Can a blueprint actor "hear" a C++ function firing in its components?

Development Programming & Scripting Blueprint
1

I’m working on an item system, 99% of it takes place in C++ but I’m trying to use blueprint to create “holder” actors whose job is to retain a reference to my item struct until the player interacts with them and takes the item they’re storing, at which point the actor itself needs to self-destruct (so it can’t be looted again).

I wrote an actor component which actually holds the item data and does all the heavy lifting to figure out if it can be looted, and gave it what I thought were two events that blueprint could see and subscribe to, the idea being that my C++ logic would detect when it needed to destroy itself, and fire an event to inform its actor of this fact:


UFUNCTION(Category = "Interaction", BlueprintImplementableEvent)
		void PickedUp();

		UFUNCTION(Category = "Interaction", BlueprintImplementableEvent)
		void NotPickedUp();

However, when I get a reference to my component in blueprint I can’t see either of these events, even with the context sensitive turned off. Is there something I neglected to place in the UFUNCTION macro, or am I going about this in a fundamentally wrong way?

2

I do this from the pawn and it works:



UFUNCTION(BlueprintImplementableEvent, meta = (DisplayName = "MMT Physics Tick"), Category = "MMT physics sub-stepping")
void MMTPhysicsTick(float SubstepDeltaTime);

Have you tried to find this event in the blueprint of the component itself instead of trying to call it from a reference to component?

3

Hmm that’s weird, I copied & pasted directly from your example and it still won’t show up, so it’s definitely something funny that I’m doing. Per your second question, and probably directly related to the problem, I don’t actually have a blueprint of the component; it’s a C++ component that I mark as a BlueprintSpawnableComponent in its UCLASS macro, but if I right-click on it in the content browser “Create blueprint class based on…” is greyed out for every class of type UActorComponent.

That being the case, I just made an actor BP and added my class through the Add Component tab. It works fine and everything, it just can’t actually see the implementable events I’m adding.

4

Perhaps your c++ component have to be marked as blueprintable for your event to be blueprint implementable. Unfortunately I don’t have any macro example for blueprintable component, but source of ActorComponent or SceneComponent should have such macro.

5

Hmm okay, thank you :slight_smile:

6

One thing, code of the event that I have is declared in custom Pawn, not in custom component.

7

Yeap, I forgot about this:

mechanism for components is different!