bevymod2d_hierarchy
Bevy plugin for more ergonomic 2D.
- Specialized 2D transform and propagation systems.
- Independent of the Bevy 3D transform systems, can use both in the same project.
- Compatible with existing plugins as long as they only query for
GlobalTransform and not Transform.
- Control 2D transform propagation behaviour.
- Performance similar to the 3D Transform. The propagation control has a cost, but some operations cheaper in 2D.
- No quaternions.
- Supports Bevy 0.9
Usage
Add the dependency to your Cargo.toml
toml
[dependencies]
bevy_mod_2d_hierarchy = "0.3"
Add the plugin to your Bevy App:
```rust
use bevy::prelude::;
use bevy_mod_2d_hierarachy::prelude::;
fn main() {
App::new()
.addplugins(DefaultPlugins)
.addplugin(Transform2dPlugin)
// .. rest of systems etc
.run();
}
```
Then spawn some sprites
rust
pub fn spawn(
mut commands: Commands,
asset_server: Res<AssetServer>,
) {
commands.spawn(Camera2dBundle2::default());
commands.spawn(SpriteBundle2 {
texture: asset_server.load("sprite.png"),
transform2: Transform2::from_rotation(0.5 * PI).with_scale(3.),
..Default::default()
})
.with_children(|builder| {
builder.spawn(SpriteBundle2 {
sprite: Sprite {
color: Color::YELLOW,
..Default::default()
},
texture: asset_server.load("sprite.png"),
transform2: Transform2::from_xy(0., 32.),
propagate: Propagate::TRANSLATION,
..Default::default()
});
});
}
Notes
See also: https://github.com/devil-ira/bevymodtransform2d.
Major differences Transform2d vs 2d_hierarchy:
- Transform2d is compatible with systems that query for Transform. No 3rd party physics and collision detection crates will work with 2d_hierarchy; for that reason alone, Transform2d is the better choice for most users.
- 2dhierarchy is marginally more efficient (but neither library is performance focused, and you probably won't even be to able to measure the difference). Might be room to improve 2dhierarchy
- 2d_hierarchy uses a single f32 for scale and Transform2d uses a Vec2.
- Transform2d has a seperate component for Z depth, while 2d_hierarchy keeps it in the transform.
- Because 2d_hierarchy is incompatible with Transform you can't use Bevy's builtin bundles like SpriteBundle and have to use the provided replacement SpriteBundle2 (or make your own bundle).
- You can have mix entities with Transform2d and regular Transforms in the same transform tree. 2d_hierarchy you can't. Useful if you want to mix 2d and 3d.
- Transform2d there is the worry of transform synchronization problems, but they aren't likely and should be easy to fix etc.
- 2d_hierarchy you can control which properties are propagated down the transform tree (useful for text captions above rotated and scaled sprites).
You could even use Transform2d and 2d_hierarchy together if you really wanted. That would be really silly though.