返回该向量的平方长度。(只读)
向量 v
的大小以 Mathf.Sqrt(Vector3.Dot(v, v)) 方式进行计算。
但是,Sqrt 计算相当复杂,
执行时间比普通算术运算要长。
计算平方数代替使用 magnitude 属性要快得多 -
计算基本相同,只是消除了执行缓慢的 Sqrt 调用。
如果您只将大小用于比较距离的目的,则也可以将平方数与距离的平方进行比较,
因为这种比较也会给出相同的结果。
另请参阅:magnitude。
using UnityEngine; using System.Collections;
public class ExampleClass : MonoBehaviour { // detects when the other transform is closer than closeDistance // this is faster than using Vector3.magnitude public Transform other; public float closeDistance = 5.0f;
void Update() { if (other) { Vector3 offset = other.position - transform.position; float sqrLen = offset.sqrMagnitude;
// square the distance we compare with if (sqrLen < closeDistance * closeDistance) { print("The other transform is close to me!"); } } } }
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