t04_blackboard.cpp

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#include "behaviortree_cpp/xml_parsing.h"
#include "behaviortree_cpp/loggers/bt_cout_logger.h"
#include "behaviortree_cpp/blackboard/blackboard_local.h"

#include "movebase_node.h"

using namespace BT;

// clang-format off
const std::string xml_text = R"(

 <root main_tree_to_execute = "MainTree" >
     <BehaviorTree ID="MainTree">
        <SequenceStar name="root">
            <CalculateGoalPose/>
            <MoveBase  goal="${GoalPose}" />
            <SetBlackboard key="OtherGoal" value="-1;3;0.5" />
            <MoveBase  goal="${OtherGoal}" />
        </SequenceStar>
     </BehaviorTree>
 </root>
 )";

// clang-format on

// Write into the blackboard key: [GoalPose]
// Use this function to create a SimpleActionNode that can access the blackboard
NodeStatus CalculateGoalPose(TreeNode& self)
{
    const Pose2D mygoal = {1.1, 2.3, 1.54};

    // RECOMMENDED: check if the blackboard is nullptr first
    if (self.blackboard())
    {
        // store it in the blackboard
        self.blackboard()->set("GoalPose", mygoal);
        return NodeStatus::SUCCESS;
    }
    else
    {
        return NodeStatus::FAILURE;
    }
}

int main()
{
    using namespace BT;

    BehaviorTreeFactory factory;
    factory.registerSimpleAction("CalculateGoalPose", CalculateGoalPose);
    factory.registerNodeType<MoveBaseAction>("MoveBase");

    // create a Blackboard from BlackboardLocal (simple, not persistent, local storage)
    auto blackboard = Blackboard::create<BlackboardLocal>();

    // Important: when the object tree goes out of scope, all the TreeNodes are destroyed
    auto tree = buildTreeFromText(factory, xml_text, blackboard);

    NodeStatus status = NodeStatus::RUNNING;
    while (status == NodeStatus::RUNNING)
    {
        status = tree.root_node->executeTick();
        SleepMS(1);   // optional sleep to avoid "busy loops"
    }
    return 0;
}