Unreal Engine 4：学习笔记（八）PlayerController

悠悠 2022-05-17 09:35 333阅读 0赞

首先，PlayerController自身也是一个Actor，通过它，玩家才能控制游戏中的Actor、Pawn、Character等。

UObject-+
            |-AActor-+
                     |-AController--+
                                    |-APlayerController

## 如何设置PlayerController才能绑定事件？ ##

**对于Actor**

在Actor的Blueprint中，通过 Input -> Auto Receive Input  设置，Unreal中的源码如下：

void AActor::PreInitializeComponents()
    {
    	if (AutoReceiveInput != EAutoReceiveInput::Disabled)
    	{
    		const int32 PlayerIndex = int32(AutoReceiveInput.GetValue()) - 1;
    
    		APlayerController* PC = UGameplayStatics::GetPlayerController(this, PlayerIndex);
    		if (PC)
    		{
    			EnableInput(PC);
    		}
    		else
    		{
    			GetWorld()->PersistentLevel->RegisterActorForAutoReceiveInput(this, PlayerIndex);
    		}
    	}
    }
    
    void AActor::EnableInput(APlayerController* PlayerController)
    {
    	if (PlayerController)
    	{
    		// If it doesn't exist create it and bind delegates
    		if (!InputComponent)
    		{
    			InputComponent = NewObject<UInputComponent>(this);
    			InputComponent->RegisterComponent();
    			InputComponent->bBlockInput = bBlockInput;
    			InputComponent->Priority = InputPriority;
    
    			if (UInputDelegateBinding::SupportsInputDelegate(GetClass()))
    			{
    				UInputDelegateBinding::BindInputDelegates(GetClass(), InputComponent);
    			}
    		}
    		else
    		{
    			// Make sure we only have one instance of the InputComponent on the stack
    			PlayerController->PopInputComponent(InputComponent);
    		}
    
    		PlayerController->PushInputComponent(InputComponent);
    	}
    }

以上代码就是Unreal Engine 4中的具体实现。

设置完成后，就可以在自己的实现类的void AActor::BeginPlay()中使用InputComponent绑定事件了，比如：

if (InputComponent != nullptr)
    {
    	InputComponent->BindAction("Fire", IE_Pressed, this, &ABatteryActor::Fire);
    }

**对于Pawn**

在Pawn的Blueprint中，通过 Pawn -> Auto Possess Player 中设置，Unreal中的源码如下：

void APawn::PreInitializeComponents()
    {
    	Super::PreInitializeComponents();
    
    	if (Instigator == nullptr)
    	{
    		Instigator = this;
    	}
    
    	if (AutoPossessPlayer != EAutoReceiveInput::Disabled && GetNetMode() != NM_Client )
    	{
    		const int32 PlayerIndex = int32(AutoPossessPlayer.GetValue()) - 1;
    
    		APlayerController* PC = UGameplayStatics::GetPlayerController(this, PlayerIndex);
    		if (PC)
    		{
    			PC->Possess(this);   // 此方法内会将  AController* APawn::Controller 设置成PC
    		}
    		else
    		{
    			GetWorld()->PersistentLevel->RegisterActorForAutoReceiveInput(this, PlayerIndex);
    		}
    	}
    
    	UpdateNavigationRelevance();
    }

以上代码就是Unreal Engine 4中的具体实现。

设置完成后，就可以在void APawn::SetupPlayerInputComponent(UInputComponent\* PlayerInputComponent)中使用InputComponent绑定事件了。

而SetupPlayerInputComponent方法是在如下方法中被调用的：

void APawn::PawnClientRestart()
    {
    	Restart();
    
    	APlayerController* PC = Cast<APlayerController>(Controller);
    	if (PC && PC->IsLocalController())
    	{
    		// Handle camera possession
    		if (PC->bAutoManageActiveCameraTarget)
    		{
    			PC->AutoManageActiveCameraTarget(this);
    		}
    
    		// Set up player input component, if there isn't one already.
    		if (InputComponent == NULL)
    		{
    			InputComponent = CreatePlayerInputComponent();
    			if (InputComponent)
    			{
    				SetupPlayerInputComponent(InputComponent);
    				InputComponent->RegisterComponent();
    				if (UInputDelegateBinding::SupportsInputDelegate(GetClass()))
    				{
    					InputComponent->bBlockInput = bBlockInput;
    					UInputDelegateBinding::BindInputDelegates(GetClass(), InputComponent);
    				}
    
    			}
    		}
    	}
    }