UE::Geometry::TPointHashGrid2< PointDataType, RealType > Class Template Reference

#include <PointHashGrid2.h>

Public Member Functions
	TPointHashGrid2 (RealType cellSize, PointDataType InvalidValue)
void	Reserve (int32 Num)
PointDataType	GetInvalidValue () const
void	InsertPoint (const PointDataType &Value, const TVector2< RealType > &Position)
void	InsertPointUnsafe (const PointDataType &Value, const TVector2< RealType > &Position)
bool	RemovePoint (const PointDataType &Value, const TVector2< RealType > &Position)
bool	RemovePointUnsafe (const PointDataType &Value, const TVector2< RealType > &Position)
void	UpdatePoint (const PointDataType &Value, const TVector2< RealType > &OldPosition, const TVector2< RealType > &NewPosition)
void	UpdatePointUnsafe (const PointDataType &Value, const TVector2< RealType > &OldPosition, const TVector2< RealType > &NewPosition)
TPair< PointDataType, RealType >	FindNearestInRadius (const TVector2< RealType > &QueryPoint, RealType Radius, TFunctionRef< RealType(const PointDataType &)> DistanceSqFunc, TFunctionRef< bool(const PointDataType &)> IgnoreFunc=[](const PointDataType &data) { return false;}) const

Detailed Description

template<typename PointDataType, typename RealType>
class UE::Geometry::TPointHashGrid2< PointDataType, RealType >

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.

Constructor & Destructor Documentation

TPointHashGrid2()

template<typename PointDataType , typename RealType >

UE::Geometry::TPointHashGrid2< PointDataType, RealType >::TPointHashGrid2 ( RealType  cellSize, PointDataType  InvalidValue  )

inline

Construct 2D hash grid

Parameters

cellSize	size of grid cells
InvalidValue	this value will be returned by queries if no valid result is found (e.g. bounded-distance query)

Member Function Documentation

FindNearestInRadius()

template<typename PointDataType , typename RealType >

TPair< PointDataType, RealType > UE::Geometry::TPointHashGrid2< PointDataType, RealType >::FindNearestInRadius ( const TVector2< RealType > &  QueryPoint, RealType  Radius, TFunctionRef< RealType(const PointDataType &)>  DistanceSqFunc, TFunctionRef< bool(const PointDataType &)>  IgnoreFunc = [](const PointDataType& data) { return false; }  ) const

inline

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

Parameters

QueryPoint	the center of the query sphere
Radius	the radius of the query sphere
DistanceFunc	Function you provide which measures the distance between QueryPoint and a Value
IgnoreFunc	optional Function you may provide which will result in a Value being ignored if IgnoreFunc(Value) returns true

Returns

the found pair (Value,DistanceFunc(Value)), or (InvalidValue,MaxDouble) if not found

GetInvalidValue()

template<typename PointDataType , typename RealType >

PointDataType UE::Geometry::TPointHashGrid2< PointDataType, RealType >::GetInvalidValue ( ) const

inline

Invalid grid value

InsertPoint()

template<typename PointDataType , typename RealType >

void UE::Geometry::TPointHashGrid2< PointDataType, RealType >::InsertPoint ( const PointDataType &  Value, const TVector2< RealType > &  Position  )

inline

Insert at given position. This function is thread-safe.

Parameters

Value	the point/value to insert
Position	the position associated with this value

InsertPointUnsafe()

template<typename PointDataType , typename RealType >

void UE::Geometry::TPointHashGrid2< PointDataType, RealType >::InsertPointUnsafe ( const PointDataType &  Value, const TVector2< RealType > &  Position  )

inline

Insert at given position, without locking / thread-safety

Parameters

Value	the point/value to insert
Position	the position associated with this value

RemovePoint()

template<typename PointDataType , typename RealType >

bool UE::Geometry::TPointHashGrid2< PointDataType, RealType >::RemovePoint ( const PointDataType &  Value, const TVector2< RealType > &  Position  )

inline

Remove at given position. This function is thread-safe.

Parameters

Value	the point/value to remove
Position	the position associated with this value

Returns

true if the value existed at this position

RemovePointUnsafe()

template<typename PointDataType , typename RealType >

bool UE::Geometry::TPointHashGrid2< PointDataType, RealType >::RemovePointUnsafe ( const PointDataType &  Value, const TVector2< RealType > &  Position  )

inline

Remove at given position, without locking / thread-safety

Parameters

Value	the point/value to remove
Position	the position associated with this value

Returns

true if the value existed at this position

Reserve()

template<typename PointDataType , typename RealType >

void UE::Geometry::TPointHashGrid2< PointDataType, RealType >::Reserve ( int32  Num )

inline

Reserve space in the underlying hash map

Parameters

Num	amount of elements to reserve

UpdatePoint()

template<typename PointDataType , typename RealType >

void UE::Geometry::TPointHashGrid2< PointDataType, RealType >::UpdatePoint ( const PointDataType &  Value, const TVector2< RealType > &  OldPosition, const TVector2< RealType > &  NewPosition  )

inline

Move value from old to new position. This function is thread-safe.

Parameters

Value	the point/value to update
OldPosition	the current position associated with this value
NewPosition	the new position for this value

UpdatePointUnsafe()

template<typename PointDataType , typename RealType >

void UE::Geometry::TPointHashGrid2< PointDataType, RealType >::UpdatePointUnsafe ( const PointDataType &  Value, const TVector2< RealType > &  OldPosition, const TVector2< RealType > &  NewPosition  )

inline

Move value from old to new position, without locking / thread-safety

Parameters

Value	the point/value to update
OldPosition	the current position associated with this value
NewPosition	the new position for this value

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

• Engine/Source/Runtime/GeometryCore/Public/Spatial/PointHashGrid2.h