Add enter and leave events for targetable interface

Introduces two new events for the targetable interface:

• One that is fired when a targetable actor gains focus.
• One complementary event that fires when a targetable actor loses focus.

Source/DisplayClusterExtensions/Private/Pawn/BasicVRInteractionComponent.cpp

@@ -104,15 +104,44 @@ void UBasicVRInteractionComponent::TickComponent(float DeltaTime, ELevelTick Tic
 
 	const FTwoVectors StartEnd = GetHandRay(MaxClickDistance);
 	TOptional<FHitResult> Hit = RaytraceForFirstHit(StartEnd);
+
 	if (!Hit.IsSet())
+	{
+
+		// Execute leave event on the actor that lost the focus if there was one
+		if (LastActorHit && LastActorHit->Implements<UTargetable>())
+		{
+				ITargetable::Execute_OnTargetedLeave(LastActorHit);
+		}
+
+		LastActorHit = nullptr;
 		return;
+	}
+	
 	AActor* HitActor = Hit->GetActor();
 
+	// Execute Leave and enter events when the focused actor changed
+	if (HitActor != LastActorHit)
+	{
+		//We can always execute the enter event as we are sure that a hit occured
+		if (HitActor->Implements<UTargetable>())
+		{
+			ITargetable::Execute_OnTargetedEnter(HitActor);
+		}
+
+		//Only execute the Leave Event if there was an actor that was focused previously
+		if (LastActorHit != nullptr && LastActorHit->Implements<UTargetable>())
+		{
+			ITargetable::Execute_OnTargetedLeave(LastActorHit);
+		}
+	}
+
 	// for now uses the same distance as clicking
 	if (HitActor->Implements<UTargetable>() && Hit->Distance < MaxClickDistance)
 	{
 		ITargetable::Execute_OnTargeted(HitActor, Hit->Location);
 	}
+	LastActorHit = HitActor; // Store the actor that was hit to have access to it in the next frame as well
 }
 
 void UBasicVRInteractionComponent::Initialize(USceneComponent* RayEmitter, float InMaxGrabDistance, float InMaxClickDistance)