Above, Unity - simulated AI vision has implemented the enemy field of view detection function. This article will improve the enemy AI.
Note: If you want to read this article, be sure to read it after reading Unity - Simulating AI Vision.
Effect preview:
AI enemy pursuit
Next, use the simplest way to implement the enemy's AI state machine. First, define the enemy's three states - standby, attack and return.
enum AIState
{
Idle, //待机状态
Attack, //进攻状态
Back, //返回状态
} Then change the Update function to the state machine mode and implement it directly with the switch-case statement.
enum AIState
{
Idle, //待机状态
Attack, //进攻状态
Back, //返回状态
}
AIState state;
void Update()
{
switch (state)
{
case AIState.Idle:
{
//待机状态。进行实现检测，若发现玩家则进攻
FieldOfView();
}
break;
case AIState.Attack:
{
//进攻状态，若离玩家或起点太远，则返回
}
break ;
case AIState.Back:
{
//返回状态
}
break;
}
}The principle of the state machine is relatively complex, but it only needs to be implemented with a switch-case statement, or it can be written with an if statement. After that, you only need to write the design ideas into program code step by step.
- In the standby state, radiation detection must be continuously performed. If the ray detection detects a player, the player's reference can be saved for later use in attacks. It should be noted that the tags of the player and its sub-objects should be changed to Player to facilitate judgment.
- In the offensive state, continuously move towards the target location (using the navigation system). At the same time, it detects the distance between the current position and the starting point or the player, and returns if the distance is too far.
- In the return state, first move towards the starting point, and then turn to the front and return to the original orientation after the movement is in place. It is necessary to record the initial position and orientation at the beginning, which are homePos and homeRot respectively.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class AIEnemy : MonoBehaviour
{
Transform target; //目标角色
Vector3 homePos; //起始位置
Quaternion homeRot; //起点的朝向
UnityEngine.AI.NavMeshAgent agent;
public int viewRadius = 4; //视野距离
public int viewLines = 30; //射线数量
public MeshFilter viewMeshFilter;
List<Vector3> viewVerts; //定点列表
List<int> viewIndices; //定点序号列表
enum AIState
{
Idle, //待机状态
Attack, //进攻状态
Back, //返回状态
}
AIState state; //AI状态机的状态
void Start()
{
Transform view = transform.Find("view");
viewMeshFilter = view.GetComponent<MeshFilter>();
agent=GetComponent<UnityEngine.AI.NavMeshAgent>();
viewVerts = new List<Vector3>();
viewIndices = new List<int>();
state = AIState.Idle;
homePos = transform.position;
homeRot = transform.rotation;
}
void Update()
{
switch (state)
{
case AIState.Idle:
{
//待机状态。进行射线检测，若发现玩家则进攻
FieldOfView();
if (target != null)
{
state= AIState.Attack; //切换状态
}
}
break;
case AIState.Attack:
{
//进攻状态，若离玩家或起点太远，则返回
agent.SetDestination(target.position);
if(Vector3.Distance(transform.position, target.position) > 10)
{
target = null;
state= AIState.Back;
}
if (Vector3.Distance(transform.position, homePos)>15)
{
target = null;
state = AIState.Back;
}
}
break ;
case AIState.Back:
{
//返回状态
agent.SetDestination(homePos);
if (!agent.hasPath)
{
//回到起点，匀速转到正面
if(Quaternion.Angle(homeRot,transform.rotation)>0.5f)
{
//逐步向目标角度转动，每次最多转2°
Quaternion q = Quaternion.RotateTowards(transform.rotation, homeRot, 2f);
transform.rotation = q;
}
else
{
state = AIState.Idle;
}
}
}
break;
}
}
void FieldOfView()
{
viewVerts.Clear();
viewVerts.Add(Vector3.zero); //加入起点坐标，局部坐标系
//获得最左边那条射线的向量，相对正前方，角度是-45°
Vector3 forward_left = Quaternion.Euler(0, -45, 0) * transform.forward * viewRadius;
//依次处理每条射线
for (int i = 0; i <= viewLines; i++)
{
Vector3 v = Quaternion.Euler(0, (90.0f / viewLines) * i, 0) * forward_left;
//角色位置+v,就是射线终点pos
Vector3 pos = transform.position + v;
//实际发射射线。注意RayCast的参数，重载很多容易搞错
RaycastHit hitInfo;
if (Physics.Raycast(transform.position, v, out hitInfo, viewRadius))
{
//碰到物体，终点改为碰到的点
pos = hitInfo.point;
if (hitInfo.transform.CompareTag("Player"))
{
target=hitInfo.transform;
}
}
//将每个点的位置加入列表，注意转为局部坐标系
Vector3 p = transform.InverseTransformPoint(pos);
viewVerts.Add(p);
}
//根据顶点绘制模型
RefreshView();
}
void RefreshView()
{
viewIndices.Clear();
//逐个加入三角面，每个三角面都以起点开始
for (int i = 1; i < viewVerts.Count - 1; i++)
{
viewIndices.Add(0);
viewIndices.Add(i);
viewIndices.Add(i + 1);
}
//填写Mesh信息
Mesh mesh = new Mesh();
mesh.vertices = viewVerts.ToArray();
mesh.triangles = viewIndices.ToArray();
viewMeshFilter.mesh = mesh;
}
}