u4初步使用整理（一）

1.关键方法

1. GetActorForwardVector()，获取Actor前进方向，以ArrorwComponent方向一致。
2. GetActorRightVector()
3. AddMovementInput()
4. AddControllerYawInput()
5. AddControllerPitchInput()
6. InputComponent->BindAxis("Pitch", this, &AAvatar::Pitch); 输入绑定需要先在config里做按键配置。

2.注意问题

1. 动态添加USphereComponent，需要重写构造函数，并初始化，否则崩溃。

   public:
   ANPC(const FObjectInitializer& ObjectInitializer);
   public:
   UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = Collision)
   TSubobjectPtr<class USphereComponent> ProxSphere;
   
   ANPC::ANPC(const FObjectInitializer& ObjectInitializer)
   {
       ProxSphere = ObjectInitializer.CreateDefaultSubobject<USphereComponent>(this,   TEXT("ProxSphere"));
   }
   

2. UPROPERTY EditAnywhere 能在bp中修改的变量需要为public。
3. A Private function cannot be a BlueprintNativeEvent
4. 基于c++类建bp，一定要在bp下compile，这是个坑，c++里动态加入的component需要compile下才能更新到bp。

5. sphere碰撞触发处理： UFUNCTION(BlueprintNativeEvent, Category = "Collision") void Prox(AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult & SweepResult);

   ANPC::ANPC(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
   {
       TTTProxSphere = ObjectInitializer.CreateDefaultSubobject<USphereComponent>(this, TEXT("XXXXXSphere"));
       TTTProxSphere->AttachTo(RootComponent);
       TTTProxSphere->SetSphereRadius(50.f);
       TTTProxSphere->OnComponentBeginOverlap.AddDynamic(this, &ANPC::Prox);
       NpcMessage = "Default  Message.";
   }
   
   void ANPC::Prox_Implementation(AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult & SweepResult)
   {
       if (Cast<AAvatar>(OtherActor) == nullptr)
       {
           return;
       }
       APlayerController *PController = GetWorld()->GetFirstPlayerController();
       if (PController)
       {
           AMyHUD *hud = Cast<AMyHUD>(PController->GetHUD());
           hud->addMessage(Message(NpcMessage, 5.f, FColor::White));
       }
   }