c# - Unity - 在没有物理的情况下将变换移动到特定位置(以特定速度)的最佳方法？

Question

我想知道我应该如何将变换移动到特定点(不使用物理)。

目前我让我的物体看向目标位置:

transform.LookAt(m_TargetPos, UnityEngine.Vector3.up);

然后我用一定的速度在每一帧更新它的位置:

transform.position += transform.forward * (m_Speed * Time.deltaTime);

最后，我使用 sqrMagnitude 来了解转换是否到达了位置:

if ((transform.position - m_TargetPos).sqrMagnitude < 0.0025f) // 0.0025 = 0.05f * 0.05f
        return true;

我面临的问题是有时实体会超出目标位置永远向前推进。

我应该如何对条件进行编码以使其永远不会超出目标位置？

非常感谢。

Answer 1

使用MoveTowards这最终避免了过度:

Calculate a position between the points specified by current and target, moving no farther than the distance specified by maxDistanceDelta.

transform.position = Vector3.MoveTowards(transform.position, m_TargetPos, m_Speed * Time.deltaTime);

---

要检查您是否已经到达位置，您可以简单地使用 ==

if (transform.position == m_TargetPos)
    return true;

它的精度为 1e-5 所以它等于使用 Vector3.Distance阈值为 0.00001

if(Vector3.Distance(transform.position, m_TargetPos) < 0.00001f)
    return true;

在这里你现在可以定义一个更宽的阈值

if(Vector3.Distance(transform.position, m_TargetPos) < 0.0025f)
    return true;

或者更精确的例子，例如

if(Vector3.Distance(transform.position, m_TargetPos) < 0.0000001f)
    return true;

根据您的需要。

---

如果你想使用Lerp我宁愿使用 Coroutine简而言之

// TODO: either block concurrent routines with a bool flag
// TODO: or stop the running routine before starting a new one
StartCoroutine(MoveTo(targetPosition, speed));

...

private IEnumerator MoveTo(Vector3 targetPos, float speed)
{
    var currentPos = transform.position;
    var distance = Vector3.Distance(currentPos, targetPos);
    // TODO: make sure speed is always > 0
    var duration = distance / speed;

    var timePassed = 0f;
    while(timePassed < duration)
    {
        // always a factor between 0 and 1
        var factor = timePassed / duration;

        transform.position = Vector3.Lerp(currentPos, targetPos, factor);

        // increase timePassed with Mathf.Min to avoid overshooting
        timePassed += Math.Min(Time.deltaTime, duration - timePassed);

        // "Pause" the routine here, render this frame and continue
        // from here in the next frame
        yield return null;
    }

    transform.position = targetPos;

    // Something you want to do when moving is done
}