⚠️ Beta State

PyBevy is in an early and experimental stage. The API is incomplete, subject to breaking changes without notice, and you should expect bugs. Many features are still under development.

Plugin

Create and register a custom plugin that prints a message at regular intervals.

Introduction

Plugins are the building blocks of PyBevy applications. They bundle related components, resources, and systems into reusable modules. This example creates a simple plugin that prints a message on a timer.

from pybevy.prelude import *
from pybevy.decorators import plugin

Plugin Definition

A plugin is a class that implements build(), which receives the App and can add systems, resources, and other plugins.

@plugin
class PrintMessagePlugin(Plugin):
    def __init__(self, wait_duration: float, message: str):
        super().__init__()
        self.wait_duration = wait_duration
        self.message = message
 
    def build(self, app: App) -> None:
        app.insert_resource(PrintMessageState(
            message=self.message,
            timer=Timer(self.wait_duration, TimerMode.REPEATING),
        ))
        app.add_systems(Update, print_message_system)

Plugin State

@resource
class PrintMessageState(Resource):
    def __init__(self, message: str, timer: Timer):
        self.message = message
        self.timer = timer
 
 
def print_message_system(state: ResMut[PrintMessageState], time: Res[Time]) -> None:
    state.timer.tick(time.delta_secs())
    if state.timer.is_finished():
        print(state.message)

Running the App

@entrypoint
def main(app: App) -> App:
    return (
        app
        .add_plugins(DefaultPlugins)
        .add_plugins(PrintMessagePlugin(wait_duration=1.0, message="Hello from plugin!"))
    )
 
if __name__ == "__main__":
    main().run()

Running this example

Use PyBevy's hot reload feature to run and develop this example. If you don't have PyBevy installed, check out the Quick Start guide.

$pybevy watch plugin.py

The code will reload automatically when you make changes to the file.

From Python to Rust

Notice how the core concepts in the code—Commands, Assets, App, and Systems—are identical to the original Bevy example?

This is the power of pybevy! It lets you learn Bevy's powerful, data-driven architecture in friendly Python.

When your project grows and you're ready for maximum, native performance, you'll already know the concepts to start writing systems in Bevy Engine with Rust.