一文足矣：Unity&行为树（二）

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
/// <summary>
/// Database is the blackboard in a classic blackboard system. 
/// (I found the name "blackboard" a bit hard to understand so I call it database ;p)
/// 
/// It is the place to store data from local nodes, cross-tree nodes, and even other scripts.
/// Nodes can read the data inside a database by the use of a string, or an int id of the data.
/// The latter one is prefered for efficiency's sake.
/// </summary>
public class Database : MonoBehaviour {
  // _database & _dataNames are 1 to 1 relationship
  private List<object> _database = new List<object>();
  private List<string> _dataNames = new List<string>();
  // Should use dataId as parameter to get data instead of this
  public T GetData<T> (string dataName) {
    int dataId = IndexOfDataId(dataName);
    if (dataId == -1) Debug.LogError("Database: Data for " + dataName + " does not exist!");
    return (T) _database[dataId];
  }
  // Should use this function to get data!
  public T GetData<T> (int dataId) {
    if (BT.BTConfiguration.ENABLE_DATABASE_LOG) {
      Debug.Log("Database: getting data for " + _dataNames[dataId]);
    }
    return (T) _database[dataId];
  }
  public void SetData<T> (string dataName, T data) {
    int dataId = GetDataId(dataName);
    _database[dataId] = (object) data;
  }
  public void SetData<T> (int dataId, T data) {
    _database[dataId] = (object) data;
  }
  public int GetDataId (string dataName) {
    int dataId = IndexOfDataId(dataName);
    if (dataId == -1) {
      _dataNames.Add(dataName);
      _database.Add(null);
      dataId = _dataNames.Count - 1;
    }
    return dataId;
  }
  private int IndexOfDataId (string dataName) {
    for (int i=0; i<_dataNames.Count; i++) {
      if (_dataNames[i].Equals(dataName)) return i;
    }
    return -1;
  }
  public bool ContainsData (string dataName) {
    return IndexOfDataId(dataName) != -1;
  }
}
// IMPORTANT: users may want to put Jargon in a separate file
//public enum Jargon {
//  ShouldReset = 1,
//}

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using BT;
// How to use:
// 1. Initiate values in the database for the children to use.
// 2. Initiate BT _root
// 3. Some actions & preconditions that will be used later
// 4. Add children nodes
// 5. Activate the _root, including the children nodes' initialization
public abstract class BTTree : MonoBehaviour {
  protected BTNode _root = null;
  [HideInInspector]
  public Database database;
  [HideInInspector]
  public bool isRunning = true;
  public const string RESET = "Rest";
  private static int _resetId;
  void Awake () {
    Init();
    _root.Activate(database);
  }
  void Update () {
    if (!isRunning) return;
    if (database.GetData<bool>(RESET)) {
      Reset();  
      database.SetData<bool>(RESET, false);
    }
    // Iterate the BT tree now!
    if (_root.Evaluate()) {
      _root.Tick();
    }
  }
  void OnDestroy () {
    if (_root != null) {
      _root.Clear();
    }
  }
  // Need to be called at the initialization code in the children.
  protected virtual void Init () {
    database = GetComponent<Database>();
    if (database == null) {
      database = gameObject.AddComponent<Database>();
    }
    _resetId = database.GetDataId(RESET);
    database.SetData<bool>(_resetId, false);
  }
  protected void Reset () {
    if (_root != null) {
      _root.Clear();  
    }
  }
}