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.
System Param
Shows the different system parameter types available in PyBevy.
Introduction
System functions in PyBevy receive their data through typed parameters. The engine inspects the function signature and automatically provides the requested data. This example demonstrates the common system parameter types.
from pybevy.prelude import *Available System Parameters
Commands— Create/modify entitiesQuery[T]— Iterate over entities with component TRes[T]/ResMut[T]— Read/write global resourcesTime— Access frame timingView[T]— High-performance batch access
@resource
class Counter(Resource):
def __init__(self):
self.value = 0
def demo_system(commands: Commands, time: Res[Time], counter: ResMut[Counter]) -> None:
counter.value += 1
if counter.value % 60 == 0:
print(f"Elapsed: {time.elapsed_secs():.1f}s, Frames: {counter.value}")Running the App
@entrypoint
def main(app: App) -> App:
return (
app
.add_plugins(DefaultPlugins)
.insert_resource(Counter())
.add_systems(Update, demo_system)
)
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.
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.