bevy/examples/2d/text2d.rs
Daniel McNab c893b99224 Optional .system (#2398)
This can be your 6 months post-christmas present.

# Objective

- Make `.system` optional
- yeet
- It's ugly
- Alternative title: `.system` is dead; long live `.system`
- **yeet**

## Solution

- Use a higher ranked lifetime, and some trait magic.

N.B. This PR does not actually remove any `.system`s, except in a couple of examples. Once this is merged we can do that piecemeal across crates, and decide on syntax for labels.
2021-06-27 00:40:09 +00:00

82 lines
2.6 KiB
Rust

use bevy::prelude::*;
fn main() {
App::build()
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.add_system(animate_translation)
.add_system(animate_rotation)
.add_system(animate_scale)
.run();
}
struct AnimateTranslation;
struct AnimateRotation;
struct AnimateScale;
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
let font = asset_server.load("fonts/FiraSans-Bold.ttf");
let text_style = TextStyle {
font,
font_size: 60.0,
color: Color::WHITE,
};
let text_alignment = TextAlignment {
vertical: VerticalAlign::Center,
horizontal: HorizontalAlign::Center,
};
// 2d camera
commands.spawn_bundle(OrthographicCameraBundle::new_2d());
// Demonstrate changing translation
commands
.spawn_bundle(Text2dBundle {
text: Text::with_section("translation", text_style.clone(), text_alignment),
..Default::default()
})
.insert(AnimateTranslation);
// Demonstrate changing rotation
commands
.spawn_bundle(Text2dBundle {
text: Text::with_section("rotation", text_style.clone(), text_alignment),
..Default::default()
})
.insert(AnimateRotation);
// Demonstrate changing scale
commands
.spawn_bundle(Text2dBundle {
text: Text::with_section("scale", text_style, text_alignment),
..Default::default()
})
.insert(AnimateScale);
}
fn animate_translation(
time: Res<Time>,
mut query: Query<&mut Transform, (With<Text>, With<AnimateTranslation>)>,
) {
for mut transform in query.iter_mut() {
transform.translation.x = 100.0 * time.seconds_since_startup().sin() as f32 - 400.0;
transform.translation.y = 100.0 * time.seconds_since_startup().cos() as f32;
}
}
fn animate_rotation(
time: Res<Time>,
mut query: Query<&mut Transform, (With<Text>, With<AnimateRotation>)>,
) {
for mut transform in query.iter_mut() {
transform.rotation = Quat::from_rotation_z(time.seconds_since_startup().cos() as f32);
}
}
fn animate_scale(
time: Res<Time>,
mut query: Query<&mut Transform, (With<Text>, With<AnimateScale>)>,
) {
// Consider changing font-size instead of scaling the transform. Scaling a Text2D will scale the
// rendered quad, resulting in a pixellated look.
for mut transform in query.iter_mut() {
transform.translation = Vec3::new(400.0, 0.0, 0.0);
transform.scale = Vec3::splat((time.seconds_since_startup().sin() as f32 + 1.1) * 2.0);
}
}