Struggling with Grabber Component and Enhanced Input System (Crypt Raider)

[evolvingdev]

I’m following the UE5 course and I’m trying to draw the Debug Sphere at the End vector of the Grabber component. I’m using UE5.2 and because of that, I want to use the Enhanced Input System. Currently I implemented a AddOnScreenDebugMessage() functionality in CryptRaiderCharacter.cpp that triggers if the Grab action started.

The two functions in CryptRaiderCharacter.cpp:

void ACryptRaiderCharacter::Grabbed(const FInputActionValue& Value)
{
	const bool Grabbed = Value.Get<bool>();
	if(Grabbed){
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Grabbed"));

	}
}

void ACryptRaiderCharacter::Released(const FInputActionValue& Value)
{
	const bool Released = Value.Get<bool>();
	if (!Released) {
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Blue, TEXT("Released"));
	}
}

The code in SetupPlayerInputComponent():

void ACryptRaiderCharacter::SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent)
{
	// Set up action bindings
	if (UEnhancedInputComponent* EnhancedInputComponent = CastChecked<UEnhancedInputComponent>(PlayerInputComponent))
	{
		...

		//Grabbing
		EnhancedInputComponent->BindAction(GrabAction, ETriggerEvent::Started, this, &ACryptRaiderCharacter::Grabbed);
		EnhancedInputComponent->BindAction(GrabAction, ETriggerEvent::Completed, this, &ACryptRaiderCharacter::Released);
	}
}

The problem is that the Scene Component Grabber does all the job when it comes to drawing the debug line:

void UGrabber::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction); 
	FVector Start = GetComponentLocation();
	FVector End = Start + GetForwardVector() * MaxGrabDist;
	
	DrawDebugLine(GetWorld(), Start, End, FColor::Red);
	//DrawDebugSphere(GetWorld(), End, 10, 10, FColor::Blue, true, 5);

	...
}

Since I only want to draw the Debug Sphere if I click on a button, how can I access

FVector End

from UGrabber.cpp in my CryptRaiderCharacter.cpp? Or is there a better way to do this?

I tried to implement the Input System in Grabber.h and Grabber.cpp but the build fails with the reason, that SetupPlayerInputComponent is not a member of USceneComponent.

[DanM]

You would need to add the grabber component in C++

ACryptRaiderCharacter::ACryptRaiderCharacter()
{
    //...
    Grabber = CreateDefaultSubobject<UGrabberComponent>(); //declared in header
}

Then use that how you wish

void ACryptRaiderCharacter::Grabbed(const FInputActionValue& Value)
{
	const bool Grabbed = Value.Get<bool>();
	if(Grabbed){
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Grabbed"))
        Grabber->//..do something;
	}
}

[evolvingdev]

Thanks for the answer, I just tried it out and ran into the following problems:

Adding the Grabber component:

no instance of overloaded function “ACryptRaiderCharacter::CreateDefaultSubobject” matches the argument list

Using Grabber like this:

void ACryptRaiderCharacter::Grabbed(const FInputActionValue& Value)
{
	const bool Grabbed = Value.Get<bool>();
	if(Grabbed){
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Grabbed"));
		Grabber->DrawDebugSphere(GetWorld(), End, 10, 10, FColor::Blue, true, 5);
	}
}

causes

class “UGrabber” has no member “DrawDebugSphere”

[DanM]

Grabber doesn’t have that function. You’d need grab and release functions to call on it.

You also need to name the component(sorry I missed it)

CreateDefaultSubobject<...>(TEXT("GrabberComponent"));

[evolvingdev]

Thank you, naming the component solved this problem, I think I’m almost there, now I only get the error:

CryptRaiderCharacter.cpp(54): error C4458: declaration of ‘Grabber’ hides class member.
CryptRaiderCharacter.h(80): note: see declaration of ‘ACryptRaiderCharacter::Grabber’

Edit:

In the header file I declared Grabber like this:

class UGrabber* Grabber;

[DanM]

You likely have the class name in the constructor which means you are creating a local variable instead of assigning your member variable

[evolvingdev]

That fixed it, thank you very much!