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> Unreal Engine API Reference > Runtime > AIModule > FGraphAStar

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FGraphAStar

Generic graph A* implementation

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References

Module	AIModule
Header	/Engine/Source/Runtime/AIModule/Public/GraphAStar.h
Include	#include "GraphAStar.h"

Syntax

template<typename TGraph, typename Policy, typename TSearchNode>
struct FGraphAStar

Remarks

Generic graph A* implementation

TGraph holds graph representation. Needs to implement functions: int32 GetNeighbourCount(FNodeRef NodeRef) const; - returns number of neighbours that the graph node identified with NodeRef has bool IsValidRef(FNodeRef NodeRef) const; - returns whether given node identyfication is correct FNodeRef GetNeighbour(const FNodeRef NodeRef, const int32 NeighbourIndex) const; - returns neighbour ref

it also needs to specify node type FNodeRef - type used as identification of nodes in the graph

TQueryFilter (FindPath's parameter) filter class is what decides which graph edges can be used and at what cost. It needs to implement following functions: float GetHeuristicScale() const; - used as GetHeuristicCost's multiplier float GetHeuristicCost(const FNodeRef StartNodeRef, const FNodeRef EndNodeRef) const; - estimate of cost from StartNodeRef to EndNodeRef float GetTraversalCost(const FNodeRef StartNodeRef, const FNodeRef EndNodeRef) const; - real cost of traveling from StartNodeRef directly to EndNodeRef bool IsTraversalAllowed(const FNodeRef NodeA, const FNodeRef NodeB) const; - whether traversing given edge is allowed bool WantsPartialSolution() const; - whether to accept solutions that do not reach the goal

Variables

		Name	Description
	const TGraph &	Graph
	FNodePool	NodePool
	FNodeSorter	NodeSorter
	FOpenList	OpenList

Constructors

	Name	Description
	FGraphAStar ( const TGraph& InGraph )

Functions

	Name	Description
EGraphAStarR...	FindPath ( const FGraphNodeRef StartNodeRef, const FGraphNodeRef EndNodeRef, const TQueryFilter& Filter, TArray< FGraphNodeRef >& OutPath )	Performs the actual search.
EGraphAStarR...	FloodFrom ( const FGraphNodeRef StartNodeRef, const TQueryFilter& Filter )	Floods node pool until running out of either free nodes or open set
bool	ProcessSingleNode ( const FGraphNodeRef EndNodeRef, const bool bIsBound, const TQueryFilter& Filter, int32& OutBestNodeIndex, float& OutBestNodeCost )	Single run of A* loop: get node from open set and process neighbors returns true if loop should be continued

Classes

	Name	Description
	FNodePool
	FNodeSorter
	FOpenList

Typedefs

Name	Description
FGraphNodeRef
FSearchNode

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