Why does GetPlayerController() returns nullptr in C++ but proper value in Blueprints?

Development Programming & Scripting
1

My Case

Briefly, in construction script I have some logic which uses Player Camera Manager, but when I call the same exact function but from inside c++ function i get an engine crash due to access violation. I did some debugging and found out that Player Controller is not yet instanced by the time I try to access it.

Blueprints

So when I call the pure function GetPlayerCameraManager (which implicitly calls UGameplayStatics::GetPlayerController) in Blueprints, everything works as intended.

I have something like this in my code (oversimplified):

  • Construction Script

338232-construction-script.png

  • The function that calls Get Player Camera Manager

338233-get-player-camera-manager.png

The Problem

In the base class that my Blueprint is based on I added this function:

void ATestActor::CallGetPlayerCameraManager()
{
	APlayerCameraManager* CameraManager = UGameplayStatics::GetPlayerCameraManager(GetWorld(), 0);
	if (IsValid(GEngine))
		GEngine->AddOnScreenDebugMessage(0, 3.f, FColor::Red, CameraManager->GetName());
}

Then when I try to call this function in construction script the engine crashes:

338234-c-construction-script.png

Most importantly, the debugger shows that the problem is that UGameplayStatics::GetPlayerController() (which is used in GetPlayerCameraManager()) returns nullptr. The question therefore is why this happens and how can I change my code for it to work

2

Have you tried running the function off of the BeginPlay event, as opposed to the Construction Strip?

3

It’s probably returning null because the PlayerController hasn’t been created yet. Try calling it after the constructors e.g. from BeginPlay or PostInitializeComponents.

4

Why though it works in blueprints? And why can’t I call the same exact function from c++. It’s crucial for my implementation because I need my Level Designers to see the result before BeginPlay() (it must be visible in the viewport) So that’s the problem. Could you give any advice on that?