# Objective NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267. "Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365). ## Solution This adds "base sets" as a variant of `SystemSet`: A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive: ```rust #[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)] #[system_set(base)] enum MyBaseSet { A, B, } ``` **Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build. **Base sets cannot belong to other sets**: this is where the word "base" comes from Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set. ```rust app.add_system(foo.in_base_set(MyBaseSet::A)) // X must be a normal set ... base sets cannot be added to base sets .configure_set(X.in_base_set(MyBaseSet::A)) ``` Base sets can still be configured like normal sets: ```rust app.add_system(MyBaseSet::B.after(MyBaseSet::Ap)) ``` The primary use case for base sets is enabling a "default base set": ```rust schedule.set_default_base_set(CoreSet::Update) // this will belong to CoreSet::Update by default .add_system(foo) // this will override the default base set with PostUpdate .add_system(bar.in_base_set(CoreSet::PostUpdate)) ``` This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides. --- ## Changelog - Added "base sets" and ported CoreSet to use them. ## Migration Guide TODO
		
			
				
	
	
		
			325 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			325 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! This example illustrates the various features of Bevy UI.
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use bevy::{
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    input::mouse::{MouseScrollUnit, MouseWheel},
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    prelude::*,
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    winit::WinitSettings,
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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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        // Only run the app when there is user input. This will significantly reduce CPU/GPU use.
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        .insert_resource(WinitSettings::desktop_app())
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        .add_startup_system(setup)
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        .add_system(mouse_scroll)
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        .run();
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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    // Camera
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    commands.spawn(Camera2dBundle::default());
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    // root node
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    commands
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        .spawn(NodeBundle {
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            style: Style {
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                size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
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                justify_content: JustifyContent::SpaceBetween,
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                ..default()
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            },
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            ..default()
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        })
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        .with_children(|parent| {
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            // left vertical fill (border)
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            parent
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                .spawn(NodeBundle {
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                    style: Style {
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                        size: Size::new(Val::Px(200.0), Val::Percent(100.0)),
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                        border: UiRect::all(Val::Px(2.0)),
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                        ..default()
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                    },
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                    background_color: Color::rgb(0.65, 0.65, 0.65).into(),
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                    ..default()
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                })
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                .with_children(|parent| {
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                    // left vertical fill (content)
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                    parent
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                        .spawn(NodeBundle {
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                            style: Style {
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                                size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
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                                ..default()
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                            },
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                            background_color: Color::rgb(0.15, 0.15, 0.15).into(),
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                            ..default()
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                        })
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                        .with_children(|parent| {
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                            // text
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                            parent.spawn(
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                                TextBundle::from_section(
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                                    "Text Example",
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                                    TextStyle {
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                                        font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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                                        font_size: 30.0,
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                                        color: Color::WHITE,
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                                    },
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                                )
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                                .with_style(Style {
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                                    margin: UiRect::all(Val::Px(5.0)),
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                                    ..default()
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                                }),
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                            );
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                        });
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                });
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            // right vertical fill
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            parent
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                .spawn(NodeBundle {
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                    style: Style {
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                        flex_direction: FlexDirection::Column,
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                        justify_content: JustifyContent::Center,
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                        size: Size::new(Val::Px(200.0), Val::Percent(100.0)),
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                        ..default()
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                    },
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                    background_color: Color::rgb(0.15, 0.15, 0.15).into(),
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                    ..default()
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                })
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                .with_children(|parent| {
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                    // Title
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                    parent.spawn(
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                        TextBundle::from_section(
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                            "Scrolling list",
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                            TextStyle {
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                                font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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                                font_size: 25.,
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                                color: Color::WHITE,
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                            },
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                        )
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                        .with_style(Style {
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                            size: Size::new(Val::Undefined, Val::Px(25.)),
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                            margin: UiRect {
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                                left: Val::Auto,
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                                right: Val::Auto,
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                                ..default()
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                            },
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                            ..default()
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                        }),
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                    );
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                    // List with hidden overflow
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                    parent
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                        .spawn(NodeBundle {
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                            style: Style {
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                                flex_direction: FlexDirection::Column,
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                                align_self: AlignSelf::Center,
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                                size: Size::new(Val::Percent(100.0), Val::Percent(50.0)),
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                                overflow: Overflow::Hidden,
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                                ..default()
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                            },
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                            background_color: Color::rgb(0.10, 0.10, 0.10).into(),
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                            ..default()
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                        })
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                        .with_children(|parent| {
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                            // Moving panel
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                            parent
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                                .spawn((
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                                    NodeBundle {
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                                        style: Style {
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                                            flex_direction: FlexDirection::Column,
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                                            flex_grow: 1.0,
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                                            max_size: Size::UNDEFINED,
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                                            ..default()
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                                        },
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                                        ..default()
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                                    },
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                                    ScrollingList::default(),
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                                ))
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                                .with_children(|parent| {
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                                    // List items
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                                    for i in 0..30 {
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                                        parent.spawn(
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                                            TextBundle::from_section(
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                                                format!("Item {i}"),
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                                                TextStyle {
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                                                    font: asset_server
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                                                        .load("fonts/FiraSans-Bold.ttf"),
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                                                    font_size: 20.,
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                                                    color: Color::WHITE,
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                                                },
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                                            )
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                                            .with_style(Style {
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                                                flex_shrink: 0.,
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                                                size: Size::new(Val::Undefined, Val::Px(20.)),
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                                                margin: UiRect {
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                                                    left: Val::Auto,
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                                                    right: Val::Auto,
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                                                    ..default()
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                                                },
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                                                ..default()
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                                            }),
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                                        );
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                                    }
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                                });
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                        });
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                });
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            parent
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                .spawn(NodeBundle {
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                    style: Style {
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                        size: Size::new(Val::Px(200.0), Val::Px(200.0)),
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                        position_type: PositionType::Absolute,
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                        position: UiRect {
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                            left: Val::Px(210.0),
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                            bottom: Val::Px(10.0),
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                            ..default()
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                        },
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                        border: UiRect::all(Val::Px(20.0)),
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                        ..default()
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                    },
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                    background_color: Color::rgb(0.4, 0.4, 1.0).into(),
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                    ..default()
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                })
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                .with_children(|parent| {
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                    parent.spawn(NodeBundle {
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                        style: Style {
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                            size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
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                            ..default()
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                        },
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                        background_color: Color::rgb(0.8, 0.8, 1.0).into(),
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                        ..default()
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                    });
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                });
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            // render order test: reddest in the back, whitest in the front (flex center)
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            parent
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                .spawn(NodeBundle {
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                    style: Style {
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                        size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
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                        position_type: PositionType::Absolute,
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                        align_items: AlignItems::Center,
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                        justify_content: JustifyContent::Center,
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                        ..default()
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                    },
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                    ..default()
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                })
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                .with_children(|parent| {
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                    parent
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                        .spawn(NodeBundle {
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                            style: Style {
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                                size: Size::new(Val::Px(100.0), Val::Px(100.0)),
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                                ..default()
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                            },
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                            background_color: Color::rgb(1.0, 0.0, 0.0).into(),
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                            ..default()
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                        })
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                        .with_children(|parent| {
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                            parent.spawn(NodeBundle {
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                                style: Style {
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                                    size: Size::new(Val::Px(100.0), Val::Px(100.0)),
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                                    position_type: PositionType::Absolute,
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                                    position: UiRect {
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                                        left: Val::Px(20.0),
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                                        bottom: Val::Px(20.0),
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                                        ..default()
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                                    },
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                                    ..default()
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                                },
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                                background_color: Color::rgb(1.0, 0.3, 0.3).into(),
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                                ..default()
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                            });
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                            parent.spawn(NodeBundle {
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                                style: Style {
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                                    size: Size::new(Val::Px(100.0), Val::Px(100.0)),
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                                    position_type: PositionType::Absolute,
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                                    position: UiRect {
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                                        left: Val::Px(40.0),
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                                        bottom: Val::Px(40.0),
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                                        ..default()
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                                    },
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                                    ..default()
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                                },
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                                background_color: Color::rgb(1.0, 0.5, 0.5).into(),
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                                ..default()
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                            });
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                            parent.spawn(NodeBundle {
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                                style: Style {
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                                    size: Size::new(Val::Px(100.0), Val::Px(100.0)),
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                                    position_type: PositionType::Absolute,
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                                    position: UiRect {
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                                        left: Val::Px(60.0),
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                                        bottom: Val::Px(60.0),
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                                        ..default()
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                                    },
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                                    ..default()
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                                },
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                                background_color: Color::rgb(1.0, 0.7, 0.7).into(),
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                                ..default()
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                            });
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                            // alpha test
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                            parent.spawn(NodeBundle {
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                                style: Style {
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                                    size: Size::new(Val::Px(100.0), Val::Px(100.0)),
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                                    position_type: PositionType::Absolute,
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                                    position: UiRect {
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                                        left: Val::Px(80.0),
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                                        bottom: Val::Px(80.0),
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                                        ..default()
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                                    },
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                                    ..default()
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                                },
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                                background_color: Color::rgba(1.0, 0.9, 0.9, 0.4).into(),
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                                ..default()
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                            });
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                        });
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                });
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            // bevy logo (flex center)
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            parent
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                .spawn(NodeBundle {
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                    style: Style {
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                        size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
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                        position_type: PositionType::Absolute,
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                        justify_content: JustifyContent::Center,
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                        align_items: AlignItems::FlexStart,
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                        ..default()
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                    },
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                    ..default()
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                })
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                .with_children(|parent| {
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                    // bevy logo (image)
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                    parent.spawn(ImageBundle {
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                        style: Style {
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                            size: Size::new(Val::Px(500.0), Val::Auto),
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                            ..default()
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                        },
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                        image: asset_server.load("branding/bevy_logo_dark_big.png").into(),
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                        ..default()
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                    });
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                });
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        });
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}
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#[derive(Component, Default)]
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struct ScrollingList {
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    position: f32,
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}
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fn mouse_scroll(
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    mut mouse_wheel_events: EventReader<MouseWheel>,
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    mut query_list: Query<(&mut ScrollingList, &mut Style, &Children, &Node)>,
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    query_item: Query<&Node>,
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) {
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    for mouse_wheel_event in mouse_wheel_events.iter() {
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        for (mut scrolling_list, mut style, children, uinode) in &mut query_list {
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            let items_height: f32 = children
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                .iter()
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                .map(|entity| query_item.get(*entity).unwrap().size().y)
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                .sum();
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            let panel_height = uinode.size().y;
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            let max_scroll = (items_height - panel_height).max(0.);
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            let dy = match mouse_wheel_event.unit {
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                MouseScrollUnit::Line => mouse_wheel_event.y * 20.,
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                MouseScrollUnit::Pixel => mouse_wheel_event.y,
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            };
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            scrolling_list.position += dy;
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            scrolling_list.position = scrolling_list.position.clamp(-max_scroll, 0.);
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            style.position.top = Val::Px(scrolling_list.position);
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        }
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    }
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}
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