UE4学习笔记4th

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在这一节中，我们来处理对输入的响应

双击打开MyPawn在vs中进行编辑。

在MypPawn.h中添加以下定义：

void Move_XAxis(float AxisValue);

void Move_YAxis(float AxisValue);

void StartGrowing();

void StopGrowing();

//输入变量

FVector CurrentVelocity;

bool bGrowing;

前两个用于前后左右方向上的处理，后两个处理跳跃。
它们在运行时，会改变变量中的值，从而确定在游戏中应执行的操作。

切换到MyPawn.cpp，对这四个函数进行编程。
在最下方输入

void AMyPawn::Move_XAxis(float AxisValue)

{

//前后

CurrentVelocity.X = FMath::Clamp(AxisValue, -1.0f, 1.0f)*100.0f;

}

void AMyPawn::Move_YAxis(float AxisValue)

{

//左右

CurrentVelocity.Y = FMath::Clamp(AxisValue, -1.0f, 1.0f)*100.0f;

}

//跳跃

void AMyPawn::StartGrowing()

{

bGrowing = true;

}

void AMyPawn::StopGrowing()

{

bGrowing = false;

}

现在我们已经完成了对输入函数的定义，接下来要将它们进行绑定

在AMyPawn::SetupPlayerInputComponent函数中输入以下代码：

//响应Grow键

InputComponent->BindAction("Grow",IE_Pressed,this,&AMyPawn::StartGrowing);

InputComponent->BindAction("Grow",IE_Released,this,&AMyPawn::StopGrowing);

//响应两个坐标轴值

InputComponent->BindAxis("MoveX", this, &AMyPawn::Move_XAxis);

InputComponent->BindAxis("MoveY", this, &AMyPawn::Move_YAxis);

现在我完成了对输入的绑定，接下来我要将它们在视口中体现出来。
在AMyPawn::Tick中添加如下代码：

//基于Grow操作来处理增长和收缩

{

float CurrentScale = OurVisibleComponent->GetComponentScale().X;

if (bGrowing)

{

//在一秒内增长到两倍大小

CurrentScale += DeltaTime;

}

else

{

//随着增长收缩到一半

CurrentScale -= (DeltaTime*0.5f);

}

//确认不小于初始大小、增长前的两倍大小

CurrentScale = FMath::Clamp(CurrentScale, 1.0f, 2.0f);

OurVisibleComponent->SetWorldScale3D(FVector(CurrentScale));

}

//基于MoveX和MoveY来处理移动

{

if (!CurrentVelocity.IsZero())

{

FVector NewLoaction = GetActorLocation() + (CurrentVelocity*DeltaTime);

SetActorLocation(NewLoaction);

}

}
完成后编译，效果如下

编译

编译完代码后，在编辑器中按下 Play ，应该可以使用WASD键来控制 Pawn ，而且我们应该可以通过按住空格键来使之增大，并在松开后看着其缩小。

下面是完整的代码：
MyPawn.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "GameFramework/Pawn.h"

#include "MyPawn.generated.h"

UCLASS()

class HOWTO_PLAYERINPUT_API AMyPawn : public APawn

{

GENERATED_BODY()

public:

// Sets default values for this pawn's properties

AMyPawn();

// Called when the game starts or when spawned

virtual void BeginPlay() override;

// Called every frame

virtual void Tick( float DeltaSeconds ) override;

// Called to bind functionality to input

virtual void SetupPlayerInputComponent(class UInputComponent* InputComponent) override;

UPROPERTY(EditAnywhere)

USceneComponent* OurVisibleComponent;

//输入函数

void Move_XAxis(float AxisValue);

void Move_YAxis(float AxisValue);

void StartGrowing();

void StopGrowing();

//输入变量

FVector CurrentVelocity;

bool bGrowing;

};

MyPawn.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "HowTo_PlayerInput.h"

#include "MyPawn.h"

// Sets default values

AMyPawn::AMyPawn()

{

// 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;

//设置为玩家控制

AutoPossessPlayer = EAutoReceiveInput::Player0;

//添加一个可以添加对象的空根组件

RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));

//创建相机和可见项目

UCameraComponent* OurCamera = CreateDefaultSubobject<UCameraComponent>(TEXT("OurCamera"));

OurVisibleComponent = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("OurVisibleComponent"));

//附加相机和可见对象到根组建，偏移并旋转相机。

OurCamera->AttachTo(RootComponent);

OurCamera->SetRelativeLocation(FVector(-250.0f, 0.0f, 250.0f));

OurCamera->SetRelativeRotation(FRotator(-45.0f, 0.0f, 0.0f));

OurVisibleComponent->AttachTo(RootComponent);

}