Top-level and global simulation settings
--------------------------------------------

The entire world definition file must be contained within a top-level
tag ``<mvsim_world>``. At present, a world-definition version number may
optionally be added as an attribute, with ``1.0`` the current version.

Available parameters (all are optional):

- ``<simul_timestep>0</simul_timestep>``. The fixed timestep in seconds
  for numerical integration of the physics engine. Note that if ``T`` is larger than
  the smallest period of a given sensor, some sensor readings will be missed. That is
  why there is a "magic" value of ``T`` of ``0`` (the default) which automatically
  analyze all sensors and sets this timestep accordingly to ensure no reading is lost.

- ``<gravity>9.81</gravity>``. Gravity acceleration (m/s²), in the negative Z axis 
  direction (i.e. downwards).

- ``<joystick_enabled>false</joystick_enabled>``. If enabled, a gamepad or joystick 
  can be used to control the selected vehicle. (Default is ``false`` hence no responding to gamepads).

- ``<server_address>localhost</server_address>``. The IP address the server
  must be bound to. Refer to :ref:`architecture`.

- ``<b2d_vel_iters>8</b2d_vel_iters>`` and ``<b2d_pos_iters>3</b2d_pos_iters>``. 
  Velocity and position iteration count (refer to libbox2d docs).

- ``<collision_threshold>0.03</collision_threshold>``: If the distance between the closest points of 
  a contact manifold (see box2d docs) for two bodies is below this distance, it is marked as "in collision",
  and reported as such by the collision API.

- ``<save_to_rawlog>my_dataset.rawlog</save_to_rawlog>``: If present, all sensor observations
  will be saved into an MRPT dataset in ``.rawlog`` format. One file will be created per vehicle,
  by adding the vehicle name to the provided file name.

- ``<rawlog_odometry_rate>10.0</rawlog_odometry_rate>``: If ``save_to_rawlog`` is enabled,
  this parameter defines the rate (in Hz) to generate (wheels) odometry observations (Default is 10 Hz).

- ``<save_ground_truth_trajectory>gt.txt</save_ground_truth_trajectory>``: If non-empty, the
  ground truth trajectory of all vehicles will be saved to a text file in the 
  `TUM trajectory format <https://github.com/MichaelGrupp/evo/wiki/Formats#tum---tum-rgb-d-dataset-trajectory-format>`_.
  One file will be created per vehicle,  by adding the vehicle name to the provided file name.

- ``<ground_truth_rate>50.0</ground_truth_rate>``: If ``save_ground_truth_trajectory`` is enabled,
  this parameter defines the rate (in Hz) to generate entries in the trajectory file (Default is 50 Hz).

.. code-block:: xml
   :caption: Top-level and global settings example

	<mvsim_world version="1.0">
		<!-- General simulation options -->
		<simul_timestep>0</simul_timestep> <!-- Simulation fixed-time interval for numerical integration [s], or 0 to auto-determine -->

		<!-- Normally disabled: If this tag is present, *all* sensor data is also stored
		 into an MRPT rawlog file. Useful for collecting datasets without ROS. -->
		<!-- <save_to_rawlog>sensor_dataset.rawlog</save_to_rawlog> -->
		...
	</mvsim_world>