Unity 2018 - 在范围内时NPC 如何平滑地转向面对玩家

Question

当前代码会使NPC检测到玩家并播放所需的动画，然后朝向玩家。然而，在玩家在范围内绕着NPC走动时，NPC只会猛地转向面对玩家，而不会持续旋转。

我想修改代码，让NPC在玩家仍处于碰撞体范围内时能够持续平稳地面对角色。我认为这与void update有关，但由于转向函数目前在onTriggerEnter中，对像我一样的初学者来说有些困惑。

public class helloTrigger : MonoBehaviour
{
    public Animator anim;
    public CharacterController player;
    public Transform Player;

    void Start()
    {
        player = GameObject.FindObjectOfType<CharacterController>();
        anim = GetComponent<Animator>();
    }

    void OnTriggerEnter(Collider other)
    {
        if (other.tag != "Player") return;

        anim.Play("Hello");
        Vector3 lookAt = Player.position;
        lookAt.y = transform.position.y;
        transform.LookAt(lookAt);
    }

    void OnTriggerExit(Collider other)
    {
        if (other.tag == "Player")
        {
            anim.Play("Idle");
        }
    }
}

- ReignBeaux

---

如果你不打算使用 Update，那就把它删除。在编译时，Unity 会创建一个对象列表，如果定义了 Update，则调用该列表上的对象。因此，在不使用 Update 时拥有它会影响性能。 - AustinWBryan

Answer 1

如果你想让一个游戏对象平滑地面向另一个游戏对象，请使用Quaternion.LookRotation计算目标旋转，然后使用Quaternion.Lerp在当前旋转和使用Quaternion.LookRotation计算出的目标旋转之间进行插值。最后，根据时间进行插值。请参见此文章以了解如何在旋转上进行插值。你可以在Update函数中实现这个功能，但我会在协程函数中使用它，因为这样可以更好地控制时间。

一个简单的平滑看向函数：

IEnumerator LookAtSmoothly(Transform objectToMove, Vector3 worldPosition, float duration)
{
    Quaternion currentRot = objectToMove.rotation;
    Quaternion newRot = Quaternion.LookRotation(worldPosition -
        objectToMove.position, objectToMove.TransformDirection(Vector3.up));

    float counter = 0;
    while (counter < duration)
    {
        counter += Time.deltaTime;
        objectToMove.rotation =
            Quaternion.Lerp(currentRot, newRot, counter / duration);
        yield return null;
    }
}

您的新脚本：

---

public class helloTrigger : MonoBehaviour
{
    public Animator anim;
    public CharacterController player;
    public Transform Player;
    Coroutine smoothMove = null;

    // Use this for initialization
    void Start()
    {
        player = GameObject.FindObjectOfType<CharacterController>();
        anim = GetComponent<Animator>();
    }

    void OnTriggerEnter(Collider other)
    {
        if (other.tag == "Player")
        {
            anim.Play("Hello");
            LookSmoothly();
        }

    }

    void OnTriggerExit(Collider other)
    {
        if (other.tag == "Player")
        {
            anim.Play("Idle");
        }
    }

    void LookSmoothly()
    {
        float time = 1f;

        Vector3 lookAt = Player.position;
        lookAt.y = transform.position.y;

        //Start new look-at coroutine
        if (smoothMove == null)
            smoothMove = StartCoroutine(LookAtSmoothly(transform, lookAt, time));
        else
        {
            //Stop old one then start new one
            StopCoroutine(smoothMove);
            smoothMove = StartCoroutine(LookAtSmoothly(transform, lookAt, time));
        }
    }

    IEnumerator LookAtSmoothly(Transform objectToMove, Vector3 worldPosition, float duration)
    {
        Quaternion currentRot = objectToMove.rotation;
        Quaternion newRot = Quaternion.LookRotation(worldPosition -
            objectToMove.position, objectToMove.TransformDirection(Vector3.up));

        float counter = 0;
        while (counter < duration)
        {
            counter += Time.deltaTime;
            objectToMove.rotation =
                Quaternion.Lerp(currentRot, newRot, counter / duration);
            yield return null;
        }
    }
}

- Programmer

---

顶级的!!! 并且帮助我更清晰地看到如何以及为什么使用协程。非常感谢!!! - Confused

确实！一开始我不确定什么是协程！谢谢你！ - ReignBeaux