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  3. TPointHashGrid3

TPointHashGrid3

Hash Grid for values associated with 3D points.

API > API/Runtime > API/Runtime/GeometryCore

Hash Grid for values associated with 3D 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 3D 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 3D point for the point_data. To Update a point you need to know its old and new 3D coordinates.

   
Name TPointHashGrid3
Type class
Header File /Engine/Source/Runtime/GeometryCore/Public/Spatial/PointHashGrid3.h
Include Path #include "Spatial/PointHashGrid3.h"

Syntax

template<typename PointDataType, typename RealType>  
class TPointHashGrid3

Constructors

Name Remarks Include Path Unreal Specifiers

TPointHashGrid3 ( RealType CellSize,
PointDataType InvalidValue
)

 Construct 3D hash grid Spatial/PointHashGrid3.h  

Variables

Protected

Name Type Remarks Include Path Unreal Specifiers
Hash TMultiMap< FVector3i, PointDataType >   Spatial/PointHashGrid3.h  
Indexer TWrapAroundGridIndexer3< RealType >   Spatial/PointHashGrid3.h  
InvalidValue PointDataType   Spatial/PointHashGrid3.h  
Mutex FTransactionallySafeMutex   Spatial/PointHashGrid3.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

void EnumeratePointsInBall ( const TVector< RealType >& QueryPoint,
RealType Radius,
TFunctionRef< RealType(const PointDataType&)> DistanceSqFunc,
TFunctionRef< bool(PointDataType, double)> ProcessPointFunc,
TFunctionRef< bool(const PointDataType&)> IgnoreFunc
) const

 Call ProcessPointFunc on all points in grid within a given sphere, or until the function returns false Note: Not thread-safe to update, remove or insert points during enumeration. Spatial/PointHashGrid3.h  

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

 Find any point within radius. Spatial/PointHashGrid3.h  

TPair< PointDataType, RealType > FindAnyInRadius ( const TVector< RealType >& QueryPoint,
RealType Radius,
TFunctionRef< RealType(const PointDataType&)> DistanceSqFunc
) const

   Spatial/PointHashGrid3.h  

TPair< PointDataType, RealType > FindNearestInRadius ( const TVector< RealType >& QueryPoint,
RealType Radius,
TFunctionRef< RealType(const PointDataType&)> DistanceSqFunc
) const

   Spatial/PointHashGrid3.h  

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

 Find nearest point within radius. Spatial/PointHashGrid3.h  

int FindPointsInBall ( const TVector< RealType >& QueryPoint,
RealType Radius,
TFunctionRef< RealType(const PointDataType&)> DistanceSqFunc,
TArray< PointDataType >& ResultsOut,
TFunctionRef< bool(const PointDataType&)> IgnoreFunc
) const

 Find all points in grid within a given sphere. Spatial/PointHashGrid3.h  

PointDataType GetInvalidValue()

 Invalid grid value Spatial/PointHashGrid3.h  

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

 Insert at given position. This function is thread-safe. Spatial/PointHashGrid3.h  

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

 Insert at given position, without locking / thread-safety Spatial/PointHashGrid3.h  

bool IsCellEmpty ( const TVector< RealType >& Position
)

 Test if the cell containing Position is empty. Spatial/PointHashGrid3.h  

bool IsCellEmptyUnsafe ( const TVector< RealType >& Position
)

 Test if the whole cell containing Position is empty, without locking / thread-safety Can be used to skip a more expensive range search, in some cases. Spatial/PointHashGrid3.h  

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

 Remove at given position. This function is thread-safe. Spatial/PointHashGrid3.h  

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

 Remove at given position, without locking / thread-safety Spatial/PointHashGrid3.h  

void Reserve ( int32 Num
)

 Reserve space in the underlying hash map Spatial/PointHashGrid3.h  

void Reset ( RealType NewCellSize
)

 Remove all entries in the underlying hash map, without resizing or releasing any allocations, and reset the cell size. Spatial/PointHashGrid3.h  

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

 Move value from old to new position. This function is thread-safe. Spatial/PointHashGrid3.h  

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

 Move value from old to new position, without locking / thread-safety Spatial/PointHashGrid3.h  

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