U++ C++编程 相机视角切换

.h

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#pragma once

#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 DeltaSeconds ) override;

    UPROPERTY(EditAnywhere)
    AActor* CameraOne;

    UPROPERTY(EditAnywhere)
    AActor* CameraTwo;

    float TimeToNextCameraChange;
};

.cpp

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#include "HowTo_AutoCamera.h"
#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;//间隔几秒开始进行相机切换
    const float SmoothBlendTime = 0.75f;//相机切换所需的时间
    TimeToNextCameraChange -= DeltaTime;//判断当前电脑的性能延迟
    if (TimeToNextCameraChange <= 0.0f)//若延迟过高
    {
        TimeToNextCameraChange += TimeBetweenCameraChanges;//则加上一个相机切换时间

        //Find the actor that handles control for the local player.
        APlayerController* OurPlayerController = UGameplayStatics::GetPlayerController(this, 0);//创建一个用于切换相机视角的玩家控制器
        if (OurPlayerController)//若玩家控制器创建成功
        {
            if ((OurPlayerController->GetViewTarget() != CameraOne) && (CameraOne != nullptr))//若要切相机去CameraOne，并且当前控制的相机不为CameraOne，且CameraOne是存在的，不为空的。
            {
                //Cut instantly to camera one.
                OurPlayerController->SetViewTarget(CameraOne);//若满足以上条件则且相机至CameraOne
            }
            else if ((OurPlayerController->GetViewTarget() != CameraTwo) && (CameraTwo != nullptr))//同理
            {
                //Blend smoothly to camera two.
                OurPlayerController->SetViewTargetWithBlend(CameraTwo, SmoothBlendTime);//且相机过度事件为SmoothBlendTime
            }
        }
    }
}