接上期…

UPROPERTY

可以带上分类属性,直接创建了Damage这个分类

UPROPERTY(EditAnywhere, Category="Damage")
int32 TotalDamage;

可见但不可编辑的属性

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

Transient表示不会保存到硬盘

构造函数初始化

下面2个程序功能一样:

AMyActor::AMyActor()
{
    TotalDamage = 200;
    DamageTimeInSeconds = 1.f;
}

AMyActor::AMyActor() :
    TotalDamage(200),
    DamageTimeInSeconds(1.f)
{
}

如果不手动初始化,引擎会自动设为0或空指针

可以根据TotalDamage与DamageTimeInSeconds对DamagePerSecond进行初始化

.h文件里加入

virtual void PostInitProperties() override;

.cpp文件里加入

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

通过蓝图扩展C++类

上面的只是初始化,并不会实时计算DPS,要想实现,需作如下修改:

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

其中if…endif这一段只是给编辑器用,并不会在游戏中生成.

使蓝图可从C++调用

只要在声明的语句前加上宏,如下:

UFUNCTION(BlueprintCallable, Category="Damage")
void CalculateValues();

使C++可从蓝图调用

UFUNCTION(BlueprintImplementableEvent, Category = "Damage")
         void CalledFromCpp();

蓝图自己使用的方法

UFUNCTION(BlueprintNativeEvent, Category="Damage")
void CalledFromCpp();

宏里带有BlueprintNativeEvent,必须在.cpp文件里写实现的方法,否则编译失败

void AMyActor::CalledFromCpp_Implementation()
{
    // Do something cool here
}