Lerp的使用

In our above example, we call Vector3.Lerp() like this:

transform.position = Vector3.Lerp(_startPosition, _endPosition, percentageComplete); // 可以是时间的分数，也可以是距离的分数

However, the method for calling Lerp you see in many tutorials online looks like this:

transform.position = Vector3.Lerp(transform.position, _endPosition, speed*Time.deltaTime);

第一种transform的值会最终固定

第二种不永远的在接近endposition位置摇摆。

1. It’s non-linear ie. the speed is not constant. This is easy to see in the official video tutorial; the object moves quickly at first, and slows down as it nears its destination
2. The object’s speed varies with the user’s framerate. The higher the user’s framerate, the faster the object will move. This defeats the purpose of using FixedUpdate() to begin with, which is supposed to alleviate this problem.
3. The object never reaches its destination since we only move a percentage closer each frame. Actually, due to floating-point rounding, it may or may not ever reach its destination. Additionally, because of problem 2, whether or not it ever reaches its destination depends on the user’s framerate. Ouch

 

 the code in the video is still framerate-dependent. Moving 4% towards a destination 25 times a second is not the same as moving 2% towards it 50 times a second.