c# - 如何在 Unity 中的两点之间移动对象？

Question

我正在尝试使用 unity 的 lerp 功能将棋子上下移动。但是，每当我触发此脚本时，整个 session 都会卡住。

使用统一调试器，我已将问题缩小到这部分代码。

            do
        {
            float distCovered = (Time.time - startTime) * speed;
            fracJourney = distCovered / journeyLength;
            Debug.Log(fracJourney);
            transform.position = Vector3.Lerp(startPoint, endPoint, speed);
        } while (fracJourney <= 1);

因为看起来没有任何变量在改变，因此整个循环是无限的。

这是专门用于处理运动的整个代码部分(矢量值目前是任意的)。

    public class MovePiece : MonoBehaviour {
    Vector3 startPoint;
    Vector3 endPoint;
    float speed = 10;
    float startTime;
    private bool moving = false;
    private bool up = false;
    private bool across = false;
    private bool down = false;
    public void Start()
    {
        startPoint = gameObject.GetComponent<Transform>().position;
        startTime = Time.time;
        moving = true;
        Debug.Log("Moving Piece");
    }

    void Update() {
        if (!moving)
        {
            Destroy(this);
            return;
        }
        moveManager();
            }
    void moveManager()
    {
        if (!up)
        {
            lerpUp();
            return;
        }
        if (!across)
        {
            lerpAcross();
            return;
        }
        if (!down)
        {
            lerpDown();
            return;
        }
    }

    private void lerpUp()
    {
        Debug.Log("Upwards");
        startPoint = gameObject.GetComponent<Transform>().position;
        endPoint = startPoint + new Vector3(0, 0, 50);
        float journeyLength = Vector3.Distance(startPoint, endPoint);
        float fracJourney;
        do
        {
            float distCovered = (Time.time - startTime) * speed;
            fracJourney = distCovered / journeyLength;
            Debug.Log(fracJourney);
            transform.position = Vector3.Lerp(startPoint, endPoint, speed);
        } while (fracJourney <= 1);
        up = true;
        Debug.Log("Upwards Finished");
        return;
    }
    private void lerpAcross()
         {
             Debug.Log("Across");
             startPoint = gameObject.GetComponent<Transform>().position;
             endPoint = startPoint + new Vector3(0, 50, 0);
              float journeyLength = Vector3.Distance(startPoint, endPoint);
             float fracJourney;
             do
             {
                 float distCovered = (Time.time - startTime) * speed;
                 fracJourney = distCovered / journeyLength;
                 transform.position = Vector3.Lerp(startPoint, endPoint, speed);
             } while (fracJourney <= 1);
        across = true;
        Debug.Log("Across Finished");
        return;
         }
    private void lerpDown()
    {
        Debug.Log("Down");
        startPoint = gameObject.GetComponent<Transform>().position;
        endPoint = startPoint + new Vector3(0, 0, -50);
        float journeyLength = Vector3.Distance(startPoint, endPoint);
        float fracJourney;
        do
        {
            float distCovered = (Time.time - startTime) * speed;
            fracJourney = distCovered / journeyLength;
            transform.position = Vector3.Lerp(startPoint, endPoint, speed);
        } while (fracJourney <= 1);
        down = true;
        Debug.Log("Down Finished");
        moving = false;
        Debug.Log("Moving Finished");
        return;
    }

}
}

几天来我一直在努力缩小这个问题的范围，但无济于事，因此非常感谢您的帮助。

Answer 1

do
    {
        float distCovered = (Time.time - startTime) * speed;
        fracJourney = distCovered / journeyLength;
        Debug.Log(fracJourney);
        transform.position = Vector3.Lerp(startPoint, endPoint, speed);
    } while (fracJourney <= 1);

Update()每帧只运行一次，Time只有在更新时才会更新，所以 Time永远不会改变一件事情Update() , 所以 (Time.time - startTime) * speed将永远保持不变，所以 distCovered永远不会改变，所以fracJourney永远不会改变，所以fracJourney <= 1永远不会改变，所以你永远陷入循环。

如果您正在寻找修复程序，则不需要 while在 Update() 中循环功能，几乎没有。使用 Update()将自身作为循环运行，或使用 IEnumerator在这里你可以屈服并让一个框架通过，这样:

public IEnumerator MyLoop()
{
    while (fracJourney <= 1)
    {
        float distCovered = (Time.time - startTime) * speed;
        fracJourney = distCovered / journeyLength;
        Debug.Log(fracJourney);
        transform.position = Vector3.Lerp(startPoint, endPoint, speed);

        yield return null;     //< --- yield out and let a frame pass
    }
}