bevy/examples/animation/animation_events.rs
andristarr 7482a0d26d
aligning public apis of Time,Timer and Stopwatch (#15962)
Fixes #15834

## Migration Guide

The APIs of `Time`, `Timer` and `Stopwatch` have been cleaned up for
consistency with each other and the standard library's `Duration` type.
The following methods have been renamed:

- `Stowatch::paused` -> `Stopwatch::is_paused`
- `Time::elapsed_seconds` -> `Time::elasped_secs` (including `_f64` and
`_wrapped` variants)
2024-10-16 21:09:32 +00:00

116 lines
3 KiB
Rust

//! Demonstrate how to use animation events.
use bevy::{
color::palettes::css::{ALICE_BLUE, BLACK, CRIMSON},
core_pipeline::bloom::Bloom,
prelude::*,
};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_event::<MessageEvent>()
.add_systems(Startup, setup)
.add_systems(PreUpdate, (animate_text_opacity, edit_message))
.run();
}
#[derive(Component)]
struct MessageText;
#[derive(Event, Reflect, Clone)]
#[reflect(AnimationEvent)]
struct MessageEvent {
value: String,
color: Color,
}
// AnimationEvent can also be derived, but doing so will
// trigger it as an observer event which is triggered in PostUpdate.
// We need to set the message text before that so it is
// updated before rendering without a one frame delay.
impl AnimationEvent for MessageEvent {
fn trigger(&self, _time: f32, _weight: f32, _entity: Entity, world: &mut World) {
world.send_event(self.clone());
}
}
fn edit_message(
mut event_reader: EventReader<MessageEvent>,
text: Single<(&mut Text2d, &mut TextColor), With<MessageText>>,
) {
let (mut text, mut color) = text.into_inner();
for event in event_reader.read() {
text.0 = event.value.clone();
color.0 = event.color;
}
}
fn setup(
mut commands: Commands,
mut animations: ResMut<Assets<AnimationClip>>,
mut graphs: ResMut<Assets<AnimationGraph>>,
) {
// Camera
commands.spawn((
Camera2d,
Camera {
clear_color: ClearColorConfig::Custom(BLACK.into()),
hdr: true,
..Default::default()
},
Bloom {
intensity: 0.4,
..Bloom::NATURAL
},
));
// The text that will be changed by animation events.
commands.spawn((
MessageText,
Text2d::default(),
TextFont {
font_size: 119.0,
..default()
},
TextColor(Color::NONE),
));
// Create a new animation clip.
let mut animation = AnimationClip::default();
// This is only necessary if you want the duration of the
// animation to be longer than the last event in the clip.
animation.set_duration(2.0);
// Add events at the specified time.
animation.add_event(
0.0,
MessageEvent {
value: "HELLO".into(),
color: ALICE_BLUE.into(),
},
);
animation.add_event(
1.0,
MessageEvent {
value: "BYE".into(),
color: CRIMSON.into(),
},
);
// Create the animation graph.
let (graph, animation_index) = AnimationGraph::from_clip(animations.add(animation));
let mut player = AnimationPlayer::default();
player.play(animation_index).repeat();
commands.spawn((AnimationGraphHandle(graphs.add(graph)), player));
}
// Slowly fade out the text opacity.
fn animate_text_opacity(mut colors: Query<&mut TextColor>, time: Res<Time>) {
for mut color in &mut colors {
let a = color.0.alpha();
color.0.set_alpha(a - time.delta_secs());
}
}