How to get a BTTaskNode working with an editor based behavior tree

Development Programming & Scripting AI
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1

Hi, i’m currently starting work on changing some of my projects blueprint functionalities into C++. I’m starting by making my task nodes in C++ however i’m struggling to find resources to show me how to set up task nodes in C++. I’ve created the task node C++ class but that’s about as far as I’ve got at the moment.

Could someone please show me how to set up a basic BTTaskNode for usage in an editor based Behavior Tree? Or point me to resources that can help me figure this out.

Thank you.

2

  1. add AIModule and GameplayTasks to your Build.cs file to be able to use the ai module
    PublicDependencyModuleNames.AddRange(new string[] {
    “Core”,
    “CoreUObject”,
    “Engine”,
    “InputCore”,
    “HeadMountedDisplay”,
    “AIModule”,
    “GameplayTasks”
    });

  2. Add AIModule to your uproject if it was not already added

    		"AdditionalDependencies": [
			"Engine",
			"AIModule"
		]

  3. Generate Visual Studio Project Files, to regenerate the needed code

  4. In Unreal create a new C++ class based on BTTaskNode (don’t forget to check “Show all classes” in the class selector otherwise you will not see the BTTaskNode)

  5. override ExecuteTask in your newly created BTTaskNode

e.g.:
MyBTTaskNode.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "BehaviorTree/BTTaskNode.h"
#include "MyBTTaskNode.generated.h"

/**
 * 
 */
UCLASS()
class ANSWERHUBANSWERS_API UMyBTTaskNode : public UBTTaskNode
{
	GENERATED_BODY()

public:
	virtual EBTNodeResult::Type ExecuteTask(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory) override;
};

MyBTTaskNode.cpp

// Fill out your copyright notice in the Description page of Project Settings.


#include "MyBTTaskNode.h"

EBTNodeResult::Type UMyBTTaskNode::ExecuteTask(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory)
{
	UE_LOG(LogTemp, Error, TEXT("Log Some Stuff!"));
	return EBTNodeResult::Succeeded;
}
3

Thanks for your help, this works :slight_smile: