Unreal Engine and C++ (1)

개요

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Class 마법사(Unreal Engine에서 새로운 Class 만들기)

File > New C++ Class >

MyActor.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

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

UCLASS()
class CPPTEST_API AMyActor : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AMyActor();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

};

• BeingPalay()는 액터가 플레이 가능한 상태로 게임에 들어왔음을 알려주는 이벤트
• Tick()는 지난번 들여온 이후의 경과된 시간만큼 프레임당 한 번씩 호출된다

MyActor.Cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "MyActor.h"

// Sets default values
AMyActor::AMyActor()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void AMyActor::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AMyActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

• PrimaryActorTick.bCanEverTick = true를 제거함으로써 필요치 않은 반복 로직을 제거할 수 있다

컴파일

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Class

접두사

• A : 스폰가능한 게임플레이 오브젝트의 베이스 클래스에서 확장(Actor, 월드에서 바로 스폰 가능)
• U : 모든 게임플레이 오브젝트의 베이스 클래스에서 확장(월드에서 바로 인스턴싱 불가, 엑터에 속해야함, 컴포넌트와 같은 오브젝트)

선언

UCLASS([specifier, specifier, ...], [meta(key = value, key = value, ...)])
class ClassName : public ParentName // 클래스의 상속
{
    GENERATED_BODY()
}

• UCLASS매크로에 클래스 지정자나 메타데이터와 같은 지시어가 전달됨
• GENERATED_BODY()매크로는 본문 제일 처음에 와야함
• 아래의 Class Specifier를 위의 specifier란에 용도에 맞게 적어서 쓸 수 있다

Class Specifier

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프로퍼티가 에디터에 보이도록 만들기

MyActor.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

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

UCLASS()
class CPPTEST_API AMyActor : public AActor
{
	GENERATED_BODY()
	
public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Damage")
	    int32 TotalDamge;

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

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

};

• GENERATED_BODY()와 UPROPERTY()뒤에는 ;을 붙이지 않는다
• 아래의 프로퍼티 지정자를 UPROPERTY()에 적절히 사용함으로써 위의 상황에선 다음과 같은 설정을 할 수 있다

MyActor.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

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

UCLASS()
class CPPTEST_API AMyActor : public AActor
{
	GENERATED_BODY()
	
public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Damage")
		int32 TotalDamage;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Damage")
		float DamageTimeInSeconds;

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, Transient, Category = "Damage")
		float DamagePerSecond;

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

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

};

MyActor.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "MyActor.h"

// Sets default values
AMyActor::AMyActor()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	TotalDamage = 200;
	DamageTimeInSeconds = 1.f;

}

// Called when the game starts or when spawned
void AMyActor::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AMyActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

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종속적인 프로퍼티 계산 시키기

void AMyActor::PostInitProperties()
{
    Super::PostInitProperties();
    DamagePerSecond = TotalDamage / DamageTimeInSeconds;
}

위와 같이 선언해주면 초기값만 계산한다

MyActor.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

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

UCLASS()
class CPPTEST_API AMyActor : public AActor
{
	GENERATED_BODY()
	
public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Damage")
		int32 TotalDamage;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Damage")
		float DamageTimeInSeconds;

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, Transient, Category = "Damage")
		float DamagePerSecond;

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

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;
	void PostInitProperties();
	void CalculateValues();
	void PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent);
};

MyActor.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "MyActor.h"

// Sets default values
AMyActor::AMyActor()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	TotalDamage = 200;
	DamageTimeInSeconds = 1.f;

}

// Called when the game starts or when spawned
void AMyActor::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AMyActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

void AMyActor::PostInitProperties()
{
	Super::PostInitProperties();

	CalculateValues();
}

void AMyActor::CalculateValues()
{
	DamagePerSecond = TotalDamage / DamageTimeInSeconds;
}

#if WITH_EDITOR
void AMyActor::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	CalculateValues();

	Super::PostEditChangeProperty(PropertyChangedEvent);
}
#endif

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여러가지 프로퍼티 지정자

프로퍼티 지정자