拆分行为树

拆分行为树有两种方法，我倾向用不修改C++的方法

main_tree.xml如下

<root main_tree_to_execute = "MainTree">
    <include path="./subtree_A.xml" />
    <include path="./subtree_B.xml" />
    <BehaviorTree ID="MainTree">
        <Sequence>
            <SaySomething message="starting MainTree" />
            <SubTree ID="SubTreeA" />
            <SubTree ID="SubTreeB" />
        </Sequence>
    </BehaviorTree>
<root>

<root>
    <BehaviorTree ID="SubTreeA">
        <SaySomething message="Executing Sub_A" />
    </BehaviorTree>
</root>

<root>
    <BehaviorTree ID="SubTreeB">
        <SaySomething message="Executing Sub_B" />
    </BehaviorTree>
</root>

include path可以用绝对路径，也可以用相对路径。

factory.createTreeFromFile("main_tree.xml")

拆分后，用Groot2打开main_tree.xml，可以正常编辑和跳转到子树。

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函数Tree BT::BehaviorTreeFactory::createTreeFromFile写的不好，加载xml失败也不知道，最好返回类型是Bool，false代表加载失败。

Tree BehaviorTreeFactory::createTreeFromFile(const std::string& file_path,
                                              Blackboard::Ptr blackboard)
 {
   if(!parser_->registeredBehaviorTrees().empty()) {
     std::cout << "WARNING: You executed BehaviorTreeFactory::createTreeFromFile "
                  "after registerBehaviorTreeFrom[File/Text].\n"
                  "This is NOTm probably, what you want to do.\n"
                  "You should probably use BehaviorTreeFactory::createTree, instead"
               << std::endl;
   }
 
   XMLParser parser(*this);
   parser.loadFromFile(file_path);
   auto tree = parser.instantiateTree(blackboard);
   tree.manifests = this->manifests();
   return tree;
 }