Getting a Vector from my Player

Development Programming & Scripting C++
1

Hey! I am pretty new to C++ programming in Unreal and was wondering how I could get this to work. I am trying to get a Vector from the players camera. I did the following:



FVector AWeapon::GetFirePosition()
{
	AFPSCharacter* pl = OwnerPawn ? Cast<AFPSCharacter>(OwnerPawn) : NULL;
	FVector FPos = pl->FirstPersonCameraComponent->GetComponentLocation();
	return FPos;
}

Which is inspired by this:



FVector AShooterWeapon::GetCameraAim() const
{
	AShooterPlayerController* const PlayerController = Instigator ? Cast<AShooterPlayerController>(Instigator->Controller) : NULL;
	FVector FinalAim = FVector::ZeroVector;

	if (PlayerController)
	{
		FVector CamLoc;
		FRotator CamRot;
		PlayerController->GetPlayerViewPoint(CamLoc, CamRot);
		FinalAim = CamRot.Vector();
	}
	else if (Instigator)
	{
		FinalAim = Instigator->GetBaseAimRotation().Vector();		
	}

	return FinalAim;
}

Its mainly the “?” and “Instigator->Controller” that are putting me off. How can I cast it so that it also works with my Character class? Would really appreciated it if someone helped me with this! Thank you in advance.

2

“?” is the ternary operator.

it works like this:



(Evaluation) ? (Do this if Evaluation is true) : (Do this if evaluation is false)

As for “Instigator->Controller”, Instigator is a pointer to some actor class, and Controller is a member of the Instigator class.
The operator “->” is sort of analogous to the dot “.” operator in that you can access members of a pointer.

The code can be rewritten as follows:



AShooterPlayerController* const PlayerController
FinalAim = FVector::ZeroVector;

// Check that Instigator is not null
if(Instigator)
{
    // Cast the Instigator's Controller (Instigator->Controller) to AShooterPlayerController
    PlayerController = Cast<AShooterPlayerController>(Instigator->Controller);
    
    // Check that our cast player controller is not null
    if(PlayerController)
    {
		FVector CamLoc;
		FRotator CamRot;
		PlayerController->GetPlayerViewPoint(CamLoc, CamRot);
		FinalAim = CamRot.Vector();
    }
    else
    {
		FinalAim = Instigator->GetBaseAimRotation().Vector();
    }
	
	return FinalAim;
}

So, you can replace



AShooterPlayerController

with your PlayerController class.

3

Hey, thanks for the reply and the explanation (it was very useful). Does that mean I have to create a controller class? Because at the moment I don’t have one (as far as I know).

4

No, you don’t need to create one. The game framework uses “PlayerController” by default, so you can try that.

5

Alright, thanks man! I am no longer getting any errors. I cant really say if its working (I have not implemented the function properly yet), but it seems to be working. Just one question: I assume that “Instigator” is just a variable that is automatically assigned to the player who calls the function? Anyway, here is the code I ended up using:


FVector AWeapon::GetFirePosition()
{
	AController* PlayerController;
	FVector FinalAim = FVector::ZeroVector;
	if (Instigator)
	{
		// Cast the Instigator's Controller (Instigator->Controller) to AShooterPlayerController
		PlayerController = Cast<AController>(Instigator->Controller);

		// Check that our cast player controller is not null
		if (PlayerController)
		{
			FVector CamLoc;
			FRotator CamRot;
			PlayerController->GetPlayerViewPoint(CamLoc, CamRot);
			FinalAim = CamRot.Vector();
		}
		else
		{
			FinalAim = Instigator->GetBaseAimRotation().Vector();
		}
	}
	return FinalAim;
}
6

https://docs.unrealengine.com/latest/INT/Programming/UnrealArchitecture/Actors/Spawning/index.html

Instigator is of type Pawn, and seems like it can be set when spawning an actor - so when you spawn your weapon, just make sure to pass the pawn from which you’re spawning it into the spawn function.
You can use the “this” keyword to get a reference to your pawn instance inside your pawn class.

7

Ahhhh! Alright thank you very much!