IMImeamangryang
VelogGitHub
← Blog

ENGINEERING NOTE

[Unreal Engine] Tick 함수 최적화

해당 포스팅은 Stuart Butler , Tom Oliver의 Game Development Patterns with Unreal Engine 5를 바탕으로 작성한 내용입니다.위와 같이 적을 색적하기 위한 감시 타워 오브젝트를 만들었다.해당 코드로 실행을 해도 목표로

25 min read
Unreal Engine
해당 포스팅은 Stuart Butler , Tom Oliver의 Game Development Patterns with Unreal Engine 5를 바탕으로 작성한 내용입니다.

Tick 함수를 최적화해보자.

위와 같이 적을 색적하기 위한 감시 타워 오브젝트를 만들었다.

cpp
// GuardTower.h
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "GuardTower_CH5_1.generated.h"

class UArrowComponent;
class USpotLightComponent;
UCLASS()
class RTS_AI_API AGuardTower_CH5_1 : public AActor
{
	GENERATED_BODY()

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<UStaticMeshComponent> _TowerMesh;
	
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<USceneComponent> _LightPivot;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<UStaticMeshComponent> _LightMesh;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<USpotLightComponent> _SpotLight;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<UArrowComponent> _Arrow;

public:	
	// Sets default values for this actor's properties
	AGuardTower_CH5_1();

	virtual void Tick(float DeltaTime) override;

protected:
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	bool _RotateForward;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	bool _EnemySpotted;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	float _DetectionRange;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	float _DetectionRadius;
};
cpp
// GuardTower.cpp
#include "GuardTower_CH5_1.h"

#include "Components/ArrowComponent.h"
#include "Components/SpotLightComponent.h"
#include "GameFramework/Character.h"
#include "Kismet/KismetSystemLibrary.h"

AGuardTower_CH5_1::AGuardTower_CH5_1()
{
	PrimaryActorTick.bCanEverTick = true;
	_RotateForward = true;
	_EnemySpotted = false;
	_DetectionRange = 4000.f;
	_DetectionRadius = 250.f;

	_TowerMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("TowerMesh"));
	RootComponent = _TowerMesh;
	
	_LightPivot = CreateDefaultSubobject<USceneComponent>(TEXT("LightPivot"));
	_LightPivot->SetupAttachment(_TowerMesh);
	
	_LightMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("LightMesh"));
	_LightMesh->SetupAttachment(_LightPivot);
	
	_SpotLight = CreateDefaultSubobject<USpotLightComponent>(TEXT("SpotLight"));
	_SpotLight->SetupAttachment(_LightMesh);
	
	_Arrow = CreateDefaultSubobject<UArrowComponent>(TEXT("Arrow"));
	_Arrow->SetupAttachment(_LightMesh);
}

void AGuardTower_CH5_1::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);
	
	// 시작 위치와 끝 위치 계산 (전방으로 DetectionRange만큼)
	FVector startLocation = _Arrow->GetComponentLocation();
	FVector endLocation = _Arrow->GetComponentLocation() + (_Arrow->GetForwardVector() * _DetectionRange);

	// 구체(스피어) 트레이스 결과 저장용
	FHitResult hit;
	TArray<AActor*> ActorsToIgnore;

	// 스피어 트레이스 실행
	UKismetSystemLibrary::SphereTraceSingle(
		GetWorld(), 
		startLocation, 
		endLocation, 
		_DetectionRadius,
		UEngineTypes::ConvertToTraceType(ECC_Visibility), 
		false,
		ActorsToIgnore, 
		EDrawDebugTrace::ForOneFrame, 
		hit, 
		true
	);

	// 히트된 액터를 캐릭터로 캐스팅해 적 탐지 여부 확인
	ACharacter* otherCasted = Cast<ACharacter>(hit.GetActor());
	_EnemySpotted = (otherCasted != nullptr);

	// 적이 없을 때만 라이트를 좌우로 회전
	if(!_EnemySpotted)
	{
		if(_RotateForward)
		{
			// 오른쪽(또는 지정 방향)으로 회전
			_LightPivot->AddLocalRotation(FRotator(0.0, 0.2, 0.0));

			// Yaw가 40도에 거의 도달하면 회전 방향 반전
			if(FMath::IsNearlyEqual(_LightPivot->GetRelativeRotation().Yaw, 40.f))
			{
				_RotateForward = false;
			}
		}
		else
		{
			// 반대 방향으로 회전
			_LightPivot->AddLocalRotation(FRotator(0.0, -0.2, 0.0));

			// Yaw가 -40도에 거의 도달하면 회전 방향 반전
			if(FMath::IsNearlyEqual(_LightPivot->GetRelativeRotation().Yaw, -40.f))
			{
				_RotateForward = true;
			}
		}
	}
}

해당 코드로 실행을 해도 목표로 하는 동작은 정상적으로 수행된다. 하지만 이러한 코드는 잠재적으로 여러가지 문제점을 내포하고 있다.

1. 모든 로직이 Tick 안에 존재

  • 스피어 트레이스, 라이트 회전, 적 탐지 모두 Tick에서 수행
  • 매 프레임 불필요한 연산 발생 → 성능 저하 가능

2. 매 프레임 Getter/Vector 연산 반복

  • _Arrow->GetComponentLocation() 같은 함수가 매 프레임 반복 호출됨
  • 불필요한 함수 호출과 Vector 연산 발생

3. 형변환(Cast) 연산 반복

  • ACharacter* otherCasted = Cast<ACharacter>(hit.GetActor());
  • 매 Tick마다 수행 → 캐릭터가 많으면 비용 증가

4. 회전 로직의 하드코딩

  • Yaw 제한값(-40, 40)과 회전량(0.2f) 하드코딩

5. Gated Polling 미흡

  • 적이 감지되지 않은 상태에서도 매 Tick 라이트 회전 계속 수행
  • 적 발견 시에도 트레이스나 회전 체크가 Tick에서 계속 이루어짐

최적화 방안

1. Tick 의존 제거 → 이벤트 기반

  • SphereComponent의 Overlap 이벤트(OnSphereOverlapBegin, OnSphereOverlapEnd)를 활용해 적 감지
  • 적이 들어왔을 때만 LineTrace 수행 → 불필요한 매 프레임 검사 제거 (Gated Polling 적용)
cpp
// GuardTower.h
UFUNCTION()
void OnSphereOverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool FromSweep, const FHitResult& SweepResult);

UFUNCTION()
void OnSphereOverlapEnd(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);
cpp
// GuardTower.cpp
_Sphere = CreateDefaultSubobject<USphereComponent>(TEXT("Sphere"));
_Sphere->SetupAttachment(_LightMesh);
_Sphere->OnComponentBeginOverlap.AddDynamic(this, &AGuardTower_CH5_3::OnSphereOverlapBegin);
_Sphere->OnComponentEndOverlap.AddDynamic(this, &AGuardTower_CH5_3::OnSphereOverlapEnd);

...

void AGuardTower_CH5_3::OnSphereOverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool FromSweep, const FHitResult& SweepResult)
{
	if(_EnemyUnit != nullptr) return;

	_EnemyUnit = Cast<ACharacter>(OtherActor);
	if(_EnemyUnit == nullptr) return;
	
	// 필요할 때만 LineTrace 수행
	FHitResult hit(ForceInit);
	FVector start = _Arrow->GetComponentLocation();
	FVector end = _EnemyUnit->GetActorLocation();
	TArray<AActor*> ActorsToIgnore;
	ActorsToIgnore.Add(_EnemyUnit);

	if(UKismetSystemLibrary::LineTraceSingle(GetWorld(), start, end,
		UEngineTypes::ConvertToTraceType(ECC_Visibility), false,
		ActorsToIgnore, EDrawDebugTrace::ForDuration, hit, true, FLinearColor::Red,
		FLinearColor::Green, 0.5f))
	{
		if(hit.GetActor() != OtherActor) return;
	}
	
	_EnemySpotted = true;
	StopRotation();
}

2. 라인 트레이스 최소화

  • _Arrow->GetComponentLocation() 같은 Getter 호출을 이벤트 발생 시점으로 제한
  • 매 Tick마다 불필요한 연산 제거
cpp
FVector start = _Arrow->GetComponentLocation();
FVector end = _EnemyUnit->GetActorLocation();
TArray<AActor*> ActorsToIgnore;
ActorsToIgnore.Add(_EnemyUnit);

UKismetSystemLibrary::LineTraceSingle(GetWorld(), start, end,
	UEngineTypes::ConvertToTraceType(ECC_Visibility), false,
	ActorsToIgnore, EDrawDebugTrace::ForDuration, hit, true, FLinearColor::Red,
	FLinearColor::Green, 0.5f);

3. 회전 로직 개선(Timeline)

  • Timeline + CurveFloat를 사용해 프레임 독립적 회전 구현
  • FRotator::SetRelativeRotation(FMath::Lerp(-40.f, 40.f, val))로 부드러운 회전
  • 하드코딩 값은 Curve에서 관리 가능
cpp
// GuardTower.h
// Timeline 관련 Delegate
FOnTimelineFloat onTimeline_Update;
FOnTimelineEventStatic onTimeline_Finished;

// Timeline 처리 함수
UFUNCTION()
void Handle_RotateLight_Update(float val);

UFUNCTION()
void Handle_RotateLight_Finished();

// Timeline 제어
void StartRotation();
void StopRotation();

// Timeline 컴포넌트
UPROPERTY(EditAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
TObjectPtr<UTimelineComponent> T_RotateLight;

// CurveFloat
UPROPERTY(EditAnywhere)
UCurveFloat* _Curve;
cpp
// GuardTower.cpp
AGuardTower_CH5_3::AGuardTower_CH5_3()
{
	...
	
	T_RotateLight = CreateDefaultSubobject<UTimelineComponent>(TEXT("T_RotateLight"));
	onTimeline_Update.BindUFunction(this, FName("Handle_RotateLight_Update"));
	onTimeline_Finished.BindUFunction(this, FName("Handle_RotateLight_Finished"));
}

void AGuardTower_CH5_3::BeginPlay()
{
	Super::BeginPlay();

	if(_Curve == nullptr) { return;}
	T_RotateLight->AddInterpFloat(_Curve, onTimeline_Update, FName("Alpha"));
	T_RotateLight->SetTimelineFinishedFunc(onTimeline_Finished);
	T_RotateLight->SetLooping(false);
	T_RotateLight->SetIgnoreTimeDilation(true);
	StartRotation();
}

void AGuardTower_CH5_3::Handle_RotateLight_Update(float val)
{
	// Curve 기반 Lerp로 부드럽게 회전
	_LightPivot->SetRelativeRotation(
		FRotator(0.f, FMath::Lerp(-40.f, 40.f, val), 0.f));
}

void AGuardTower_CH5_3::Handle_RotateLight_Finished()
{
	// 회전 방향 토글
	_RotateForward = !_RotateForward;
	StartRotation();
}

void AGuardTower_CH5_3::StartRotation()
{
	if(_RotateForward)
		T_RotateLight->Play();
	else
		T_RotateLight->Reverse();
}

void AGuardTower_CH5_3::StopRotation()
{
	T_RotateLight->Stop();
}

4. Gated Polling 적용

  • _EnemySpotted 값에 따라 Timeline 회전 제어
  • 적 발견 시 Timeline 중지 → 불필요한 반복 제거
  • 적이 사라지면 Timeline 다시 재생
cpp
void AGuardTower_CH5_3::OnSphereOverlapEnd(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex)
{
	if(_EnemyUnit != OtherActor) return;
	
	_EnemySpotted = false;
	_EnemyUnit = nullptr;
	StartRotation(); // 적이 사라지면 다시 회전 시작
}

5. 로직 함수 분리

  • 최종적으로 회전 처리, Timeline 제어, 적 감지 처리 등을 Tick함수에서 개별 함수로 분리
  • 코드 가독성 및 유지보수성 향상
cpp
// 회전 처리
void AGuardTower_CH5_3::Handle_RotateLight_Update(float val);

// 회전 종료 후 방향 토글
void AGuardTower_CH5_3::Handle_RotateLight_Finished();

// Timeline 제어
void AGuardTower_CH5_3::StartRotation();
void AGuardTower_CH5_3::StopRotation();

// 적 감지 처리
void AGuardTower_CH5_3::OnSphereOverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool FromSweep, const FHitResult& SweepResult);

void AGuardTower_CH5_3::OnSphereOverlapEnd(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);

최종 코드 전체

cpp
// GuardTower.h 개선 버전
// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "Components/SphereComponent.h"
#include "Components/TimelineComponent.h"
#include "GameFramework/Actor.h"
#include "GuardTower_CH5_3.generated.h"

class ACharacter;
class UArrowComponent;
class USpotLightComponent;
UCLASS()
class RTS_AI_API AGuardTower_CH5_3 : public AActor
{
	GENERATED_BODY()

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<UStaticMeshComponent> _TowerMesh;
	
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<USceneComponent> _LightPivot;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<UStaticMeshComponent> _LightMesh;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<USpotLightComponent> _SpotLight;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<UArrowComponent> _Arrow;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, meta=(AllowPrivateAccess = true))
	TObjectPtr<USphereComponent> _Sphere;

	FOnTimelineFloat onTimeline_Update;
	FOnTimelineEventStatic onTimeline_Finished;
	UFUNCTION()
	void Handle_RotateLight_Update(float val);
	UFUNCTION()
	void Handle_RotateLight_Finished();
	void StartRotation();
	void StopRotation();
	
public:
	AGuardTower_CH5_3();

protected:
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	bool _RotateForward;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	bool _EnemySpotted;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	float _DetectionRange;
	
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	float _DetectionRadius;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	TObjectPtr<ACharacter> _EnemyUnit;

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	TObjectPtr<UTimelineComponent> T_RotateLight;

	UPROPERTY(EditAnywhere)
	UCurveFloat* _Curve;
	
	virtual void BeginPlay() override;

	UFUNCTION()
	void OnSphereOverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool FromSweep, const FHitResult& SweepResult);

	UFUNCTION()
	void OnSphereOverlapEnd(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);
};
cpp
// GuardTower.cpp 개선 버전
#include "GuardTower_CH5_3.h"

#include "Components/ArrowComponent.h"
#include "Components/SpotLightComponent.h"
#include "GameFramework/Character.h"
#include "Kismet/KismetSystemLibrary.h"

AGuardTower_CH5_3::AGuardTower_CH5_3()
{
	PrimaryActorTick.bCanEverTick = true;
	_RotateForward = true;
	_EnemySpotted = false;
	_DetectionRange = 4000.f;
	_DetectionRadius = 250.f;

	_TowerMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("TowerMesh"));
	RootComponent = _TowerMesh;
	
	_LightPivot = CreateDefaultSubobject<USceneComponent>(TEXT("LightPivot"));
	_LightPivot->SetupAttachment(_TowerMesh);
	
	_LightMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("LightMesh"));
	_LightMesh->SetupAttachment(_LightPivot);
	
	_SpotLight = CreateDefaultSubobject<USpotLightComponent>(TEXT("SpotLight"));
	_SpotLight->SetupAttachment(_LightMesh);
	
	_Arrow = CreateDefaultSubobject<UArrowComponent>(TEXT("Arrow"));
	_Arrow->SetupAttachment(_LightMesh);

	_Sphere = CreateDefaultSubobject<USphereComponent>(TEXT("Sphere"));
	_Sphere->SetupAttachment(_LightMesh);
	_Sphere->OnComponentBeginOverlap.AddDynamic(this, &AGuardTower_CH5_3::OnSphereOverlapBegin);
	_Sphere->OnComponentEndOverlap.AddDynamic(this, &AGuardTower_CH5_3::OnSphereOverlapEnd);
	
	T_RotateLight = CreateDefaultSubobject<UTimelineComponent>(TEXT("T_RotateLight"));
	onTimeline_Update.BindUFunction(this, FName("Handle_RotateLight_Update"));
	onTimeline_Finished.BindUFunction(this, FName("Handle_RotateLight_Finished"));
}

void AGuardTower_CH5_3::BeginPlay()
{
	Super::BeginPlay();

	if(_Curve == nullptr) { return;}
	T_RotateLight->AddInterpFloat(_Curve, onTimeline_Update, FName("Alpha"));
	T_RotateLight->SetTimelineFinishedFunc(onTimeline_Finished);
	T_RotateLight->SetLooping(false);
	T_RotateLight->SetIgnoreTimeDilation(true);
	StartRotation();
}

void AGuardTower_CH5_3::Handle_RotateLight_Update(float val)
{
	_LightPivot->SetRelativeRotation(
		FRotator(0.f, FMath::Lerp(-40.f, 40.f, val), 0.f));
}

void AGuardTower_CH5_3::Handle_RotateLight_Finished()
{
	_RotateForward = !_RotateForward;
	StartRotation();
}

void AGuardTower_CH5_3::StartRotation()
{
	if(_RotateForward)
	{
		T_RotateLight->Play();
	}
	else
	{
		T_RotateLight->Reverse();
	}
}

void AGuardTower_CH5_3::StopRotation()
{
	T_RotateLight->Stop();
}

void AGuardTower_CH5_3::OnSphereOverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool FromSweep, const FHitResult& SweepResult)
{
	if(_EnemyUnit != nullptr) {return;}

	_EnemyUnit = Cast<ACharacter>(OtherActor);
	if(_EnemyUnit == nullptr) {return;}
	
	FHitResult hit(ForceInit);
	FVector start = _Arrow->GetComponentLocation();
	FVector end = _EnemyUnit->GetActorLocation();
	TArray<AActor*> ActorsToIgnore;
	ActorsToIgnore.Add(_EnemyUnit);
	if(UKismetSystemLibrary::LineTraceSingle(GetWorld(), start, end,
		UEngineTypes::ConvertToTraceType(ECC_Visibility), false,
		ActorsToIgnore, EDrawDebugTrace::ForDuration, hit, true, FLinearColor::Red,
		FLinearColor::Green, 0.5f))
	{
		if(hit.GetActor() != OtherActor) return;
	}
	
	_EnemySpotted = true;
	StopRotation();
}

void AGuardTower_CH5_3::OnSphereOverlapEnd(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex)
{
	if(_EnemyUnit != OtherActor) {return;}
	
	_EnemySpotted = false;
	_EnemyUnit = nullptr;
	StartRotation();
}

요약 비교

항목수정 전수정 후
적 감지매 Tick 스피어 트레이스SphereComponent Overlap 이벤트 + LineTrace
라이트 회전Tick에서 AddLocalRotation, 하드코딩Timeline + CurveFloat로 프레임 독립적 회전
Gated Polling미적용, 항상 검사적 발견 여부에 따라 회전/트레이스 제어
성능매 프레임 불필요 연산이벤트 발생 시에만 최소 연산
가독성Tick에 모든 로직 포함함수 분리, 역할 별 모듈화