Migration from Gazebo-classic: Sensor API

When migrating plugins from Gazebo-classic to Gazebo, developers will notice that the C++ APIs for both simulators are quite different. Be sure to check the plugin migration tutorial to get a high-level view of the architecture differences before using this guide.

This tutorial is meant to serve as a reference guide for developers migrating functions from the gazebo::sensors::Sensor class.

If you're trying to use some API which doesn't have an equivalent on Gazebo yet, feel free to ticket an issue.

Sensor API

Gazebo-classic's gazebo::sensors::Sensor provides lots of functionality, which can be divided in these categories:

Properties: Setting / getting properties
- Example: Sensor::Name
Read family: Getting parent
- Example: Sensor::ParentName
Write family: Changing parent
- Example: Sensor::SetParent
Lifecycle: Functions to control the sensor's lifecycle
- Example: Sensor::Init

You'll find the Gazebo APIs below on the following headers:

It's worth remembering that most of this functionality can be performed using the EntityComponentManager directly.

As an example the Sensor::Pose() is a convienient function for querying the Pose component from the EntityComponentManager, i.e.

math::Pose3d pose = _ecm.Component<components::Pose>(sensorEntityId)->Data();

The functions presented in the sections below exist for convenience and readability. The items marked as TODO means that the equivalent API is not implemented yet in Gazebo.

Properties

Most of Gazebo-classic's Sensor API is related to setting and getting properties. These functions are great candidates to have equivalents on Gazebo Gazebo, because the Entity-Component-System architecture is perfect for setting components (properties) into entities such as sensors.

Classic	Gazebo
Category	TODO
FillMsg	TODO
Id	`ignition::gazebo::Sensor::Entity`
IsActive	TODO
LastMeasurementTime	TODO
LastUpdateTime	TODO
Name	`ignition::gazebo::Sensor::Name`
NextRequiredTimestamp	TODO
Noise	TODO
Pose	`ignition::gazebo::Sensor::Pose`
ResetLastUpdateTime	TODO
ScopedName	`ignition::gazebo::scopedName`
SetActive	TODO
SetPose	TODO
SetUpdateRate	TODO
Topic	`ignition::gazebo::Sensor::Topic`
Type	`ignition::gazebo::entityType`
UpdateRate	TODO
Visualize	TODO
WorldName	`ignition::gazebo::worldEntity`

Read family

These APIs deal with reading information related to parent relationship.

The main difference in these APIs across Gazebo generations is that on classic, they deal with shared pointers to entities, while on Gazebo, they deal with entity IDs.

Classic	Gazebo
ParentId	`ignition::gazebo::Sensor::Parent`
ParentName	`ignition::gazebo::Sensor::Parent`

Write family

These functions deal with modifying the entity tree, attaching children to new parents.

Classic	Gazebo
SetParent	TODO

Lifecycle

These functions aren't related to the state of a sensor, but perform some processing related to the sensor's lifecycle, like initializing, updating or terminating it.

Classic	Gazebo
ConnectUpdated	TODO
Fini	N/A
Init	N/A
Load	`ignition::gazebo::SdfEntityCreator::CreateEntities`
Update	Entities are updated by systems