Unreal教學（6）——玩家輸入和Pawn（Player Input and Pawns）

Pawn這個單詞不會翻譯，找不到可以形象描述這個單詞的漢語，大概的意思就是可以通過很多的Components合成一個含有多種屬性狀態的物體。

這裏主要是如果獲取鍵盤和鼠標的輸入，

在Edit  -- Project Setting -- Engine -- Input裏面控制,有兩種屬性，一種是Action Mappings，另外一種是Axis Mapping.

這兩種是有區別的，Action主要針對不是連續的，比如跳，射擊等,Axis是連續的，比如移動，旋轉等。

貼上代碼

MyPawn.h

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

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Pawn.h"
#include "MyPawn.generated.h"

UCLASS()
class UNREALLEARN_API AMyPawn : public APawn
{
	GENERATED_BODY()

public:
	// Sets default values for this pawn's properties
	AMyPawn();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

	// Called to bind functionality to input
	virtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;
	
	UPROPERTY(EditAnywhere)
	USceneComponent* OurVisibleComponent;

	//Input functions
	void Move_XAxis(float AxisValue);
	void Move_YAxis(float AxisValue);
	void StartGrowing();
	void StopGrowing();

	//Input variables
	FVector CurrentVelocity;
	bool bGrowing;
};

MyPawn.cpp

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


#include "MyPawn.h"
#include "Camera/CameraComponent.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;

	// Set this pawn to be controlled by the lowest-numbered player
	AutoPossessPlayer = EAutoReceiveInput::Player0;

	// Create a dummy root component we can attach things to.
	RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));
	// Create a camera and a visible object
	UCameraComponent* OurCamera = CreateDefaultSubobject<UCameraComponent>(TEXT("OurCamera"));
	OurVisibleComponent = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("OurVisibleComponent"));
	// Attach our camera and visible object to our root component. Offset and rotate the camera.
	OurCamera->SetupAttachment(RootComponent);
	OurCamera->SetRelativeLocation(FVector(-250.0f, 0.0f, 250.0f));
	OurCamera->SetRelativeRotation(FRotator(-45.0f, 0.0f, 0.0f));
	OurVisibleComponent->SetupAttachment(RootComponent);

}

// Called when the game starts or when spawned
void AMyPawn::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AMyPawn::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);
	// Handle growing and shrinking based on our "Grow" action
    {
        float CurrentScale = OurVisibleComponent->GetComponentScale().X;
        if (bGrowing)
        {
            // Grow to double size over the course of one second
            CurrentScale += DeltaTime;
        }
        else
        {
            // Shrink half as fast as we grow
            CurrentScale -= (DeltaTime * 0.5f);
        }
        // Make sure we never drop below our starting size, or increase past double size.
        CurrentScale = FMath::Clamp(CurrentScale, 1.0f, 2.0f);
        OurVisibleComponent->SetWorldScale3D(FVector(CurrentScale));
    }

    // Handle movement based on our "MoveX" and "MoveY" axes
    {
        if (!CurrentVelocity.IsZero())
        {
            FVector NewLocation = GetActorLocation() + (CurrentVelocity * DeltaTime);
            SetActorLocation(NewLocation);
        }
    }
}

// Called to bind functionality to input
void AMyPawn::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
	Super::SetupPlayerInputComponent(PlayerInputComponent);

	// Respond when our "Grow" key is pressed or released.
    InputComponent->BindAction("Grow", IE_Pressed, this, &AMyPawn::StartGrowing);
    InputComponent->BindAction("Grow", IE_Released, this, &AMyPawn::StopGrowing);

    // Respond every frame to the values of our two movement axes, "MoveX" and "MoveY".
    InputComponent->BindAxis("MoveX", this, &AMyPawn::Move_XAxis);
    InputComponent->BindAxis("MoveY", this, &AMyPawn::Move_YAxis);
}

void AMyPawn::Move_XAxis(float AxisValue)
{
    // Move at 100 units per second forward or backward
    CurrentVelocity.X = FMath::Clamp(AxisValue, -1.0f, 1.0f) * 100.0f;
}

void AMyPawn::Move_YAxis(float AxisValue)
{
    // Move at 100 units per second right or left
    CurrentVelocity.Y = FMath::Clamp(AxisValue, -1.0f, 1.0f) * 100.0f;
}

void AMyPawn::StartGrowing()
{
    bGrowing = true;
}

void AMyPawn::StopGrowing()
{
    bGrowing = false;
}