Arguments of SpawnEmitterAtLocation

Development Programming & Scripting C++
,
1

Hi

I’m trying to add some explosion effect to my spheres

I’ve created a


UPROPERTY()
		class UParticleSystemComponent* DestroyParticleSystem;

Then I’ adding it into the cpp file

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After that i’m gonna use particle system in my OnHit function to destroy the sphere with an explosion

void AEnemy::OnCompHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit)
{
	if (IsValid(OtherActor) && IsValid(OtherComp)) 
	{ // Check that these are not nullptr and not pending kill
		UGameplayStatics::SpawnEmitterAtLocation( ???, DestroyParticleSystem, this->GetActorLocation(), FRotator::ZeroRotator, true, NAME_None, false);
		AddDeathCount();
	}
}

What are the correct arguments for the SpawnEmitterAtLocation? What is the correct argument should be instead of “???”

I’ m using this version of the function:

static UParticleSystemComponent * SpawnEmitterAtLocation
(
    const UObject * WorldContextObject,
    UParticleSystem * EmitterTemplate,
    FVector Location,
    FRotator Rotation,
    bool bAutoDestroy,
    EPSCPoolMethod PoolingMethod,
    bool bAutoActivateSystem
)

Also could you explain the meaning of all arguments of this function? I understand the meaning of Location and Rotation, AutoDestroy, but WorldContextObject, PoolingMethod and AutoActivateSystem(a little bit) are incomprehensible to me

2

You want a world location. Typically you want the world location of the impact point where the explosion hit (you may get this from collision testing/handling) but, worst case, just use the actor world location of the exploding actor.

PoolingMethod has to do with if you have tons of explosions, and want them to re-use rendering resources (and limit the max number going at the same time.)
AutoActivateSystem means it will start playing right away, you don’t have to separately call Activate on it to make it start emitting particles and animate.
WorldContextObject is the object that tells this system which world to spawn into. 99.9999% of the time, you’ll want to use the object that’s exploding, or if that’s already gone, use perhaps the player(controller) viewing the explosion.

2 Likes
4

Thanks for the explanation. Now it became much clearer to me

As I don’t understand how to use my Actor as a UObject class (maybe I should use cast, but it’s not gonna work), I decided to use this overriden version:

static UParticleSystemComponent * SpawnEmitterAtLocation
(
    UWorld * World,
    UParticleSystem * EmitterTemplate,
    const FTransform & SpawnTransform,
    bool bAutoDestroy,
    EPSCPoolMethod PoolingMethod,
    bool bAutoActivate
)

In this way:

UGameplayStatics::SpawnEmitterAtLocation(this->GetWorld(), DestroyParticleSystem, this->GetTransform(), true, NAME_None, false);

However I still don’t understand the pooling method. I’m trying to create a variable EPSCPoolMethod Pool but I can’t assign any value to it

5

Clear, thanks!

But whar are the ways of setting Objects to UParticleSystem variable? Can’t find anything in documentation

8

Okay, the things are really easier than I thought)

After all the fixes project compiled but there is no particle effect onhit (as no autodestroy as well)

I’m trying to use the function this way:

void AEnemy::OnCompHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit)
{
	if (IsValid(OtherActor) && IsValid(OtherComp)) 
	{
		UGameplayStatics::SpawnEmitterAtLocation(GetWorld(), DestroyParticleSystem, GetTransform(), true, EPSCPoolMethod::None, false);
		AddDeathCount();
//		Destroy(); // Destroy self if we hit anything
	}
}