创建C++项目

 编辑器偏好设置

 本次将要用蓝图实现这样一个效果

创建一个继承于Actor的蓝图，蓝图配置如下

 然后创建一个继承于Actor的C++类

下一步

 这时会在自动生成两个文件，一个头文件和一个C++文件

ConeActor.h

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

#pragma once

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


UCLASS()
class MYPROJECT_API AConeActor final : public AActor
{
    GENERATED_BODY()

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

protected:
    UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Components")
    USceneComponent* Scene;

    UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Components")
    UStaticMeshComponent* ConeMesh;

    UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category="ConeActor|Anywere")
    uint8 bIsUp:1;

    UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category="ConeActor|Anywere")
    float MinHigh;

    UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category="ConeActor|Anywere")
    float MaxHigh;

    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="ConeActor")
    float Max;

    UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category="ConeActor")
    float CurrentZ;

    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="ConeActor")
    float Speed;


public:
    // Called when the game starts or when spawned
    virtual auto BeginPlay() -> void override;


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

 ConeActor.cpp

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


#include "ConeActor.h"

// Sets default values
AConeActor::AConeActor()
{
    // 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;
    Scene = CreateDefaultSubobject(TEXT("Scene"));
    ConeMesh = CreateDefaultSubobject(TEXT("ConeMesh"));
    Scene->SetupAttachment(GetRootComponent());
    ConeMesh->SetupAttachment(Scene);
    Speed = 50;
    Max = 200;
    
}

// Called when the game starts or when spawned
void AConeActor::BeginPlay()
{
    Super::BeginPlay();
    const FVector Location = GetActorLocation();
    CurrentZ = Location.Z;
    MinHigh = Location.Z;
    MaxHigh = Location.Z + Max;
    bIsUp = true;
}


// Called every frame


void AConeActor::Tick(const float DeltaTime)
{
    Super::Tick(DeltaTime);
    const float Var = DeltaTime * Speed;
    if (bIsUp)
    {
        CurrentZ = CurrentZ + Var;
    }
    else
    {
        CurrentZ = CurrentZ - Var;
    }
    FVector Location = GetActorLocation();
    Location.Z = CurrentZ;
    SetActorLocation(Location);

    if (CurrentZ > MaxHigh)
    {
        bIsUp = false;
    }
    else if (CurrentZ < MinHigh)
    {
        bIsUp = true;
    }
}

 编译之后，项目中新建蓝图，继承上面的C++类

 然后添加同样的静态网格模型，可以看到这里面没有写蓝图逻辑

Actor放到项目中，实现同样的效果

 小提示

Unreal C++常用类命名规范

• 继承UObject的类以大写字母U开头
• 继承AActor的类以大写字母A开头
• 继承Structs的类以大写字母F开头
• 继承Enums的类以大写字母E开头
• 其它的基本都是以大写字母F开头　　

代码结构和命名约定

• 变量用驼峰命名法，每个单词首字母必须大写
• Boolean类型变量必须以小写字母b开头，bIsUp
• if语句即使只有一行，也需要大括号包起来{}
• 大括号必须是在单独的一行

使用uint8定义布尔变量，可以节省内存，虚幻官方用的都是这种方式

　　uint8 bIsUp：1；