306c1ac617
# Objective Following discussion on #3536 and #3522, `Handle::as_weak()` takes a type `U`, reinterpreting the handle as of another asset type while keeping the same ID. This is mainly used today in font atlas code. This PR does two things: - Rename the method to `cast_weak()` to make its intent more clear - Actually change the type uuid in the handle if it's not an asset path variant. ## Migration Guide - Rename `Handle::as_weak` uses to `Handle::cast_weak` The method now properly sets the associated type uuid if the handle is a direct reference (e.g. not a reference to an `AssetPath`), so adjust you code accordingly if you relied on the previous behavior.
109 lines
3.2 KiB
Rust
109 lines
3.2 KiB
Rust
//! This example illustrates how `FontAtlas`'s are populated.
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//! Bevy uses `FontAtlas`'s under the hood to optimize text rendering.
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use bevy::{prelude::*, text::FontAtlasSet};
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fn main() {
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App::new()
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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)
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.add_system(text_update_system)
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.add_system(atlas_render_system)
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.run();
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}
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#[derive(Resource)]
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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, TimerMode::Repeating),
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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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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.cast_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(ImageBundle {
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image: texture_atlas.texture.clone().into(),
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style: Style {
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position_type: PositionType::Absolute,
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position: UiRect {
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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()
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},
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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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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 &mut query {
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let c = rand::random::<u8>() as char;
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let string = &mut text.sections[0].value;
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if !string.contains(c) {
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string.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(Camera2dBundle::default());
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commands
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.spawn(NodeBundle {
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background_color: Color::NONE.into(),
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style: Style {
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position_type: PositionType::Absolute,
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position: UiRect {
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bottom: Val::Px(0.0),
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..default()
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},
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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.spawn(TextBundle::from_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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));
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});
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}
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