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  3. TPointHashGrid2

TPointHashGrid2

Hash Grid for values associated with 2D points.

API > API/Runtime > API/Runtime/GeometryCore

Hash Grid for values associated with 2D points.

This class addresses the situation where you have a list of (point, point_data) and you would like to be able to do efficient proximity queries, i.e. find the nearest point_data for a given query point.

We don't store copies of the 2D points. You provide a point_data type. This could just be the integer index into your list for example, a pointer to something more complex, etc. Insert and Remove functions require you to pass in the 2D point for the point_data. To Update a point you need to know its old and new 2D coordinates.

   
Name TPointHashGrid2
Type class
Header File /Engine/Source/Runtime/GeometryCore/Public/Spatial/PointHashGrid2.h
Include Path #include "Spatial/PointHashGrid2.h"

Syntax

template<typename PointDataType, typename RealType>  
class TPointHashGrid2

Constructors

Name Remarks Include Path Unreal Specifiers

TPointHashGrid2 ( RealType cellSize,
PointDataType InvalidValue
)

 Construct 2D hash grid Spatial/PointHashGrid2.h  

Variables

Protected

Name Type Remarks Include Path Unreal Specifiers
CriticalSection FCriticalSection   Spatial/PointHashGrid2.h  
Hash TMultiMap< FVector2i, PointDataType >   Spatial/PointHashGrid2.h  
Indexer TScaleGridIndexer2< RealType >   Spatial/PointHashGrid2.h  
InvalidValue PointDataType   Spatial/PointHashGrid2.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

TPair< PointDataType, RealType > FindNearestInRadius ( const TVector2< RealType >& QueryPoint,
RealType Radius,
TFunctionRef< RealType(const PointDataType&)> DistanceSqFunc,
TFunctionRef< bool(const PointDataType&)> IgnoreFunc
) const

 Find nearest point in grid, within a given sphere, without locking / thread-safety. Spatial/PointHashGrid2.h  

PointDataType GetInvalidValue()

 Invalid grid value Spatial/PointHashGrid2.h  

void InsertPoint ( const PointDataType& Value,
const TVector2< RealType >& Position
)

 Insert at given position. This function is thread-safe. Spatial/PointHashGrid2.h  

void InsertPointUnsafe ( const PointDataType& Value,
const TVector2< RealType >& Position
)

 Insert at given position, without locking / thread-safety Spatial/PointHashGrid2.h  

bool RemovePoint ( const PointDataType& Value,
const TVector2< RealType >& Position
)

 Remove at given position. This function is thread-safe. Spatial/PointHashGrid2.h  

bool RemovePointUnsafe ( const PointDataType& Value,
const TVector2< RealType >& Position
)

 Remove at given position, without locking / thread-safety Spatial/PointHashGrid2.h  

void Reserve ( int32 Num
)

 Reserve space in the underlying hash map Spatial/PointHashGrid2.h  

void UpdatePoint ( const PointDataType& Value,
const TVector2< RealType >& OldPosition,
const TVector2< RealType >& NewPosition
)

 Move value from old to new position. This function is thread-safe. Spatial/PointHashGrid2.h  

void UpdatePointUnsafe ( const PointDataType& Value,
const TVector2< RealType >& OldPosition,
const TVector2< RealType >& NewPosition
)

 Move value from old to new position, without locking / thread-safety Spatial/PointHashGrid2.h  

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