# RCLGD [](https://doi.org/10.5281/zenodo.18440938) An implementation of a ros2 client library for the Godot Engine based on [ROS Babel Fish](https://github.com/LOEWE-emergenCITY/ros_babel_fish)

Features

As for now only the basic set of the rclcpp api are implemented, keep in mind this is highly experimental and not suited yet for production. But it serves as the groundbase for implementing awesome simulation environments and visualizers using the powerful features of the godot engine.

• rclgd Singleton
• Dynamic Msg Type Support
• Nodes
• Publishers
• Subscribers
• Service Clients
• Service Servers
• Timers
• Action Clients & Servers
• Parameters
• TF2 Publishers and Listeners
• TF2 Listeners And Broadcasters as 3D Nodes in godot (Will be deprecated in future update)
• Node and TF Namespacing
• ROS Graph Inspection
• QoS -> Through QoS RosQoS resource
• Godot template project
• Godot Editor Support -> Pseudo-Static Type Wrappers
• Simulation Time -> -p publish_sim_time:=true publishes the Godot physics clock on /clock; the standard -p use_sim_time:=true makes clocks and timers follow /clock
• Native RCLGD packages in colcon

Repository layout

The suite is split into independently releasable ROS 2 packages:

The system-test suite (rclgd_tests, itself a native rclgd package) is maintained separately so this repository contains only the releasable packages.

Installation

Clone this repository into your workspace and install dependencies, build it and source it. The build downloads the pinned Godot editor binary (SHA-512 verified against the official release sums) and installs it as lib/rclgd/godot-bin, next to librclgd.so — the install is complete out of the box, no extra step.

rosdep install --from-paths src --ignore-src -y -r
colcon build --packages-up-to rclgd
source install/setup.bash

To run the system tests, put the rclgd_tests package in your workspace and build it (it dogfoods the whole build_type: rclgd pipeline — it needs the suite above built and sourced first), then run it like any other rclgd package:

colcon build --packages-select rclgd_tests && source install/setup.bash
ros2 run rclgd_tests rclgd_tests --headless   # exits 0 only if all tests pass

The build installs exactly the Godot version librclgd was compiled against (the version of the godot-cpp bindings; recorded in share/rclgd/godot_version). To use a different Godot version, retarget the godot-cpp submodule to the corresponding branch, edit GODOT_VERSION and the GODOT_SHA512_* pins in rclgd/CMakeLists.txt, and rebuild.

Command line tools

rclgd ships a ros2 rclgd command:

Typed GDScript wrappers (shadow classes) are generated automatically: when a project opens in the editor, the rclgd plugin reads the dependencies declared in the project’s package.xml and (re)generates wrappers for their message types into res://addons/rclgd/gen. Add a <depend> to package.xml, reopen the editor (or use Project > Tools > Regenerate ROS2 Types), and the typed classes appear. The generated wrappers are plain GDScript files meant to be committed with the project — they regenerate automatically whenever the dependency set changes.

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