# Objective Continue improving the user experience of our UI Node API in the direction specified by [Bevy's Next Generation Scene / UI System](https://github.com/bevyengine/bevy/discussions/14437) ## Solution As specified in the document above, merge `Style` fields into `Node`, and move "computed Node fields" into `ComputedNode` (I chose this name over something like `ComputedNodeLayout` because it currently contains more than just layout info. If we want to break this up / rename these concepts, lets do that in a separate PR). `Style` has been removed. This accomplishes a number of goals: ## Ergonomics wins Specifying both `Node` and `Style` is now no longer required for non-default styles Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` ## Conceptual clarity `Style` was never a comprehensive "style sheet". It only defined "core" style properties that all `Nodes` shared. Any "styled property" that couldn't fit that mold had to be in a separate component. A "real" style system would style properties _across_ components (`Node`, `Button`, etc). We have plans to build a true style system (see the doc linked above). By moving the `Style` fields to `Node`, we fully embrace `Node` as the driving concept and remove the "style system" confusion. ## Next Steps * Consider identifying and splitting out "style properties that aren't core to Node". This should not happen for Bevy 0.15. --- ## Migration Guide Move any fields set on `Style` into `Node` and replace all `Style` component usage with `Node`. Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` For any usage of the "computed node properties" that used to live on `Node`, use `ComputedNode` instead: Before: ```rust fn system(nodes: Query<&Node>) { for node in &nodes { let computed_size = node.size(); } } ``` After: ```rust fn system(computed_nodes: Query<&ComputedNode>) { for computed_node in &computed_nodes { let computed_size = computed_node.size(); } } ```
		
			
				
	
	
		
			92 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
| //! Loads and renders a glTF file as a scene, and list all the different `gltf_extras`.
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| 
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| use bevy::{
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|     gltf::{GltfExtras, GltfMaterialExtras, GltfMeshExtras, GltfSceneExtras},
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|     prelude::*,
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| };
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| 
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| fn main() {
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|     App::new()
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|         .add_plugins(DefaultPlugins)
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|         .add_systems(Startup, setup)
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|         .add_systems(Update, check_for_gltf_extras)
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|         .run();
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| }
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| 
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| #[derive(Component)]
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| struct ExampleDisplay;
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| 
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| fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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|     commands.spawn((
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|         Camera3d::default(),
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|         Transform::from_xyz(2.0, 2.0, 2.0).looking_at(Vec3::ZERO, Vec3::Y),
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|     ));
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| 
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|     commands.spawn(DirectionalLight {
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|         shadows_enabled: true,
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|         ..default()
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|     });
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| 
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|     // a barebones scene containing one of each gltf_extra type
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|     commands.spawn(SceneRoot(asset_server.load(
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|         GltfAssetLabel::Scene(0).from_asset("models/extras/gltf_extras.glb"),
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|     )));
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| 
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|     // a place to display the extras on screen
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|     commands.spawn((
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|         Text::default(),
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|         TextFont {
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|             font_size: 15.,
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|             ..default()
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|         },
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|         Node {
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|             position_type: PositionType::Absolute,
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|             top: Val::Px(12.0),
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|             left: Val::Px(12.0),
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|             ..default()
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|         },
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|         ExampleDisplay,
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|     ));
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| }
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| 
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| fn check_for_gltf_extras(
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|     gltf_extras_per_entity: Query<(
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|         Entity,
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|         Option<&Name>,
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|         Option<&GltfSceneExtras>,
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|         Option<&GltfExtras>,
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|         Option<&GltfMeshExtras>,
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|         Option<&GltfMaterialExtras>,
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|     )>,
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|     mut display: Single<&mut Text, With<ExampleDisplay>>,
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| ) {
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|     let mut gltf_extra_infos_lines: Vec<String> = vec![];
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| 
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|     for (id, name, scene_extras, extras, mesh_extras, material_extras) in
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|         gltf_extras_per_entity.iter()
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|     {
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|         if scene_extras.is_some()
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|             || extras.is_some()
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|             || mesh_extras.is_some()
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|             || material_extras.is_some()
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|         {
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|             let formatted_extras = format!(
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|                 "Extras per entity {} ('Name: {}'):
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|     - scene extras:     {:?}
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|     - primitive extras: {:?}
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|     - mesh extras:      {:?}
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|     - material extras:  {:?}
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|                 ",
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|                 id,
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|                 name.unwrap_or(&Name::default()),
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|                 scene_extras,
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|                 extras,
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|                 mesh_extras,
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|                 material_extras
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|             );
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|             gltf_extra_infos_lines.push(formatted_extras);
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|         }
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|         display.0 = gltf_extra_infos_lines.join("\n");
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|     }
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| }
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