d9190e4ff6
# Objective Add support for events that can be triggered from animation clips. This is useful when you need something to happen at a specific time in an animation. For example, playing a sound every time a characters feet hits the ground when walking. Closes #15494 ## Solution Added a new field to `AnimationClip`: `events`, which contains a list of `AnimationEvent`s. These are automatically triggered in `animate_targets` and `trigger_untargeted_animation_events`. ## Testing Added a couple of tests and example (`animation_events.rs`) to make sure events are triggered when expected. --- ## Showcase `Events` need to also implement `AnimationEvent` and `Reflect` to be used with animations. ```rust #[derive(Event, AnimationEvent, Reflect)] struct SomeEvent; ``` Events can be added to an `AnimationClip` by specifying a time and event. ```rust // trigger an event after 1.0 second animation_clip.add_event(1.0, SomeEvent); ``` And optionally, providing a target id. ```rust let id = AnimationTargetId::from_iter(["shoulder", "arm", "hand"]); animation_clip.add_event_to_target(id, 1.0, HandEvent); ``` I modified the `animated_fox` example to show off the feature.  --------- Co-authored-by: Matty <weatherleymatthew@gmail.com> Co-authored-by: Chris Biscardi <chris@christopherbiscardi.com> Co-authored-by: François Mockers <francois.mockers@vleue.com>
122 lines
3.2 KiB
Rust
122 lines
3.2 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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mut text: Single<&mut Text, With<MessageText>>,
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) {
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for event in event_reader.read() {
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text.sections[0].value = event.value.clone();
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text.sections[0].style.color = 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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Text2dBundle {
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text: Text::from_section(
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"",
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TextStyle {
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font_size: 119.0,
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color: Color::NONE,
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..Default::default()
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},
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),
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..Default::default()
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},
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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((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 query: Query<&mut Text>, time: Res<Time>) {
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for mut text in &mut query {
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let color = &mut text.sections[0].style.color;
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let a = color.alpha();
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color.set_alpha(a - time.delta_seconds());
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}
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}
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