⚠️ 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.

Mouse Input

Track mouse button state and detect mouse motion.

Introduction

Mouse input works like keyboard input — ButtonInput tracks button state, while motion and scroll events come through the message system.

from pybevy.prelude import *
from pybevy.input import AccumulatedMouseMotion, MouseWheel

Mouse Button System

Check mouse button state and read scroll wheel events.

def mouse_system(
    input: Res[ButtonInput],
    motion: Res[AccumulatedMouseMotion],
    scroll: MessageReader[MouseWheel],
) -> None:
    if input.just_pressed(MouseButton.Left):
        print("Left mouse button pressed")
 
    if input.just_released(MouseButton.Right):
        print("Right mouse button released")
 
    if motion.delta.x != 0.0 or motion.delta.y != 0.0:
        print(f"Mouse moved: ({motion.delta.x:.1f}, {motion.delta.y:.1f})")
 
    for event in scroll.read():
        print(f"Scroll: ({event.x:.1f}, {event.y:.1f})")

Running the App

@entrypoint
def main(app: App) -> App:
    return app.add_plugins(DefaultPlugins).add_systems(Update, mouse_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.

$pybevy watch mouse_input.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.