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vtkLocator Class Reference
abstract base class for objects that accelerate spatial searches.
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#include <vtkLocator.h>
Inheritance diagram for vtkLocator:
[legend]Collaboration diagram for vtkLocator:
[legend]List of all members.
Detailed Description
abstract base class for objects that accelerate spatial searches.
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Date:
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2000/12/10 20:08:12
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Revision:
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1.41
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.
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See also:
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vtkPointLocator vtkCellLocator vtkOBBTree vtkLocatorFilter
Definition at line 85 of file vtkLocator.h.
Constructor & Destructor Documentation
| vtkLocator::vtkLocator |
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[protected] |
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| vtkLocator::~vtkLocator |
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[protected] |
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| vtkLocator::vtkLocator |
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const vtkLocator & |
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[inline, protected] |
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Member Function Documentation
| virtual const char* vtkLocator::GetClassName |
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[virtual] |
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| int vtkLocator::IsTypeOf |
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const char * |
type |
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[static] |
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| virtual int vtkLocator::IsA |
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const char * |
type |
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[virtual] |
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| vtkLocator* vtkLocator::SafeDownCast |
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vtkObject * |
o |
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[static] |
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| void vtkLocator::PrintSelf |
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ostream & |
os, |
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vtkIndent |
indent |
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[virtual] |
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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, and vtkCellLocator. |
| virtual void vtkLocator::SetDataSet |
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vtkDataSet * |
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[virtual] |
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Build the locator from the points/cells defining this dataset. |
| virtual vtkDataSet* vtkLocator::GetDataSet |
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[virtual] |
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| virtual void vtkLocator::SetMaxLevel |
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int |
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[virtual] |
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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 |
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[virtual] |
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| virtual int vtkLocator::GetLevel |
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[virtual] |
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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 |
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int |
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[virtual] |
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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 |
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[virtual] |
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| virtual void vtkLocator::AutomaticOn |
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[virtual] |
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| virtual void vtkLocator::AutomaticOff |
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[virtual] |
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| virtual void vtkLocator::SetTolerance |
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float |
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[virtual] |
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Specify absolute tolerance (in world coordinates) for performing geometric operations. |
| virtual float vtkLocator::GetTolerance |
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[virtual] |
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| virtual void vtkLocator::SetRetainCellLists |
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int |
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[virtual] |
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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 |
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[virtual] |
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| virtual void vtkLocator::RetainCellListsOn |
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[virtual] |
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| virtual void vtkLocator::RetainCellListsOff |
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[virtual] |
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| virtual void vtkLocator::Update |
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[virtual] |
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Cause the locator to rebuild itself if it or its input dataset has changed. |
| virtual void vtkLocator::Initialize |
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[virtual] |
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| virtual void vtkLocator::BuildLocator |
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[pure virtual] |
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| virtual void vtkLocator::FreeSearchStructure |
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[pure virtual] |
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| virtual void vtkLocator::GenerateRepresentation |
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int |
level, |
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vtkPolyData * |
pd |
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[pure virtual] |
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| virtual unsigned long vtkLocator::GetBuildTime |
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[virtual] |
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Return the time of the last data structure build. |
| void vtkLocator::operator= |
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const vtkLocator & |
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[inline, protected] |
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Member Data Documentation
int vtkLocator::Automatic [protected]
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float vtkLocator::Tolerance [protected]
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int vtkLocator::MaxLevel [protected]
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int vtkLocator::Level [protected]
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int vtkLocator::RetainCellLists [protected]
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The documentation for this class was generated from the following file:
Generated on Wed Nov 21 12:52:46 2001 for VTK by
1.2.11.1 written by Dimitri van Heesch,
© 1997-2001