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  • 行为树的设计与实现

    查阅了一些行为树资料,目前最主要是参考了这篇文章,看完后感觉行为树实乃强大,绝对是替代状态机的不二之选。但从理论看起来很简单的行为树,真正着手起来却发现很多细节无从下手。
    
    总结起来,就是:
    1、行为树只是单纯的一棵决策树,还是决策+控制树。为了防止不必要的麻烦,我目前设计成单纯的决策树。
    2、什么时候执行行为树的问题,也就是行为树的Tick问题,是在条件变化的时候执行一次,还是只要对象激活,就在Update里面一直Tick。前者明显很节省开销,但那样设计的最终结果可能是最后陷入事件发送的泥潭中。那么一直Tick可能是最简单的办法,于是就引下面出新的问题。目前采用了一直Tick的办法。
    3、基本上可以明显节点有 Composite Node、Decorator Node、Condition Node、Action Node,但具体细节就很头疼。比如组合节点里的Sequence Node。这个节点是不是在每个Tick周期都从头迭代一次子节点,还是记录正在运行的子节点。每次都迭代子节点,就感觉开销有点大。记录运行节点就会出现条件冗余问题,具体后面再讨论。目前采用保存当前运行节点的办法。
    4、条件节点(Condition Node)的位置问题。看到很多设计都是条件节点在最后才进行判断,而实际上,如果把条件放在组合节点处,就可以有效短路判断,不再往下迭代。于是我就采用了这种方法。
    
    设计开始
    在Google Code上看到的某个行为树框架,用的是抽象类做节点。考虑到C#不能多继承,抽象类可能会导致某些时候会很棘手,所以还是用接口。虽然目前还未发现接口的好处。
    在进行抽象设计的时候,接口的纯粹性虽然看起来更加清晰,不过有时候遇到需要重复使用某些类函数的时候就挺麻烦,让人感觉有点不利于复用。
    [csharp] view plaincopy 
    public enum RunStatus  
    {  
        Completed,  
        Failure,  
        Running,  
    }  
      
    public interface IBehaviourTreeNode  
    {  
        RunStatus status { get; set; }  
        string nodeName { get; set; }  
        bool Enter(object input);  
        bool Leave(object input);  
        bool Tick(object input, object output);  
        RenderableNode renderNode { get; set; }  
        IBehaviourTreeNode parent { get; set; }  
        IBehaviourTreeNode Clone();  
    }  
      
    /************************************************************************/  
    /* 组合结点                                                             */  
    /************************************************************************/  
    public interface ICompositeNode : IBehaviourTreeNode  
    {  
        void AddNode(IBehaviourTreeNode node);  
        void RemoveNode(IBehaviourTreeNode node);  
        bool HasNode(IBehaviourTreeNode node);  
      
        void AddCondition(IConditionNode node);  
        void RemoveCondition(IConditionNode node);  
        bool HasCondition(IConditionNode node);  
      
        ArrayList nodeList { get; }  
        ArrayList conditionList { get; }  
    }  
      
    /************************************************************************/  
    /* 选择节点                                                             */  
    /************************************************************************/  
    public interface ISelectorNode : ICompositeNode  
    {  
      
    }  
      
    /************************************************************************/  
    /*顺序节点                                                              */  
    /************************************************************************/  
    public interface ISequenceNode : ICompositeNode  
    {  
      
    }  
      
    /************************************************************************/  
    /* 平行(并列)节点                                                             */  
    /************************************************************************/  
    public interface IParallelNode : ICompositeNode  
    {  
      
    }  
      
    //////////////////////////////////////////////////////////////////////////  
      
    /************************************************************************/  
    /* 装饰结点                                                             */  
    /************************************************************************/  
    public interface IDecoratorNode : IBehaviourTreeNode  
    {  
      
    }  
      
    /************************************************************************/  
    /* 条件节点                                                             */  
    /************************************************************************/  
    public interface IConditionNode  
    {  
        string nodeName { get; set; }  
        bool ExternalCondition();  
    }  
      
    /************************************************************************/  
    /* 行为节点                                                             */  
    /************************************************************************/  
    public interface IActionNode : IBehaviourTreeNode  
    {  
      
    }  
      
    public interface IBehaviourTree  
    {  
          
    }  
    
    很多节点的接口都是空的,目前唯一的作用就是用于类型判断,很可能在最后也没有什么实际的作用,搞不好就是所谓的过度设计。如果最终确定没有用再删掉吧。
    接口里出现了一个渲染节点,目的是为了能够更方便的把这个节点和负责渲染的节点联系到一起,方便节点的可视化。
    
    如果只有接口,每次实现接口都要重复做很多工作,为了利用面向对象的复用特性,就来实现一些父类
    
    [csharp] view plaincopy 
    public class BaseNode  
    {  
        public BaseNode() { nodeName_ = this.GetType().Name + "
    "; }  
      
        protected RunStatus status_ = RunStatus.Completed;  
        protected string nodeName_;  
        protected RenderableNode renderNode_;  
        protected IBehaviourTreeNode parent_;  
      
        public virtual RunStatus status { get { return status_; } set { status_ = value; } }  
        public virtual string nodeName { get { return nodeName_; } set { nodeName_ = value; } }  
        public virtual RenderableNode renderNode { get { return renderNode_; } set { renderNode_ = value; } }  
        public virtual IBehaviourTreeNode parent { get { return parent_; } set { parent_ = value; } }  
        public virtual IBehaviourTreeNode Clone() {  
            var clone = new BaseNode();  
            clone.status_ = status_;  
            clone.nodeName_ = nodeName_;  
            clone.renderNode_ = renderNode_;  
            clone.parent_ = parent_;  
            return clone as IBehaviourTreeNode;  
        }  
    }  
      
    public class BaseActionNode : IActionNode  
    {  
        public BaseActionNode() { nodeName_ = this.GetType().Name + "
    "; }  
        protected RunStatus status_ = RunStatus.Completed;  
        protected string nodeName_;  
        protected RenderableNode renderNode_;  
        protected IBehaviourTreeNode parent_;  
        public virtual RunStatus status { get { return status_; } set { status_ = value; } }  
        public virtual string nodeName { get { return nodeName_; } set { nodeName_ = value; } }  
        public virtual RenderableNode renderNode { get { return renderNode_; } set { renderNode_ = value; } }  
        public virtual IBehaviourTreeNode parent { get { return parent_; } set { parent_ = value; } }  
        public virtual IBehaviourTreeNode Clone()  
        {  
            var clone = new BaseActionNode();  
            clone.status_ = status_;  
            clone.nodeName_ = nodeName_;  
            clone.renderNode_ = renderNode_;  
            clone.parent_ = parent_;  
            return clone as IBehaviourTreeNode;  
        }  
      
        public virtual bool Enter(object input)  
        {  
            status_ = RunStatus.Running;  
            return true;  
        }  
      
        public virtual bool Leave(object input)  
        {  
            status_ = RunStatus.Completed;  
            return true;  
        }  
      
        public virtual bool Tick(object input, object output)  
        {  
            return true;  
        }  
    }  
    public class BaseCondictionNode {  
        protected string nodeName_;  
        public virtual string nodeName { get { return nodeName_; } set { nodeName_ = value; } }  
        public BaseCondictionNode() { nodeName_ = this.GetType().Name+"
    "; }  
        public delegate bool ExternalFunc();  
        protected ExternalFunc externalFunc;  
        public static ExternalFunc GetExternalFunc(BaseCondictionNode node) {  
            return node.externalFunc;  
        }  
    }  
      
    public class Precondition : BaseCondictionNode, IConditionNode{  
        public Precondition(ExternalFunc func) { externalFunc = func; }  
        public Precondition(BaseCondictionNode pre) { externalFunc = BaseCondictionNode.GetExternalFunc(pre); }  
        public bool ExternalCondition()  
        {  
            if (externalFunc != null) return externalFunc();  
            else return false;  
        }  
    }  
      
    public class PreconditionNOT : BaseCondictionNode, IConditionNode  
    {  
        public PreconditionNOT(ExternalFunc func) { externalFunc = func; }  
        public PreconditionNOT(BaseCondictionNode pre) { externalFunc = BaseCondictionNode.GetExternalFunc(pre); }  
        public bool ExternalCondition()  
        {  
            if (externalFunc != null) return !externalFunc();  
            else return false;  
        }  
    }  
      
    public class BaseCompositeNode : BaseNode{  
        protected ArrayList nodeList_ = new ArrayList();  
        protected ArrayList conditionList_ = new ArrayList();  
        protected int runningNodeIndex = 0;  
        protected bool CheckNodeAndCondition() {  
            if (nodeList_.Count == 0)  
            {  
                status_ = RunStatus.Failure;  
                Debug.Log("SequenceNode has no node!");  
                return false;  
            }  
            return CheckCondition();  
        }  
        protected bool CheckCondition() {  
            foreach (var node in conditionList_)  
            {  
                var condiction = node as IConditionNode;  
                if (!condiction.ExternalCondition())  
                    return false;  
            }  
            return true;  
        }  
        public virtual void AddNode(IBehaviourTreeNode node) { node.parent = (IBehaviourTreeNode)this; nodeList_.Add(node); }  
        public virtual void RemoveNode(IBehaviourTreeNode node) { nodeList_.Remove(node); }  
        public virtual bool HasNode(IBehaviourTreeNode node) { return nodeList_.Contains(node); }  
      
        public virtual void AddCondition(IConditionNode node) { conditionList_.Add(node); }  
        public virtual void RemoveCondition(IConditionNode node) { conditionList_.Remove(node); }  
        public virtual bool HasCondition(IConditionNode node) { return conditionList_.Contains(node); }  
      
        public virtual ArrayList nodeList { get { return nodeList_; } }  
        public virtual ArrayList conditionList { get { return conditionList_; } }  
      
        public override IBehaviourTreeNode Clone()  
        {  
            var clone = base.Clone() as BaseCompositeNode;  
            clone.nodeList_.AddRange(nodeList_);  
            clone.conditionList_.AddRange(conditionList_);  
            clone.runningNodeIndex = runningNodeIndex;  
            return clone as IBehaviourTreeNode;  
        }  
    }  
    
    然后实现具体的节点,先是序列节点
    [csharp] view plaincopy 
    public class SequenceNode : BaseCompositeNode, ISequenceNode  
    {  
        public SequenceNode(bool canContinue_ = false) { canContinue = canContinue_; }  
        public bool canContinue = false;  
      
      
        public bool Enter(object input)  
        {  
            var checkOk = CheckNodeAndCondition();  
            if (!checkOk) return false;  
            var runningNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
            checkOk = runningNode.Enter(input);  
            if (!checkOk) return false;  
            status_ = RunStatus.Running;  
            return true;  
        }  
      
        public bool Leave(object input)  
        {  
            if (nodeList_.Count == 0)  
            {  
                status_ = RunStatus.Failure;  
                Debug.Log("SequenceNode has no node!");  
                return false;  
            }  
            var runningNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
            runningNode.Leave(input);  
            if (canContinue)  
            {  
                runningNodeIndex++;  
                runningNodeIndex %= nodeList_.Count;  
            }  
            status_ = RunStatus.Completed;  
            return true;  
        }  
      
        public bool Tick(object input, object output)  
        {  
            if (status_ == RunStatus.Failure) return false;  
            if (status_ == RunStatus.Completed) return true;  
              
            var runningNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
            var checkOk = CheckCondition();  
            if (!checkOk)  
            {  
                return false;  
            }  
      
            switch (runningNode.status)  
            {  
                case RunStatus.Running:  
                    if (!runningNode.Tick(input, output))  
                    {  
                        runningNode.Leave(input);  
                        return false;  
                    }  
      
                    break;  
                default:  
                    runningNode.Leave(input);  
                    runningNodeIndex++;  
                    if(runningNodeIndex >= nodeList_.Count)break;  
                    var nextNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
                    var check = nextNode.Enter(input);  
                    if (!check) return false;  
                    break;  
            }  
            return true;  
        }  
      
        public override IBehaviourTreeNode Clone()  
        {  
            var clone = base.Clone() as SequenceNode;  
            clone.canContinue = canContinue;  
            return clone;  
        }  
    }  
    这就是序列节点的设计,但是明显看起来很不爽,里面还出现了一个别扭的变量canContinue 。为什么会出现这个?因为序列节点的特点就是遇到一个子节点FALSE,就会停止并返回FALSE,但是这里我想用序列节点来做根节点,如果是根节点遇到这种情况,那么就不会执行下一个节点,而我看了很多种对于几大节点的描述,似乎都没提到这个。很多都用序列节点做根节点,有些就直接说是根节点。那么要么根节点另外实现,要么改一下序列节点。因为如果序列节点是非根节点的情况下,如果不是每次都从头开始,似乎又会引来新的问题,虽然目前还没想到会出什么问题。不过最后实现执行起来之后发现,用选择节点其实是一样的。所以目前这样的设计,可能是有根本上的问题。希望哪位大神可以指点一下。
    
    然后是选择节点,根据了所有FALSE才返回FALSE的特点设计了
    
    [csharp] view plaincopy 
    public class SelectorNode : BaseCompositeNode, ISelectorNode  
    {  
        public bool Enter(object input)  
        {  
            var checkOk = CheckNodeAndCondition();  
            if (!checkOk) return false;  
             
            do  
            {  
                var runningNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
                checkOk = runningNode.Enter(input);  
                if (checkOk) break;  
                runningNodeIndex++;  
                if (runningNodeIndex >= nodeList_.Count) return false;  
            } while (!checkOk);  
              
            status_ = RunStatus.Running;  
            return true;  
        }  
      
        public bool Leave(object input)  
        {  
            var runningNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
            runningNode.Leave(input);  
            runningNodeIndex = 0;  
            status_ = RunStatus.Completed;  
            return true;  
        }  
      
        public bool Tick(object input, object output)  
        {  
            if (status_ == RunStatus.Failure) return false;  
            if (status_ == RunStatus.Completed) return true;  
            var checkOk1 = CheckCondition();  
            if (!checkOk1) return false;  
            var runningNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
            switch (runningNode.status)  
            {  
                case RunStatus.Running:  
                    if (!runningNode.Tick(input, output))  
                    {  
                        runningNode.Leave(input);  
                        return false;  
                    }  
      
                    break;  
                default:  
                    runningNode.Leave(input);  
                    runningNodeIndex++;  
                    if (runningNodeIndex >= nodeList_.Count) return false;  
      
                    bool checkOk = false;  
                    do  
                    {  
                        var nextNode = nodeList_[runningNodeIndex] as IBehaviourTreeNode;  
                        checkOk = nextNode.Enter(input);  
                        if (checkOk) break;  
                        runningNodeIndex++;  
                        if (runningNodeIndex >= nodeList_.Count) return false;  
                    } while (!checkOk);  
                    break;  
            }  
            return true;  
        }  
    }  
    
    目前对于我的简单DEMO,组合节点只需要这两个就够了,实际上只需要选择节点、条件节点、动作节点就够了。所以说设计是不完全的,虽然能够实现目标需求,但是实际工作量仍挺大,具体接下来会说明。
    
    行为节点
    
    
    先放一些渲染节点的代码。实际上我基本上是第一次接触自己去渲染一种数据结构,看完网上的大牛们随随便便就能写出个数据结构的示意图,不得不佩服。我一时半会没想出怎么渲染出树状结构,于是就简单的把树按层分组,一层一层渲染,缺点就是不能很好的表现树的样子,父子关系不能很好的表示。这里放出来希望能抛砖引玉。我以后可能会去完事它,但是现在首先是要搞清楚行为树。实现这个完全是为了看看节点是否正确放置,以方便调试。
    [csharp] view plaincopy 
    public class RenderableNode  
    {  
        public RenderableNode parent;  
        public IBehaviourTreeNode targetNode;  
        public Rect posRect = new Rect();  
        public string name;  
        public int layer;  
        public RunStatus staus;  
        public override string ToString()  
        {  
            return name + "
    " + staus.ToString();  
        }  
        public virtual void Render()  
        {  
            bool running = staus == RunStatus.Running;  
            var rect = posRect;  
            rect.y -= (posRect.height / 2);  
      
            var oldColor = GUI.color;  
             if (running)  
            {  
                GUI.color = Color.green;  
            }  
            GUI.Box(rect, ToString());  
            GUI.color = oldColor;  
      
            if (parent == null && targetNode != null && targetNode.parent!=null)  
            {  
                parent = targetNode.parent.renderNode;  
            }  
            if (parent != null)  
            {  
                Vector2 parentPos = new Vector2();  
                parentPos.x = parent.posRect.x + parent.posRect.width;  
                parentPos.y = parent.posRect.y;  
                GUIHelper.DrawLine(new Vector2(rect.x, rect.y + rect.height / 2), parentPos, running?Color.green:Color.yellow);  
            }  
              
        }  
    }  
      
    public class RenderableCondictionNode : RenderableNode  
    {  
        public IConditionNode targetCondictionNode;  
        public override string ToString() { parent = null; return name; }  
        public override void Render()  
        {  
            var rect = posRect;  
            rect.y -= (posRect.height / 2);  
      
            var oldColor = GUI.color;  
            if (targetCondictionNode.ExternalCondition())  
                GUI.color = Color.green;  
            else  
                GUI.color = Color.blue;  
            GUI.Box(rect, ToString());  
            GUI.color = oldColor;  
        }  
    }  
      
    public class EmptyNode : RenderableNode { public override void Render() { } }  
      
    public class NodeBox  
    {  
        public Rect posRect = new Rect();  
        public List<RenderableNode> nodeList = new List<RenderableNode>();  
        public void AddNode(RenderableNode node)  
        {  
            nodeList.Add(node);  
        }  
        public void Render()  
        {  
            posRect.y = Screen.height / 2;  
            Rect rect = new Rect();  
      
            foreach (var node in nodeList)  
            {  
                var n = node;  
                rect.height += (n.posRect.height + 1);  
                rect.width = n.posRect.width + 10;  
            }  
            rect.height += 10;  
            rect.x = posRect.x - rect.width / 2;  
            rect.y = posRect.y - rect.height / 2;  
            //GUI.Box(rect, "");  
            posRect.width = rect.width;  
            posRect.height = rect.height;  
            float height = 0;  
            for (var i = 0; i < nodeList.Count; i++)  
            {  
                var n = nodeList[i];  
                n.posRect.y = rect.y + height + n.posRect.height / 2 + 5;  
                n.posRect.x = rect.x + 5;  
                n.Render();  
                height += n.posRect.height + 1;  
            }  
        }  
    }  
    
    
    放一张渲染出来的效果
    
    虽然每一组都只是简单的居中,不过效果看起来还可以接受
    
    然后从图中就可以看到问题了。所有正条件,都会有一个反条件,不这么做就无法在条件改变时,让当前节点返回FALSE,从而让行为树去寻找其他节点。而如果用状态机来做的话,条件肯定只用判断一次,比如
    [csharp] view plaincopy 
    if(run){  
       Run();  
    }  
    else{  
       Walk();  
    }  
    那么可能就回到最初的组合节点的设计了,组合节点就不得不每次都扫描条件。其实本质上我是在担心开销问题,因为变成节点后,就不在是if else那么简单,而是变成了函数调用的开销。简单的AI还好,如果大量复杂的AI,每次对整棵树进行扫描估计够呛。但是目前的设计,条件节点就会非常多,条件不完备就会出现BUG,似乎也不是非常好的情况。
    
    
    最后放出一些细节
    [csharp] view plaincopy 
    class PatrolAction : BaseActionNode {  
      
            public PatrolAction() { nodeName_ += "巡逻行为"; }  
      
            public override bool Tick(object input_, object output_)  
            {  
               // var input = input_ as WarriorInputData;  
                var output = output_ as WarriorOutPutData;  
                output.action = WarriorActon.ePatrol;  
                return true;  
            }  
        }  
      
        class RunAwayAction : BaseActionNode {  
            public RunAwayAction() { nodeName_ += "逃跑行为"; }  
      
            public override bool Tick(object input_, object output_)  
            {  
                // var input = input_ as WarriorInputData;  
                var output = output_ as WarriorOutPutData;  
                output.action = WarriorActon.eRunAway;  
                return true;  
            }  
        }  
      
        class AttackAction : BaseActionNode {  
            public AttackAction() { nodeName_ += "攻击行为"; }  
      
            public override bool Tick(object input_, object output_)  
            {  
                // var input = input_ as WarriorInputData;  
                var output = output_ as WarriorOutPutData;  
                output.action = WarriorActon.eAttack;  
                return true;  
            }  
        }  
      
        class CrazyAttackAction : BaseActionNode {  
            public CrazyAttackAction() { nodeName_ += "疯狂攻击行为"; }  
      
            public override bool Tick(object input_, object output_)  
            {  
                // var input = input_ as WarriorInputData;  
                var output = output_ as WarriorOutPutData;  
                output.action = WarriorActon.eCrazyAttack;  
                return true;  
            }  
        }  
      
        class AlertAction : BaseActionNode  
        {  
            public AlertAction() { nodeName_ += "警戒行为"; }  
            public override bool Tick(object input_, object output_)  
            {  
                // var input = input_ as WarriorInputData;  
                var output = output_ as WarriorOutPutData;  
                output.action = WarriorActon.eAlert;  
                return true;  
            }  
        }  
    
    
    [csharp] view plaincopy 
    private ICompositeNode rootNode = new SelectorNode();  
        private WarriorInputData inputData = new WarriorInputData();  
        private WarriorOutPutData outputData = new WarriorOutPutData();  
        // Use this for initialization  
        public void Start()  
        {  
            inputData.attribute = GetComponent<CharacterAttribute>();  
      
            rootNode.nodeName += "";  
      
            //条件  
            var hasNoTarget = new PreconditionNOT(() => { return inputData.attribute.hasTarget; });  
            hasNoTarget.nodeName = "无目标";  
            var hasTarget = new Precondition(hasNoTarget);  
            hasTarget.nodeName = "发现目标";  
            var isAnger = new Precondition(() => { return inputData.attribute.isAnger; });  
            isAnger.nodeName = "愤怒状态";  
            var isNotAnger = new PreconditionNOT(isAnger);  
            isNotAnger.nodeName = "非愤怒状态";  
            var HPLessThan500 = new Precondition(() => { return inputData.attribute.health < 500; });  
            HPLessThan500.nodeName = "血少于500";  
            var HPMoreThan500 = new PreconditionNOT(HPLessThan500);  
            HPMoreThan500.nodeName = "血大于500";  
            var isAlert = new Precondition(() => { return inputData.attribute.isAlert; });  
            isAlert.nodeName = "警戒";  
            var isNotAlert = new PreconditionNOT(isAlert);  
            isNotAlert.nodeName = "非警戒";  
      
      
            var patrolNode = new SequenceNode();  
            patrolNode.nodeName += "巡逻";  
            patrolNode.AddCondition(hasNoTarget);  
            patrolNode.AddCondition(isNotAlert);  
            patrolNode.AddNode(new PatrolAction());  
      
            var alert = new SequenceNode();  
            alert.nodeName += "警戒";  
            alert.AddCondition(hasNoTarget);  
            alert.AddCondition(isAlert);  
            alert.AddNode(new AlertAction());  
              
            var runaway = new SequenceNode();  
            runaway.nodeName += "逃跑";  
            runaway.AddCondition(hasTarget);  
            runaway.AddCondition(HPLessThan500);  
            runaway.AddNode(new RunAwayAction());  
      
            var attack = new SelectorNode();  
            attack.nodeName += "攻击";  
            attack.AddCondition(hasTarget);  
            attack.AddCondition(HPMoreThan500);  
      
            var attackCrazy = new SequenceNode();  
            attackCrazy.nodeName += "疯狂攻击";  
            attackCrazy.AddCondition(isAnger);  
            attackCrazy.AddNode(new CrazyAttackAction());  
            attack.AddNode(attackCrazy);  
      
            var attackNormal = new SequenceNode();  
            attackNormal.nodeName += "普通攻击";  
            attackNormal.AddCondition(isNotAnger);  
            attackNormal.AddNode(new AttackAction());  
            attack.AddNode(attackNormal);  
      
            rootNode.AddNode(patrolNode);  
            rootNode.AddNode(alert);  
            rootNode.AddNode(runaway);  
            rootNode.AddNode(attack);  
            var ret = rootNode.Enter(inputData);  
            if (!ret)  
            {  
                Debug.Log("无可执行节点!");  
            }  
        }  
          
        // Update is called once per frame  
        void Update () {  
            var ret = rootNode.Tick(inputData, outputData);  
      
            if (!ret)  
                rootNode.Leave(inputData);  
      
            if (rootNode.status == RunStatus.Completed)  
            {  
                ret = rootNode.Enter(inputData);  
                if (!ret)  
                    rootNode.Leave(inputData);  
            }  
            else if (rootNode.status == RunStatus.Failure)  
            {  
                Debug.Log("BT Failed");  
                enabled = false;  
            }  
      
            if (outputData.action != inputData.action)  
            {  
                OnActionChange(outputData.action, inputData.action);  
                inputData.action = outputData.action;  
            }  
        }  
      
        void OnActionChange(WarriorActon action, WarriorActon lastAction) {  
          //  print("OnActionChange "+action+" last:"+lastAction);  
            switch (lastAction)  
            {  
                case WarriorActon.ePatrol:  
                    GetComponent<WarriorPatrol>().enabled = false;  
                    break;  
                case WarriorActon.eAttack:  
                case WarriorActon.eCrazyAttack:  
                    GetComponent<WarriorAttack>().enabled = false;  
                    break;  
                case WarriorActon.eRunAway:  
                    GetComponent<WarriorRunAway>().enabled = false;  
                    break;  
                case WarriorActon.eAlert:  
                    GetComponent<WarriorAlert>().enabled = false;  
                    break;  
            }  
      
            switch (action) {   
                case WarriorActon.ePatrol:  
                    GetComponent<WarriorPatrol>().enabled = true;  
                    break;  
                case WarriorActon.eAttack:  
                    var attack = GetComponent<WarriorAttack>();  
                    attack.revenge = false;  
                    attack.enabled = true;  
                    break;  
                case WarriorActon.eCrazyAttack:  
                    var crazyAttack = GetComponent<WarriorAttack>();  
                    crazyAttack.revenge = true;  
                    crazyAttack.enabled = true;  
                    break;  
                case WarriorActon.eRunAway:  
                    GetComponent<WarriorRunAway>().enabled = true;  
                    break;  
                case WarriorActon.eAlert:  
                    GetComponent<WarriorAlert>().enabled = true;  
                    break;  
                case WarriorActon.eIdle:  
                    GetComponent<WarriorPatrol>().enabled = false;  
                    GetComponent<WarriorAttack>().enabled = false;  
                    GetComponent<WarriorRunAway>().enabled = false;  
                    break;  
            }  
        }  

    原地址:http://blog.csdn.net/luyuncsd123/article/details/18351137

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  • 原文地址:https://www.cnblogs.com/123ing/p/3706159.html
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