[Unity插件]Lua行为树(四)：条件节点和行为节点

条件节点和行为节点，这两种节点本身的设计比较简单，项目中编写行为树节点一般就是扩展这两种节点，而Decorator和Composite节点只需要使用内置的就足够了。

它们的继承关系如下：

Conditional->Task

Action->Task

代码如下：

BTAction.lua

 BTAction = BTTask:New();

 local this = BTAction;

 function this:New()
     local o = {};
     setmetatable(o, self);
     self.__index = self;
     return o;
 end

BTConditional.lua

 BTConditional = BTTask:New();

 local this = BTConditional;

 function this:New()
     local o = {};
     setmetatable(o, self);
     self.__index = self;
     return o;
 end

BTLog.lua

 --[[
 参考BehaviorDesigner-Action-Log
 --]]
 BTLog = BTAction:New();

 local this = BTLog;

 function this:New(text)
     local o = {};
     setmetatable(o, self);
     self.__index = self;
     o.text = text;
     return o;
 end

 function this:OnUpdate()
     print(self.text);
     return BTTaskStatus.Success;
 end

BTIsNullOrEmpty.lua

 --[[
 参考BehaviorDesigner-Conditional-IsNullOrEmpty
 --]]
 BTIsNullOrEmpty = BTConditional:New();

 local this = BTIsNullOrEmpty;

 function this:New(text)
     local o = {};
     setmetatable(o, self);
     self.__index = self;
     o.text = text;
     return o;
 end

 function this:OnUpdate()
     if (not self.text or self.text == "") then
         return BTTaskStatus.Success;
     else
         return BTTaskStatus.Failure;
     end
 end

TestBehaviorTree.lua

 TestBehaviorTree = BTBehaviorTree:New();

 local this = TestBehaviorTree;

 function this:New()
     local o = {};
     setmetatable(o, self);
     self.__index = self;
     this:Init();
     return o;
 end

 function this:Init()
     local sequence = BTSequence:New();
     local isNullOrEmpty = BTIsNullOrEmpty:New("");
     local log = BTLog:New("This is a empty string");
     sequence:AddChild(isNullOrEmpty);
     sequence:AddChild(log);
     this:PushTask(sequence);
 end

输出如下：