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bevy/examples/ui/font_atlas_debug.rs
Zachary Harrold 90b3ac7f3a
Added Val::ZERO Constant ()
# Objective

- Fixes 

## Solution

* Added `Val::ZERO` as a constant which is defined as `Val::Px(0.)`.
* Added manual `PartialEq` implementation for `Val` which allows any
zero value to equal any other zero value. E.g., `Val::Px(0.) ==
Val::Percent(0.)` etc. This is technically a breaking change, as
`Val::Px(0.) == Val::Percent(0.)` now equals `true` instead of `false`
(as an example)
* Replaced instances of `Val::Px(0.)`, `Val::Percent(0.)`, etc. with
`Val::ZERO`
* Fixed `bevy_ui::layout::convert::tests::test_convert_from` test to
account for Taffy not equating `Points(0.)` and `Percent(0.)`. These
tests now use `assert_eq!(...)` instead of `assert!(matches!(...))`
which gives easier to diagnose error messages.
2023-08-26 14:00:53 +00:00

101 lines
3 KiB
Rust

//! This example illustrates how `FontAtlas`'s are populated.
//! Bevy uses `FontAtlas`'s under the hood to optimize text rendering.
use bevy::{prelude::*, text::FontAtlasSet};
fn main() {
App::new()
.init_resource::<State>()
.insert_resource(ClearColor(Color::BLACK))
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, (text_update_system, atlas_render_system))
.run();
}
#[derive(Resource)]
struct State {
atlas_count: u32,
handle: Handle<Font>,
timer: Timer,
}
impl Default for State {
fn default() -> Self {
Self {
atlas_count: 0,
handle: Handle::default(),
timer: Timer::from_seconds(0.05, TimerMode::Repeating),
}
}
}
fn atlas_render_system(
mut commands: Commands,
mut state: ResMut<State>,
font_atlas_sets: Res<Assets<FontAtlasSet>>,
texture_atlases: Res<Assets<TextureAtlas>>,
) {
if let Some(set) = font_atlas_sets.get(&state.handle.cast_weak::<FontAtlasSet>()) {
if let Some((_size, font_atlas)) = set.iter().next() {
let x_offset = state.atlas_count as f32;
if state.atlas_count == font_atlas.len() as u32 {
return;
}
let texture_atlas = texture_atlases
.get(&font_atlas[state.atlas_count as usize].texture_atlas)
.unwrap();
state.atlas_count += 1;
commands.spawn(ImageBundle {
image: texture_atlas.texture.clone().into(),
style: Style {
position_type: PositionType::Absolute,
top: Val::ZERO,
left: Val::Px(512.0 * x_offset),
..default()
},
..default()
});
}
}
}
fn text_update_system(mut state: ResMut<State>, time: Res<Time>, mut query: Query<&mut Text>) {
if state.timer.tick(time.delta()).finished() {
for mut text in &mut query {
let c = rand::random::<u8>() as char;
let string = &mut text.sections[0].value;
if !string.contains(c) {
string.push(c);
}
}
state.timer.reset();
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>, mut state: ResMut<State>) {
let font_handle = asset_server.load("fonts/FiraSans-Bold.ttf");
state.handle = font_handle.clone();
commands.spawn(Camera2dBundle::default());
commands
.spawn(NodeBundle {
background_color: Color::NONE.into(),
style: Style {
position_type: PositionType::Absolute,
bottom: Val::ZERO,
..default()
},
..default()
})
.with_children(|parent| {
parent.spawn(TextBundle::from_section(
"a",
TextStyle {
font: font_handle,
font_size: 60.0,
color: Color::YELLOW,
},
));
});
}