92 lines
2.8 KiB
Rust
92 lines
2.8 KiB
Rust
use bevy::{prelude::*, text::FontAtlasSet};
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/// This example illustrates how FontAtlases are populated. Bevy uses FontAtlases under the hood to 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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.add_default_plugins()
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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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added: bool,
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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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added: false,
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handle: Handle::default(),
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timer: Timer::from_seconds(0.05),
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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 state.added {
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return;
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}
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if let Some(set) = font_atlas_sets.get(&state.handle.as_handle::<FontAtlasSet>()) {
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if let Some((_size, font_atlas)) = set.iter().next() {
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state.added = true;
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let texture_atlas = texture_atlases.get(&font_atlas.texture_atlas).unwrap();
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commands.spawn(ImageComponents {
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material: materials.add(texture_atlas.texture.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(0.0),
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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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for mut text in &mut query.iter() {
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state.timer.tick(time.delta_seconds);
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if state.timer.finished {
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text.value = format!("{}", rand::random::<u8>() as char);
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state.timer.reset();
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}
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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("assets/fonts/FiraSans-Bold.ttf").unwrap();
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state.handle = font_handle;
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commands
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.spawn(UiCameraComponents::default())
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.spawn(TextComponents {
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style: Style {
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size: Size::new(Val::Px(250.0), Val::Px(60.0)),
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..Default::default()
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},
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text: Text {
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value: "a".to_string(),
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font: font_handle,
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style: TextStyle {
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font_size: 60.0,
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color: Color::WHITE,
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},
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},
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..Default::default()
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});
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}
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