists are maintained, but if the locator is being used as a geometry simplification technique, there is no need to keep them.

virtual void vtkLocator::RetainCellListsOff | ( |  | ) | `[virtual]`

| Boolean controls whether to maintain list of entities in each bucket. Normally the lists are maintained, but if the locator is being used as a geometry simplification technique, there is no need to keep them.

virtual void vtkLocator::Update | ( |  | ) | `[virtual]`

| Cause the locator to rebuild itself if it or its input dataset has changed.

virtual void vtkLocator::Initialize | ( |  | ) | `[virtual]`

| Initialize locator. Frees memory and resets object as appropriate. Reimplemented in vtkPointLocator, and vtkPointLocator2D.

virtual void vtkLocator::BuildLocator | ( |  | ) | `[pure virtual]`

| Build the locator from the input dataset. Implemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, and vtkOBBTree.

virtual void vtkLocator::FreeSearchStructure | ( |  | ) | `[pure virtual]`

| Free the memory required for the spatial data structure. Implemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, and vtkOBBTree.

virtual void vtkLocator::GenerateRepresentation | ( | int | level,
|  | vtkPolyData * | pd
| ) | `[pure 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. Implemented in vtkPointLocator, vtkPointLocator2D, vtkCellLocator, and vtkOBBTree.

virtual unsigned long vtkLocator::GetBuildTime | ( |  | ) | `[virtual]`

| Return the time of the last data structure build.

## Member Data Documentation

vtkDataSet* vtkLocator::DataSet`[protected]`

| Definition at line 155 of file vtkLocator.h.

int vtkLocator::Automatic`[protected]`

| Definition at line 156 of file vtkLocator.h.

float vtkLocator::Tolerance`[protected]`

| Definition at line 157 of file vtkLocator.h.

int vtkLocator::MaxLevel`[protected]`

| Definition at line 158 of file vtkLocator.h.

int vtkLocator::Level`[protected]`

| Definition at line 159 of file vtkLocator.h.

int vtkLocator::RetainCellLists`[protected]`

| Definition at line 160 of file vtkLocator.h.

vtkTimeStamp vtkLocator::BuildTime`[protected]`

| Definition at line 162 of file vtkLocator.h.

The documentation for this class was generated from the following file:

- Common/vtkLocator.h