Unreal教学（7）——控制玩家相机（Player-Controlled Cameras）

下面这个设置好像只有一个有作用，无法同时控制两个物体。

    //Take control of the default Player    AutoPossessPlayer = EAutoReceiveInput::Player0;

这个程序是让物体附加一个相机，应该移动和视图都是针对物体的，和之前的Game-Controlled Cameras还是有区别的，Game-Controlled Camera没有依附特定的物体，直接写在程序的两个变量上进行控制，而这个例子使用的是UCameraComponent，attach到根节点。

放上代码，和之前的例子没有什么区别，那么这个C++ Programming Tutorials中的七个例子还剩下两个例子，First Person Shooter Tutorial和User Interface With UMG.这两个例子暂时先不写，已经能写基本的程序，需要弄清楚它们的类是干什么的。很明显的tutorial上有个错误是编译不过的，但是自己参考API修改过来了。

Performing 3 actions (4 in parallel)@progress 'Compiling C++ source code...' 0%[2/3] Compile PawnWithCamera.cpp[1/3] Compile PawnWithCamera.gen.cpp/home/wang/Documents/Unreal Projects/UnrealLearn/Source/UnrealLearn/PawnWithCamera.cpp:75:43: error:       no member named 'SafeNormal' in 'FVector2D'            MovementInput = MovementInput.SafeNormal() * 100.0f;                            ~~~~~~~~~~~~~ ^1 error generated.@progress 'Compiling C++ source code...' 25%@progress 'Compiling C++ source code...' 50%@progress 'Compiling C++ source code...' 75%

可以看到编译的时候SafeNormal编译提示上说FVector2D没有这个方法，所以查看Document发现应该使用GetSafeNormal(),所以会查阅还是很重要的，之前就有很多的头文件都是通过查找获取来的，这点官网还做得比较好，附上代码。

PawnWithCamera.h

// Fill out your copyright notice in the Description page of Project Settings.#pragma once#include "CoreMinimal.h"#include "GameFramework/Pawn.h"#include "GameFramework/SpringArmComponent.h"#include "Camera/CameraComponent.h"#include "PawnWithCamera.generated.h"UCLASS()class UNREALLEARN_API APawnWithCamera : public APawn{GENERATED_BODY()public:// Sets default values for this pawn's propertiesAPawnWithCamera();protected:// Called when the game starts or when spawnedvirtual void BeginPlay() override;public:// Called every framevirtual void Tick(float DeltaTime) override;// Called to bind functionality to inputvirtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;protected:    UPROPERTY(EditAnywhere)    USpringArmComponent* OurCameraSpringArm;    UCameraComponent* OurCamera;//Input variables    FVector2D MovementInput;    FVector2D CameraInput;    float ZoomFactor;    bool bZoomingIn;    //Input functions    void MoveForward(float AxisValue);    void MoveRight(float AxisValue);    void PitchCamera(float AxisValue);    void YawCamera(float AxisValue);    void ZoomIn();    void ZoomOut();};

PawnWithCamera.cpp

// Fill out your copyright notice in the Description page of Project Settings.#include "PawnWithCamera.h"// Sets default valuesAPawnWithCamera::APawnWithCamera(){ // Set this pawn to call Tick() every frame.  You can turn this off to improve performance if you don't need it.PrimaryActorTick.bCanEverTick = true;//Create our components    RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));    OurCameraSpringArm = CreateDefaultSubobject<USpringArmComponent>(TEXT("CameraSpringArm"));    OurCameraSpringArm->SetupAttachment(RootComponent);    OurCameraSpringArm->SetRelativeLocationAndRotation(FVector(0.0f, 0.0f, 50.0f), FRotator(-60.0f, 0.0f, 0.0f));    OurCameraSpringArm->TargetArmLength = 400.f;    OurCameraSpringArm->bEnableCameraLag = true;    OurCameraSpringArm->CameraLagSpeed = 3.0f;    OurCamera = CreateDefaultSubobject<UCameraComponent>(TEXT("GameCamera"));    OurCamera->SetupAttachment(OurCameraSpringArm, USpringArmComponent::SocketName);    //Take control of the default Player    AutoPossessPlayer = EAutoReceiveInput::Player0;}// Called when the game starts or when spawnedvoid APawnWithCamera::BeginPlay(){Super::BeginPlay();}// Called every framevoid APawnWithCamera::Tick(float DeltaTime){Super::Tick(DeltaTime);//Zoom in if ZoomIn button is down, zoom back out if it's not    {        if (bZoomingIn)        {            ZoomFactor += DeltaTime / 0.5f;         //Zoom in over half a second        }        else        {            ZoomFactor -= DeltaTime / 0.25f;        //Zoom out over a quarter of a second        }        ZoomFactor = FMath::Clamp<float>(ZoomFactor, 0.0f, 1.0f);        //Blend our camera's FOV and our SpringArm's length based on ZoomFactor        OurCamera->FieldOfView = FMath::Lerp<float>(90.0f, 60.0f, ZoomFactor);        OurCameraSpringArm->TargetArmLength = FMath::Lerp<float>(400.0f, 300.0f, ZoomFactor);    }    //Rotate our actor's yaw, which will turn our camera because we're attached to it    {        FRotator NewRotation = GetActorRotation();        NewRotation.Yaw += CameraInput.X;        SetActorRotation(NewRotation);    }    //Rotate our camera's pitch, but limit it so we're always looking downward    {        FRotator NewRotation = OurCameraSpringArm->GetComponentRotation();        NewRotation.Pitch = FMath::Clamp(NewRotation.Pitch + CameraInput.Y, -80.0f, -15.0f);        OurCameraSpringArm->SetWorldRotation(NewRotation);    }    //Handle movement based on our "MoveX" and "MoveY" axes    {        if (!MovementInput.IsZero())        {            //Scale our movement input axis values by 100 units per second            MovementInput = MovementInput.GetSafeNormal() * 100.0f;            FVector NewLocation = GetActorLocation();            NewLocation += GetActorForwardVector() * MovementInput.X * DeltaTime;            NewLocation += GetActorRightVector() * MovementInput.Y * DeltaTime;            SetActorLocation(NewLocation);        }    }}// Called to bind functionality to inputvoid APawnWithCamera::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent){Super::SetupPlayerInputComponent(PlayerInputComponent);//Hook up events for "ZoomIn"    InputComponent->BindAction("ZoomIn", IE_Pressed, this, &APawnWithCamera::ZoomIn);    InputComponent->BindAction("ZoomIn", IE_Released, this, &APawnWithCamera::ZoomOut);    //Hook up every-frame handling for our four axes    InputComponent->BindAxis("MoveForward", this, &APawnWithCamera::MoveForward);    InputComponent->BindAxis("MoveRight", this, &APawnWithCamera::MoveRight);    InputComponent->BindAxis("CameraPitch", this, &APawnWithCamera::PitchCamera);    InputComponent->BindAxis("CameraYaw", this, &APawnWithCamera::YawCamera);}//Input functionsvoid APawnWithCamera::MoveForward(float AxisValue){    MovementInput.X = FMath::Clamp<float>(AxisValue, -1.0f, 1.0f);}void APawnWithCamera::MoveRight(float AxisValue){    MovementInput.Y = FMath::Clamp<float>(AxisValue, -1.0f, 1.0f);}void APawnWithCamera::PitchCamera(float AxisValue){    CameraInput.Y = AxisValue;}void APawnWithCamera::YawCamera(float AxisValue){    CameraInput.X = AxisValue;}void APawnWithCamera::ZoomIn(){    bZoomingIn = true;}void APawnWithCamera::ZoomOut(){    bZoomingIn = false;}