mirror of
https://github.com/bevyengine/bevy
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6f7d0e5725
# Objective
Currently text is recomputed unnecessarily on any changes to its color,
which is extremely expensive.
## Solution
Split up `TextStyle` into two separate components `TextFont` and
`TextColor`.
## Testing
I added this system to `many_buttons`:
```rust
fn set_text_colors_changed(mut colors: Query<&mut TextColor>) {
for mut text_color in colors.iter_mut() {
text_color.set_changed();
}
}
```
reports ~4fps on main, ~50fps with this PR.
## Migration Guide
`TextStyle` has been renamed to `TextFont` and its `color` field has
been moved to a separate component named `TextColor` which newtypes
`Color`.
116 lines
3 KiB
Rust
116 lines
3 KiB
Rust
//! Demonstrate how to use animation events.
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use bevy::{
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color::palettes::css::{ALICE_BLUE, BLACK, CRIMSON},
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core_pipeline::bloom::Bloom,
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prelude::*,
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};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.add_event::<MessageEvent>()
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.add_systems(Startup, setup)
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.add_systems(PreUpdate, (animate_text_opacity, edit_message))
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.run();
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}
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#[derive(Component)]
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struct MessageText;
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#[derive(Event, Reflect, Clone)]
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#[reflect(AnimationEvent)]
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struct MessageEvent {
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value: String,
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color: Color,
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}
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// AnimationEvent can also be derived, but doing so will
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// trigger it as an observer event which is triggered in PostUpdate.
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// We need to set the message text before that so it is
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// updated before rendering without a one frame delay.
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impl AnimationEvent for MessageEvent {
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fn trigger(&self, _time: f32, _weight: f32, _entity: Entity, world: &mut World) {
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world.send_event(self.clone());
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}
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}
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fn edit_message(
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mut event_reader: EventReader<MessageEvent>,
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text: Single<(&mut Text2d, &mut TextColor), With<MessageText>>,
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) {
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let (mut text, mut color) = text.into_inner();
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for event in event_reader.read() {
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text.0 = event.value.clone();
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color.0 = event.color;
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}
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}
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fn setup(
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mut commands: Commands,
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mut animations: ResMut<Assets<AnimationClip>>,
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mut graphs: ResMut<Assets<AnimationGraph>>,
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) {
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// Camera
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commands.spawn((
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Camera2d,
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Camera {
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clear_color: ClearColorConfig::Custom(BLACK.into()),
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hdr: true,
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..Default::default()
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},
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Bloom {
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intensity: 0.4,
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..Bloom::NATURAL
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},
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));
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// The text that will be changed by animation events.
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commands.spawn((
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MessageText,
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Text2d::default(),
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TextFont {
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font_size: 119.0,
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..default()
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},
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TextColor(Color::NONE),
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));
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// Create a new animation clip.
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let mut animation = AnimationClip::default();
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// This is only necessary if you want the duration of the
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// animation to be longer than the last event in the clip.
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animation.set_duration(2.0);
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// Add events at the specified time.
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animation.add_event(
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0.0,
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MessageEvent {
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value: "HELLO".into(),
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color: ALICE_BLUE.into(),
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},
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);
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animation.add_event(
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1.0,
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MessageEvent {
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value: "BYE".into(),
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color: CRIMSON.into(),
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},
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);
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// Create the animation graph.
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let (graph, animation_index) = AnimationGraph::from_clip(animations.add(animation));
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let mut player = AnimationPlayer::default();
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player.play(animation_index).repeat();
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commands.spawn((AnimationGraphHandle(graphs.add(graph)), player));
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}
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// Slowly fade out the text opacity.
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fn animate_text_opacity(mut colors: Query<&mut TextColor>, time: Res<Time>) {
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for mut color in &mut colors {
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let a = color.0.alpha();
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color.0.set_alpha(a - time.delta_seconds());
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}
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}
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