Event dispatcher pattern for decoupled communication between actors

Pattern: Actor A declares EventDispatcher OnScoreChanged(int NewScore). Actor B (listener) BeginPlay: GetActorOfClass(A) → BindEvent(OnScoreChanged) → custom event handler. Actor A calls OnScoreChanged.Broadcast(Score) when score changes. Bind in BeginPlay, Unbind in EndPlay to avoid dangling references.

Interface

A contract a Blueprint can implement, exposing a set of functions other code can call without knowing the class. Used for decoupled comms.

UnPossess — detach Controller from currently possessed Pawn

Possess — make a Controller possess a Pawn

Less (float) — A < B

Not_PreBool — logical NOT

Pickup and collectible system with overlap trigger

Pattern: Pickup actor with SphereCollision(overlap), StaticMesh visual. OnComponentBeginOverlap → CastTo PlayerCharacter → Success: call AddScore/AddItem interface on player → PlaySoundAtLocation → SpawnEmitterAtLocation → DestroyActor(self). Set collision to OverlapOnlyPawn for performance.

DoN — execute N times then stop

Sequence — execute multiple output pins in order

Add more output pins as needed. Pin names: Then 0, Then 1, etc.

BreakVector2D — decompose FVector2D into X Y