Feature request LaserScan support

[ajsampathk]

Feature request

The plugin only supports publishes PointCloudPacked messages, this is fine for most cases, however, for a 2D lidar (vertical samples =1), it would make sense to have LaserScan being published instead of a point cloud. The gazebo_plugin takes care of this somehow and publishes laser scan for 2D lidars. At this point I am not entirely sure how or where the decision is made in that plugin.

And trying to use pointcloud_to_laserscan to get around this also has its own draw backs, namely, it does not copy intensity values refer here and adds overhead.

I have a suggestion here and a branch with these changes that have been tested,

• add an optional publish_laserscan param to the sdf parser
• if a lidar instance has the publish_laserscan param set to true, AND the number of vertical samples is 1, then
  • use the resultDistances API to get the ranges
  • create and LaserScan msg instead of a PointCloudPacked msg.
• if it is not set or is set to false, continue as normal with PointCloudPacked msg

Please let me know if this is a useful addition and I would be happy to create a PR with these changes or add any other modifications.

Thanks!

[PawelLiberadzki]

Hi @ajsampathk, thank you for this investigation and your work! I must say that I would have to put some more time into an investigation of gazebo laser plugin to determine how does it exactly work.

Nonetheless, your proposition sounds reasonable, in terms of compatibility and added value. We would be really grateful if you will make a PR with your proposed changes. Now, in December, we have a lot of work closing ongoing topics, but we would surely dedicate time to make a review and merge this PR in the first half of January.

Thank you for your contribution!