Open CASCADE Technology  7.4.1.dev
BVH_BaseTraverse< MetricType > Class Template Reference

The classes implement the traverse of the BVH tree. More...

#include <BVH_Traverse.hxx>

Inheritance diagram for BVH_BaseTraverse< MetricType >:
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Public Member Functions

Metrics comparison for choosing the best branch
virtual Standard_Boolean IsMetricBetter (const MetricType &, const MetricType &) const
 Compares the two metrics and chooses the best one. Returns true if the first metric is better than the second, false otherwise. More...
 
Rejection of the node by metric
virtual Standard_Boolean RejectMetric (const MetricType &) const
 Rejects the node by the metric. More...
 
Condition to stop the descend
virtual Standard_Boolean Stop () const
 Returns the flag controlling the tree descend. Returns true if the tree descend should be stopped. More...
 

Protected Member Functions

Constructors
 BVH_BaseTraverse ()
 Constructor. More...
 
virtual ~BVH_BaseTraverse ()
 Destructor. More...
 

Detailed Description

template<class MetricType>
class BVH_BaseTraverse< MetricType >

The classes implement the traverse of the BVH tree.

There are two traverse methods implemented:

To perform Selection of the elements from BVH_Tree using the traverse methods implemented here it is required to define Acceptance/Rejection rules in the following methods:

The selector of a single tree has an extra method which allows accepting the whole branches without any further checks (e.g. full inclusion test):

Two ways of selection are possible:

  1. Set the BVH set containing the tree and use the method Select() which allows using common interface for setting the BVH Set for accessing the BVH tree and elements in the Accept method.
  2. Keep the BVHSetType void, do not set the BVH set and use the method Select (const BVH_Tree<>&) which allows performing selection on the arbitrary BVH tree.

Here is the example of usage of the traverse to find the point-triangulation minimal distance.

// Structure to contain points of the triangle
struct Triangle
{
Triangle() {}
Triangle(const BVH_Vec3d& theNode1,
const BVH_Vec3d& theNode2,
const BVH_Vec3d& theNode3)
: Node1 (theNode1), Node2 (theNode2), Node3 (theNode3)
{}
BVH_Vec3d Node1;
BVH_Vec3d Node2;
BVH_Vec3d Node3;
};
// Selector for min point-triangulation distance
class BVH_PointTriangulationSqDist :
public BVH_Distance<Standard_Real, 3, BVH_Vec3d, BVH_BoxSet<Standard_Real, 3, Triangle>>
{
public:
// Computes the distance from the point to bounding box
virtual Standard_Boolean RejectNode (const BVH_Vec3d& theCMin,
const BVH_Vec3d& theCMax,
Standard_Real& theDistance) const Standard_OVERRIDE
{
theDistance = BVH_Tools<Standard_Real, 3>::PointBoxSquareDistance (myObject, theCMin, theCMax);
return RejectMetric (theDistance);
}
// Computes the distance from the point to triangle
virtual Standard_Boolean Accept (const Standard_Integer theIndex,
{
const Triangle& aTri = myBVHSet->Element (theIndex);
Standard_Real aDist = BVH_Tools<Standard_Real, 3>::PointTriangleSquareDistance (myObject, aTri.Node1, aTri.Node2, aTri.Node3);
if (aDist < myDistance)
{
myDistance = aDist;
return Standard_True;
}
}
};
// Point to which the distance is required
BVH_Vec3d aPoint = ...;
// BVH Set containing triangulation
BVH_PointTriangulationSqDist aDistTool;
aDistTool.SetObject (aPoint);
aDistTool.SetBVHSet (aTriangulationSet.get());
aDistTool.ComputeDistance();
if (aDistTool.IsDone())
{
Standard_Real aPointTriSqDist = aDistTool.Distance();
}

Abstract class implementing the base Traverse interface required for selection of the elements from BVH tree.

Template Parameters
MetricTypeType of metric to perform more optimal tree descend

Constructor & Destructor Documentation

◆ BVH_BaseTraverse()

template<class MetricType>
BVH_BaseTraverse< MetricType >::BVH_BaseTraverse ( )
inlineprotected

Constructor.

◆ ~BVH_BaseTraverse()

template<class MetricType>
virtual BVH_BaseTraverse< MetricType >::~BVH_BaseTraverse ( )
inlineprotectedvirtual

Destructor.

Member Function Documentation

◆ IsMetricBetter()

template<class MetricType>
virtual Standard_Boolean BVH_BaseTraverse< MetricType >::IsMetricBetter ( const MetricType &  ,
const MetricType &   
) const
inlinevirtual

Compares the two metrics and chooses the best one. Returns true if the first metric is better than the second, false otherwise.

Reimplemented in BVH_Distance< NumType, Dimension, ObjectType, BVHSetType >, and BVH_PairDistance< NumType, Dimension, BVHSetType >.

◆ RejectMetric()

template<class MetricType>
virtual Standard_Boolean BVH_BaseTraverse< MetricType >::RejectMetric ( const MetricType &  ) const
inlinevirtual

◆ Stop()

template<class MetricType>
virtual Standard_Boolean BVH_BaseTraverse< MetricType >::Stop ( ) const
inlinevirtual

Returns the flag controlling the tree descend. Returns true if the tree descend should be stopped.

Reimplemented in BVH_PairDistance< NumType, Dimension, BVHSetType >, and BVH_Distance< NumType, Dimension, ObjectType, BVHSetType >.


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