**Ready for review. Examples migration progress: 100%.** # Objective - Implement https://github.com/bevyengine/bevy/discussions/15014 ## Solution This implements [cart's proposal](https://github.com/bevyengine/bevy/discussions/15014#discussioncomment-10574459) faithfully except for one change. I separated `TextSpan` from `TextSpan2d` because `TextSpan` needs to require the `GhostNode` component, which is a `bevy_ui` component only usable by UI. Extra changes: - Added `EntityCommands::commands_mut` that returns a mutable reference. This is a blocker for extension methods that return something other than `self`. Note that `sickle_ui`'s `UiBuilder::commands` returns a mutable reference for this reason. ## Testing - [x] Text examples all work. --- ## Showcase TODO: showcase-worthy ## Migration Guide TODO: very breaking ### Accessing text spans by index Text sections are now text sections on different entities in a hierarchy, Use the new `TextReader` and `TextWriter` system parameters to access spans by index. Before: ```rust fn refresh_text(mut query: Query<&mut Text, With<TimeText>>, time: Res<Time>) { let text = query.single_mut(); text.sections[1].value = format_time(time.elapsed()); } ``` After: ```rust fn refresh_text( query: Query<Entity, With<TimeText>>, mut writer: UiTextWriter, time: Res<Time> ) { let entity = query.single(); *writer.text(entity, 1) = format_time(time.elapsed()); } ``` ### Iterating text spans Text spans are now entities in a hierarchy, so the new `UiTextReader` and `UiTextWriter` system parameters provide ways to iterate that hierarchy. The `UiTextReader::iter` method will give you a normal iterator over spans, and `UiTextWriter::for_each` lets you visit each of the spans. --------- Co-authored-by: ickshonpe <david.curthoys@googlemail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
		
			
				
	
	
		
			111 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			111 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! This example showcases atmospheric fog
 | 
						|
//!
 | 
						|
//! ## Controls
 | 
						|
//!
 | 
						|
//! | Key Binding        | Action                                 |
 | 
						|
//! |:-------------------|:---------------------------------------|
 | 
						|
//! | `Spacebar`         | Toggle Atmospheric Fog                 |
 | 
						|
//! | `S`                | Toggle Directional Light Fog Influence |
 | 
						|
 | 
						|
use bevy::{
 | 
						|
    pbr::{CascadeShadowConfigBuilder, NotShadowCaster},
 | 
						|
    prelude::*,
 | 
						|
};
 | 
						|
 | 
						|
fn main() {
 | 
						|
    App::new()
 | 
						|
        .add_plugins(DefaultPlugins)
 | 
						|
        .add_systems(
 | 
						|
            Startup,
 | 
						|
            (setup_camera_fog, setup_terrain_scene, setup_instructions),
 | 
						|
        )
 | 
						|
        .add_systems(Update, toggle_system)
 | 
						|
        .run();
 | 
						|
}
 | 
						|
 | 
						|
fn setup_camera_fog(mut commands: Commands) {
 | 
						|
    commands.spawn((
 | 
						|
        Camera3d::default(),
 | 
						|
        Transform::from_xyz(-1.0, 0.1, 1.0).looking_at(Vec3::new(0.0, 0.0, 0.0), Vec3::Y),
 | 
						|
        DistanceFog {
 | 
						|
            color: Color::srgba(0.35, 0.48, 0.66, 1.0),
 | 
						|
            directional_light_color: Color::srgba(1.0, 0.95, 0.85, 0.5),
 | 
						|
            directional_light_exponent: 30.0,
 | 
						|
            falloff: FogFalloff::from_visibility_colors(
 | 
						|
                15.0, // distance in world units up to which objects retain visibility (>= 5% contrast)
 | 
						|
                Color::srgb(0.35, 0.5, 0.66), // atmospheric extinction color (after light is lost due to absorption by atmospheric particles)
 | 
						|
                Color::srgb(0.8, 0.844, 1.0), // atmospheric inscattering color (light gained due to scattering from the sun)
 | 
						|
            ),
 | 
						|
        },
 | 
						|
    ));
 | 
						|
}
 | 
						|
 | 
						|
fn setup_terrain_scene(
 | 
						|
    mut commands: Commands,
 | 
						|
    mut meshes: ResMut<Assets<Mesh>>,
 | 
						|
    mut materials: ResMut<Assets<StandardMaterial>>,
 | 
						|
    asset_server: Res<AssetServer>,
 | 
						|
) {
 | 
						|
    // Configure a properly scaled cascade shadow map for this scene (defaults are too large, mesh units are in km)
 | 
						|
    let cascade_shadow_config = CascadeShadowConfigBuilder {
 | 
						|
        first_cascade_far_bound: 0.3,
 | 
						|
        maximum_distance: 3.0,
 | 
						|
        ..default()
 | 
						|
    }
 | 
						|
    .build();
 | 
						|
 | 
						|
    // Sun
 | 
						|
    commands.spawn((
 | 
						|
        DirectionalLight {
 | 
						|
            color: Color::srgb(0.98, 0.95, 0.82),
 | 
						|
            shadows_enabled: true,
 | 
						|
            ..default()
 | 
						|
        },
 | 
						|
        Transform::from_xyz(0.0, 0.0, 0.0).looking_at(Vec3::new(-0.15, -0.05, 0.25), Vec3::Y),
 | 
						|
        cascade_shadow_config,
 | 
						|
    ));
 | 
						|
 | 
						|
    // Terrain
 | 
						|
    commands.spawn(SceneRoot(asset_server.load(
 | 
						|
        GltfAssetLabel::Scene(0).from_asset("models/terrain/Mountains.gltf"),
 | 
						|
    )));
 | 
						|
 | 
						|
    // Sky
 | 
						|
    commands.spawn((
 | 
						|
        Mesh3d(meshes.add(Cuboid::new(2.0, 1.0, 1.0))),
 | 
						|
        MeshMaterial3d(materials.add(StandardMaterial {
 | 
						|
            base_color: Srgba::hex("888888").unwrap().into(),
 | 
						|
            unlit: true,
 | 
						|
            cull_mode: None,
 | 
						|
            ..default()
 | 
						|
        })),
 | 
						|
        Transform::from_scale(Vec3::splat(20.0)),
 | 
						|
        NotShadowCaster,
 | 
						|
    ));
 | 
						|
}
 | 
						|
 | 
						|
fn setup_instructions(mut commands: Commands) {
 | 
						|
    commands.spawn((Text::new("Press Spacebar to Toggle Atmospheric Fog.\nPress S to Toggle Directional Light Fog Influence."),
 | 
						|
        Style {
 | 
						|
            position_type: PositionType::Absolute,
 | 
						|
            bottom: Val::Px(12.0),
 | 
						|
            left: Val::Px(12.0),
 | 
						|
            ..default()
 | 
						|
        })
 | 
						|
    );
 | 
						|
}
 | 
						|
 | 
						|
fn toggle_system(keycode: Res<ButtonInput<KeyCode>>, mut fog: Query<&mut DistanceFog>) {
 | 
						|
    let mut fog = fog.single_mut();
 | 
						|
 | 
						|
    if keycode.just_pressed(KeyCode::Space) {
 | 
						|
        let a = fog.color.alpha();
 | 
						|
        fog.color.set_alpha(1.0 - a);
 | 
						|
    }
 | 
						|
 | 
						|
    if keycode.just_pressed(KeyCode::KeyS) {
 | 
						|
        let a = fog.directional_light_color.alpha();
 | 
						|
        fog.directional_light_color.set_alpha(0.5 - a);
 | 
						|
    }
 | 
						|
}
 |