Unreal教學（3）——遊戲相機控制（Game-Controlled Cameras）

可以設置兩臺相機在代碼中進行切換達到變換視圖的效果。

首先在場景中加入兩個Camera，可以通過直接拖拽的方式添加，然後寫下面的代碼進行調用。

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

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "CameraDirector.generated.h"

UCLASS()
class HOWTO_AUTOCAMERA_API ACameraDirector : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	ACameraDirector();

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

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

	UPROPERTY(EditAnywhere)
	AActor* CameraOne;
	
	UPROPERTY(EditAnywhere)
	AActor* CameraTwo;

	float TimeToNextCameraChange;
	
};

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


#include "CameraDirector.h"
#include "Kismet/GameplayStatics.h"


// Sets default values
ACameraDirector::ACameraDirector()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

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

// Called every frame
void ACameraDirector::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);
	const float TimeBetweenCameraChanges = 2.0f;
	const float SmoothBlendTime = 0.75f;
	TimeToNextCameraChange -= DeltaTime;
	if (TimeToNextCameraChange <= 0.0f)
	{
		TimeToNextCameraChange += TimeBetweenCameraChanges;

		// Find the actor that handles control for the local player.
		APlayerController* OurPlayerController = UGameplayStatics::GetPlayerController(this, 0);
		if (OurPlayerController)
		{
			if ((OurPlayerController->GetViewTarget() != CameraOne) && (CameraOne != nullptr))
			{
				// Cut instantly to camera one.
				OurPlayerController->SetViewTarget(CameraOne);
			}
			else if ((OurPlayerController->GetViewTarget() != CameraTwo) && (CameraTwo != nullptr))
			{
				// Blend smoothly to camera two.
				OurPlayerController->SetViewTargetWithBlend(CameraTwo, SmoothBlendTime);
			}
		}
	}
}

每隔兩秒鐘都會進行一次場景的變換。