mirror of
https://github.com/bevyengine/bevy
synced 2024-12-23 19:43:07 +00:00
8aa84babee
# Objective `bevy_animation::PlayingAnimation` derives `Reflect` but is not registered. ## Solution Register `bevy_animation::PlayingAnimation`.
615 lines
21 KiB
Rust
615 lines
21 KiB
Rust
//! Animation for the game engine Bevy
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#![warn(missing_docs)]
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#![allow(clippy::type_complexity)]
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use std::ops::Deref;
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use std::time::Duration;
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use bevy_app::{App, Plugin, PostUpdate};
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use bevy_asset::{AddAsset, Assets, Handle};
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use bevy_core::Name;
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use bevy_ecs::prelude::*;
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use bevy_hierarchy::{Children, Parent};
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use bevy_math::{Quat, Vec3};
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use bevy_reflect::{Reflect, TypeUuid};
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use bevy_render::mesh::morph::MorphWeights;
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use bevy_time::Time;
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use bevy_transform::{prelude::Transform, TransformSystem};
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use bevy_utils::{tracing::warn, HashMap};
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#[allow(missing_docs)]
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pub mod prelude {
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#[doc(hidden)]
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pub use crate::{
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AnimationClip, AnimationPlayer, AnimationPlugin, EntityPath, Keyframes, VariableCurve,
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};
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}
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/// List of keyframes for one of the attribute of a [`Transform`].
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#[derive(Reflect, Clone, Debug)]
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pub enum Keyframes {
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/// Keyframes for rotation.
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Rotation(Vec<Quat>),
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/// Keyframes for translation.
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Translation(Vec<Vec3>),
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/// Keyframes for scale.
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Scale(Vec<Vec3>),
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/// Keyframes for morph target weights.
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///
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/// Note that in `.0`, each contiguous `target_count` values is a single
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/// keyframe representing the weight values at given keyframe.
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///
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/// This follows the [glTF design].
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///
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/// [glTF design]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#animations
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Weights(Vec<f32>),
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}
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/// Describes how an attribute of a [`Transform`] or [`MorphWeights`] should be animated.
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///
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/// `keyframe_timestamps` and `keyframes` should have the same length.
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#[derive(Reflect, Clone, Debug)]
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pub struct VariableCurve {
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/// Timestamp for each of the keyframes.
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pub keyframe_timestamps: Vec<f32>,
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/// List of the keyframes.
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pub keyframes: Keyframes,
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}
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/// Path to an entity, with [`Name`]s. Each entity in a path must have a name.
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#[derive(Reflect, Clone, Debug, Hash, PartialEq, Eq, Default)]
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pub struct EntityPath {
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/// Parts of the path
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pub parts: Vec<Name>,
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}
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/// A list of [`VariableCurve`], and the [`EntityPath`] to which they apply.
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#[derive(Reflect, Clone, TypeUuid, Debug, Default)]
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#[uuid = "d81b7179-0448-4eb0-89fe-c067222725bf"]
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pub struct AnimationClip {
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curves: Vec<Vec<VariableCurve>>,
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paths: HashMap<EntityPath, usize>,
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duration: f32,
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}
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impl AnimationClip {
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#[inline]
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/// [`VariableCurve`]s for each bone. Indexed by the bone ID.
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pub fn curves(&self) -> &Vec<Vec<VariableCurve>> {
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&self.curves
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}
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/// Gets the curves for a bone.
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///
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/// Returns `None` if the bone is invalid.
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#[inline]
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pub fn get_curves(&self, bone_id: usize) -> Option<&'_ Vec<VariableCurve>> {
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self.curves.get(bone_id)
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}
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/// Gets the curves by it's [`EntityPath`].
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///
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/// Returns `None` if the bone is invalid.
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#[inline]
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pub fn get_curves_by_path(&self, path: &EntityPath) -> Option<&'_ Vec<VariableCurve>> {
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self.paths.get(path).and_then(|id| self.curves.get(*id))
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}
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/// Duration of the clip, represented in seconds
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#[inline]
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pub fn duration(&self) -> f32 {
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self.duration
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}
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/// Add a [`VariableCurve`] to an [`EntityPath`].
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pub fn add_curve_to_path(&mut self, path: EntityPath, curve: VariableCurve) {
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// Update the duration of the animation by this curve duration if it's longer
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self.duration = self
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.duration
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.max(*curve.keyframe_timestamps.last().unwrap_or(&0.0));
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if let Some(bone_id) = self.paths.get(&path) {
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self.curves[*bone_id].push(curve);
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} else {
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let idx = self.curves.len();
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self.curves.push(vec![curve]);
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self.paths.insert(path, idx);
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}
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}
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/// Whether this animation clip can run on entity with given [`Name`].
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pub fn compatible_with(&self, name: &Name) -> bool {
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self.paths.keys().all(|path| &path.parts[0] == name)
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}
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}
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#[derive(Reflect)]
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struct PlayingAnimation {
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repeat: bool,
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speed: f32,
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elapsed: f32,
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animation_clip: Handle<AnimationClip>,
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path_cache: Vec<Vec<Option<Entity>>>,
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}
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impl Default for PlayingAnimation {
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fn default() -> Self {
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Self {
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repeat: false,
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speed: 1.0,
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elapsed: 0.0,
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animation_clip: Default::default(),
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path_cache: Vec::new(),
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}
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}
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}
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/// An animation that is being faded out as part of a transition
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struct AnimationTransition {
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/// The current weight. Starts at 1.0 and goes to 0.0 during the fade-out.
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current_weight: f32,
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/// How much to decrease `current_weight` per second
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weight_decline_per_sec: f32,
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/// The animation that is being faded out
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animation: PlayingAnimation,
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}
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/// Animation controls
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#[derive(Component, Default, Reflect)]
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#[reflect(Component)]
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pub struct AnimationPlayer {
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paused: bool,
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animation: PlayingAnimation,
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// List of previous animations we're currently transitioning away from.
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// Usually this is empty, when transitioning between animations, there is
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// one entry. When another animation transition happens while a transition
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// is still ongoing, then there can be more than one entry.
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// Once a transition is finished, it will be automatically removed from the list
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#[reflect(ignore)]
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transitions: Vec<AnimationTransition>,
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}
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impl AnimationPlayer {
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/// Start playing an animation, resetting state of the player
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/// This will use a linear blending between the previous and the new animation to make a smooth transition
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pub fn start(&mut self, handle: Handle<AnimationClip>) -> &mut Self {
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self.animation = PlayingAnimation {
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animation_clip: handle,
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..Default::default()
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};
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// We want a hard transition.
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// In case any previous transitions are still playing, stop them
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self.transitions.clear();
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self
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}
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/// Start playing an animation, resetting state of the player
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/// This will use a linear blending between the previous and the new animation to make a smooth transition
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pub fn start_with_transition(
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&mut self,
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handle: Handle<AnimationClip>,
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transition_duration: Duration,
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) -> &mut Self {
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let mut animation = PlayingAnimation {
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animation_clip: handle,
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..Default::default()
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};
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std::mem::swap(&mut animation, &mut self.animation);
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// Add the current transition. If other transitions are still ongoing,
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// this will keep those transitions running and cause a transition between
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// the output of that previous transition to the new animation.
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self.transitions.push(AnimationTransition {
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current_weight: 1.0,
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weight_decline_per_sec: 1.0 / transition_duration.as_secs_f32(),
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animation,
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});
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self
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}
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/// Start playing an animation, resetting state of the player, unless the requested animation is already playing.
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/// If `transition_duration` is set, this will use a linear blending
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/// between the previous and the new animation to make a smooth transition
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pub fn play(&mut self, handle: Handle<AnimationClip>) -> &mut Self {
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if self.animation.animation_clip != handle || self.is_paused() {
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self.start(handle);
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}
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self
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}
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/// Start playing an animation, resetting state of the player, unless the requested animation is already playing.
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/// This will use a linear blending between the previous and the new animation to make a smooth transition
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pub fn play_with_transition(
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&mut self,
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handle: Handle<AnimationClip>,
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transition_duration: Duration,
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) -> &mut Self {
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if self.animation.animation_clip != handle || self.is_paused() {
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self.start_with_transition(handle, transition_duration);
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}
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self
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}
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/// Set the animation to repeat
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pub fn repeat(&mut self) -> &mut Self {
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self.animation.repeat = true;
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self
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}
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/// Stop the animation from repeating
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pub fn stop_repeating(&mut self) -> &mut Self {
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self.animation.repeat = false;
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self
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}
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/// Pause the animation
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pub fn pause(&mut self) {
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self.paused = true;
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}
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/// Unpause the animation
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pub fn resume(&mut self) {
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self.paused = false;
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}
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/// Is the animation paused
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pub fn is_paused(&self) -> bool {
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self.paused
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}
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/// Speed of the animation playback
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pub fn speed(&self) -> f32 {
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self.animation.speed
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}
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/// Set the speed of the animation playback
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pub fn set_speed(&mut self, speed: f32) -> &mut Self {
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self.animation.speed = speed;
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self
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}
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/// Time elapsed playing the animation
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pub fn elapsed(&self) -> f32 {
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self.animation.elapsed
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}
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/// Seek to a specific time in the animation
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pub fn set_elapsed(&mut self, elapsed: f32) -> &mut Self {
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self.animation.elapsed = elapsed;
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self
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}
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}
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fn entity_from_path(
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root: Entity,
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path: &EntityPath,
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children: &Query<&Children>,
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names: &Query<&Name>,
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path_cache: &mut Vec<Option<Entity>>,
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) -> Option<Entity> {
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// PERF: finding the target entity can be optimised
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let mut current_entity = root;
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path_cache.resize(path.parts.len(), None);
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// Ignore the first name, it is the root node which we already have
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for (idx, part) in path.parts.iter().enumerate().skip(1) {
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let mut found = false;
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let children = children.get(current_entity).ok()?;
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if let Some(cached) = path_cache[idx] {
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if children.contains(&cached) {
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if let Ok(name) = names.get(cached) {
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if name == part {
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current_entity = cached;
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found = true;
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}
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}
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}
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}
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if !found {
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for child in children.deref() {
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if let Ok(name) = names.get(*child) {
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if name == part {
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// Found a children with the right name, continue to the next part
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current_entity = *child;
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path_cache[idx] = Some(*child);
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found = true;
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break;
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}
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}
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}
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}
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if !found {
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warn!("Entity not found for path {:?} on part {:?}", path, part);
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return None;
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}
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}
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Some(current_entity)
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}
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/// Verify that there are no ancestors of a given entity that have an [`AnimationPlayer`].
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fn verify_no_ancestor_player(
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player_parent: Option<&Parent>,
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parents: &Query<(Option<With<AnimationPlayer>>, Option<&Parent>)>,
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) -> bool {
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let Some(mut current) = player_parent.map(Parent::get) else { return true };
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loop {
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let Ok((maybe_player, parent)) = parents.get(current) else { return true };
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if maybe_player.is_some() {
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return false;
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}
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if let Some(parent) = parent {
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current = parent.get();
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} else {
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return true;
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}
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}
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}
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/// System that will play all animations, using any entity with a [`AnimationPlayer`]
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/// and a [`Handle<AnimationClip>`] as an animation root
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#[allow(clippy::too_many_arguments)]
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pub fn animation_player(
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time: Res<Time>,
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animations: Res<Assets<AnimationClip>>,
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children: Query<&Children>,
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names: Query<&Name>,
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transforms: Query<&mut Transform>,
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morphs: Query<&mut MorphWeights>,
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parents: Query<(Option<With<AnimationPlayer>>, Option<&Parent>)>,
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mut animation_players: Query<(Entity, Option<&Parent>, &mut AnimationPlayer)>,
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) {
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animation_players
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.par_iter_mut()
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.for_each_mut(|(root, maybe_parent, mut player)| {
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update_transitions(&mut player, &time);
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run_animation_player(
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root,
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player,
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&time,
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&animations,
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&names,
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&transforms,
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&morphs,
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maybe_parent,
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&parents,
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&children,
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);
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});
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}
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#[allow(clippy::too_many_arguments)]
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fn run_animation_player(
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root: Entity,
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mut player: Mut<AnimationPlayer>,
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time: &Time,
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animations: &Assets<AnimationClip>,
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names: &Query<&Name>,
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transforms: &Query<&mut Transform>,
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morphs: &Query<&mut MorphWeights>,
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maybe_parent: Option<&Parent>,
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parents: &Query<(Option<With<AnimationPlayer>>, Option<&Parent>)>,
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children: &Query<&Children>,
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) {
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let paused = player.paused;
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// Continue if paused unless the `AnimationPlayer` was changed
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// This allow the animation to still be updated if the player.elapsed field was manually updated in pause
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if paused && !player.is_changed() {
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return;
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}
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// Apply the main animation
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apply_animation(
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1.0,
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&mut player.animation,
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paused,
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root,
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time,
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animations,
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names,
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transforms,
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morphs,
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maybe_parent,
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parents,
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children,
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);
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// Apply any potential fade-out transitions from previous animations
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for AnimationTransition {
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current_weight,
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animation,
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..
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} in &mut player.transitions
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{
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apply_animation(
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*current_weight,
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animation,
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paused,
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root,
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time,
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animations,
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names,
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transforms,
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morphs,
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maybe_parent,
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parents,
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children,
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);
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}
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}
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/// Update `weights` based on weights in `keyframes` at index `key_index`
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/// with a linear interpolation on `key_lerp`.
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///
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/// # Panics
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///
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/// When `key_index * target_count` is larger than `keyframes`
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///
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/// This happens when `keyframes` is not formatted as described in
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/// [`Keyframes::Weights`]. A possible cause is [`AnimationClip`] not being
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/// meant to be used for the [`MorphWeights`] of the entity it's being applied to.
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fn lerp_morph_weights(weights: &mut [f32], key_lerp: f32, keyframes: &[f32], key_index: usize) {
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let target_count = weights.len();
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let start = target_count * key_index;
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let end = target_count * (key_index + 1);
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let zipped = weights.iter_mut().zip(&keyframes[start..end]);
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for (morph_weight, keyframe) in zipped {
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let minus_lerp = 1.0 - key_lerp;
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*morph_weight = (*morph_weight * minus_lerp) + (keyframe * key_lerp);
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}
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}
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#[allow(clippy::too_many_arguments)]
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fn apply_animation(
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weight: f32,
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animation: &mut PlayingAnimation,
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paused: bool,
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root: Entity,
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time: &Time,
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animations: &Assets<AnimationClip>,
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names: &Query<&Name>,
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transforms: &Query<&mut Transform>,
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morphs: &Query<&mut MorphWeights>,
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maybe_parent: Option<&Parent>,
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parents: &Query<(Option<With<AnimationPlayer>>, Option<&Parent>)>,
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children: &Query<&Children>,
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) {
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if let Some(animation_clip) = animations.get(&animation.animation_clip) {
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if !paused {
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animation.elapsed += time.delta_seconds() * animation.speed;
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}
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let mut elapsed = animation.elapsed;
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if animation.repeat {
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elapsed %= animation_clip.duration;
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}
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if elapsed < 0.0 {
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elapsed += animation_clip.duration;
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}
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if animation.path_cache.len() != animation_clip.paths.len() {
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animation.path_cache = vec![Vec::new(); animation_clip.paths.len()];
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}
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if !verify_no_ancestor_player(maybe_parent, parents) {
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warn!("Animation player on {:?} has a conflicting animation player on an ancestor. Cannot safely animate.", root);
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return;
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}
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for (path, bone_id) in &animation_clip.paths {
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let cached_path = &mut animation.path_cache[*bone_id];
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let curves = animation_clip.get_curves(*bone_id).unwrap();
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let Some(target) = entity_from_path(root, path, children, names, cached_path) else { continue };
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// SAFETY: The verify_no_ancestor_player check above ensures that two animation players cannot alias
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// any of their descendant Transforms.
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//
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// The system scheduler prevents any other system from mutating Transforms at the same time,
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// so the only way this fetch can alias is if two AnimationPlayers are targeting the same bone.
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// This can only happen if there are two or more AnimationPlayers are ancestors to the same
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// entities. By verifying that there is no other AnimationPlayer in the ancestors of a
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// running AnimationPlayer before animating any entity, this fetch cannot alias.
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//
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// This means only the AnimationPlayers closest to the root of the hierarchy will be able
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// to run their animation. Any players in the children or descendants will log a warning
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// and do nothing.
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let Ok(mut transform) = (unsafe { transforms.get_unchecked(target) }) else { continue };
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let mut morphs = unsafe { morphs.get_unchecked(target) };
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for curve in curves {
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// Some curves have only one keyframe used to set a transform
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if curve.keyframe_timestamps.len() == 1 {
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match &curve.keyframes {
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|
Keyframes::Rotation(keyframes) => {
|
|
transform.rotation = transform.rotation.slerp(keyframes[0], weight);
|
|
}
|
|
Keyframes::Translation(keyframes) => {
|
|
transform.translation =
|
|
transform.translation.lerp(keyframes[0], weight);
|
|
}
|
|
Keyframes::Scale(keyframes) => {
|
|
transform.scale = transform.scale.lerp(keyframes[0], weight);
|
|
}
|
|
Keyframes::Weights(keyframes) => {
|
|
if let Ok(morphs) = &mut morphs {
|
|
lerp_morph_weights(morphs.weights_mut(), weight, keyframes, 0);
|
|
}
|
|
}
|
|
}
|
|
continue;
|
|
}
|
|
|
|
// Find the current keyframe
|
|
// PERF: finding the current keyframe can be optimised
|
|
let step_start = match curve
|
|
.keyframe_timestamps
|
|
.binary_search_by(|probe| probe.partial_cmp(&elapsed).unwrap())
|
|
{
|
|
Ok(n) if n >= curve.keyframe_timestamps.len() - 1 => continue, // this curve is finished
|
|
Ok(i) => i,
|
|
Err(0) => continue, // this curve isn't started yet
|
|
Err(n) if n > curve.keyframe_timestamps.len() - 1 => continue, // this curve is finished
|
|
Err(i) => i - 1,
|
|
};
|
|
let ts_start = curve.keyframe_timestamps[step_start];
|
|
let ts_end = curve.keyframe_timestamps[step_start + 1];
|
|
let lerp = (elapsed - ts_start) / (ts_end - ts_start);
|
|
|
|
// Apply the keyframe
|
|
match &curve.keyframes {
|
|
Keyframes::Rotation(keyframes) => {
|
|
let rot_start = keyframes[step_start];
|
|
let mut rot_end = keyframes[step_start + 1];
|
|
// Choose the smallest angle for the rotation
|
|
if rot_end.dot(rot_start) < 0.0 {
|
|
rot_end = -rot_end;
|
|
}
|
|
// Rotations are using a spherical linear interpolation
|
|
let rot = rot_start.normalize().slerp(rot_end.normalize(), lerp);
|
|
transform.rotation = transform.rotation.slerp(rot, weight);
|
|
}
|
|
Keyframes::Translation(keyframes) => {
|
|
let translation_start = keyframes[step_start];
|
|
let translation_end = keyframes[step_start + 1];
|
|
let result = translation_start.lerp(translation_end, lerp);
|
|
transform.translation = transform.translation.lerp(result, weight);
|
|
}
|
|
Keyframes::Scale(keyframes) => {
|
|
let scale_start = keyframes[step_start];
|
|
let scale_end = keyframes[step_start + 1];
|
|
let result = scale_start.lerp(scale_end, lerp);
|
|
transform.scale = transform.scale.lerp(result, weight);
|
|
}
|
|
Keyframes::Weights(keyframes) => {
|
|
if let Ok(morphs) = &mut morphs {
|
|
lerp_morph_weights(morphs.weights_mut(), weight, keyframes, step_start);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn update_transitions(player: &mut AnimationPlayer, time: &Time) {
|
|
player.transitions.retain_mut(|animation| {
|
|
animation.current_weight -= animation.weight_decline_per_sec * time.delta_seconds();
|
|
animation.current_weight > 0.0
|
|
});
|
|
}
|
|
|
|
/// Adds animation support to an app
|
|
#[derive(Default)]
|
|
pub struct AnimationPlugin;
|
|
|
|
impl Plugin for AnimationPlugin {
|
|
fn build(&self, app: &mut App) {
|
|
app.add_asset::<AnimationClip>()
|
|
.register_asset_reflect::<AnimationClip>()
|
|
.register_type::<AnimationPlayer>()
|
|
.register_type::<PlayingAnimation>()
|
|
.add_systems(
|
|
PostUpdate,
|
|
animation_player.before(TransformSystem::TransformPropagate),
|
|
);
|
|
}
|
|
}
|