UGraph | Unreal Engine 5.5 Documentation | Epic Developer Community

API > API/Plugins > API/Plugins/GameplayGraph > API/Plugins/GameplayGraph/Graph

Inheritance Hierarchy

References


Module	GameplayGraph
Header	/Engine/Plugins/Experimental/GameplayGraph/Source/GameplayGraph/Public/Graph/Graph.h
Include	#include "Graph/Graph.h"

Syntax

UCLASS ()  
class UGraph : public UObject

Remarks

A UGraph is a collection of nodes and edges. This graph representation is meant to be easily integrable into gameplay systems in the Unreal Engine.

Conceptually, you can imagine that a graph is meant to easily represent relationships so we can answer queries such as:

Are these two nodes connected to each other?
How far away are these two nodes?
Who is the closest node that has XYZ?
etc.

UGraph provides an interface to be able to run such queries. However, ultimately what makes the graph useful is not only the relationships represented by the edges, but also the data that is stored on each node and each edge. Depending on what the user wants to represent, the user will have to subclass UGraphVertex and UGraphEdge to hold that data.

As the user adds nodes and edges into the graph, they will also be implicitly creating "islands" (i.e. a connected component in the graph). Each graph may have multiple islands. Users of the graph can disable the island detection/creation if needed.

Note that this is an UNDIRECTED GRAPH.

Variables

	Type	Name	Description
	FOnGraphEdgeCreated	OnEdgeCreated
	FOnGraphEdgeRemoved	OnEdgeRemoved
	FOnGraphIslandCreated	OnIslandCreated
	FOnGraphVertexCreated	OnVertexCreated

Constructors

	Type	Name	Description
		UGraph ()

Functions

Type	Name	Description
void	ChangeVertexHandle ( const FGraphVertexHandle& OldVertexHandle, const FGraphVertexHandle& NewVertexHandle )	Changes a node handle, updating all the references. The vertex must exist.
void	CreateBulkEdges ( TArray< FEdgeSpecifier >&& NodesToConnect )	Creates edges in bulk.
FGraphVertexHandle	CreateVertex ( FGraphUniqueIndex InUniqueIndex )	Create a node with the specified subclass, adds it to the graph, and returns a handle to it.
void	Empty ()
void	FinalizeVertex ( const FGraphVertexHandle& InHandle )	This should be called immediately after a node and any relevant edges have been added to the graph.
void	ForEachIsland ( TLambda&& Lambda )
FGraphVertexHandle	GetCompleteNodeHandle ( const FGraphVertexHandle& InHandle )	Given a node handle, find the handle in the current graph with a proper element set.
const TMap< FGraphIslandHandle, TObjectPtr< UGraphIsland > > &	GetIslands ()
const FGraphProperties &	GetProperties ()
UGraphIsland *	GetSafeIslandFromHandle ( const FGraphIslandHandle& Handle )
UGraphVertex *	GetSafeVertexFromHandle ( const FGraphVertexHandle& Handle )
const TMap< FGraphVertexHandle, TObjectPtr< UGraphVertex > > &	GetVertices ()
void	InitializeFromProperties ( const FGraphProperties& Properties )
void	MergeOrCreateIslands ( const TArray< FEdgeSpecifier >& InEdges )	When we add multiple edges into the graph.
int32	NumIslands ()
int32	NumVertices ()
void	RefreshIslandConnectivity ( const FGraphIslandHandle& IslandHandle )	Refresh the connectivity of the given island (re-check to see whether it should be split).
void	RemoveBulkVertices ( const TArray< FGraphVertexHandle >& InHandles )
void	RemoveIsland ( const FGraphIslandHandle& IslandHandle )	Remove an island from the graph.
void	RemoveOrSplitIsland ( TObjectPtr< UGraphIsland > Island )	After a change, this function will remove the island if it's empty or will attempt to split it into two smaller islands.
void	RemoveVertex ( const FGraphVertexHandle& NodeHandle )	Removes a node from the graph along with any edges that contain it.
void	ReserveIslands ( int32 Delta )
void	ReserveVertices ( int32 Delta )	Used for bulk loading in vertices/edges/islands.

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