1、敌人发现主角有两种形式：

　　a、看见主角（主角出现在敌人的视野之内）

　　b、听见主角（听见主角走路声或者是跑步声）

a：看(see)

首先判断主角是否在敌人视野角度内，那么我们只需要判断B<0.5*A能不能成立

b：听（listen）

代码如下：

using UnityEngine;
using System.Collections;
using UnityEngine.AI;

public class EnemySight : MonoBehaviour {

private float seeAngle=120;//敌人视野角度
    private bool isSeePlay = false;

private Vector3 lastPos;// 玩家的最后位置
    private Vector3 alermPos=Vector3.zero; //警报位置

private Animator anim;  //主角动画，作用是判断主角是否在运动
    private SphereCollidersphereCollider;//敌人身上的碰撞器，该碰撞器是用来触发检测主角是否在敌人可见，可听范围内
    private NavMeshAgentnavMeshAgent; //AI组件

void Awake()
    {
        anim =
GameObject.FindGameObjectWithTag(Tags.player).GetComponent();
        lastPos = GameController._instance.lastPlayerPostion;
        navMeshAgent =
GetComponent();
    }

void Update()
    {
        //同步主角位置
        if (lastPos !=
GameController._instance.lastPlayerPostion)//触发警报后玩家位置改变
        {
            alermPos =
GameController._instance.lastPlayerPostion; //更新警报位置
            lastPos =
GameController._instance.lastPlayerPostion;
        }
        
    }

void OnTriggleStay(Collider other)
    {
        if (other.tag==Tags.player)
        {
            //看玩家
            Vector3 startDir
= transform.forward;//敌人开始朝向
            Vector3
currDir = other.transform.position - transform.position; //敌人看向玩家的向量
            float angle
= Vector3.Angle(startDir, currDir);//敌人开始朝向与看见玩家朝向的夹角
            if (angle
<seeAngle * 0.5f) //视野角度一半以内可见
            {
               
//主角在敌人的视野之内
               
isSeePlay = true;
               
alermPos = other.transform.position;//把玩家的位置设置为警报位置
               
GameController._instance.SeePlayer(other.transform);
            }
            else
            {
               
isSeePlay = false;
            }

//听脚步声音
            if
(anim.GetCurrentAnimatorStateInfo(0).IsName("Locomotion"))//如果玩家在运动
            {
               
NavMeshPath path = new NavMeshPath();
               
if (navMeshAgent.CalculatePath(other.transform.position, path))
               
{
                   
Vector3[] wayPoints = new Vector3[path.corners.Length+2];
                   
wayPoints[0] = transform.position;
                   
wayPoints[wayPoints.Length - 1] = other.transform.position;
                   
for (inti = 0; i<path.corners.Length; i++)
                   
{
                       
wayPoints[i + 1] = path.corners[i];  
                   
}
                   
float length = 0;
                   
for (inti = 1; i<wayPoints.Length; i++)
                   
{
                       
length += (wayPoints[i] - wayPoints[i - 1]).magnitude; //所有节点连接的折线的总长度
                   
}
                   
if (length <= sphereCollider.radius) //在听力范围内
                   
{
                       
alermPos = other.transform.position;
                   
}
               
}
            }

}
    }

void OnTriggleExit(Collider other)
    {
        if (other.tag == Tags.player)
        {
            isSeePlay =
false;
        }
    }