Spawn Actor and AIController problem

Development Programming & Scripting AI
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1

Hi guys, I’m literally losing my mind, hope someone can help me understand what I’m doing wrong.

So, in my level script I spawn an actor:

AEnemy Enemy = Cast<AEnemy>(GetWorld()->SpawnActor<AEnemy>(EnemyBlueprint, EnemyLocation, EnemyRotation));

Then, I set in the actor Blueprint “Auto Possess by AI when Spawned”.

Then In my AIController on BeginPlay()

AEnemy* PossessedEnemy = Cast<AEnemy>(GetPawn());

And it crashes.

Tried disabling the auto possess option and after the spwn calling

Enemy -> SpawnDefaultController();

And it changes nothing. Tried to call after the spawning:

AMyAIController EnemyController = Cast<AMyAIController>(Enemy -> GetController());
EnemyController -> Possess(Enemy);

And it chenges nothing.

I understand that BeginPlay of the controller is being called before the actual possession, but why?
I know I can resolve this thing in some way but I want to understand why, The cronological order in which Unreal call the functions is a big mystery for me.

2

Hi there! the thing is that order differs for spawned actors and for regular level actors

- Spawn:

LogBlueprintUserMessages: [BP_AI_C_2] Controller Begin Play

LogBlueprintUserMessages: [BP_Pawn_C_1] Pawn Possessed

LogBlueprintUserMessages: [BP_AI_C_2] Controller Possessed

LogBlueprintUserMessages: [BP_Pawn_C_1] Pawn Begin Play

- Level Actor:

LogBlueprintUserMessages: [BP_Pawn_2] Pawn Possessed

LogBlueprintUserMessages: [BP_AI_C_0] Controller Possessed

LogBlueprintUserMessages: [BP_AI_C_0] Controller Begin Play

LogBlueprintUserMessages: [BP_Pawn_2] Pawn Begin Play

4 Likes
3

Hi Kehel, thanks!
Now it’s all clear, what workaround do you suggest keeping the code in the controller? Maybe some other method I can use? I’m thinking to add custom event or call the code from the Pawn BeginPlay at this point.

4

Can you be more precise - what type of logic do you have and want to put in Controller class?

5

Oh nevermind, I have resolved this with a setter in the BeginPlay() of the pawn class, thanks a lot sir!

6

Resolved, thanks to @Kehel18 :slight_smile:

7

I was stuck on this for a few days! I had a NavMesh and verified active with “P”, my placed actor would move, and I was calling SpawnDefaultController() and my behavior tree was running but my spawned actor wouldn’t move. Noticed a warning I had in my logs about not having the pawn after BeginPlay was called.

This helped me understand why I had no pawn on my AI controller subclass in BeginPlay when I would spawn the actor. Didn’t realize the start sequence order would be different. I overrode OnPossess and only called my init function after both BeginPlay and OnPossess occurred to cover both the placed actor and spawned actor cases consistently.

8

Initially my code was designed to work on actors placed by the level designer and not by spawning.

This response made me aware that I should move my logic from void AShooterAIController::BeginPlay() to void AShooterAIController::OnPossess(APawn* InPawn)

3 Likes
9

OH MY GOD it took me FOREVER to find this answer and it fixed everything immediately.

1 Like
10

Wow, I can’t understand why there is such a huge inconsistency in the call-order. This is still an issue in Unreal Engine 5.0 btw

also calling

SpawnDefaultController();

is essential

11

can anyone help me i have solve possessing’s issue but have kind of prroblem my PlayerPawn is valid in beginplay it brokes in ticks that is my spawning ai doesnt have valid aicontoller when i set my ai to posses ai controller place or spawn in the wolrd here is the codes am i missin somethig please point out void AAIShooterController::Tick(float DeltaSeconds)
{
Super::Tick(DeltaSeconds);
APawn* PlayerPawn =Cast( UGameplayStatics::GetPlayerPawn(GetWorld(), 0));

  if (!PlayerPawn)
{
    UE_LOG(LogTemp, Warning, TEXT("PlayerPawn is valid."));
}
else
{
    UE_LOG(LogTemp, Warning, TEXT("PlayerPawn is NULL."));
    return; // Exit early to prevent further issues if PlayerPawn is NULL
}   here is my spawn actor  AAIShooterController* NewPoliceController = GetWorld()->SpawnActor<AAIShooterController>(AAIShooterController::StaticClass(), FTransform::Identity);
            if (NewPoliceController)
            {
                NewPoliceController->Possess(NewPolice);
                NewPoliceController->RunBehaviorTree(PoliceBehaviorTree);