#!/usr/bin/env python # -*- coding: utf-8 -*- from dora import Node, Ros2Context, Ros2NodeOptions, Ros2QosPolicies CHECK_TICK = 50 # Create a ROS2 Context ros2_context = Ros2Context() ros2_node = ros2_context.new_node( "turtle_teleop", "/ros2_demo", Ros2NodeOptions(rosout=True), ) # Define a ROS2 QOS topic_qos = Ros2QosPolicies(reliable=True, max_blocking_time=0.1) # Create a publisher to cmd_vel topic turtle_twist_topic = ros2_node.create_topic( "/turtle1/cmd_vel", "geometry_msgs/Twist", topic_qos ) twist_writer = ros2_node.create_publisher(turtle_twist_topic) # Create a listener to pose topic turtle_pose_topic = ros2_node.create_topic("/turtle1/pose", "turtlesim/Pose", topic_qos) pose_reader = ros2_node.create_subscription(turtle_pose_topic) # Create a dora node dora_node = Node() # Listen for both stream on the same loop as Python does not handle well multiprocessing dora_node.merge_external_events(pose_reader) print("looping", flush=True) # take track of minimum and maximum coordinates of turtle min_x = 1000 max_x = 0 min_y = 1000 max_y = 0 for i in range(500): event = dora_node.next() if event is None: break event_kind = event["kind"] # Dora event if event_kind == "dora": event_type = event["type"] if event_type == "INPUT": event_id = event["id"] if event_id == "direction": twist_writer.publish(event["value"]) # ROS2 Event elif event_kind == "external": pose = event.inner()[0].as_py() min_x = min([min_x, pose["x"]]) max_x = max([max_x, pose["x"]]) min_y = min([min_y, pose["y"]]) max_y = max([max_y, pose["y"]]) dora_node.send_output("turtle_pose", event.inner()) assert max_x - min_x > 1 or max_y - min_y > 1, "no turtle movement"