# HowTo_PlayerInput

**Repository Path**: wblong/how-to_-player-input

## Basic Information

- **Project Name**: HowTo_PlayerInput
- **Description**: 对Pawn类进行扩展，以便响应玩家的输入操作。
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-07-30
- **Last Updated**: 2021-10-21

## Categories & Tags

**Categories**: Uncategorized

**Tags**: Cpp, UE4

## README

# 玩家输入和Pawn

对Pawn类进行扩展，以便响应玩家的输入操作。


## Code

### 可视化相机

```cpp
// 创建可附加内容的虚拟根组件。
RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));
// 创建相机和可见对象
UCameraComponent* OurCamera = CreateDefaultSubobject<UCameraComponent>(TEXT("OurCamera"));
OurVisibleComponent = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("OurVisibleComponent"));
// 将相机和可见对象附加到根组件。偏移并旋转相机。
OurCamera->SetupAttachment(RootComponent);
OurCamera->SetRelativeLocation(FVector(-250.0f, 0.0f, 250.0f));
OurCamera->SetRelativeRotation(FRotator(-45.0f, 0.0f, 0.0f));
OurVisibleComponent->SetupAttachment(RootComponent);
```
![可视化相机](./Images/HowTo_PlayerInput.png)

### 绑定输入函数

```cpp


//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;

//AMyPawn::SetupPlayerInputComponent 
// 在按下或松开"Grow"键时做出响应。
InputComponent->BindAction("Grow", IE_Pressed, this, &AMyPawn::StartGrowing);
InputComponent->BindAction("Grow", IE_Released, this, &AMyPawn::StopGrowing);

// 对两个移动轴"MoveX"和"MoveY"的值逐帧反应。
InputComponent->BindAxis("MoveX", this, &AMyPawn::Move_XAxis);
InputComponent->BindAxis("MoveY", this, &AMyPawn::Move_YAxis);
```
### 处理操作

```cpp
// 根据"Grow"操作处理增长和缩减
{
    float CurrentScale = OurVisibleComponent->GetComponentScale().X;
    if (bGrowing)
    {
        // 一秒内增长到两倍大小
        CurrentScale += DeltaTime;
    }
    else
    {
        // 以增长速度缩减一半
        CurrentScale -= (DeltaTime * 0.5f);
    }
    // 确保不会降至初始大小以下，或者增至两倍大小以上。
    CurrentScale = FMath::Clamp(CurrentScale, 1.0f, 2.0f);
    OurVisibleComponent->SetWorldScale3D(FVector(CurrentScale));
}

// 根据"MoveX"和"MoveY"轴处理移动
{
    if (!CurrentVelocity.IsZero())
    {
        FVector NewLocation = GetActorLocation() + (CurrentVelocity * DeltaTime);
        SetActorLocation(NewLocation);
    }
}
```
## Note

```cpp
/** Component that handles input for this actor, if input is enabled. */
// 如果启用了输入，则处理此角色的输入的组件。
UPROPERTY(DuplicateTransient)
class UInputComponent* InputComponent;

```
## Reference

1. [玩家输入和Pawn - https://docs.unrealengine.com/4.26/zh-CN/ProgrammingAndScripting/ProgrammingWithCPP/CPPTutorials/PlayerInput/](https://docs.unrealengine.com/4.26/zh-CN/ProgrammingAndScripting/ProgrammingWithCPP/CPPTutorials/PlayerInput/)