在UE中实现一个属性组件

¶先创建属性组件

class ACTIONROGUELIKE_API USAttributeComponent : public UActorComponent

¶属性组件肯定要有数据啦

UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Attributes")
float Health;

¶创建委托事件

//.h
DECLARE_DYNAMIC_MULTICAST_DELEGATE_FourParams(FOnHealthChanged, AActor*, InstigatorActor, USAttributeComponent*, OwningComp, float, NewHealth, float, Delta);


UFUNCTION(BlueprintCallable, Category = "Attributes")
bool ApplyHealthChange(float Delta);

UPROPERTY(BlueprintAssignable)
FOnHealthChanged OnHealthChanged;


//.cpp
bool USAttributeComponent::ApplyHealthChange(float Delta)
{
    Health += Delta;
    OnHealthChanged.Broadcast(nullptr, this, Health, Delta);
    return true;
}

¶交互的开始

¶C++初始

给需要属性的Actor添加组件

// ACharacter or APawn
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Components")
USAttributeComponent* AttributeComp;

void ASCharacter::PostInitializeComponents()
{
    Super::PostInitializeComponents();
    AttributeComp->OnHealthChanged.AddDynamic(this, &ASCharacter::OnHealthChanged);
}
void ASCharacter::OnHealthChanged(AActor* InstigatorActor, USAttributeComponent* OwningComp, float NewHealth,
    float Delta)
{
    if(NewHealth <= 0.f && Delta < 0.f)
    {
        APlayerController* PC = Cast<APlayerController>(GetController());
        DisableInput(PC);
    }
}

¶蓝图初始

在蓝图中选中需要属性的Actor，添加属性组件，选中属性组件，在属性面板中重载属性变更事件OnHealthChanged

blueprint

¶C++交互

ASMagicProjectile::ASMagicProjectile()
{
    SphereComp->SetSphereRadius(20.0f);
    SphereComp->OnComponentBeginOverlap.AddDynamic(this, &ASMagicProjectile::OnActorOverlap);

    DamageAmount = 20.0f;
}

void ASMagicProjectile::OnActorOverlap(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
                                       UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep,
                                       const FHitResult& SweepResult)
{
    if (OtherActor && OtherActor != GetInstigator())
    {
        USAttributeComponent* AttributeComp = Cast<USAttributeComponent>(
            OtherActor->GetComponentByClass(USAttributeComponent::StaticClass()));
        if (AttributeComp)
        {
            AttributeComp->ApplyHealthChange(-DamageAmount); // 在需要触发属性变更的地方调用，这个使用的是魔珐弹碰撞时时触发
            Explode();
        }
    }
}