Adding single-terminal launch instructions (#1260)

Adding instructions (for advanced users) for launching the simulation stack on a single terminal, including the multi-robot example.

nav2_bringup/bringup/README.md

@@ -7,19 +7,19 @@ The `nav2_bringup` package is an example bringup system for Navigation2 applicat
 * Install Navigation2
 
     ```sudo apt install ros-<ros2_distro>-navigation2```
-    
+
 * Install Navigation2 Bringup
 
     ```sudo apt install ros-<ros2_distro>-nav2-bringup```
 
 * Install your robot specific package (ex:[Turtlebot 3](http://emanual.robotis.com/docs/en/platform/turtlebot3/ros2/))
 
-## Launch Navigation2 in Simulation with Gazebo
+## Launch Navigation2 in *Simulation* with Gazebo
 ### Pre-requisites:
 
 * [Install Gazebo](http://gazebosim.org/tutorials?tut=install_ubuntu&cat=install)
 * gazebo_ros_pkgs for ROS2 installed on the system
-    
+
     ```sudo apt-get install ros-<ros2-distro>-gazebo*```
 * A Gazebo world for simulating the robot ([Gazebo tutorials](http://gazebosim.org/tutorials?tut=quick_start))
 * A map of that world saved to a map.pgm and map.yaml ([ROS Navigation Tutorials](https://github.com/ros-planning/navigation2/tree/master/doc/use_cases))
@@ -28,7 +28,7 @@ The `nav2_bringup` package is an example bringup system for Navigation2 applicat
 
 Example: See [turtlebot3_gazebo models](https://github.com/ROBOTIS-GIT/turtlebot3_simulations/tree/ros2/turtlebot3_gazebo/models) for details
 
-```
+```bash
 export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:<full/path/to/my_robot/models>
 gazebo --verbose -s libgazebo_ros_init.so <full/path/to/my_gazebo.world>
 ```
@@ -37,7 +37,7 @@ gazebo --verbose -s libgazebo_ros_init.so <full/path/to/my_gazebo.world>
 
 Example: See [turtlebot3_gazebo](https://github.com/ROBOTIS-GIT/turtlebot3_simulations/tree/ros2/turtlebot3_gazebo) for details
 
-```
+```bash
 source /opt/ros/dashing/setup.bash
 export TURTLEBOT3_MODEL=waffle
 ros2 launch turtlebot3_bringup turtlebot3_state_publisher.launch.py use_sim_time:=True
@@ -45,17 +45,19 @@ ros2 launch turtlebot3_bringup turtlebot3_state_publisher.launch.py use_sim_time
 
 ### Terminal 3: Launch Navigation2
 
-```
+```bash
 source /opt/ros/dashing/setup.bash
 ros2 launch nav2_bringup nav2_bringup_launch.py use_sim_time:=True autostart:=True \
 map:=<full/path/to/map.yaml>
 ```
 
 ### Terminal 4: Run RViz with Navigation2 config file
-```
+
+```bash
 source /opt/ros/dashing/setup.bash
 ros2 run rviz2 rviz2 -d $(ros2 pkg prefix nav2_bringup)/share/nav2_bringup/launch/nav2_default_view.rviz
 ```
+
 In RViz:
 * You should see the map
 * Localize the robot using “2D Pose Estimate” button.
@@ -66,12 +68,46 @@ Note: this uses a ROS2 Action to send the goal, and a pop-up window will appear
 To view the robot model in RViz:
 * Add "RobotModel", set "Description Source" with "File", set "Description File" with the name of the urdf file for your robot (example: turtlebot3_burger.urdf)"
 
-## Launch Navigation2 on a Robot
+### Advanced: single-terminal launch
+
+A convenience file is provided to launch Gazebo, RVIZ and Navigation2 using a single command:
+
+```bash
+ros2 launch nav2_bringup nav2_tb3_simulation_launch.py <settings>
+```
+
+Where `<settings>` can used to replace any of the default options, for example:
+
+```
+world:=<full/path/to/gazebo.world>
+map:=<full/path/to/map.yaml>
+rviz_config_file:=<full/path/to/rviz_config.rviz>
+simulator:=<gzserver or gazebo>
+bt_xml_file:=<full/path/to/bt_tree.xml>
+```
+
+
+Before running the command make sure you are sourcing the `ROS2` workspace, setting the path to the Gazebo model and defining the TB3 robot model to use.
+
+```bash
+source <full/path/to/ros2/setup.bash>
+export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:<full/path/to/my_robot/models>
+export TURTLEBOT3_MODEL=waffle
+```
+
+Also, a file for launching **two** robots with **independent** navigation stacks is provided:
+
+```bash
+ros2 launch nav2_bringup nav2_multi_tb3_simulation_launch.py <settings>
+```
+
+
+## Launch Navigation2 on a *Robot*
 
 ### Pre-requisites:
-* Run SLAM with Navigation 2 or tele-op to drive the robot and generate a map of an area for testing first. The directions below assume this has already been done or there is already a map of the area. 
+* Run SLAM with Navigation 2 or tele-op to drive the robot and generate a map of an area for testing first. The directions below assume this has already been done or there is already a map of the area.
 
-* Learn more about how to use Navigation 2 with SLAM to create maps; 
+* Learn more about how to use Navigation 2 with SLAM to create maps;
 
     - [Navigation 2 with SLAM](https://github.com/ros-planning/navigation2/blob/master/doc/use_cases/navigation_with_slam.md)
 
@@ -82,14 +118,14 @@ To view the robot model in RViz:
 
 ### Terminal 1 : Launch Navigation2 using your map.yaml
 
-```
+```bash
 source /opt/ros/dashing/setup.bash
 ros2 launch nav2_bringup nav2_bringup_launch.py map:=<full/path/to/map.yaml> map_type:=occupancy
 ```
 
 ### Terminal 2 : Launch RVIZ
 
-```
+```bash
 source /opt/ros/dashing/setup.bash
 ros2 run rviz2 rviz2 -d $(ros2 pkg prefix nav2_bringup)/share/nav2_bringup/launch/nav2_default_view.rviz
 ```