Begin overlap not working but end overlap is!?

Development World Creation
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1

Working on a simple inventory system where the player picks up items as they collide with them.

For the life of me I can’t get my OnComponentBeginOverlap delegate to be called. But my OnComponentEndOverlap delegate does get called. Does this make any sense?

Both the character and the item itself are set to bGenerateOverlapEvents = true.

relevant Item.h:

UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Item)
UShapeComponent *CollisionShape;


UFUNCTION()
	void BeginCollision(UPrimitiveComponent* OverlappedComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);

UFUNCTION()
	void EndCollision(UPrimitiveComponent* OverlappedComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);

relevant Item.cpp:
(In constructor)

CollisionShape = CreateDefaultSubobject<UBoxComponent>(TEXT("CollisionShape"));
CollisionShape->bGenerateOverlapEvents = true;
RootComponent = CollisionShape;
	
CollisionShape->OnComponentBeginOverlap.AddDynamic(this, &AItem::BeginCollision);
CollisionShape->OnComponentEndOverlap.AddDynamic(this, &AItem::EndCollision);

Delegate functions:

void AItem::BeginCollision(UPrimitiveComponent* OverlappedComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
		UE_LOG(LogTemp, Warning, TEXT("player collided with item"));
		GEngine->AddOnScreenDebugMessage(1, 5.f, FColor::Green, FString("PlayerCollided with item"));
		Destroy();
	
}

void AItem::EndCollision(UPrimitiveComponent * OverlappedComp, AActor * OtherActor, UPrimitiveComponent * OtherComp, int32 OtherBodyIndex)
{
	UE_LOG(LogTemp, Warning, TEXT("collision ended"));
	GEngine->AddOnScreenDebugMessage(1, 5.f, FColor::Green, FString("collision ended"));
}
2

Does it call OnComponentBeginOverlap after it calls OnComponentEndOverlap? OnComponentBeginOverlap will not get called if the component is already overlapping when it spawns.

3

Begin overlap never gets called. I’ll walk my character into the object and begin overlap does not get called. But when I walk the character out, end overlap is called. I assume this means that my collision rules are working as intended. But I can’t for the life of me figure out why begin overlap isn’t being called.

4

Hmm. That isn’t compiling. It looks like it wants the UPrimitiveComponent after the AActor.
How do you know the parameters changed? The documentation I’m using is here: OnComponentBeginOverlap | Unreal Engine Documentation

Here’s the compile error after making your change:

error C2664: ‘void TBaseDynamicMulticastDelegate::__Internal_AddDynamic(UserClass ,void (__cdecl AMayhemItem:: )(UPrimitiveComponent *,AActor *,UPrimitiveComponent ,int32,bool,const FHitResult &),FName)’: cannot convert argument 2 from 'void (__cdecl AMayhemItem:: )(UPrimitiveComponent *,AActor ,int32,bool,const FHitResult &)’ to 'void (__cdecl AMayhemItem:: )(UPrimitiveComponent *,AActor *,UPrimitiveComponent *,int32,bool,const FHitResult &)’

Thanks for the help.

5

Parameters changed in 4.12. Can you try removing “OtherComp” from your BeginCollision and EndCollision? so for example,

void BeginCollision(UPrimitiveComponent* OverlappedComp, AActor* OtherActor, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);

That’s how I have it and it works for me.

6

I figured it out, kind of. I renamed my delegates and deleted and recreated the blueprint class that extends my item class and it now works. Not sure which step fixed it.