Unity：点击 UI 按钮时平滑的相机移动

Question

I'm trying to make the camera move to a certain position after clicking a UI button. For the positioning, I use empty game objects' (CameraPositionStart and CameraPositionFinish) coordinates. For some reason, the camera just teleports to the position needed instead of smoothly moving to it. Here's my code:

using UnityEngine; 
using UnityEngine.UI;

public class CameraMover : MonoBehaviour
{
    public float speed;
    public Button ButtonStartNew;
    public GameObject CameraPositionStart;
    public GameObject CameraPositionFinish;

    private void Update()
    {
        ButtonStartNew.onClick.AddListener(moveCamera);
    }

    public void moveCamera()
    {
        transform.position = Vector3.Lerp(transform.position, CameraPositionFinish.transform.position, Time.deltaTime * speed);
    }
}

Answer 1

This behavior is likely caused because of two reasons.

The method Update is executed once every frame. Here every frame you are adding an additional call that should be made when you click the button on the UI. The result of this, I suspect, is that when the several hundred calls to moveCamera all happen at the same time, and despite moveCamera only moving the transform by Lerp(Time.DeltaTime * Speed) -- the object moves closer (since you're lerping) instantly because you're calling it a bunch.

private void Update()
{
    ButtonStartNew.onClick.AddListener(moveCamera);
}

Consider only adding one call to moveCamera to the on click event. We can do this in Start or Awake since they're only called once.

private void Start()
{
    ButtonStartNew.onClick.AddListener(moveCamera);
}

However this along does not solve the problem. Because if we do that moveCamera will only be called once and the result would be the camera would move very slightly toward the target and stop.

Consider implementing a Coroutine that will move the transform over time(every frame) until it has reached the target.

private void moveCamera()
{
    // A coroutine runs every frame until it stops returning values
    StartCoroutine(MoveCamera);
}

private IEnumerator MoveCamera()
{
    // check the distance and see if we still need to move towards the destination ​
    while(Vector3.Distance(transform.position, CameraPositionFinish.transform.position) > 1.0f)
   ​{

       transform.position = Vector3.Lerp(transform.position, CameraPositionFinish.transform.position, Time.deltaTime * speed);
   
       // Return  nothing meaningful and wait until next frame​
       yield return null;
    }
}