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https://github.com/bevyengine/bevy
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81b53d15d4
Resolves #1253 #1562 This makes the Commands apis consistent with World apis. This moves to a "type state" pattern (like World) where the "current entity" is stored in an `EntityCommands` builder. In general this tends to cuts down on indentation and line count. It comes at the cost of needing to type `commands` more and adding more semicolons to terminate expressions. I also added `spawn_bundle` to Commands because this is a common enough operation that I think its worth providing a shorthand.
94 lines
3.1 KiB
Rust
94 lines
3.1 KiB
Rust
use bevy::prelude::*;
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/// This example illustrates how to create a button that changes color and text based on its
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/// interaction state.
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fn main() {
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App::build()
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.add_plugins(DefaultPlugins)
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.init_resource::<ButtonMaterials>()
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.add_startup_system(setup.system())
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.add_system(button_system.system())
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.run();
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}
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struct ButtonMaterials {
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normal: Handle<ColorMaterial>,
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hovered: Handle<ColorMaterial>,
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pressed: Handle<ColorMaterial>,
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}
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impl FromWorld for ButtonMaterials {
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fn from_world(world: &mut World) -> Self {
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let mut materials = world.get_resource_mut::<Assets<ColorMaterial>>().unwrap();
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ButtonMaterials {
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normal: materials.add(Color::rgb(0.15, 0.15, 0.15).into()),
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hovered: materials.add(Color::rgb(0.25, 0.25, 0.25).into()),
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pressed: materials.add(Color::rgb(0.35, 0.75, 0.35).into()),
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}
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}
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}
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fn button_system(
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button_materials: Res<ButtonMaterials>,
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mut interaction_query: Query<
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(&Interaction, &mut Handle<ColorMaterial>, &Children),
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(Changed<Interaction>, With<Button>),
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>,
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mut text_query: Query<&mut Text>,
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) {
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for (interaction, mut material, children) in interaction_query.iter_mut() {
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let mut text = text_query.get_mut(children[0]).unwrap();
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match *interaction {
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Interaction::Clicked => {
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text.sections[0].value = "Press".to_string();
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*material = button_materials.pressed.clone();
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}
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Interaction::Hovered => {
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text.sections[0].value = "Hover".to_string();
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*material = button_materials.hovered.clone();
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}
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Interaction::None => {
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text.sections[0].value = "Button".to_string();
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*material = button_materials.normal.clone();
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}
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}
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}
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}
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fn setup(
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mut commands: Commands,
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asset_server: Res<AssetServer>,
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button_materials: Res<ButtonMaterials>,
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) {
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// ui camera
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commands.spawn_bundle(UiCameraBundle::default());
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commands
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.spawn_bundle(ButtonBundle {
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style: Style {
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size: Size::new(Val::Px(150.0), Val::Px(65.0)),
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// center button
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margin: Rect::all(Val::Auto),
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// horizontally center child text
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justify_content: JustifyContent::Center,
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// vertically center child text
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align_items: AlignItems::Center,
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..Default::default()
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},
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material: button_materials.normal.clone(),
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..Default::default()
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})
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.with_children(|parent| {
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parent.spawn_bundle(TextBundle {
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text: Text::with_section(
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"Button",
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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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Default::default(),
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),
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..Default::default()
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});
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});
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}
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