# 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
		
			
				
	
	
		
			81 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			81 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Showcases the `RelativeCursorPosition` component, used to check the position of the cursor relative to a UI node.
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use bevy::{prelude::*, ui::RelativeCursorPosition, winit::WinitSettings};
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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(relative_cursor_position_system)
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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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    commands.spawn(Camera2dBundle::default());
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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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                align_items: AlignItems::Center,
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                justify_content: JustifyContent::Center,
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                flex_direction: FlexDirection::Column,
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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(250.0), Val::Px(250.0)),
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                        margin: UiRect::new(Val::Px(0.), Val::Px(0.), Val::Px(0.), Val::Px(15.)),
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                        ..default()
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                    },
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                    background_color: Color::rgb(235., 35., 12.).into(),
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                    ..default()
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                })
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                .insert(RelativeCursorPosition::default());
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            parent.spawn(TextBundle {
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                text: Text::from_section(
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                    "(0.0, 0.0)",
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                    TextStyle {
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                        font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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                        font_size: 40.0,
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                        color: Color::rgb(0.9, 0.9, 0.9),
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                    },
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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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/// This systems polls the relative cursor position and displays its value in a text component.
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fn relative_cursor_position_system(
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    relative_cursor_position_query: Query<&RelativeCursorPosition>,
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    mut output_query: Query<&mut Text>,
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) {
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    let relative_cursor_position = relative_cursor_position_query.single();
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    let mut output = output_query.single_mut();
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    output.sections[0].value =
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        if let Some(relative_cursor_position) = relative_cursor_position.normalized {
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            format!(
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                "({:.1}, {:.1})",
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                relative_cursor_position.x, relative_cursor_position.y
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            )
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        } else {
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            "unknown".to_string()
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        };
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    output.sections[0].style.color = if relative_cursor_position.mouse_over() {
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        Color::rgb(0.1, 0.9, 0.1)
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    } else {
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        Color::rgb(0.9, 0.1, 0.1)
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    };
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}
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