godot_ros

This repo is a Godot Module meant to connect Robotic Operating System 2 (ROS2) and the Godot Game Engine.

Update: Support for Godot4

When compiling, recommended commands are the following, setting the path where you have downloaded the godot_ros module:

source /opt/ros/${ROS_DISTRO}/setup.bash
scons -j$(nproc) custom_modules=/ABS_PATH_TO/godot_4_modules

Quick Start

Make sure to have both ROS 2 and the Godot source installed on your workstation.

Clone this repo into your godot/modules/ directory.

Alternatively you can place this module in an external ~/modules directory and pass in the filepath to scons at build time.

Modify the godot_ros/SCsub file with your ROS2 distro and desired cpp compiler flag.

# godot_ros/SCsub file within this repo, lines 5 and 6
ros_distro = "galactic"
cpp_version = "-std=c++17"

Compile Godot:

# make sure you are in the Godot source root directory
cd godot/
scons -j8 platform=x11  # specific for linux/ubuntu

If you have placed the godot_ros module in an external ~/module/ directory, pass in the filepath to scons with the following command:

cd godot/
scons -j8 platform=x11 custom_modules=/path/to/modules/directory

Once compiled, you should be able to start Godot:

cd godot/
./bin/godot.x11.tools.64

A simple GDScript talker demo would look something like this:

extends Node2D

signal timeout

# calls rclcpp::init(0, nullptr) to make sure ROS is started up
var ros_talker = Talker.new()

var g_timer = null

var count = 1

# Called when the node enters the scene tree for the first time.
func _ready():
    # spin nodes that were added to executors
    # not really need for talker demo but will be needed later for subscribing
    # to ROS2 topics
    ros_talker.spin_some()

    g_timer = Timer.new()
    add_child(g_timer)
    # connect the talk signal with the talk callback
    g_timer.connect("timeout", self, "_on_Timer_timeout")
    g_timer.set_wait_time(1.0)
    g_timer.set_one_shot(false)
    g_timer.start()
    pass # Replace with function body.

func _on_Timer_timeout():
  print("godot is talking: " + String(count))
  ros_talker.talk(count)
  count += 1

Other GDScript examples are in the gdscript/ directory

Troubleshooting

Make sure you have sourced your ROS overlay before trying to start Godot....otherwise you will see this error:

./bin/godot.x11.tools.64: error while loading shared libraries: librclcpp.so: cannot open shared object file: No such file or directory

To solve this, just run source /opt/ros/<ros-distro>/setup.bash and restart Godot.

Future work

• support other platforms, should be just configuring the SCsub file I think (i.e. Windows)
• add other ROS2 features to godot_ros
• generate documentation for this module
• add more demos/examples to documentation