Why cant projectile subobject trigger onHit or OnOverlapBegin events?

Development Programming & Scripting
,
1

I created a specific C++ class for my projectile:

ABasicProjectile::ABasicProjectile()
{

    CollisionComp = CreateDefaultSubobject<USphereComponent>(TEXT("SphereComp"));
    CollisionComp->InitSphereRadius(500.0f);  // Increase to 20.0f for test
    CollisionComp->OnComponentBeginOverlap.AddDynamic(this, &ABasicProjectile::OnOverlapBegin);

    CollisionComp->OnComponentHit.AddDynamic(this, &ABasicProjectile::OnHit);
    RootComponent = CollisionComp;
    SetRootComponent(CollisionComp);

    ProjectileMovement = CreateDefaultSubobject<UProjectileMovementComponent>(TEXT("ProjectileComp"));
    ProjectileMovement->UpdatedComponent = CollisionComp;
    ProjectileMovement->InitialSpeed = 3000.0f;
    ProjectileMovement->MaxSpeed = 3000.0f;
    ProjectileMovement->bRotationFollowsVelocity = true;
    ProjectileMovement->bShouldBounce = false;
    ProjectileMovement->ProjectileGravityScale = 0.0f;

    SetLifeSpan(3.0f);

}

with onHit and OnOverlapBegin:


void ABasicProjectile::OnHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit)
{
    
    UE_LOG(LogTemp, Warning, TEXT("Projectile OnHit triggered with %s"), *OtherActor->GetName());

    if (OtherActor && OtherActor != this && OtherActor != GetInstigator() && OtherComp)
    {
        UHealthComponent* HealthComp = OtherActor->FindComponentByClass<UHealthComponent>();
        if (HealthComp)
        {
            UE_LOG(LogTemp, Warning, TEXT("HealthComp found on %s, applying %f damage"), *OtherActor->GetName(), Damage);
            HealthComp->TakeDamage(Damage);
        }
        else {
            UE_LOG(LogTemp, Error, TEXT("No HealthComp on %s"), *OtherActor->GetName());
        }
    }
    Destroy();
}

void ABasicProjectile::OnOverlapBegin(UPrimitiveComponent* OverlappedComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
    UE_LOG(LogTemp, Warning, TEXT("Projectile OnOverlap triggered with %s"), *OtherActor->GetName());

    if (OtherActor && OtherActor != this && OtherActor != GetInstigator() && OtherComp)
    {
        UHealthComponent* HealthComp = OtherActor->FindComponentByClass<UHealthComponent>();
        if (HealthComp)
        {
            UE_LOG(LogTemp, Warning, TEXT("HealthComp found on %s, applying %f damage"), *OtherActor->GetName(), Damage);
            HealthComp->TakeDamage(Damage);
        }
        else {
            UE_LOG(LogTemp, Error, TEXT("No HealthComp on %s"), *OtherActor->GetName());
        }
        Destroy();
    }
}

I also have proper collision in the Blueprint setup:

image
image469×705 15.1 KB

With all this setup, I have no logs from my events.

I have a similar setup between other components, where it looks fine, but I used:

GetCapsuleComponent()->OnComponentBeginOverlap.AddDynamic(this, &AMainEnemy::OnOverlapBegin);

So I assume the issue may be related to how CreateDefaultSubobject works; I am not sure.

2

So I found the issue myself. The solution is to put the event binding into the BeginPlay() call:

void ABasicProjectile::BeginPlay()
{
	Super::BeginPlay();
    CollisionComp->OnComponentBeginOverlap.AddDynamic(this, &ABasicProjectile::OnOverlapBegin);
    CollisionComp->OnComponentHit.AddDynamic(this, &ABasicProjectile::OnHit);
}

For some reason, it is not working in the constructor method, so this may fix it for you as well.