[언리얼] Helper Function : 오브젝트 생성 및 애셋 불러오기

오브젝트 생성 및 애셋 불러오기

언리얼에서 오브젝트를 생성하고 애셋을 불러올 때는 보통 CreateDefaultSubobject 로 CDO 를 만들어 준 다음, ConstructorHelpers::FObjectFinder 로 애셋을 연결시켜 준다. 이 과정을 단축시켜주는 Helper Function 을 만들어 사용해 보자.

 

CHelpers.h

#pragma once

#include "CoreMinimal.h"
#include "Components/SkeletalMeshComponent.h"
#include "Kismet/GameplayStatics.h"
#include "Particles/ParticleSystem.h"
#include "NiagaraSystem.h"
#include "NiagaraFunctionLibrary.h"

class UE_PROJECT_NAME_API CHelpers
{
public:
	template<typename T>
	static void GetAsset(T** OutObject, FString InPath)
	{
		ConstructorHelpers::FObjectFinder<T> asset(*InPath);
		*OutObject = asset.Object;
	}

	template<typename T>
	static void GetAssetDynamic(T** OutObject, FString InPath)
	{
		*OutObject = Cast<T>(StaticLoadObject(T::StaticClass(), NULL, *InPath));
	}

	template<typename T>
	static void GetClass(TSubclassOf<T>* OutClass, FString InPath)
	{
		ConstructorHelpers::FClassFinder<T> asset(*InPath);
		*OutClass = asset.Class;
	}

	template<typename T>
	static void CreateComponent(AActor* InActor, T** OutComponent, FName InName, USceneComponent* InParent = NULL)
	{
		*OutComponent = InActor->CreateDefaultSubobject<T>(InName);

		if (!!InParent)
		{
			(*OutComponent)->SetupAttachment(InParent);

			return;
		}

		InActor->SetRootComponent(*OutComponent);
	}

	template<typename T>
	static void CreateActorComponent(AActor* InActor, T** OutComponent, FName InName)
	{
		*OutComponent = InActor->CreateDefaultSubobject<T>(InName);
	}

	template<typename T>
	static T* FindActor(UWorld* InWorld, int32 InIndex = 0)
	{
		TArray<AActor*> actors;
		UGameplayStatics::GetAllActorsOfClass(InWorld, T::StaticClass(), actors);

		if (actors.Num() < 1)
			return NULL;

		return Cast<T>(actors[InIndex]);
	}

	template<typename T>
	static void FindActors(UWorld* InWorld, TArray<T*>& OutActors)
	{
		TArray<AActor*> actors;
		UGameplayStatics::GetAllActorsOfClass(InWorld, T::StaticClass(), actors);

		for (AActor* actor : actors)
		{
			T* obj = Cast<T>(actor);

			if (!!obj)
				OutActors.Add(obj);
		}
	}

	static FLinearColor GetRandomColor()
	{
		FLinearColor color;
		color.R = UKismetMathLibrary::RandomFloatInRange(0, 1);
		color.G = UKismetMathLibrary::RandomFloatInRange(0, 1);
		color.B = UKismetMathLibrary::RandomFloatInRange(0, 1);
		color.A = 1.0f;

		return color;
	}

	template<typename T>
	static T* GetComponent(AActor* InActor)
	{
		return Cast<T>(InActor->GetComponentByClass(T::StaticClass()));
	}

	template<typename T>
	static T* GetComponent(AActor* InActor, FString InComponentName)
	{
		TArray<T*> components;
		InActor->GetComponents<T>(components);

		for(T* component : components)
		{
			if (component->GetName() == InComponentName)
				return component;
		}

		return NULL;
	}

	static FString GetStringFromEnum(FString InTypeName, int32 InIndex)
	{
		UEnum* ptr = FindObject<UEnum>(ANY_PACKAGE, *InTypeName, true);
		return ptr->GetNameStringByIndex(InIndex);
	}

	static void PlayEffect(UWorld* InWorld, UFXSystemAsset* InEffect, FTransform& InTransform, USkeletalMeshComponent* InMesh = NULL, FName InSocketName = NAME_None)
	{
		UParticleSystem* particle = Cast<UParticleSystem>(InEffect);
		UNiagaraSystem* niagara = Cast<UNiagaraSystem>(InEffect);

		FVector location = InTransform.GetLocation();
		FRotator rotation = FRotator(InTransform.GetRotation());
		FVector scale = InTransform.GetScale3D();
		if (InMesh)
		{
			if (particle)
			{
				UGameplayStatics::SpawnEmitterAttached(particle, InMesh, InSocketName, location, rotation, scale);

				return;
			}

			if (niagara)
			{
				UNiagaraFunctionLibrary::SpawnSystemAttached(niagara, InMesh, InSocketName, location, rotation, scale, EAttachLocation::KeepRelativeOffset, true, ENCPoolMethod::None);
			
				return;
			}
		}

		if (particle)
		{
			UGameplayStatics::SpawnEmitterAtLocation(InWorld, particle, InTransform);

			return;
		}

		if (niagara)
			UNiagaraFunctionLibrary::SpawnSystemAtLocation(InWorld ,niagara, location, rotation, scale);
	}
};

CreateActorComponent 로 UObject 를 생성하고, GetAsset 으로 애셋을 대입시킨다. GetComponent 로 특정 액터의 액터 컴포넌트를 조회할 수도 있다. GetActor 를 이용해 World 에 스폰된 액터들을 조회하거나, PlayEffect 를 이용해 파티클 시스템/나이아가라 시스템을 이용할 수도 있다.

예시 코드를 보자.

 

Example.cpp

CHelpers::CreateComponent<USpringArmComponent>(this, &SpringArm, "SpringArm", GetMesh());
CHelpers::CreateComponent<UCameraComponent>(this, &Camera, "SpringArm", SpringArm);
CHelpers::CreateActorComponent<UStatusComponent>(this, &Status, "Status");

USkeletalMesh* mesh;
CHelpers::GetAsset<USkeletalMesh>(&mesh, "SkeletalMesh'/Game/Character/Mesh/SK_Mannequin.SK_Mannequin'");
GetMesh()->SetSkeletalMesh(mesh);

TSubclassOf<UAnimInstance> animInstance;
CHelpers::GetClass<UAnimInstance>(&animInstance, "AnimBlueprint'/Game/BP_CAnimInstance.BP_CAnimInstance_C'");
GetMesh()->SetAnimInstanceClass(animInstance);

...

ACharacter* OwnerCharacter;

State = CHelpers::GetComponent<UCStateComponent>(OwnerCharacter);
Status = CHelpers::GetComponent<UCStatusComponent>(OwnerCharacter);