Add a launch file for 2d localization demo with gRPC. (#682)

cartographer_ros/cartographer_ros/cartographer_grpc/node_grpc_main.cc

@@ -37,6 +37,7 @@ DEFINE_bool(
 DEFINE_string(
     save_map_filename, "",
     "If non-empty, serialize state and write it to disk before shutting down.");
+DEFINE_string(map_filename, "", "If non-empty, filename of a map to load.");
 
 namespace cartographer_ros {
 namespace cartographer_grpc {
@@ -55,6 +56,10 @@ void Run() {
       ::cartographer_grpc::mapping::MapBuilderStub>(FLAGS_server_address);
   Node node(node_options, std::move(map_builder), &tf_buffer);
 
+  if (!FLAGS_map_filename.empty()) {
+    node.LoadMap(FLAGS_map_filename);
+  }
+
   if (FLAGS_start_trajectory_with_default_topics) {
     node.StartTrajectoryWithDefaultTopics(trajectory_options);
   }

cartographer_ros/launch/grpc_demo_backpack_2d_localization.launch

@@ -0,0 +1,39 @@
+<!--
+  Copyright 2018 The Cartographer Authors
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<launch>
+  <param name="/use_sim_time" value="true" />
+
+  <param name="robot_description"
+    textfile="$(find cartographer_ros)/urdf/backpack_2d.urdf" />
+
+  <node name="robot_state_publisher" pkg="robot_state_publisher"
+    type="robot_state_publisher" />
+
+  <node name="cartographer_grpc_node" pkg="cartographer_ros"
+      type="cartographer_grpc_node" args="
+          -configuration_directory $(find cartographer_ros)/configuration_files
+          -configuration_basename backpack_2d.lua
+          -map_filename $(arg map_filename)"
+      output="screen">
+    <remap from="echoes" to="horizontal_laser_2d" />
+  </node>
+
+  <node name="playbag" pkg="rosbag" type="play"
+        args="--clock $(arg bag_filename)" />
+  <node name="rviz" pkg="rviz" type="rviz" required="true"
+      args="-d $(find cartographer_ros)/configuration_files/demo_2d.rviz" />
+</launch>