[UnityAI]行为树的中断机制

参考链接：

https://www.cnblogs.com/01zxs/p/9863715.html

https://blog.csdn.net/AcmHonor/article/details/123234763

https://blog.csdn.net/u012632851/article/details/89647097?spm=1001.2101.3001.6650.2&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-2-89647097-blog-82943972.pc_relevant_3mothn_strategy_and_data_recovery&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-2-89647097-blog-82943972.pc_relevant_3mothn_strategy_and_data_recovery&utm_relevant_index=3

https://blog.csdn.net/wuming2016/article/details/116858357

BehaviorDesigner下载

https://gitcode.net/linxinfa/unitybehaviordesigner

一.制作一颗简单的行为树

如下，是一颗简单的怪物行为树，当看见主角时，向主角移动；否则保持站立状态

AICanSeeObj.cs

 1 using BehaviorDesigner.Runtime;
 2 using BehaviorDesigner.Runtime.Tasks;
 3 using UnityEngine;
 4 
 5 public class AICanSeeObj : Conditional
 6 {
 7     public float distance = 2f;
 8     public SharedTransform target;
 9 
10     public override TaskStatus OnUpdate()
11     {
12         if (Vector3.Distance(transform.position, target.Value.position) < distance)
13         {
14             return TaskStatus.Success;
15         }
16         else
17         {
18             return TaskStatus.Failure;
19         }
20     }
21 }

AIMoveTo.cs

 1 using BehaviorDesigner.Runtime;
 2 using BehaviorDesigner.Runtime.Tasks;
 3 using UnityEngine;
 4 
 5 //移动到指定的目标
 6 public class AIMoveTo : Action
 7 {
 8     public float speed = 1f;
 9     public SharedTransform target;
10 
11     public override TaskStatus OnUpdate()
12     {
13         if (Vector3.Distance(transform.position, target.Value.position) < 0.1f)
14         {
15             return TaskStatus.Success;
16         }
17         transform.position = Vector3.MoveTowards(transform.position, target.Value.position, speed * Time.deltaTime);
18         return TaskStatus.Running;
19     }
20 }

AIIdle.cs

1 using BehaviorDesigner.Runtime.Tasks;
2 
3 public class AIIdle : Action
4 {
5     public override TaskStatus OnUpdate()
6     {
7         return TaskStatus.Running;
8     }
9 }

二.行为树的特点以及中断机制

在行为树中，一般一个节点返回Success或者Failure后，这个节点就不会再执行了(除非行为树重新执行或者该节点在Repeater节点下)

如下，白色是主角，红色是怪物，一开始两者距离较远，怪物处于Idle状态，即使后面拉近距离，AIIdle也不会被打断，不符合我们设定的AI逻辑(距离较近时向主角移动)