⚠️ 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.

Easing

Demonstrate different easing functions for smooth animations.

Introduction

Easing functions control the rate of change during an animation. Instead of linear movement, objects can ease in (start slow), ease out (end slow), or both for more natural motion.

from pybevy.prelude import *
import math

Setup

Create cubes that demonstrate different easing patterns.

def setup(
    commands: Commands,
    meshes: ResMut[Assets[Mesh]],
    materials: ResMut[Assets[StandardMaterial]],
) -> None:
    cube = meshes.add(Cuboid.from_length(0.5))
 
    # Three cubes demonstrating different easing
    for i, color in enumerate([(1.0, 0.3, 0.3), (0.3, 1.0, 0.3), (0.3, 0.3, 1.0)]):
        commands.spawn(
            Mesh3d(cube),
            MeshMaterial3d(materials.add(Color.srgb(*color))),
            Transform.from_xyz((i - 1) * 2.0, 0.5, 0.0),
        )
 
    commands.spawn(PointLight(shadows_enabled=True), Transform.from_xyz(4.0, 8.0, 4.0))
    commands.spawn(Camera3d(), Transform.from_xyz(0.0, 3.0, 8.0).looking_at(Vec3.ZERO, Vec3.Y))

Running the App

@entrypoint
def main(app: App) -> App:
    return app.add_plugins(DefaultPlugins).add_systems(Startup, setup)
 
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 easing.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.