Component Hooks, WMTS, and Same State Transitions

This week Component Hooks get improvements to authoring ergonomics, Depth of Field gets easier to use, and automatic directional navigation landed! A popular feature request, same-state transitions also makes it in.

A number of crates shared their progress in showcases this week, while Foresight shared their Streaming WMTS renderer and wgsl-analyzer got a major update.

Processing gains experimental WebGPU support through Bevy and more!

Improve Component Hook Ergonomics

Component Hooks have been around for awhile, but with #21800 the derive macros can defer to associated functions impl'd on a type, improving ergonomics around where they can be defined by default.

use bevy_ecs::lifecycle::HookContext;
use bevy_ecs::prelude::*;
use bevy_ecs::world::DeferredWorld;

#[derive(Component)]
#[component(on_add, on_insert, on_despawn, on_remove=on_remove)]
struct Tile;

impl Tile {
    fn on_add(_world: DeferredWorld, _context: HookContext) {
        println!("added");
    }
    fn on_insert(_world: DeferredWorld, _context: HookContext) {
        println!("inserted");
    }
    fn on_despawn(_world: DeferredWorld, _context: HookContext) {
        println!("despawned");
    }
}

fn on_remove(_world: DeferredWorld, _context: HookContext) {
    println!("removed");
}

fn main() {
    let mut world = World::new();
    let entity = world.spawn(Tile);
    entity.despawn();
}

Depth of Field Improvements

The Depth of Field effect is physically accurate, which is sometimes confusing for those not familiar with the physical implications! This can be improved by clamping certain values that would lead to "disabling" the Depth of Field effect unintentionally.

Automatic Directional Navigation Graph Generation

In #21668, a lower boilerplate method of generating directional navigation that is resistant to dynamic UI changes. Now you can add the AutoDirectionalNavigation component to your UI entities, and Bevy will automatically compute navigation connections based on spatial positioning. The system intelligently finds the nearest neighbor in each of the 8 compass directions (North, Northeast, East, etc.), considering:

• Distance: Closer elements are preferred
• Alignment: Elements that are more directly in line with the navigation direction are favored
• Overlap: For cardinal directions (N/S/E/W), the system ensures sufficient perpendicular overlap

commands.spawn((
    Button,
    Node { /* ... */ },
    AutoDirectionalNavigation::default(),
));

Same State Transitions

Same State transitions are when a state is set to the same state that the application currently exists in. As of #19363 this is possible via a new NextStat::set_forced method, which will cause the State's OnExit and OnEnter to fire.

This can be useful for actions like reloading a level.

Cosmic Text 0.15

#21699 updates cosmic-text to 0.15.

Node BorderRadius

#21781 adds a border_radius field to Node.

HitData for window pointer hits

#21802 adds HitData to Pointer<Move> events when an observer is added to the window.

use bevy::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .run();
}

fn setup(mut commands: Commands) {
    commands.spawn(Camera2d);
    commands
        .spawn(Window::default())
        .observe(|trigger: On<Pointer<Move>>| {
            assert!(
                trigger.hit.position.is_some(),
                "Position should not be None"
            );
        });
}