A 2D Transform component for Bevy.

Run cargo add bevy_mod_transform2d.

Or add the dependency to your Cargo.toml

[dependencies]
bevy_mod_transform2d = "0.6"

Example:

use bevy::prelude::*;
use bevy_mod_transform2d::prelude::*;

fn main() {
    App::new()
        .add_plugins((
            DefaultPlugins,
            // Add the Transform2dPlugin
            Transform2dPlugin,
        ))
        .add_systems(Startup, setup)
        .add_systems(Update, orbit)
        .run();
}

fn setup(mut commands: Commands) {
    commands.spawn(Camera2dBundle::default());

    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                custom_size: Some(Vec2::splat(50.)),
                ..default()
            },
            ..default()
        },
        // Add a Transform2d component
        Transform2d::from_xy(200., 0.),
    ));
}

// Make the sprite orbit the center
fn orbit(mut query: Query<&mut Transform2d, With<Sprite>>, time: Res<Time>) {
    for mut transform in &mut query {
        // No quaternions in sight!
        transform.rotate_around(Vec2::ZERO, time.delta_seconds());
    }
}

Take a look at the other examples.

Note that the Transform2d component does not replace Transform component, instead it writes to it. The Transform and GlobalTransform components are required for Transform2d to function.

This makes this crate compatible with crates that interact with Transform (eg. bevy_rapier2d and bevy_xpbd_2d) at the cost of performance, and it supports parenting 3D transforms to 2D transforms and vice versa.

To integrate with another library that modifies Transform the state of Transform and Transform2d will need to be synchronised back and forth at the right times.

Integrations with bevy_rapier2d and bevy_xpbd_2d are included and can be enabled as a feature:

[dependencies]
bevy_mod_transform2d = { version = "0.6", features = ["bevy_rapier2d"] }
# or
bevy_mod_transform2d = { version = "0.6", features = ["bevy_xpbd_2d"] }

If there is another plugin that interacts with the transform here's how you would synchronise the state to make Transform2d compatible with that plugin.

• When a system needs to read from Transfrom add the provided sync_transform_2d_to_3d system before it.
• When a system writes to Transfrom add the provided sync_transform_3d_to_2d system after it.