【Unity】Mathf

1.Math与Mathf

推荐使用Mathf

Math是C#中封装好的用于数学计算的工具类，Math位于System命名空间中
Mathf是Unity中封装好的用于数学计算的工具结构体，Mathf位于UnityEngine命名空间中
Mathf比Math方法多，不仅包含Math中的方法还多了适用于游戏开发的方法

2.常用成员

Π PI

Debug.Log(Mathf.PI);//3.141593

绝对值 Abs

Debug.Log(Mathf.Abs(-1));//1

向上取整 CeilToInt

Debug.Log(Mathf.CeilToInt(1.1f));//2

向下取整 FloorToInt

Debug.Log(Mathf.FloorToInt(1.99f));//1

钳制函数 Clamp

Debug.Log(Mathf.Clamp(5, 1, 10));//5
Debug.Log(Mathf.Clamp(0, 1, 10));//1
Debug.Log(Mathf.Clamp(11, 1, 10));//10

最大值 Max

Debug.Log(Mathf.Max(1, 2, 3, 4, 5, 8, 9, 10));//10

最小值 Min

Debug.Log(Mathf.Min(5, 6, 8, 1, 8));//1

数的n次幂 Pow

Debug.Log(Mathf.Pow(2, 4));//16

四舍五入 RoundToInt

Debug.Log(Mathf.RoundToInt(1.5f));//2
Debug.Log(Mathf.RoundToInt(1.49f));//1

平方根 Sqrt

Debug.Log(Mathf.Sqrt(64));//8

是否是2的n次方 IsPowerOfTwo

Debug.Log(Mathf.IsPowerOfTwo(4));//true
Debug.Log(Mathf.IsPowerOfTwo(3));//false

是否正负数 Sign

Debug.Log(Mathf.Sign(0));//1
Debug.Log(Mathf.Sign(-10));//-1
Debug.Log(Mathf.Sign(11));//1

角度转换成弧度 Deg2Rad

180° == Π 弧度
Debug.Log(30 * Mathf.Deg2Rad);//0.5235988

弧度转换角度 Rad2Deg

Debug.Log(0.5235988 * Mathf.Rad2Deg);//30.0000017482986

正弦(弧度) Sin

Debug.Log(Mathf.Sin(30 * Mathf.Deg2Rad));//0.5

余弦(弧度) Cos

Debug.Log(Mathf.Cos(60 * Mathf.Deg2Rad));//0.5

反正弦得到弧度 Asin

Debug.Log(Mathf.Asin(0.5f) * Mathf.Rad2Deg);//30

反余弦得到弧度 Acos

Debug.Log(Mathf.Acos(0.5f) * Mathf.Rad2Deg);//60

3.插值Mathf.Lerp

公式 Lerp : result = start + (end - start) * t

private float start = 0;
private float end = 0;
private float time = 0;
// Update is called once per frame
void Update()
{
    //插值Lerp : result = start + (end - start) * t
    //先快后慢 (end - start) 由大到小， 无限接近 但不会到达目标
    start = Mathf.Lerp(start, 10, Time.deltaTime);

    //优化 匀速变化 会达到目标
    time += Time.deltaTime;
    end = Mathf.Lerp(start, 10, time);
}

4.案例跟随

public GameObject Player;
public float speed;
private Vector3 pos;

private Vector3 targetPos;
private Vector3 startPos;
private float time;

void Update()
{
    //先快后慢
    //pos = transform.position;
    //pos.x = Mathf.Lerp(pos.x, Player.transform.position.x, Time.deltaTime * speed);
    //pos.y = Mathf.Lerp(pos.y, Player.transform.position.y, Time.deltaTime * speed);
    //pos.z = Mathf.Lerp(pos.z, Player.transform.position.z, Time.deltaTime * speed);
    //transform.position = pos;

    //匀速
    if (targetPos != Player.transform.position)
    {
        time = 0;
        targetPos = Player.transform.position;
        startPos = transform.position;
    }
    time += Time.deltaTime;
    pos.x = Mathf.Lerp(startPos.x, targetPos.x, time * speed);
    pos.y = Mathf.Lerp(startPos.y, targetPos.y, time * speed);
    pos.z = Mathf.Lerp(startPos.z, targetPos.z, time * speed);
    transform.position = pos;
}