Subsystem and empty world

Development Programming & Scripting C++
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1

I want to create a subsystem that will do some actors search and store their references for later optimized use.

I’ve made a subsystem subclassed from UWorldSubsystem. But I’m surprised that in my method Initialize(FSubsystemCollectionBase& Collection) the
GetWorld() return a world not yet populated with actors. Is it too early? I also tried to subclass from other subsystem without success.

2

Example from LyraAudioMixEffectsSubsystem ( Lyra )

LyraAudioMixEffectsSubsystem.h

UCLASS()
class LYRAGAME_API ULyraAudioMixEffectsSubsystem : public UWorldSubsystem
{
	GENERATED_BODY()

public:
	// USubsystem implementation Begin
	virtual void Initialize(FSubsystemCollectionBase& Collection) override;
	virtual void Deinitialize() override;
	// USubsystem implementation End

	virtual bool ShouldCreateSubsystem(UObject* Outer) const override;

	/** Called once all UWorldSubsystems have been initialized */
	virtual void PostInitialize() override;

	/** Called when world is ready to start gameplay before the game mode transitions to the correct state and call BeginPlay on all actors */
	virtual void OnWorldBeginPlay(UWorld& InWorld) override;
	
protected:
	// Called when determining whether to create this Subsystem
	virtual bool DoesSupportWorldType(const EWorldType::Type WorldType) const override;

	...
};

LyraAudioMixEffectsSubsystem.cpp

void ULyraAudioMixEffectsSubsystem::Initialize(FSubsystemCollectionBase& Collection)
{
	Super::Initialize(Collection);
}

void ULyraAudioMixEffectsSubsystem::Deinitialize()
{
	//...

	Super::Deinitialize();
}

bool ULyraAudioMixEffectsSubsystem::ShouldCreateSubsystem(UObject* Outer) const
{
	bool bShouldCreateSubsystem = Super::ShouldCreateSubsystem(Outer);

	if (Outer)
	{
		if (UWorld* World = Outer->GetWorld())
		{
			bShouldCreateSubsystem = DoesSupportWorldType(World->WorldType) && bShouldCreateSubsystem;
		}
	}

	return bShouldCreateSubsystem;
}

void ULyraAudioMixEffectsSubsystem::PostInitialize()
{
	// Load your variables
}

void ULyraAudioMixEffectsSubsystem::OnWorldBeginPlay(UWorld& InWorld)
{
	if (const UWorld* World = InWorld.GetWorld())
	{
		//...
	}
}

bool ULyraAudioMixEffectsSubsystem::DoesSupportWorldType(const EWorldType::Type World) const
{
	// We only need this subsystem on Game worlds (PIE included)
	return (World == EWorldType::Game || World == EWorldType::PIE);
}
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