Unity FSM 有限状态机

  1 using System;
  2 using System.Collections;
  3 using System.Collections.Generic;
  4 using UnityEngine;
  5 
  6 /**
  7 A Finite State Machine System based on Chapter 3.1 of Game Programming Gems 1 by Eric Dybsand
  8  
  9 Written by Roberto Cezar Bianchini, July 2010
 10  
 11  
 12 How to use:
 13     1. Place the labels for the transitions and the states of the Finite State System
 14         in the corresponding enums.
 15  
 16     2. Write new class(es) inheriting from FSMState and fill each one with pairs (transition-state).
 17         These pairs represent the state S2 the FSMSystem should be if while being on state S1, a
 18         transition T is fired and state S1 has a transition from it to S2. Remember this is a Deterministic（确定的） FSM. 
 19         You can‘t have one transition leading to two different states.
 20  
 21        Method Reason is used to determine which transition should be fired.
 22        You can write the code to fire transitions in another place, and leave this method empty if you
 23        feel it‘s more appropriate 合适 to your project.
 24  
 25        Method Act has the code to perform the actions the NPC is supposed do if it‘s on this state.
 26        You can write the code for the actions in another place, and leave this method empty if you
 27        feel it‘s more appropriate to your project.
 28  
 29     3. Create an instance of FSMSystem class and add the states to it.
 30  
 31     4. Call Reason and Act (or whichever methods you have for firing transitions and making the NPCs
 32          behave in your game) from your Update or FixedUpdate methods.
 33  
 34     Asynchronous transitions from Unity Engine, like OnTriggerEnter, SendMessage, can also be used, 
 35     just call the Method PerformTransition from your FSMSystem instance with the correct Transition 
 36     when the event occurs 重现.
 37  
 38  
 39  
 40 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
 41 INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE 
 42 AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
 43 DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
 44 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 45 */
 46 
 47 
 48 /// <summary>
 49 /// Place the labels for the Transitions in this enum.
 50 /// Don‘t change the first label, NullTransition as FSMSystem class uses it.
 51 /// 为过渡加入枚举标签
 52 /// 不要修改第一个标签，NullTransition会在FSMSytem类中使用
 53 /// </summary>
 54 public enum Transition
 55 {
 56     NullTransition = 0, // Use this transition to represent a non-existing transition in your system
 57     //用这个过度来代表你的系统中不存在的状态
 58     SawPlayer,//这里配合NPCControl添加两个NPC的过渡
 59     LostPlayer,
 60 }
 61 
 62 /// <summary>
 63 /// Place the labels for the States in this enum.
 64 /// Don‘t change the first label, NullStateID as FSMSystem class uses it.
 65 /// 为状态加入枚举标签
 66 /// 不要修改第一个标签，NullStateID会在FSMSytem中使用 
 67 /// </summary>
 68 public enum StateID
 69 {
 70     NullStateID = 0, // Use this ID to represent a non-existing State in your syste
 71     //使用这个ID来代表你系统中不存在的状态ID    
 72     ChasingPlayer,//这里配合NPCControl添加两个状态
 73     FollowingPath,
 74 
 75 }
 76 
 77 /// <summary>
 78 /// This class represents the States in the Finite State System.
 79 /// Each state has a Dictionary with pairs (transition-state) showing
 80 /// which state the FSM should be if a transition is fired while this state
 81 /// is the current state.
 82 /// Method Reason is used to determine which transition should be fired .
 83 /// Method Act has the code to perform the actions the NPC is supposed do if it‘s on this state.
 84 /// 这个类代表状态在有限状态机系统中
 85 /// 每个状态都有一个由一对搭档（过渡-状态）组成的字典来表示当前状态下如果一个过渡被触发状态机会进入那个状态
 86 /// Reason方法被用来决定那个过渡会被触发
 87 /// Act方法来表现NPC出在当前状态的行为
 88 /// </summary>
 89 public abstract class FSMState
 90 {
 91     protected Dictionary<Transition, StateID> map = new Dictionary<Transition, StateID>();
 92     protected StateID stateID;
 93     public StateID ID { get { return stateID; } }
 94 
 95     public void AddTransition(Transition trans, StateID id)
 96     {
 97         // Check if anyone of the args is invalid
 98         //验证每个参数是否合法
 99         if (trans == Transition.NullTransition)
100         {
101             Debug.LogError("FSMState ERROR: NullTransition is not allowed for a real transition");
102             return;
103         }
104 
105         if (id == StateID.NullStateID)
106         {
107             Debug.LogError("FSMState ERROR: NullStateID is not allowed for a real ID");
108             return;
109         }
110 
111         // Since this is a Deterministic FSM,
112         //   check if the current transition was already inside the map
113         //要知道这是一个确定的有限状态机（每个状态后金对应一种状态，而不能产生分支）
114         //检查当前的过渡是否已经在地图字典中了
115         if (map.ContainsKey(trans))
116         {
117             Debug.LogError("FSMState ERROR: State " + stateID.ToString() + " already has transition " + trans.ToString() +
118                            "Impossible to assign to another state");
119             return;
120         }
121 
122         map.Add(trans, id);
123     }
124 
125     /// <summary>
126     /// This method deletes a pair transition-state from this state‘s map.
127     /// If the transition was not inside the state‘s map, an ERROR message is printed.
128     /// 这个方法用来在状态地图中删除transition-state对儿
129     /// 如果过渡并不存在于状态地图中，那么将会打印出一个错误
130     /// </summary>
131     public void DeleteTransition(Transition trans)
132     {
133         // Check for NullTransition
134         if (trans == Transition.NullTransition)
135         {
136             Debug.LogError("FSMState ERROR: NullTransition is not allowed");
137             return;
138         }
139 
140         // Check if the pair is inside the map before deleting
141         //再删除之前确认该键值对是否存在于状态地图中（键值对集合）
142         if (map.ContainsKey(trans))
143         {
144             map.Remove(trans);
145             return;
146         }
147         Debug.LogError("FSMState ERROR: Transition " + trans.ToString() + " passed to " + stateID.ToString() +
148                        " was not on the state‘s transition list");
149     }
150 
151     /// <summary>
152     /// This method returns the new state the FSM should be if
153     ///    this state receives a transition and 
154     /// 该方法在该状态接收到一个过渡时返回状态机需要成为的新状态
155     /// </summary>
156     public StateID GetOutputState(Transition trans)
157     {
158         // Check if the map has this transition
159         if (map.ContainsKey(trans))
160         {
161             return map[trans];
162         }
163         return StateID.NullStateID;
164     }
165 
166     /// <summary>
167     /// This method is used to set up the State condition before entering it.
168     /// It is called automatically by the FSMSystem class before assigning it
169     /// to the current state.
170     /// 这个方法用来设立进入状态前的条件
171     /// 在状态机分配它到当前状态之前他会被自动调用
172     /// </summary>
173     public virtual void DoBeforeEntering() { }
174 
175     /// <summary>
176     /// This method is used to make anything necessary, as reseting variables
177     /// before the FSMSystem changes to another one. It is called automatically
178     /// by the FSMSystem before changing to a new state.
179     /// 这个方法用来让一切都是必要的，例如在有限状态机变化的另一个时重置变量。
180     /// 在状态机切换到新的状态之前它会被自动调用。
181     /// </summary>
182     public virtual void DoBeforeLeaving() { }
183 
184     /// <summary>
185     /// This method decides if the state should transition to another on its list
186     /// 动机-->这个方法用来决定当前状态是否需要过渡到列表中的其他状态
187     /// NPC is a reference to the object that is controlled by this class
188     /// NPC是被该类约束下对象的一个引用
189     /// </summary>
190     public abstract void Reason(GameObject player, GameObject npc);
191 
192     /// <summary>
193     /// This method controls the behavior of the NPC in the game World.
194     /// 表现-->该方法用来控制NPC在游戏世界中的行为
195     /// Every action, movement or communication the NPC does should be placed here
196     /// NPC的任何动作，移动或者交流都需要防止在这儿
197     /// NPC is a reference to the object that is controlled by this class
198     /// NPC是被该类约束下对象的一个引用
199     /// </summary>
200     public abstract void Act(GameObject player, GameObject npc);
201 
202 } // class FSMState
203 
204 
205 /// <summary>
206 /// FSMSystem class represents the Finite State Machine class.
207 ///  It has a List with the States the NPC has and methods to add,
208 ///  delete a state, and to change the current state the Machine is on.
209 /// 该类便是有限状态机类
210 /// 它持有者NPC的状态集合并且有添加，删除状态的方法，以及改变当前正在执行的状态
211 /// </summary>
212 public class FSMSystem
213 {
214     private List<FSMState> states;
215 
216     // The only way one can change the state of the FSM is by performing a transition
217     // Don‘t change the CurrentState directly
218     //通过预装一个过渡的唯一方式来盖面状态机的状态
219     //不要直接改变当前的状态
220     private StateID currentStateID;
221     public StateID CurrentStateID { get { return currentStateID; } }
222     private FSMState currentState;
223     public FSMState CurrentState { get { return currentState; } }
224 
225     public FSMSystem()
226     {
227         states = new List<FSMState>();
228     }
229     /// <summary>
230     /// This method places new states inside the FSM,
231     /// or prints an ERROR message if the state was already inside the List.
232     /// First state added is also the initial state.
233     /// 这个方法为有限状态机置入新的状态
234     /// 或者在该状态已经存在于列表中时打印错误信息
235     /// 第一个添加的状态也是最初的状态!
236     /// </summary>
237     public void AddState(FSMState s)
238     {
239         // Check for Null reference before deleting
240         //在添加前检测空引用
241         if (s == null)
242         {
243             Debug.LogError("FSM ERROR: Null reference is not allowed");
244         }
245 
246        
247 
248         // First State inserted is also the Initial state,
249         //   the state the machine is in when the   begins
250         //被装在的第一个状态也是初始状态
251         //这个状态便是状态机开始时的状态
252         if (states.Count == 0)
253         {
254             states.Add(s);
255             currentState = s;
256             currentStateID = s.ID;
257             return;
258         }
259 
260         // Add the state to the List if it‘s not inside it
261         //如果该状态未被添加过，则加入集合
262         foreach (FSMState state in states)
263         {
264             if (state.ID == s.ID)
265             {
266                 Debug.LogError("FSM ERROR: Impossible to add state " + s.ID.ToString() +
267                                " because state has already been added");
268                 return;
269             }
270         }
271         states.Add(s);
272     }
273 
274     /// <summary>
275     /// This method delete a state from the FSM List if it exists, 
276     ///   or prints an ERROR message if the state was not on the List.
277     /// 该方法删除一个已存在以状态几个中的状态
278     /// 在它不存在时打印错误信息
279     /// </summary>
280     public void DeleteState(StateID id)
281     {
282         // Check for NullState before deleting
283         //在删除前检查其是否为空状态
284         if (id == StateID.NullStateID)
285         {
286             Debug.LogError("FSM ERROR: NullStateID is not allowed for a real state");
287             return;
288         }
289 
290         // Search the List and delete the state if it‘s inside it
291         //遍历集合如果存在该状态则删除它
292         foreach (FSMState state in states)
293         {
294             if (state.ID == id)
295             {
296                 states.Remove(state);
297                 return;
298             }
299         }
300         Debug.LogError("FSM ERROR: Impossible to delete state " + id.ToString() +
301                        ". It was not on the list of states");
302     }
303 
304     /// <summary>
305     /// This method tries to change the state the FSM is in based on
306     /// the current state and the transition passed. If current state
307     ///  doesn‘t have a target state for the transition passed, 
308     /// an ERROR message is printed.
309     /// 该方法基于当前状态和过渡是否通过来尝试改变状态机的状态，当当前的状态没有目标状态用来过渡（叫通道应该更合适吧）时通过时则打印错误消息
310     /// </summary>
311     public void PerformTransition(Transition trans)
312     {
313         // Check for NullTransition before changing the current state
314         //在改变当前状态前检测NullTransition
315         if (trans == Transition.NullTransition)
316         {
317             Debug.LogError("FSM ERROR: NullTransition is not allowed for a real transition");
318             return;
319         }
320 
321         // Check if the currentState has the transition passed as argument
322         //在改变当前状态前检测当前状态是否可作为过渡的参数
323 
324         StateID id = currentState.GetOutputState(trans);
325         if (id == StateID.NullStateID)
326         {
327             Debug.LogError("FSM ERROR: State " + currentStateID.ToString() + " does not have a target state " +
328                            " for transition " + trans.ToString());
329             return;
330         }
331 
332         // Update the currentStateID and currentState        
333         //更新当前的状态个和状态编号
334         currentStateID = id;
335         foreach (FSMState state in states)
336         {
337             if (state.ID == currentStateID)
338             {
339                 // Do the post processing of the state before setting the new one
340                 //在状态变为新状态前执行后处理
341                 currentState.DoBeforeLeaving();
342 
343                 currentState = state;
344 
345                 // Reset the state to its desired condition before it can reason or act
346                 //在状态可以使用Reason（动机）或者Act(行为)之前为它的的决定条件重置它自己
347                 currentState.DoBeforeEntering();
348                 break;
349             }
350         }
351 
352     } // PerformTransition()
353 
354 } //class FSMSystem

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Text;
  4 using UnityEngine;
  5 
  6 [RequireComponent(typeof(Rigidbody))]
  7 public class NPCControl : MonoBehaviour
  8 {
  9     public GameObject player;
 10     public Transform[] path;
 11     private FSMSystem fsm;
 12 
 13     public void SetTransition(Transition t)
 14     {
 15         //该方法用来改变有限状态机的状体，有限状态机基于当前的状态和通过的过渡状态。
 16         //如果当前的状态没有用来通过的过度状态，则会抛出错误
 17         fsm.PerformTransition(t);
 18     }
 19 
 20     public void Start()
 21     {
 22         MakeFSM();
 23     }
 24 
 25     public void FixedUpdate()
 26     {
 27         fsm.CurrentState.Reason(player, gameObject);
 28         fsm.CurrentState.Act(player, gameObject);
 29     }
 30 
 31     
 32     //NPC有两个状态分别是在路径中巡逻和追逐玩家
 33     //如果他在第一个状态并且SawPlayer 过度状态被出发了，它就转变到ChasePlayer状态
 34     //如果他在ChasePlayer状态并且LostPlayer状态被触发了，它就转变到FollowPath状态
 35 
 36     private void MakeFSM()//建造状态机
 37     {
 38         FollowPathState follow = new FollowPathState(path);
 39         follow.AddTransition(Transition.SawPlayer, StateID.ChasingPlayer);
 40 
 41         ChasePlayerState chase = new ChasePlayerState();
 42         chase.AddTransition(Transition.LostPlayer, StateID.FollowingPath);
 43 
 44         fsm = new FSMSystem();
 45         fsm.AddState(follow);//添加状态到状态机，第一个添加的状态将作为初始状态
 46         fsm.AddState(chase);
 47     }
 48 }
 49 
 50 public class FollowPathState : FSMState
 51 {
 52     private int currentWayPoint;
 53     private Transform[] waypoints;
 54 
 55     //构造函数装填自己
 56     public FollowPathState(Transform[] wp)
 57     {
 58         waypoints = wp;
 59         currentWayPoint = 0;
 60         stateID = StateID.FollowingPath;
 61     }
 62 
 63     public override void DoBeforeEntering()
 64     {
 65         Debug.Log("FollowingPath BeforeEntering--------");
 66     }
 67 
 68     public override void DoBeforeLeaving()
 69     {
 70         Debug.Log("FollowingPath BeforeLeaving---------");
 71     }
 72 
 73     //重写动机方法
 74     public override void Reason(GameObject player, GameObject npc)
 75     {
 76         // If the Player passes less than 15 meters away in front of the NPC
 77         RaycastHit hit;
 78         if (Physics.Raycast(npc.transform.position, npc.transform.forward, out hit, 15F))
 79         {
 80             if (hit.transform.gameObject.tag == "Player")
 81                 npc.GetComponent<NPCControl>().SetTransition(Transition.SawPlayer);
 82         }
 83     }
 84 
 85     //重写表现方法
 86     public override void Act(GameObject player, GameObject npc)
 87     {
 88         // Follow the path of waypoints
 89         // Find the direction of the current way point 
 90         Vector3 vel = npc.GetComponent<Rigidbody>().velocity;
 91         Vector3 moveDir = waypoints[currentWayPoint].position - npc.transform.position;
 92 
 93         if (moveDir.magnitude < 1)
 94         {
 95             currentWayPoint++;
 96             if (currentWayPoint >= waypoints.Length)
 97             {
 98                 currentWayPoint = 0;
 99             }
100         }
101         else
102         {
103             vel = moveDir.normalized * 10;
104 
105             // Rotate towards the waypoint
106             npc.transform.rotation = Quaternion.Slerp(npc.transform.rotation,
107                                                       Quaternion.LookRotation(moveDir),
108                                                       5 * Time.deltaTime);
109             npc.transform.eulerAngles = new Vector3(0, npc.transform.eulerAngles.y, 0);
110 
111         }
112 
113         // Apply the Velocity
114         npc.GetComponent<Rigidbody>().velocity = vel;
115     }
116 
117 } // FollowPathState
118 
119 public class ChasePlayerState : FSMState
120 {
121     //构造函数装填自己
122     public ChasePlayerState()
123     {
124         stateID = StateID.ChasingPlayer;
125     }
126 
127     public override void DoBeforeEntering()
128     {
129         Debug.Log("ChasingPlayer BeforeEntering--------");
130     }
131 
132     public override void DoBeforeLeaving()
133     {
134         Debug.Log("ChasingPlayer BeforeLeaving---------");
135     }
136 
137     public override void Reason(GameObject player, GameObject npc)
138     {
139         // If the player has gone 30 meters away from the NPC, fire LostPlayer transition
140         if (Vector3.Distance(npc.transform.position, player.transform.position) >= 3)
141             npc.GetComponent<NPCControl>().SetTransition(Transition.LostPlayer);
142     }
143 
144     public override void Act(GameObject player, GameObject npc)
145     {
146         // Follow the path of waypoints
147         // Find the direction of the player         
148         Vector3 vel = npc.GetComponent<Rigidbody>().velocity;
149         Vector3 moveDir = player.transform.position - npc.transform.position;
150 
151         // Rotate towards the waypoint
152         npc.transform.rotation = Quaternion.Slerp(npc.transform.rotation,
153                                                   Quaternion.LookRotation(moveDir),
154                                                   5 * Time.deltaTime);
155         npc.transform.eulerAngles = new Vector3(0, npc.transform.eulerAngles.y, 0);
156 
157         vel = moveDir.normalized * 10;
158 
159         // Apply the new Velocity
160         npc.GetComponent<Rigidbody>().velocity = vel;
161     }
162 
163 } // ChasePlayerState