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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.
96 lines
3 KiB
Rust
96 lines
3 KiB
Rust
use bevy::{prelude::*, text::FontAtlasSet};
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// TODO: This is now broken. See #1243
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/// This example illustrates how FontAtlases are populated. Bevy uses FontAtlases under the hood to
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/// optimize text rendering.
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fn main() {
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App::build()
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.init_resource::<State>()
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.insert_resource(ClearColor(Color::BLACK))
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.add_plugins(DefaultPlugins)
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.add_startup_system(setup.system())
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.add_system(text_update_system.system())
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.add_system(atlas_render_system.system())
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.run();
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}
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struct State {
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atlas_count: u32,
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handle: Handle<Font>,
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timer: Timer,
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}
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impl Default for State {
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fn default() -> Self {
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Self {
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atlas_count: 0,
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handle: Handle::default(),
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timer: Timer::from_seconds(0.05, true),
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}
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}
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}
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fn atlas_render_system(
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mut commands: Commands,
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mut state: ResMut<State>,
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mut materials: ResMut<Assets<ColorMaterial>>,
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font_atlas_sets: Res<Assets<FontAtlasSet>>,
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texture_atlases: Res<Assets<TextureAtlas>>,
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) {
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if let Some(set) = font_atlas_sets.get(&state.handle.as_weak::<FontAtlasSet>()) {
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if let Some((_size, font_atlas)) = set.iter().next() {
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let x_offset = state.atlas_count as f32;
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if state.atlas_count == font_atlas.len() as u32 {
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return;
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}
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let texture_atlas = texture_atlases
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.get(&font_atlas[state.atlas_count as usize].texture_atlas)
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.unwrap();
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state.atlas_count += 1;
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commands.spawn_bundle(ImageBundle {
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material: materials.add(texture_atlas.texture.clone().into()),
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style: Style {
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position_type: PositionType::Absolute,
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position: Rect {
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top: Val::Px(0.0),
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left: Val::Px(512.0 * x_offset),
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..Default::default()
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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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}
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fn text_update_system(mut state: ResMut<State>, time: Res<Time>, mut query: Query<&mut Text>) {
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if state.timer.tick(time.delta()).finished() {
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for mut text in query.iter_mut() {
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let c = rand::random::<u8>() as char;
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if !text.sections[0].value.contains(c) {
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text.sections[0].value.push(c);
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}
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}
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state.timer.reset();
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}
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>, mut state: ResMut<State>) {
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let font_handle = asset_server.load("fonts/FiraSans-Bold.ttf");
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state.handle = font_handle.clone();
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commands.spawn_bundle(UiCameraBundle::default());
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commands.spawn_bundle(TextBundle {
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text: Text::with_section(
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"a",
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TextStyle {
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font: font_handle,
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font_size: 60.0,
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color: Color::YELLOW,
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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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