Bevy Easings

Easings on Bevy components using interpolation.

Usage

System setup

Add the plugin to your app:

use bevy::prelude::*;
use bevy_easings::EasingsPlugin;

fn main() {
    App::new()
        .add_plugin(EasingsPlugin);
}

Easing a component to a new value

And then just ease your components to their new state!

use bevy::prelude::*;
use bevy_easings::*;

fn my_system(mut commands: Commands){
    commands
        .spawn_bundle(SpriteBundle {
            ..Default::default()
        })
        .insert(
            Sprite {
                custom_size: Some(Vec2::new(10., 10.)),
                ..Default::default()
            }
            .ease_to(
                Sprite {
                    custom_size: Some(Vec2::new(100., 100.)),
                    ..Default::default()
                },
                EaseFunction::QuadraticIn,
                EasingType::PingPong {
                    duration: std::time::Duration::from_secs(1),
                    pause: Some(std::time::Duration::from_millis(500)),
                },
            ),
        );
}

If the component being eased is not already a component of the entity, the component should first be inserted for the target entity.

Chaining easing

You can chain easings, if they are not set to repeat they will happen in sequence.

use bevy::prelude::*;
use bevy_easings::*;

fn my_system(mut commands: Commands){
    commands
        .spawn_bundle(SpriteBundle {
            ..Default::default()
        })
        .insert(
            Sprite {
                custom_size: Some(Vec2::new(10., 10.)),
                ..Default::default()
            }
            .ease_to(
                Sprite {
                    custom_size: Some(Vec2::new(300., 300.)),
                    ..Default::default()
                },
                EaseFunction::QuadraticIn,
                EasingType::Once {
                    duration: std::time::Duration::from_secs(1),
                },
            )
            .ease_to(
                Sprite {
                    custom_size: Some(Vec2::new(350., 350.)),
                    ..Default::default()
                },
                EaseFunction::QuadraticIn,
                EasingType::PingPong {
                    duration: std::time::Duration::from_millis(500),
                    pause: Some(std::time::Duration::from_millis(200)),
                },
            ),
        );
}

Bundle Supported

• Sprite
• Transform
• Style

Custom component support

To be able to ease a component, it needs to implement the traits Default and Lerp. This trait is re-exported by beavy_easings.

use bevy::prelude::*;
use bevy_easings::*;

#[derive(Default, Component)]
struct CustomComponent(f32);
impl Lerp for CustomComponent {
    type Scalar = f32;

    fn lerp(&self, other: &Self, scalar: &Self::Scalar) -> Self {
        CustomComponent(interpolation::lerp(&self.0, &other.0, scalar))
    }
}

The basic formula for lerp (linear interpolation) is self + (other - self) * scalar.

Then, the system custom_ease_system::<CustomComponent> needs to be added to the application.

Examples

See examples

Ease Functions

Many ease functions are available:

• QuadraticIn
• QuadraticOut
• QuadraticInOut
• CubicIn
• CubicOut
• CubicInOut
• QuarticIn
• QuarticOut
• QuarticInOut
• QuinticIn
• QuinticOut
• QuinticInOut
• SineIn
• SineOut
• SineInOut
• CircularIn
• CircularOut
• CircularInOut
• ExponentialIn
• ExponentialOut
• ExponentialInOut
• ElasticIn
• ElasticOut
• ElasticInOut
• BackIn
• BackOut
• BackInOut
• BounceIn
• BounceOut
• BounceInOut