根据官方文档创建一个可以控制前后左右移动、旋转视角、缩放视角的Pawn 。
步骤
一、创建Pawn
1. 新建一个C++类，继承Pawn类，这里命名为“PawnWithCamera”
2. 在头文件中申明弹簧臂、摄像机和静态网格体组件
3. 在源文件中引入组件所需库
在构造函数中创建组件实例
将StaticMesh组件附加在根组件上，再将SpringArm组件附加在StaticMesh组件上，最后将Camera组件附加在SpringArm组件的末端
设置一下SpringArm组件的相对位置和旋转、弹簧臂长度、开启相机滞后、相机滞后速度
设置自动控制该Pawn
4. 编译好后，创建基于“PawnWithCamera”的蓝图类“BP_PawnWithCamera”
将“BP_PawnWithCamera”拖入视口
然后运行，可以看到我们此时视角就是“BP_PawnWithCamera”中Camera组件的视角了，但是我们现在还无法通过鼠标键盘去操控这个Pawn。
二、操控Pawn
1. 打开项目设置，添加操作映射和轴映射如下，完成输入绑定
2. 下面开始响应输入。在头文件中定义如下输入变量
定义如下输入函数
在源文件中实现输入函数
现在已经有了存储输入数据的函数，接着要告知引擎何时调用该代码。需要把Pawn的输入事件和函数相互绑定：
在Tick中处理视角缩放逻辑，当按下鼠标右键时按钮时进行放大，否则恢复正常。
继续编辑旋转逻辑
最后编辑移动逻辑如下
此时就完成了Pawn的前后左右移动、旋转视角、缩放视角的功能了。
完整代码如下：
PawnWithCamera.h
// Fill out your copyright notice in the Description page of Project Settings.#pragma once#include "CoreMinimal.h"
#include "GameFramework/Pawn.h"
#include "PawnWithCamera.generated.h"UCLASS()
class STUDY_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:void MoveForward(float AxisValue);void MoveRight(float AxisValue);void PitchCamera(float AxisValue);void YawCamera(float AxisValue);void ZoomIn();void ZoomOut();protected:UPROPERTY(EditAnywhere)class USpringArmComponent* SpringArmComp;UPROPERTY(EditAnywhere)class UCameraComponent* CameraComp;UPROPERTY(EditAnywhere)class UStaticMeshComponent* StaticMeshComp;FVector2D MovementInput;FVector2D CameraInput;float ZoomFactor = 1.0f;bool bZoomingIn = false;};
PawnWithCamera.cpp
// Fill out your copyright notice in the Description page of Project Settings.#include "GameCamera/PawnWithCamera.h"#include "GameFramework/SpringArmComponent.h"
#include "Camera/CameraComponent.h"
#include "Components/StaticMeshComponent.h"// Sets default values
APawnWithCamera::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;//创建组件RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootSenceComponent"));StaticMeshComp = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("StaticMeshComponent"));SpringArmComp = CreateDefaultSubobject<USpringArmComponent>(TEXT("SpringArmComponent"));CameraComp = CreateDefaultSubobject<UCameraComponent>(TEXT("CameraComponent"));//绑定组件StaticMeshComp->SetupAttachment(RootComponent);SpringArmComp->SetupAttachment(StaticMeshComp);CameraComp->SetupAttachment(SpringArmComp, USpringArmComponent::SocketName);//设置SpringArmSpringArmComp->SetRelativeLocationAndRotation(FVector(0.0f, 0.0f, 50.0f), FRotator(-60.0f, 0.0f, 0.0f));SpringArmComp->TargetArmLength = 400.0f;SpringArmComp->bEnableCameraLag = true;SpringArmComp->CameraLagSpeed = 3.0f;//设置默认控制玩家为本PawnAutoPossessPlayer = EAutoReceiveInput::Player0;}// Called when the game starts or when spawned
void APawnWithCamera::BeginPlay()
{Super::BeginPlay();
}// Called every frame
void APawnWithCamera::Tick(float DeltaTime)
{Super::Tick(DeltaTime);{if (bZoomingIn){ZoomFactor += DeltaTime / 0.5f;}else{ZoomFactor -= DeltaTime / 0.25f;}ZoomFactor = FMath::Clamp<float>(ZoomFactor, 0.0f, 1.0f);//根据ZoomFactor来设置摄像机的时长和弹簧臂的长度CameraComp->FieldOfView = FMath::Lerp<float>(90.0f, 60.0f, ZoomFactor);SpringArmComp->TargetArmLength = FMath::Lerp<float>(400.0f, 300.0f, ZoomFactor);}//旋转Actor的偏转角度，这样摄像机也能旋转，因为摄像机与Actor相互绑定{FRotator NewRotation = GetActorRotation();NewRotation.Yaw += CameraInput.X;SetActorRotation(NewRotation);}//旋转摄像机的俯仰角度，但要对其进行限制，这样我们就能始终俯视Actor{FRotator NewRotation = SpringArmComp->GetComponentRotation();NewRotation.Pitch = FMath::Clamp(NewRotation.Pitch + CameraInput.Y, -80.0f, -15.0f);SpringArmComp->SetWorldRotation(NewRotation);}//基于“MoveX”和“MoveY”坐标轴来处理移动if (!MovementInput.IsZero()){//把移动轴的输入数值放大100倍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 input
void APawnWithCamera::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{Super::SetupPlayerInputComponent(PlayerInputComponent);//绑定“ZoomIn”的事件InputComponent->BindAction("ZoomIn", IE_Pressed, this, &APawnWithCamera::ZoomIn);InputComponent->BindAction("ZoomIn", IE_Released, this, &APawnWithCamera::ZoomOut);//为四条轴绑定事件（每帧调用）InputComponent->BindAxis("MoveForward", this, &APawnWithCamera::MoveForward);InputComponent->BindAxis("MoveRight", this, &APawnWithCamera::MoveRight);InputComponent->BindAxis("CameraPitch", this, &APawnWithCamera::PitchCamera);InputComponent->BindAxis("CameraYaw", this, &APawnWithCamera::YawCamera);}void 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;
}官方参考文档：
https://dev.epicgames.com/documentation/zh-cn/unreal-engine/quick-start-guide-to-player-controlled-cameras-in-unreal-engine-cpp?application_version=5.3
