UBTService

Behavior Tree service nodes is designed to perform "background" tasks that update AI's knowledge.

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Inheritance Hierarchy

UObjectBase

UObjectBaseUtility

UObject

UBTNode

UBTAuxiliaryNode

UBTService

UBTService_BlackboardBase

	UBTService_DefaultFocus
	UBTService_RunEQS

UBTService_BlueprintBase

UTestBTService_Log

References

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

Syntax

class UBTService : public UBTAuxiliaryNode

Remarks

Behavior Tree service nodes is designed to perform "background" tasks that update AI's knowledge.

Services are being executed when underlying branch of behavior tree becomes active, but unlike tasks they don't return any results and can't directly affect execution flow.

Usually they perform periodical checks (see TickNode) and often store results in blackboard. If any decorator node below requires results of check beforehand, use OnSearchStart function. Keep in mind that any checks performed there have to be instantaneous!

Other typical use case is creating a marker when specific branch is being executed (see OnBecomeRelevant, OnCeaseRelevant), by setting a flag in blackboard.

Because some of them can be instanced for specific AI, following virtual functions are not marked as const:

OnBecomeRelevant (from UBTAuxiliaryNode)
OnCeaseRelevant (from UBTAuxiliaryNode)
TickNode (from UBTAuxiliaryNode)
OnSearchStart

If your node is not being instanced (default behavior), DO NOT change any properties of object within those functions! Template nodes are shared across all behavior tree components using the same tree asset and must store their runtime properties in provided NodeMemory block (allocation size determined by GetInstanceMemorySize() )

Variables

	Name	Description
uint32: 1	bCallTickOnSearchStart	Call Tick event when task search enters this node (SearchStart will be called as well)
uint32: 1	bNotifyOnSearch	If set, service will be notified about search entering underlying branch
uint32: 1	bRestartTimerOnEachActivation	If set, next tick time will be always reset to service's interval when node is activated
float	Interval	Defines time span between subsequent ticks of the service
float	RandomDeviation	Adds random range to service's Interval

Constructors

	Name	Description
	UBTService ( const FObjectInitializer& ObjectIn... )

Functions

	Name	Description
FString	GetStaticServiceDescription()	Gets the description for our service.
FString	GetStaticTickIntervalDescription()	Gets the description of our tick interval.
void	InitNotifyFlags ( TickNode, OnBecomeRelevant, OnCeaseRelevant, OnSearchStart )
void	NotifyParentActivation ( FBehaviorTreeSearchData& SearchDat... )
void	OnSearchStart ( FBehaviorTreeSearchData& SearchDat... )	Called when search enters underlying branch this function should be considered as const (don't modify state of object) if node is not instanced! bNotifyOnSearch must be set to true for this function to be called Calling INIT_SERVICE_NODE_NOTIFY_FLAGS in the constructor of the service will set this flag automatically
void	ScheduleNextTick ( UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory )	Set next tick time

Overridden from UBTAuxiliaryNode

		Name	Description
	void	TickNode ( UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory, float DeltaSeconds )	Update next tick interval this function should be considered as const (don't modify state of object) if node is not instanced! bNotifyTick must be set to true for this function to be called Calling INIT_SERVICE_NODE_NOTIFY_FLAGS in the constructor of the service will set this flag automatically

Overridden from UBTNode

		Name	Description
	FName	GetNodeIconName()	Get the name of the icon used to display this node in the editor
	FString	GetStaticDescription()