[Unity插件]Lua行为树：行为节点扩展

Posted 2021-01-06 lyh916

先看一下之前的行为节点是怎么设计的：

BTAction.lua

 1 BTAction = BTTask:New();
 2 
 3 local this = BTAction;
 4 this.taskType = BTTaskType.Action;
 5 
 6 function this:New()
 7     local o = {};
 8     setmetatable(o, self);
 9     self.__index = self;
10     return o;
11 end

 

BTLog.lua

 1 --[[
 2 参考BehaviorDesigner-Action-Log
 3 --]]
 4 BTLog = BTAction:New();
 5 
 6 local this = BTLog;
 7 this.name = "BTLog";
 8 
 9 function this:New(text)
10     local o = {};
11     setmetatable(o, self);
12     self.__index = self;
13     o.text = text;
14     return o;
15 end
16 
17 function this:OnUpdate()
18     print(self.text);
19     return BTTaskStatus.Success;
20 end

 

由上可见，行为节点的具体逻辑都是放在OnUpdate中的，那么问题来了，如果想在OnUpdate前执行一段逻辑，OnUpdate后也执行一段逻辑，类似于状态机那样，那么就需要对行为节点进行扩展。

BTAction.lua

 1 BTAction = BTTask:New();
 2 
 3 local this = BTAction;
 4 this.taskType = BTTaskType.Action;
 5 this.isEnter = false;
 6 
 7 function this:New()
 8     local o = {};
 9     setmetatable(o, self);
10     self.__index = self;
11     return o;
12 end
13 
14 function this:OnUpdate()
15     local status;
16     if (not self.isEnter) then
17         self.isEnter = true;
18         self:Enter();
19     end
20     if (self.isEnter) then
21         status = self:Execute();
22         if (status ~= BTTaskStatus.Running) then
23             self:Exit();
24             self.isEnter = false;
25         end
26     end
27     return status;
28 end
29 
30 function this:Enter()
31     print("BTAction:Enter");
32 end
33 
34 function this:Execute()
35     print("BTAction:Execute");
36     return BTTaskStatus.Success;
37 end
38 
39 function this:Exit()
40     print("BTAction:Exit");
41 end

 

BTLog.lua

 1 --[[
 2 参考BehaviorDesigner-Action-Log
 3 --]]
 4 BTLog = BTAction:New();
 5 
 6 local this = BTLog;
 7 this.name = "BTLog";
 8 
 9 function this:New(text)
10     local o = {};
11     setmetatable(o, self);
12     self.__index = self;
13     o.text = text;
14     return o;
15 end
16 
17 function this:Enter()
18     print(self.name .. ":Enter");
19 end
20 
21 function this:Execute()
22     print(self.text);
23     return BTTaskStatus.Success;
24 end
25 
26 function this:Exit()
27     print(self.name .. ":Exit");
28 end

 

TestBehaviorTree.lua

 1 TestBehaviorTree = BTBehaviorTree:New();
 2 
 3 local this = TestBehaviorTree;
 4 this.name = "TestBehaviorTree";
 5 
 6 function this:New()
 7     local o = {};
 8     setmetatable(o, self);
 9     self.__index = self;
10     o:Init();
11     return o;
12 end
13 
14 function this:Init()
15     local sequence = BTSequence:New();
16     local log = BTLog:New("This is log!!!");
17     local log2 = BTLog:New("This is log2!!!");
18     log.name = "log";
19     log2.name = "log2";
20     
21     self:SetStartTask(sequence);
22 
23     sequence:AddChild(log);
24     sequence:AddChild(log2);
25 end

 

打印如下：