cartographer的node_main.cc

先从mian函数开始

google::InitGoogleLogging(argv[0]);

初始化glog的库

google::ParseCommandLineFlags(&argc, &argv, true);

使用函数对参数初始化

CHECK(!FLAGS_configuration_directory.empty())
      << "-configuration_directory is missing.";
  CHECK(!FLAGS_configuration_basename.empty())
      << "-configuration_basename is missing.";

检查configuration_directory与configuration_basename是否为空（他们在launch中有对应的设置）

  :ros::init(argc, argv, "cartographer_node");

  ::ros::start();

  cartographer_ros::ScopedRosLogSink ros_log_sink;

  cartographer_ros::Run();

  ::ros::shutdown();

然后就是初始化节点，

启动线程，

消息输出

运行Run

关闭相关线程

DEFINE_bool(collect_metrics, false,
            "Activates the collection of runtime metrics. If activated, the "
            "metrics can be accessed via a ROS service.");
DEFINE_string(configuration_directory, "",
              "First directory in which configuration files are searched, "
              "second is always the Cartographer installation to allow "
              "including files from there.");
DEFINE_string(configuration_basename, "",
              "Basename, i.e. not containing any directory prefix, of the "
              "configuration file.");
DEFINE_string(load_state_filename, "",
              "If non-empty, filename of a .pbstream file to load, containing "
              "a saved SLAM state.");
DEFINE_bool(load_frozen_state, true,
            "Load the saved state as frozen (non-optimized) trajectories.");
DEFINE_bool(
    start_trajectory_with_default_topics, true,
    "Enable to immediately start the first trajectory with default topics.");
DEFINE_string(
    save_state_filename, "",
    "If non-empty, serialize state and write it to disk before shutting down.");

指定参数的名称、默认值和描述信息啥的

Run函数

constexpr double kTfBufferCacheTimeInSeconds = 10.;
  tf2_ros::Buffer tf_buffer{::ros::Duration(kTfBufferCacheTimeInSeconds)};
  // 开启监听tf的独立线程
  tf2_ros::TransformListener tf(tf_buffer);

整一个10秒的缓冲区和监听器。

NodeOptions node_options;
  TrajectoryOptions trajectory_options;

创建对象

std::tie(node_options, trajectory_options) =
      LoadOptions(FLAGS_configuration_directory, FLAGS_configuration_basename);

根据Lua配置文件中的内容, 为node_options, trajectory_options 赋值

auto map_builder =
      cartographer::mapping::CreateMapBuilder(node_options.map_builder_options);

将返回node_options.map_builder_options的指针

Node node(node_options, std::move(map_builder), &tf_buffer,
            FLAGS_collect_metrics);

  // 如果加载了pbstream文件, 就执行这个函数
  if (!FLAGS_load_state_filename.empty()) {
    node.LoadState(FLAGS_load_state_filename, FLAGS_load_frozen_state);
  }

  // 使用默认topic 开始轨迹
  if (FLAGS_start_trajectory_with_default_topics) {
    node.StartTrajectoryWithDefaultTopics(trajectory_options);
  }

  ::ros::spin();

  // 结束所有处于活动状态的轨迹
  node.FinishAllTrajectories();

  // 当所有的轨迹结束时, 再执行一次全局优化
  node.RunFinalOptimization();

std::move(map_builder)是将所有权转移