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> Unreal Engine API Reference > Runtime > AIModule > BehaviorTree > UBehaviorTreeComponent

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UBehaviorTreeComponent

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Inheritance Hierarchy

UObjectBase

UObjectBaseUtility

UObject

UActorComponent

UBrainComponent

UBehaviorTreeComponent

References

Module	AIModule
Header	/Engine/Source/Runtime/AIModule/Classes/BehaviorTree/BehaviorTreeComponent.h
Include	#include "BehaviorTree/BehaviorTreeComponent.h"

Syntax

class UBehaviorTreeComponent : public UBrainComponent

Variables

	Name	Description
float	AccumulatedTickDeltaTime	Accumulated DeltaTime if ticked more than predicted next delta time
uint16	ActiveInstanceIdx	Index of last active instance on stack
uint8: 1	bBranchDeactivationSuspended	If set, all branch deactivation requests will be queued up
uint8: 1	bDeferredStopTree	If set, StopTree will be called at the end of tick
uint8: 1	bIsPaused	If set, execution requests will be postponed
uint8: 1	bIsRunning	If set, tree execution is allowed
uint8: 1	bLoopExecution	Loops tree execution
uint8: 1	bRequestedFlowUpdate	Set when execution update is scheduled for next tick
uint8: 1	bRequestedStop	Set when tree stop was called
bool	bTickedOnce	Used to tell tickmanager that we want interval ticking
uint8: 1	bWaitingForLatentAborts	Set when execution is waiting for tasks to finish their latent abort (current or parallel's main)
TMap< FGameplay...	CooldownTagsMap	Behavior cooldowns mapped by tag to last time it was set
TArray< TArray<...	CurrentRestarts
TArray< TArray<...	CurrentSearchFlow	Search flow for debugger
TArray< FBehavi...	DebuggerSteps	Debugger's recorded data
TObjectPtr< UBe...	DefaultBehaviorTreeAsset	Data asset defining the tree
FBTNodeExecutio...	ExecutionRequest	Execution request, search will be performed when current task finish execution/aborting
friend	FBehaviorTreeDebugger
friend	FBehaviorTreeInstance
friend	FScopedBehaviorTreeLock
TArray< FBehavi...	InstanceStack	Stack of behavior tree instances
TArray< FBehavi...	KnownInstances	List of known subtree instances
float	LastRequestedDeltaTimeGameTime	GameTime of the last DeltaTime request, used for debugging to output warnings about ticking
float	NextTickDeltaTime	Predicted next DeltaTime
TArray< TObject...	NodeInstances	Instanced nodes
TArray< const U...	PendingBranchesToDeactivate	List of all pending branch deactivation requests
FBTPendingExecu...	PendingExecution	Result of ExecutionRequest, will be applied when current task finish aborting
TArray< FBehavi...	RemovedInstances
FBehaviorTreeSe...	SearchData	Search data being currently used
TMap< FName, FS...	SearchStartBlackboard
uint8	StopTreeLock	If set, StopTree calls will be deferred
TMultiMap< FBTN...	TaskMessageObservers	Message observers mapped by instance & execution index
FBTTreeStartInf...	TreeStartInfo	Stored data for starting new tree, waits until previously running finishes aborting
friend	UBTCompositeNode
friend	UBTNode
friend	UBTTask_RunBehavior
friend	UBTTask_RunBehaviorDynamic
friend	UBTTaskNode

Constructors

	Name	Description
	UBehaviorTreeComponent ( const FObjectInitializer& ObjectIn... )
	UBehaviorTreeComponent ( FVTableHelper& Helper )	DO NOT USE. This constructor is for internal usage only for hot-reload purposes.

Functions

	Name	Description
void	AbortCurrentTask()	Abort currently executed task
void	AddCooldownTagDuration ( FGameplayTag CooldownTag, float CooldownDuration, bool bAddToExistingDuration )	Add to the cooldown tag's duration
void	ApplyDiscardedSearch()	Apply pending node updates required for discarded search
void	ApplySearchData ( UBTNode* NewActiveNode )	Apply pending node updates from SearchData
void	ApplySearchUpdates ( const TArray< FBehaviorTreeSearchUp..., int32 NewNodeExecutionIndex, bool bPostUpdate )	Apply updates from specific list
EBTNodeRelat...	CalculateRelativePriority ( const UBTNode* NodeA, const UBTNode* NodeB )	Return NodeA's relative priority in regards to NodeB
void	CopyInstanceMemoryFromPersistent()	Copy memory block from persistent memory to running instances (rollback)
void	CopyInstanceMemoryToPersistent()	Copy memory block from running instances to persistent memory
void	DeactivateBranch ( const UBTDecorator& RequestedBy )	Deactivate a branch as the decorator condition is not passing anymore
bool	DeactivateUpTo ( UBTCompositeNode* Node, uint16 NodeInstanceIdx, EBTNodeResult::Type& NodeResult, int32& OutLastDeactivatedChildInde... )	Deactivate all nodes up to requested one
FString	DescribeActiveTasks()
FString	DescribeActiveTrees()
void	EndFrame()	Code for timing BT Search for FramePro.
void	ExecuteTask ( UBTTaskNode* TaskNode )	Execute new task
int32	FindInstanceContainingNode ( const UBTNode* Node )	Tries to find behavior tree instance in context
UBTTaskNode ...	FindNextTask ( UBTCompositeNode* ParentNode, uint16 ParentInstanceIdx, EBTNodeResult::Type LastResult )	Find next task to execute
UBTNode *...	FindTemplateNode ( const UBTNode* Node )	Tries to find template node for given instanced node
uint16	GetActiveInstanceIdx()	Get index of active instance on stack
const UBTNod...	GetActiveNode()
UBehaviorTre...	GetCurrentTree()
uint8 *	GetNodeMemory ( UBTNode* Node, int32 InstanceIdx )
UBehaviorTre...	GetRootTree()
float	GetTagCooldownEndTime ( FGameplayTag CooldownTag )
EBTTaskStatu...	GetTaskStatus ( const UBTTaskNode* TaskNode )
bool	HasActiveLatentAborts()	Return true if the current or any parallel task has a latent abort in progress
bool	IsAbortPending()
bool	IsAuxNodeActive ( const UBTAuxiliaryNode* AuxNod..., int32 InstanceIdx )
bool	IsAuxNodeActive ( const UBTAuxiliaryNode* AuxNod... )
bool	IsDebuggerActive()	Check if debugger is currently running and can gather data
bool	IsExecutingBranch ( const UBTNode* Node, int32 ChildIndex )
bool	IsInstanceStackEmpty()	Returns true if InstanceStack contains any BT runtime instances
bool	IsRestartPending()
void	OnTaskFinished ( const UBTTaskNode* TaskNode, EBTNodeResult::Type TaskResult )	Finish latent execution or abort
void	OnTreeFinished()	Called when tree runs out of nodes to execute
void	ProcessExecutionRequest()	Process execution flow
void	ProcessPendingExecution()	Apply pending execution from last task search
void	ProcessPendingInitialize()	Apply pending tree initialization
bool	PushInstance ( UBehaviorTree& TreeAsset )	Push behavior tree instance on execution stack : should never be called out-side of BT execution, meaning only BT tasks can push another BT instance!
void	RegisterMessageObserver ( const UBTTaskNode* TaskNode, FName MessageType, FAIRequestID MessageID )	Setup message observer for given task
void	RegisterMessageObserver ( const UBTTaskNode* TaskNode, FName MessageType )	Setup message observer for given task
void	RegisterParallelTask ( const UBTTaskNode* TaskNode )	Add active parallel task
void	RemoveAllInstances()	Remove instanced nodes, known subtree instances and safely clears their persistent memory
void	RequestBranchDeactivation ( const UBTDecorator& RequestedBy )	Request branch deactivation: helper for decorator
void	RequestExecution ( const UBTDecorator* RequestedB... )	Request execution change: helpers for decorator nodes
void	RequestExecution ( EBTNodeResult::Type ContinueWithRes... )	Request execution change: helpers for task nodes
void	RequestExecution ( UBTCompositeNode* RequestedOn, int32 InstanceIdx, const UBTNode* RequestedBy, int32 RequestedByChildIndex, EBTNodeResult::Type ContinueWithRes..., bool bStoreForDebugger )	Request execution change
void	RestartTree()	Restarts execution from root
void	ResumeBranchDeactivation()	Resume branch deactivation and execute all the queued up ones
void	RollbackSearchChanges()	Restore state of tree to state before search
void	ScheduleExecutionUpdate()	Schedule execution flow update in next tick
void	ScheduleNextTick ( float NextDeltaTime )	END UActorComponent overrides Schedule when will be the next tick, 0.0f means next frame, FLT_MAX means never
void	SetDynamicSubtree ( FGameplayTag InjectTag, UBehaviorTree* BehaviorAsset )	Assign subtree to RunBehaviorDynamic task specified by tag
void	StartTree ( UBehaviorTree& Asset, EBTExecutionMode::Type ExecuteMode )	Starts execution from root
void	StopTree ( EBTStopMode::Type StopMode )	Stops execution
void	StoreDebuggerBlackboard ( TMap< FName, FString >& Blackboard... )	Describe blackboard's key values
void	StoreDebuggerExecutionStep ( EBTExecutionSnap::Type SnapType )	Make a snapshot for debugger
void	StoreDebuggerInstance ( FBehaviorTreeDebuggerInstance& Ins..., uint16 InstanceIdx, EBTExecutionSnap::Type SnapType )	Make a snapshot for debugger from given subtree instance
void	StoreDebuggerRemovedInstance ( uint16 InstanceIdx )
void	StoreDebuggerRestart ( const UBTNode* Node, uint16 InstanceIdx, bool bAllowed )	Store restarting node for debugger
void	StoreDebuggerRuntimeValues ( TArray< FString >& RuntimeDescript..., UBTNode* RootNode, uint16 InstanceIdx )	Gather nodes runtime descriptions
void	StoreDebuggerSearchStep ( const UBTNode* Node, uint16 InstanceIdx, EBTNodeResult::Type NodeResult )	Store search step for debugger
void	StoreDebuggerSearchStep ( const UBTNode* Node, uint16 InstanceIdx, bool bPassed )	Store search step for debugger
void	SuspendBranchDeactivation()	Suspend any branch deactivation and queue them to be processed later by ResumeBranchDeactivation()
void	TrackNewLatentAborts()	Tracks if there are new tasks using latent abort in progress
bool	TrackPendingLatentAborts()	Returns true if execution was waiting on latent aborts and they are all finished;
bool	TreeHasBeenStarted()	Indicates instance has been initialized to work with specific BT asset
void	UnregisterAuxNodesInBranch ( const UBTCompositeNode* Node, bool bApplyImmediately )	Unregister all aux nodes in branch of tree
void	UnregisterAuxNodesInRange ( const FBTNodeIndex& FromIndex, const FBTNodeIndex& ToIndex )	Unregister all aux nodes between given execution index range: FromIndex < AuxIndex < ToIndex
void	UnregisterAuxNodesUpTo ( const FBTNodeIndex& Index )	Unregister all aux nodes less important than given index
void	UnregisterMessageObserversFrom ( const UBTTaskNode* TaskNode )	Remove message observers registered with task
void	UnregisterMessageObserversFrom ( const FBTNodeIndex& TaskIdx )	Remove message observers registered with task
void	UnregisterParallelTask ( const UBTTaskNode* TaskNode, uint16 InstanceIdx )	Remove parallel task
void	UpdateDebuggerAfterExecution ( const UBTTaskNode* TaskNode, uint16 InstanceIdx )	Update runtime description of given task node in latest debugger's snapshot
uint8	UpdateInstanceId ( UBehaviorTree* TreeAsset, const UBTNode* OriginNode, int32 OriginInstanceIdx )	Add unique Id of newly created subtree to KnownInstances list and return its index

Overridden from UBrainComponent

	Name	Description
void	Cleanup()	AI logic won't be needed anymore, stop all activity and run cleanup
void	DescribeSelfToVisLog ( FVisualLogEntry* Snapshot )
FString	GetDebugInfoString()
void	HandleMessage ( const FAIMessage& Message )
bool	IsPaused()
bool	IsRunning()
void	PauseLogic ( const FString& Reason )	Pause logic and blackboard updates.
void	RestartLogic()	Restarts currently running or previously ran brain logic.
EAILogicResu...	ResumeLogic ( const FString& Reason )	Resumes paused brain logic. MUST be called by child implementations!
void	StartLogic()	Starts brain logic. If brain is already running, will not do anything.
void	StopLogic ( const FString& Reason )	Stops currently running brain logic.

Overridden from UActorComponent

	Name	Description
void	RegisterComponentTickFunctions ( bool bRegister )	Virtual call chain to register all tick functions
void	SetComponentTickEnabled ( bool bEnabled )	Set this component's tick functions to be enabled or disabled.
void	TickComponent ( float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction* T... )	BEGIN UActorComponent overrides
void	UninitializeComponent()	Handle this component being Uninitialized.

Classes

	Name	Description
	FBTSuspendBranchDeactivationScoped

Constants

Name	Description
ActiveDebuggerCounter	Set when at least one debugger window is opened
bAddedEndFrameCallback	Code for timing BT Search for FramePro.
FrameSearchTime
NumSearchTimeCalls

Deprecated Functions

		Name	Description
	void	RequestUnregisterAuxNodesInBranch ( const UBTCompositeNode* Node )	This function is deprecated. Please use RequestBranchDeactivation instead.