[Garden] Port Placard plugin

[iche033]

Signed-off-by: Ian Chen ichen@openrobotics.org

Ported the PlacardPlugin from master branch. I added a scan_dock_deliver_task.sdf world for testing. Note that this is not the full task world as it's still missing other models and plugins like light buoy plugin and scan docker deliver scoring plugin. The new world just has the 2022 dock and placard models for testing.

To test:

1. launch the scan_dock_deliver_task world

ros2 launch vrx_gz competition.launch.py world:=scan_dock_deliver_task

1. try shuffling the placards, e.g.

gz topic -e -t /vrx/dock_2022_placard1/shuffle -m gz.msgs.Empty -p "unused: true"
gz topic -e -t /vrx/dock_2022_placard2/shuffle -m gz.msgs.Empty -p "unused: true"
gz topic -e -t /vrx/dock_2022_placard3/shuffle -m gz.msgs.Empty -p "unused: true"

1. try changing the symbol directly, e.g.

gz topic -e -t /vrx/dock_2022_placard1/symbol -m gz.msgs.StringMsg_V -p "data: ['triangle', 'red']"
gz topic -e -t /vrx/dock_2022_placard2/symbol -m gz.msgs.StringMsg_V -p "data: ['cross', 'green']"
gz topic -e -t /vrx/dock_2022_placard3/symbol -m gz.msgs.StringMsg_V -p "data: ['rectangle', 'yellow']"

[caguero]

I made some tweaks in d9b5baa.

[M1chaelM]

After building this morning I'm getting:

[ERROR] [launch]: Caught exception in launch (see debug for traceback): Caught exception when trying to load file of format [py]: No module named 'sdformat13'

Am I missing a dependency? I tried the following but it did not resolve the error:

sudo apt install libsdformat13-dev libsdformat13

[caguero]

This looks more like an issue with an SDF Python wrapper. If you compile Gazebo from source you need to set your PYTHONPATH environment variable to <YOUR_GAZEBO_WS>/install/lib/python

[M1chaelM]

Thanks! You were right--this fixed the problem:

export PYTHONPATH=$HOME/gazebo_ws/install/lib/python:$PYTHONPATH

[M1chaelM]

All working as expected. Thanks!