Intro + Q&A

Bevy💋Godot (pronounced “Bevy Kissing Godot”) is a framework that adds Bevy’s ECS on top of Godot.

This project is HEAAAVILY inspired by Godot Bevy, and it would almost certainly not exist if it didn’t come up with the idea first. On the off chance someone besides me is reading this, I would highly recommend trying that project first.

I chose to create my own library for three major reasons:

I want the ability to add Bevy components on Godot nodes in the Godot editor.
My lack of knoweldge on the internals of Bevy and Godot-Bevy made me paranoid I may encounter a bug or unexpected behavior I could not fix myself.
Godot-Bevy automates a bit too much for me. I want to create my own ExtensionLibrary, I want to access Godot nodes via a NonSend, and some third thing I’m too lazy to think of but I’m sure there’s something idk it’s been a couple months since I tinkered with it.

So I decided I could fix these things by creating my own Bevy ECS in Godot project from the ground up.

Why Bevy ECS?

Because I like using components in gamedev. And I like Rust. Idk it fun.

Why is it named that?

One may assume the name exists to reduce confusion with Godot-Bevy and distinguish this from inevitable future Bevy + Godot projects, but actually I don’t care about those things at all and it’s because I ship two male personifications of Bevy and Godot in a toxic yaoi relationship where they kiss passionately.

Add Bevy components in the Godot editor?

Using a Godot addon, the Godot’s Nodes’ inspectors now have a component list you can add your Bevy components to. Simply add the KissingComponent derive to a Bevy component to make it available!

You can use #[export] to allow properties to be modified in the editor (with the exact same options from gdext!).

Check out the Components section for more details.

use godot::prelude::*;
use bevy::prelude::*;
use bevy_kissing_godot::prelude::*;

#[derive(Component, KissingComponent)]
struct Grid {
	#[export]
	#[initial_value(Vector2i::new(10, 10))]
	size: Vector2i,

	#[export(range = (0., 10.))]
	#[initial_value = 2.]
	spacing: real,

	#[export(enum = (Orthographic, Isometric))]
	kind: i32,
}

Connect Godot signals to Bevy events in the Godot editor?

Using the same Godot addon, Godot nodes can ALSO have their signals connected to Bevy events. Just derive from KissingEvent and the event will become available in the Godot editor!

Check out the Events section for more details.

use godot::prelude::*;
use bevy::prelude::*;
use bevy_kissing_godot::prelude::*;

/// A unit Event can connect to any signal.
#[derive(Event, KissingEvent)]
struct OnAnyGodotSignal;

/// Event intended to connect to Button.toggled
#[derive(EntityEvent, KissingEvent)]
struct OnMyButtonPressed {
	// Receive entity for Button node.
	#[event_target]
	entity: Entity,

	// Receive first argument of signal; it must be a bool.
	#[godot_signal_arg(index = 0)]
	toggled_on: bool,
}

Multithreading?

Multithreading is supported as it is in Bevy, but only if you write functions that don’t access NonSend resources. Accessing Godot’s scene tree, all Godot nodes, and all Godot resources requires NonSend, so multithreading is only applicable to behavior and state stored entirely Rust-side.