Runtime Error using AI Perception's output in a custom c++ function

Development Programming & Scripting
,
1

In the blueprint of my NPC I have added the AI Perception component, configured the Sight sense in there and added an On Target Perception Updated event to the Event Graph.

I pass the Actor sensed to a custom function. Everything compiles fine but when the Actor (my playable character) is actually sensed during runtime the game crashes with an EXCEPTION_ACCESS_VIOLATION. It happens whenever I try to do anything with the Actor passed to my function.

bp_perception_chase
bp_perception_chase628×176 24.6 KB

void AEnemy::Chase(AActor* targetPawn)
{
	auto animInst = GetMesh()->GetAnimInstance();
	auto enemyAnimInst = Cast<UEnemyAnimInstance>(animInst);
	if (targetPawn != nullptr && enemyAnimInst->State == EEnemyState::Locomotion)
	{
		auto enemyController = Cast<AEnemyController>(GetController());
		enemyController->MoveToActor(targetPawn, 90.0f);
	}
	_chasedTarget = targetPawn;
}

As is, it will crash when calling MoveToActor.

Btw, I have tried the same with the PawnSensingComponent first and get the same error. I’m following the tutorial from this book:
Amazon.com: Unreal Engine 5 Game Development with C++ Scripting: Become a professional game developer and create fully functional, high-quality games: 9781804613931: ZHENYU GEORGE LI: Books

2

if it crashes at MoveActor then enemyController is null. which is possible if GetController is null or it’s not an enemycontroller.

it’s quite possible that the controller is not the right type.

2 Likes
3

You’re right. The controller class for the NPC was set to the AIController base class instead of my child class.
Thanks.

1 Like
4

:partying_face: well done turner! i’m glad it helped.

1 Like