How to use "MovetoLocation" to move character

Development Programming & Scripting AI
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1

please excuse my stupidness if i am doing something simple wrong but i am new to developing with unreal engine. What i am trying to do is move my character from start of maze to end of maze and have accomplished it using blueprints but i want to implement it in c++.

I Have assigned my characters AI Controller Class to my AIController.

in my AiController class i have

void AMyAIController::MoveEnemyToTarget(){


	AMyEnemyCharacter* const Enemy = Cast<AMyEnemyCharacter>(UGameplayStatics::GetPlayerPawn(GetWorld(), 0));

	if (Enemy != NULL){
		FVector location = FVector(1962, 1270, 260);
		AMyAIController::MoveToLocation(location, 10.0f, true, true, true);
	}

}

and then in my Characters BeginPlay() i have

Super::BeginPlay();

	AMyAIController* ai = Cast<AMyAIController>(AMyAIController::StaticClass());
	
	FVector location = FVector(1962, 1270, 260);

	if (ai != NULL){
		ai->Possess(this);
		ai->MoveEnemyToTarget();
	}

When i go to play it just dose nothing… any help greatly appreciated as it has been annoying and hold me up all day

2

Hi Dobby,

The AI Controller should automatically possess the character when it spawns so you should be able to remove that bit. To get a reference to the controller you should call GetController instead of StaticClass.

Try replacing your BeginPlay function with this

void AMyCharacter::BeginPlay()
{
	Super::BeginPlay();

	if( GetWorld() && !GetWorld()->bStartup && GetController() == nullptr )
	{
		SpawnDefaultController();
	}

	AMyAIController* ai = Cast<AMyAIController>(GetController());

	FVector location = FVector(1962, 1270, 260);

	if( ai != NULL ) {
		ai->MoveEnemyToTarget();
	}
}

In your character constructor, make sure to set the default controller class (you do use StaticClass here):

AIControllerClass = AMyAIController::StaticClass();
3

Still wont work for me :frowning: would the fact that i have the player controller class to for controlling my camera and other game objects make a difference??

4

I don’t think that would cause any problems.

Try setting a breakpoint in BeginPlay on the line where you cast to your AI Controller class. See if the variable ai is null or if MoveToLocation is failing.

5

it keeps coming back from the cast as null

6

Well, if it doesn’t cast to AIController then it’s either null or a PlayerController. This basically means whole your setup and/or assumptions are wrong and I suggest grabbing any on UE4 samples that have AI in it and see how it’s done there.

There’s a lot of places where stuff could have gone bad for you, so it’s a wast of time trying to solve it via an answerhub thread. Just look at samples.

Cheers,

–mieszko

7

Thanks Alderbit. this worked for me eventually when i created a new AI controller class and new character class… not sure what the initial problem was

8

Take a look at the UE4 sample project TopDown in C++. In that project the character moves where you click. This is done using the function MoveToLocation(…). It is very simple and well documented.

Hope this helps!