[Unity插件]Lua行为树(六)：打印树结构

经过前面的文章，已经把行为树中的四种基本类型节点介绍了下。接下来可以整理一下，打印一下整棵行为树。注意点如下：

1.可以把BTBehaviorTree也当作一种节点，这样就可以方便地进行行为树嵌套了

2.可以在BTBehaviorTree中的SetStartTask、BTParentTask中的AddChild，即在设置节点和添加节点时对节点的信息进行打印

以下面这棵行为树为例：

BTTask.lua

BTTask = {};

local this = BTTask;

function this:New()
    local o = {};
    setmetatable(o, self);
    self.__index = self;
    o.executionStatus = BTTaskStatus.Inactive;   --该节点的执行状态
    o.root = nil;                                 --根节点
    o.parent = nil;                               --父节点
    o.layer = 1;                                 --第几层
    o.index = 1;                                 --父节点下的第几个节点
    o.name = "BTTask";                           --该节点名字
    return o;
end

function this:ToString()
    local root = "root:";
    if (self.root) then
        root = root .. self.root.name;
    else
        root = root .. "nil";
    end

    local parent = "parent:";
    if (self.parent) then
        parent = parent .. self.parent.name;
    else
        parent = parent .. "nil";
    end

    local layer = "layer:" .. self.layer;
    local index = "index:" .. self.index;
    local name = "name:" .. self.name;

    print(root .. " " .. parent .. " " .. layer .. " " .. index .. " " .. name);
end

BTParentTask.lua

BTParentTask = BTTask:New();

local this = BTParentTask;

function this:New()
    local o = {};
    setmetatable(o, self);
    self.__index = self;
    o.currentChildIndex = 0;  --当前运行到第几个子节点
    o.currentChildTask = nil; --当前运行的子节点
    o.childTasks = {};        --子节点列表
    return o;
end

--添加子节点
function this:AddChild(task)
    local index = #self.childTasks + 1;
    task.index = index;
    task.layer = self.layer + 1;
    task.parent = self;
    task.root = self.root;
    self.childTasks[index] = task;

    if (BTBehaviorManager.isPrintTaskInfo) then
        print(task:ToString());
    end
end

--是否有子节点
function this:HasChild()
    if (#self.childTasks > 0) then
        return true;
    else
        return false;
    end
end

--获取子节点数目
function this:GetChildCount()
    return #self.childTasks;
end

--获取下一个要执行的子节点
function this:GetNextChild()
    if (#self.childTasks >= (self.currentChildIndex + 1)) then
        self.currentChildIndex = self.currentChildIndex + 1;
        return self.childTasks[self.currentChildIndex];
    end
    return nil;
end

--重置
function this:Reset()
    self.currentChildIndex = 0;
    self.currentChildTask = nil;
end

BTBehaviorTree.lua

--[[
树的根节点
--]]
BTBehaviorTree = BTTask:New();

local this = BTBehaviorTree;

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

function this:SetStartTask(task)
    task.root = self;
    task.parent = self;
    task.layer = self.layer + 1;
    self.startTask = task;

    if (BTBehaviorManager.isPrintTaskInfo) then
        print(task:ToString());
    end
end

function this:OnUpdate()
    if (self.startTask) then
        return self.startTask:OnUpdate();
    end
end

TestBehaviorTree.lua

TestBehaviorTree = BTBehaviorTree:New();

local this = TestBehaviorTree;
this.name = "TestBehaviorTree";

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

function this:Init()
    local repeater = BTRepeater:New(2);
    local selector = BTSelector:New();
    local sequence = BTSequence:New();
    local isNullOrEmpty = BTIsNullOrEmpty:New("123");
    local log = BTLog:New("This is a empty string!!!");
    local log2 = BTLog:New("This is not a empty string");

    self:SetStartTask(repeater);

    repeater:AddChild(selector);

    selector:AddChild(sequence);
    selector:AddChild(log2);

    sequence:AddChild(isNullOrEmpty);
    sequence:AddChild(log);
end

打印如下：