Interaction Component

The Interaction Component provides a modular and network-safe way for actors to interact with objects in the world that implement the UInteractInterface. It determines the best interactable actor nearby, handles authority checks, and triggers interactions both locally and on the server.

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Overview

The component supports:

• Automatic detection of nearby interactable actors
• Authority validation and server RPC forwarding
• Customizable colliders for interaction range detection
• Blueprint extendable logic via GetBestInteractable

This makes it ideal for use in player characters, AI, or world objects that need to perform interactions dynamically.

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Core Interaction Logic

void UInteractionComponentBase::InteractWithBest()
{
	if (!GetOwner()->HasAuthority())
	{
		Server_InteractWithBest();
		return;
	}
	
	Interact(GetBestInteractable());
}

How it works:

1. Authority Check:

   • If called on a client, it forwards the request to the server with Server_InteractWithBest().
   • If authority is already held (e.g., on the server), it continues execution immediately.

2. Interaction Execution:

   • Calls GetBestInteractable() to find the optimal target.
   • Invokes Interact() with that target.

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Setting Up the Collider

The component uses a shape collider to detect potential interactable objects. You can dynamically assign it at runtime or configure it via Blueprint.

void UInteractionComponentBase::SetInteractionCollider(UShapeComponent* Collider)
{
	InteractionCollider = Collider;
}

This collider is typically a sphere or capsule component attached to your character or pawn, representing the interaction range.

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Finding the Best Interactable

The component determines the closest valid interactable by scanning overlapping actors.

UObject* UInteractionComponentBase::GetBestInteractable_Implementation() const
{
	UE_LOG(LogTemp, Warning, TEXT("GetBestInteractable"));
	UObject* BestInteractable = nullptr;
	float BestDistance = 0.0f;
	TArray<AActor*> OverlappingActors;
	InteractionCollider->GetOverlappingActors(OverlappingActors);

	for (int i = 0; i < OverlappingActors.Num(); i++)
	{
		UObject* Interactable = OverlappingActors[i];
		if (IsValid(Interactable) && Interactable->Implements<UInteractInterface>())
		{
			float Distance = FVector::DistSquared(OverlappingActors[i]->GetActorLocation(), GetOwner()->GetActorLocation());
			if (BestInteractable == nullptr || Distance < BestDistance)
			{
				BestInteractable = Interactable;
				BestDistance = Distance;
			}
		}
	}

	return BestInteractable;
}

Key Details:

• Uses GetOverlappingActors() from the assigned collider to find nearby actors.
• Checks if each actor implements UInteractInterface.
• Calculates the closest valid interactable based on distance.
• Returns the best candidate for interaction.

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Example Blueprint Setup

1. Add a Sphere Collision component to your character.
2. Add the Interaction Component and call SetInteractionCollider() on BeginPlay.
3. Bind your Interact input to call InteractWithBest().
4. Ensure your interactable objects implement UInteractInterface.

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