Refactor tf_bridge demo (#644)

Signed-off-by: Carlos Agüero <[email protected]>

ros_gz_sim_demos/README.md

@@ -208,6 +208,6 @@ and transforms of a robot in rviz.
 
 To try the demo launch:
 
-    ros2 launch ros_gz_sim_demos tf_bridge.launch.py
+    ros2 launch ros_gz_sim_demos tf_bridge.launch.xml
 
 ![](images/tf_bridge.gif)

ros_gz_sim_demos/config/tf_bridge.yaml

@@ -0,0 +1,14 @@
+# tf_bridge configuration.
+- ros_topic_name: "/joint_states"
+  gz_topic_name: "/world/default/model/double_pendulum_with_base0/joint_state"
+  ros_type_name: "sensor_msgs/msg/JointState"
+  gz_type_name: "gz.msgs.Model"
+  lazy: true
+  direction: GZ_TO_ROS
+
+- ros_topic_name: "/tf"
+  gz_topic_name: "/model/double_pendulum_with_base0/pose"
+  ros_type_name: "tf2_msgs/msg/TFMessage"
+  gz_type_name: "gz.msgs.Pose_V"
+  lazy: true
+  direction: GZ_TO_ROS

ros_gz_sim_demos/launch/tf_bridge.launch.xml

@@ -0,0 +1,12 @@
+<launch>
+  <gz_server
+    world_sdf_file="$(find-pkg-share ros_gz_sim_demos)/models/double_pendulum_model.sdf"
+    use_composition="True"
+    create_own_container="True" />
+  <ros_gz_bridge
+    bridge_name="ros_gz_bridge"
+    config_file="$(find-pkg-share ros_gz_sim_demos)/config/tf_bridge.yaml"
+    use_composition="True" />
+  <node pkg="rviz2" exec="rviz2" args="-d $(find-pkg-share ros_gz_sim_demos)/rviz/tf_bridge.rviz" />
+  <executable cmd="gz sim -g" />
+</launch>