bevy/crates/bevy_animation/src/lib.rs
Zachary Harrold d70595b667
Add core and alloc over std Lints (#15281)
# Objective

- Fixes #6370
- Closes #6581

## Solution

- Added the following lints to the workspace:
  - `std_instead_of_core`
  - `std_instead_of_alloc`
  - `alloc_instead_of_core`
- Used `cargo +nightly fmt` with [item level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A)
to split all `use` statements into single items.
- Used `cargo clippy --workspace --all-targets --all-features --fix
--allow-dirty` to _attempt_ to resolve the new linting issues, and
intervened where the lint was unable to resolve the issue automatically
(usually due to needing an `extern crate alloc;` statement in a crate
root).
- Manually removed certain uses of `std` where negative feature gating
prevented `--all-features` from finding the offending uses.
- Used `cargo +nightly fmt` with [crate level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A)
to re-merge all `use` statements matching Bevy's previous styling.
- Manually fixed cases where the `fmt` tool could not re-merge `use`
statements due to conditional compilation attributes.

## Testing

- Ran CI locally

## Migration Guide

The MSRV is now 1.81. Please update to this version or higher.

## Notes

- This is a _massive_ change to try and push through, which is why I've
outlined the semi-automatic steps I used to create this PR, in case this
fails and someone else tries again in the future.
- Making this change has no impact on user code, but does mean Bevy
contributors will be warned to use `core` and `alloc` instead of `std`
where possible.
- This lint is a critical first step towards investigating `no_std`
options for Bevy.

---------

Co-authored-by: François Mockers <francois.mockers@vleue.com>
2024-09-27 00:59:59 +00:00

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#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![forbid(unsafe_code)]
#![doc(
html_logo_url = "https://bevyengine.org/assets/icon.png",
html_favicon_url = "https://bevyengine.org/assets/icon.png"
)]
//! Animation for the game engine Bevy
extern crate alloc;
pub mod animatable;
pub mod graph;
pub mod keyframes;
pub mod transition;
mod util;
use alloc::collections::BTreeMap;
use core::{
any::{Any, TypeId},
cell::RefCell,
fmt::Debug,
hash::{Hash, Hasher},
iter,
};
use bevy_app::{App, Plugin, PostUpdate};
use bevy_asset::{Asset, AssetApp, Assets, Handle};
use bevy_core::Name;
use bevy_ecs::{
entity::MapEntities, prelude::*, reflect::ReflectMapEntities, world::EntityMutExcept,
};
use bevy_math::FloatExt;
use bevy_reflect::{
prelude::ReflectDefault, utility::NonGenericTypeInfoCell, ApplyError, DynamicStruct, FieldIter,
FromReflect, FromType, GetTypeRegistration, NamedField, PartialReflect, Reflect,
ReflectFromPtr, ReflectKind, ReflectMut, ReflectOwned, ReflectRef, Struct, StructInfo,
TypeInfo, TypePath, TypeRegistration, Typed,
};
use bevy_time::Time;
use bevy_transform::{prelude::Transform, TransformSystem};
use bevy_ui::UiSystem;
use bevy_utils::{
hashbrown::HashMap,
tracing::{trace, warn},
NoOpHash,
};
use fixedbitset::FixedBitSet;
use graph::AnimationMask;
use petgraph::{graph::NodeIndex, Direction};
use serde::{Deserialize, Serialize};
use thread_local::ThreadLocal;
use uuid::Uuid;
/// The animation prelude.
///
/// This includes the most common types in this crate, re-exported for your convenience.
pub mod prelude {
#[doc(hidden)]
pub use crate::{
animatable::*, graph::*, keyframes::*, transition::*, AnimationClip, AnimationPlayer,
AnimationPlugin, Interpolation, VariableCurve,
};
}
use crate::{
graph::{AnimationGraph, AnimationGraphAssetLoader, AnimationNodeIndex},
keyframes::Keyframes,
transition::{advance_transitions, expire_completed_transitions, AnimationTransitions},
};
/// The [UUID namespace] of animation targets (e.g. bones).
///
/// [UUID namespace]: https://en.wikipedia.org/wiki/Universally_unique_identifier#Versions_3_and_5_(namespace_name-based)
pub static ANIMATION_TARGET_NAMESPACE: Uuid = Uuid::from_u128(0x3179f519d9274ff2b5966fd077023911);
/// Describes how an attribute of a [`Transform`] or
/// [`bevy_render::mesh::morph::MorphWeights`] should be animated.
///
/// `keyframe_timestamps` and `keyframes` should have the same length.
#[derive(Debug, TypePath)]
pub struct VariableCurve {
/// Timestamp for each of the keyframes.
pub keyframe_timestamps: Vec<f32>,
/// List of the keyframes.
///
/// The representation will depend on the interpolation type of this curve:
///
/// - for `Interpolation::Step` and `Interpolation::Linear`, each keyframe is a single value
/// - for `Interpolation::CubicSpline`, each keyframe is made of three values for `tangent_in`,
/// `keyframe_value` and `tangent_out`
pub keyframes: Box<dyn Keyframes>,
/// Interpolation method to use between keyframes.
pub interpolation: Interpolation,
}
impl Clone for VariableCurve {
fn clone(&self) -> Self {
VariableCurve {
keyframe_timestamps: self.keyframe_timestamps.clone(),
keyframes: Keyframes::clone_value(&*self.keyframes),
interpolation: self.interpolation,
}
}
}
impl VariableCurve {
/// Creates a new curve from timestamps, keyframes, and interpolation type.
///
/// The two arrays must have the same length.
pub fn new<K>(
keyframe_timestamps: Vec<f32>,
keyframes: impl Into<K>,
interpolation: Interpolation,
) -> VariableCurve
where
K: Keyframes,
{
VariableCurve {
keyframe_timestamps,
keyframes: Box::new(keyframes.into()),
interpolation,
}
}
/// Creates a new curve from timestamps and keyframes with no interpolation.
///
/// The two arrays must have the same length.
pub fn step<K>(
keyframe_timestamps: impl Into<Vec<f32>>,
keyframes: impl Into<K>,
) -> VariableCurve
where
K: Keyframes,
{
VariableCurve::new(keyframe_timestamps.into(), keyframes, Interpolation::Step)
}
/// Creates a new curve from timestamps and keyframes with linear
/// interpolation.
///
/// The two arrays must have the same length.
pub fn linear<K>(
keyframe_timestamps: impl Into<Vec<f32>>,
keyframes: impl Into<K>,
) -> VariableCurve
where
K: Keyframes,
{
VariableCurve::new(keyframe_timestamps.into(), keyframes, Interpolation::Linear)
}
/// Creates a new curve from timestamps and keyframes with no interpolation.
///
/// The two arrays must have the same length.
pub fn cubic_spline<K>(
keyframe_timestamps: impl Into<Vec<f32>>,
keyframes: impl Into<K>,
) -> VariableCurve
where
K: Keyframes,
{
VariableCurve::new(
keyframe_timestamps.into(),
keyframes,
Interpolation::CubicSpline,
)
}
/// Find the index of the keyframe at or before the current time.
///
/// Returns [`None`] if the curve is finished or not yet started.
/// To be more precise, this returns [`None`] if the frame is at or past the last keyframe:
/// we cannot get the *next* keyframe to interpolate to in that case.
pub fn find_current_keyframe(&self, seek_time: f32) -> Option<usize> {
// An Ok(keyframe_index) result means an exact result was found by binary search
// An Err result means the keyframe was not found, and the index is the keyframe
// PERF: finding the current keyframe can be optimised
let search_result = self
.keyframe_timestamps
.binary_search_by(|probe| probe.partial_cmp(&seek_time).unwrap());
// Subtract one for zero indexing!
let last_keyframe = self.keyframe_timestamps.len() - 1;
// We want to find the index of the keyframe before the current time
// If the keyframe is past the second-to-last keyframe, the animation cannot be interpolated.
let step_start = match search_result {
// An exact match was found, and it is the last keyframe (or something has gone terribly wrong).
// This means that the curve is finished.
Ok(n) if n >= last_keyframe => return None,
// An exact match was found, and it is not the last keyframe.
Ok(i) => i,
// No exact match was found, and the seek_time is before the start of the animation.
// This occurs because the binary search returns the index of where we could insert a value
// without disrupting the order of the vector.
// If the value is less than the first element, the index will be 0.
Err(0) => return None,
// No exact match was found, and it was after the last keyframe.
// The curve is finished.
Err(n) if n > last_keyframe => return None,
// No exact match was found, so return the previous keyframe to interpolate from.
Err(i) => i - 1,
};
// Consumers need to be able to interpolate between the return keyframe and the next
assert!(step_start < self.keyframe_timestamps.len());
Some(step_start)
}
/// Find the index of the keyframe at or before the current time.
///
/// Returns the first keyframe if the `seek_time` is before the first keyframe, and
/// the second-to-last keyframe if the `seek_time` is after the last keyframe.
/// Panics if there are less than 2 keyframes.
pub fn find_interpolation_start_keyframe(&self, seek_time: f32) -> usize {
// An Ok(keyframe_index) result means an exact result was found by binary search
// An Err result means the keyframe was not found, and the index is the keyframe
// PERF: finding the current keyframe can be optimised
let search_result = self
.keyframe_timestamps
.binary_search_by(|probe| probe.partial_cmp(&seek_time).unwrap());
// We want to find the index of the keyframe before the current time
// If the keyframe is past the second-to-last keyframe, the animation cannot be interpolated.
match search_result {
// An exact match was found
Ok(i) => i.clamp(0, self.keyframe_timestamps.len() - 2),
// No exact match was found, so return the previous keyframe to interpolate from.
Err(i) => (i.saturating_sub(1)).clamp(0, self.keyframe_timestamps.len() - 2),
}
}
}
// We have to implement `PartialReflect` manually because of the embedded
// `Box<dyn Keyframes>`, which can't be automatically derived yet.
impl PartialReflect for VariableCurve {
#[inline]
fn get_represented_type_info(&self) -> Option<&'static TypeInfo> {
Some(<Self as Typed>::type_info())
}
#[inline]
fn into_partial_reflect(self: Box<Self>) -> Box<dyn PartialReflect> {
self
}
#[inline]
fn as_partial_reflect(&self) -> &dyn PartialReflect {
self
}
#[inline]
fn as_partial_reflect_mut(&mut self) -> &mut dyn PartialReflect {
self
}
fn try_into_reflect(self: Box<Self>) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>> {
Ok(self)
}
#[inline]
fn try_as_reflect(&self) -> Option<&dyn Reflect> {
Some(self)
}
#[inline]
fn try_as_reflect_mut(&mut self) -> Option<&mut dyn Reflect> {
Some(self)
}
fn try_apply(&mut self, value: &dyn PartialReflect) -> Result<(), ApplyError> {
if let ReflectRef::Struct(struct_value) = value.reflect_ref() {
for (i, value) in struct_value.iter_fields().enumerate() {
let name = struct_value.name_at(i).unwrap();
if let Some(v) = self.field_mut(name) {
v.try_apply(value)?;
}
}
} else {
return Err(ApplyError::MismatchedKinds {
from_kind: value.reflect_kind(),
to_kind: ReflectKind::Struct,
});
}
Ok(())
}
fn reflect_ref(&self) -> ReflectRef {
ReflectRef::Struct(self)
}
fn reflect_mut(&mut self) -> ReflectMut {
ReflectMut::Struct(self)
}
fn reflect_owned(self: Box<Self>) -> ReflectOwned {
ReflectOwned::Struct(self)
}
fn clone_value(&self) -> Box<dyn PartialReflect> {
Box::new((*self).clone())
}
}
// We have to implement `Reflect` manually because of the embedded `Box<dyn
// Keyframes>`, which can't be automatically derived yet.
impl Reflect for VariableCurve {
#[inline]
fn into_any(self: Box<Self>) -> Box<dyn Any> {
self
}
#[inline]
fn as_any(&self) -> &dyn Any {
self
}
#[inline]
fn as_any_mut(&mut self) -> &mut dyn Any {
self
}
#[inline]
fn into_reflect(self: Box<Self>) -> Box<dyn Reflect> {
self
}
#[inline]
fn as_reflect(&self) -> &dyn Reflect {
self
}
#[inline]
fn as_reflect_mut(&mut self) -> &mut dyn Reflect {
self
}
#[inline]
fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>> {
*self = value.take()?;
Ok(())
}
}
// We have to implement `Struct` manually because of the embedded `Box<dyn
// Keyframes>`, which can't be automatically derived yet.
impl Struct for VariableCurve {
fn field(&self, name: &str) -> Option<&dyn PartialReflect> {
match name {
"keyframe_timestamps" => Some(&self.keyframe_timestamps),
"keyframes" => Some(self.keyframes.as_partial_reflect()),
"interpolation" => Some(&self.interpolation),
_ => None,
}
}
fn field_mut(&mut self, name: &str) -> Option<&mut dyn PartialReflect> {
match name {
"keyframe_timestamps" => Some(&mut self.keyframe_timestamps),
"keyframes" => Some(self.keyframes.as_partial_reflect_mut()),
"interpolation" => Some(&mut self.interpolation),
_ => None,
}
}
fn field_at(&self, index: usize) -> Option<&dyn PartialReflect> {
match index {
0 => Some(&self.keyframe_timestamps),
1 => Some(self.keyframes.as_partial_reflect()),
2 => Some(&self.interpolation),
_ => None,
}
}
fn field_at_mut(&mut self, index: usize) -> Option<&mut dyn PartialReflect> {
match index {
0 => Some(&mut self.keyframe_timestamps),
1 => Some(self.keyframes.as_partial_reflect_mut()),
2 => Some(&mut self.interpolation),
_ => None,
}
}
fn name_at(&self, index: usize) -> Option<&str> {
match index {
0 => Some("keyframe_timestamps"),
1 => Some("keyframes"),
2 => Some("interpolation"),
_ => None,
}
}
fn field_len(&self) -> usize {
3
}
fn iter_fields(&self) -> FieldIter {
FieldIter::new(self)
}
fn clone_dynamic(&self) -> DynamicStruct {
DynamicStruct::from_iter([
(
"keyframe_timestamps",
Box::new(self.keyframe_timestamps.clone()) as Box<dyn PartialReflect>,
),
("keyframes", PartialReflect::clone_value(&*self.keyframes)),
(
"interpolation",
Box::new(self.interpolation) as Box<dyn PartialReflect>,
),
])
}
}
// We have to implement `FromReflect` manually because of the embedded `Box<dyn
// Keyframes>`, which can't be automatically derived yet.
impl FromReflect for VariableCurve {
fn from_reflect(reflect: &dyn PartialReflect) -> Option<Self> {
Some(reflect.try_downcast_ref::<VariableCurve>()?.clone())
}
}
// We have to implement `GetTypeRegistration` manually because of the embedded
// `Box<dyn Keyframes>`, which can't be automatically derived yet.
impl GetTypeRegistration for VariableCurve {
fn get_type_registration() -> TypeRegistration {
let mut registration = TypeRegistration::of::<Self>();
registration.insert::<ReflectFromPtr>(FromType::<Self>::from_type());
registration
}
}
// We have to implement `Typed` manually because of the embedded `Box<dyn
// Keyframes>`, which can't be automatically derived yet.
impl Typed for VariableCurve {
fn type_info() -> &'static TypeInfo {
static CELL: NonGenericTypeInfoCell = NonGenericTypeInfoCell::new();
CELL.get_or_set(|| {
TypeInfo::Struct(StructInfo::new::<Self>(&[
NamedField::new::<Vec<f32>>("keyframe_timestamps"),
NamedField::new::<()>("keyframes"),
NamedField::new::<Interpolation>("interpolation"),
]))
})
}
}
/// Interpolation method to use between keyframes.
#[derive(Reflect, Clone, Copy, Debug)]
pub enum Interpolation {
/// Linear interpolation between the two closest keyframes.
Linear,
/// Step interpolation, the value of the start keyframe is used.
Step,
/// Cubic spline interpolation. The value of the two closest keyframes is used, with the out
/// tangent of the start keyframe and the in tangent of the end keyframe.
CubicSpline,
}
/// A list of [`VariableCurve`]s and the [`AnimationTargetId`]s to which they
/// apply.
///
/// Because animation clips refer to targets by UUID, they can target any
/// [`AnimationTarget`] with that ID.
#[derive(Asset, Reflect, Clone, Debug, Default)]
pub struct AnimationClip {
curves: AnimationCurves,
duration: f32,
}
/// A mapping from [`AnimationTargetId`] (e.g. bone in a skinned mesh) to the
/// animation curves.
pub type AnimationCurves = HashMap<AnimationTargetId, Vec<VariableCurve>, NoOpHash>;
/// A unique [UUID] for an animation target (e.g. bone in a skinned mesh).
///
/// The [`AnimationClip`] asset and the [`AnimationTarget`] component both use
/// this to refer to targets (e.g. bones in a skinned mesh) to be animated.
///
/// When importing an armature or an animation clip, asset loaders typically use
/// the full path name from the armature to the bone to generate these UUIDs.
/// The ID is unique to the full path name and based only on the names. So, for
/// example, any imported armature with a bone at the root named `Hips` will
/// assign the same [`AnimationTargetId`] to its root bone. Likewise, any
/// imported animation clip that animates a root bone named `Hips` will
/// reference the same [`AnimationTargetId`]. Any animation is playable on any
/// armature as long as the bone names match, which allows for easy animation
/// retargeting.
///
/// Note that asset loaders generally use the *full* path name to generate the
/// [`AnimationTargetId`]. Thus a bone named `Chest` directly connected to a
/// bone named `Hips` will have a different ID from a bone named `Chest` that's
/// connected to a bone named `Stomach`.
///
/// [UUID]: https://en.wikipedia.org/wiki/Universally_unique_identifier
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Reflect, Debug, Serialize, Deserialize)]
pub struct AnimationTargetId(pub Uuid);
impl Hash for AnimationTargetId {
fn hash<H: Hasher>(&self, state: &mut H) {
let (hi, lo) = self.0.as_u64_pair();
state.write_u64(hi ^ lo);
}
}
/// An entity that can be animated by an [`AnimationPlayer`].
///
/// These are frequently referred to as *bones* or *joints*, because they often
/// refer to individually-animatable parts of an armature.
///
/// Asset loaders for armatures are responsible for adding these as necessary.
/// Typically, they're generated from hashed versions of the entire name path
/// from the root of the armature to the bone. See the [`AnimationTargetId`]
/// documentation for more details.
///
/// By convention, asset loaders add [`AnimationTarget`] components to the
/// descendants of an [`AnimationPlayer`], as well as to the [`AnimationPlayer`]
/// entity itself, but Bevy doesn't require this in any way. So, for example,
/// it's entirely possible for an [`AnimationPlayer`] to animate a target that
/// it isn't an ancestor of. If you add a new bone to or delete a bone from an
/// armature at runtime, you may want to update the [`AnimationTarget`]
/// component as appropriate, as Bevy won't do this automatically.
///
/// Note that each entity can only be animated by one animation player at a
/// time. However, you can change [`AnimationTarget`]'s `player` property at
/// runtime to change which player is responsible for animating the entity.
#[derive(Clone, Copy, Component, Reflect)]
#[reflect(Component, MapEntities)]
pub struct AnimationTarget {
/// The ID of this animation target.
///
/// Typically, this is derived from the path.
pub id: AnimationTargetId,
/// The entity containing the [`AnimationPlayer`].
pub player: Entity,
}
impl AnimationClip {
#[inline]
/// [`VariableCurve`]s for each animation target. Indexed by the [`AnimationTargetId`].
pub fn curves(&self) -> &AnimationCurves {
&self.curves
}
#[inline]
/// Get mutable references of [`VariableCurve`]s for each animation target. Indexed by the [`AnimationTargetId`].
pub fn curves_mut(&mut self) -> &mut AnimationCurves {
&mut self.curves
}
/// Gets the curves for a single animation target.
///
/// Returns `None` if this clip doesn't animate the target.
#[inline]
pub fn curves_for_target(
&self,
target_id: AnimationTargetId,
) -> Option<&'_ Vec<VariableCurve>> {
self.curves.get(&target_id)
}
/// Gets mutable references of the curves for a single animation target.
///
/// Returns `None` if this clip doesn't animate the target.
#[inline]
pub fn curves_for_target_mut(
&mut self,
target_id: AnimationTargetId,
) -> Option<&'_ mut Vec<VariableCurve>> {
self.curves.get_mut(&target_id)
}
/// Duration of the clip, represented in seconds.
#[inline]
pub fn duration(&self) -> f32 {
self.duration
}
/// Set the duration of the clip in seconds.
#[inline]
pub fn set_duration(&mut self, duration_sec: f32) {
self.duration = duration_sec;
}
/// Adds a [`VariableCurve`] to an [`AnimationTarget`] named by an
/// [`AnimationTargetId`].
///
/// If the curve extends beyond the current duration of this clip, this
/// method lengthens this clip to include the entire time span that the
/// curve covers.
pub fn add_curve_to_target(&mut self, target_id: AnimationTargetId, curve: VariableCurve) {
// Update the duration of the animation by this curve duration if it's longer
self.duration = self
.duration
.max(*curve.keyframe_timestamps.last().unwrap_or(&0.0));
self.curves.entry(target_id).or_default().push(curve);
}
}
/// Repetition behavior of an animation.
#[derive(Reflect, Debug, PartialEq, Eq, Copy, Clone, Default)]
pub enum RepeatAnimation {
/// The animation will finish after running once.
#[default]
Never,
/// The animation will finish after running "n" times.
Count(u32),
/// The animation will never finish.
Forever,
}
/// Why Bevy failed to evaluate an animation.
#[derive(Clone, Debug)]
pub enum AnimationEvaluationError {
/// The `keyframes` array is too small.
///
/// For curves with `Interpolation::Step` or `Interpolation::Linear`, the
/// `keyframes` array must have at least as many elements as keyframe
/// timestamps. For curves with `Interpolation::CubicBezier`, the
/// `keyframes` array must have at least 3× the number of elements as
/// keyframe timestamps, in order to account for the tangents.
KeyframeNotPresent(usize),
/// The component to be animated isn't present on the animation target.
///
/// To fix this error, make sure the entity to be animated contains all
/// components that have animation curves.
ComponentNotPresent(TypeId),
/// The component to be animated was present, but the property on the
/// component wasn't present.
PropertyNotPresent(TypeId),
}
/// An animation that an [`AnimationPlayer`] is currently either playing or was
/// playing, but is presently paused.
///
/// An stopped animation is considered no longer active.
#[derive(Debug, Clone, Copy, Reflect)]
pub struct ActiveAnimation {
/// The factor by which the weight from the [`AnimationGraph`] is multiplied.
weight: f32,
/// The actual weight of this animation this frame, taking the
/// [`AnimationGraph`] into account.
computed_weight: f32,
/// The mask groups that are masked out (i.e. won't be animated) this frame,
/// taking the `AnimationGraph` into account.
computed_mask: AnimationMask,
repeat: RepeatAnimation,
speed: f32,
/// Total time the animation has been played.
///
/// Note: Time does not increase when the animation is paused or after it has completed.
elapsed: f32,
/// The timestamp inside of the animation clip.
///
/// Note: This will always be in the range [0.0, animation clip duration]
seek_time: f32,
/// Number of times the animation has completed.
/// If the animation is playing in reverse, this increments when the animation passes the start.
completions: u32,
paused: bool,
}
impl Default for ActiveAnimation {
fn default() -> Self {
Self {
weight: 1.0,
computed_weight: 1.0,
computed_mask: 0,
repeat: RepeatAnimation::default(),
speed: 1.0,
elapsed: 0.0,
seek_time: 0.0,
completions: 0,
paused: false,
}
}
}
impl ActiveAnimation {
/// Check if the animation has finished, based on its repetition behavior and the number of times it has repeated.
///
/// Note: An animation with `RepeatAnimation::Forever` will never finish.
#[inline]
pub fn is_finished(&self) -> bool {
match self.repeat {
RepeatAnimation::Forever => false,
RepeatAnimation::Never => self.completions >= 1,
RepeatAnimation::Count(n) => self.completions >= n,
}
}
/// Update the animation given the delta time and the duration of the clip being played.
#[inline]
fn update(&mut self, delta: f32, clip_duration: f32) {
if self.is_finished() {
return;
}
self.elapsed += delta;
self.seek_time += delta * self.speed;
let over_time = self.speed > 0.0 && self.seek_time >= clip_duration;
let under_time = self.speed < 0.0 && self.seek_time < 0.0;
if over_time || under_time {
self.completions += 1;
if self.is_finished() {
return;
}
}
if self.seek_time >= clip_duration {
self.seek_time %= clip_duration;
}
// Note: assumes delta is never lower than -clip_duration
if self.seek_time < 0.0 {
self.seek_time += clip_duration;
}
}
/// Reset back to the initial state as if no time has elapsed.
pub fn replay(&mut self) {
self.completions = 0;
self.elapsed = 0.0;
self.seek_time = 0.0;
}
/// Returns the current weight of this animation.
pub fn weight(&self) -> f32 {
self.weight
}
/// Sets the weight of this animation.
pub fn set_weight(&mut self, weight: f32) -> &mut Self {
self.weight = weight;
self
}
/// Pause the animation.
pub fn pause(&mut self) -> &mut Self {
self.paused = true;
self
}
/// Unpause the animation.
pub fn resume(&mut self) -> &mut Self {
self.paused = false;
self
}
/// Returns true if this animation is currently paused.
///
/// Note that paused animations are still [`ActiveAnimation`]s.
#[inline]
pub fn is_paused(&self) -> bool {
self.paused
}
/// Sets the repeat mode for this playing animation.
pub fn set_repeat(&mut self, repeat: RepeatAnimation) -> &mut Self {
self.repeat = repeat;
self
}
/// Marks this animation as repeating forever.
pub fn repeat(&mut self) -> &mut Self {
self.set_repeat(RepeatAnimation::Forever)
}
/// Returns the repeat mode assigned to this active animation.
pub fn repeat_mode(&self) -> RepeatAnimation {
self.repeat
}
/// Returns the number of times this animation has completed.
pub fn completions(&self) -> u32 {
self.completions
}
/// Returns true if the animation is playing in reverse.
pub fn is_playback_reversed(&self) -> bool {
self.speed < 0.0
}
/// Returns the speed of the animation playback.
pub fn speed(&self) -> f32 {
self.speed
}
/// Sets the speed of the animation playback.
pub fn set_speed(&mut self, speed: f32) -> &mut Self {
self.speed = speed;
self
}
/// Returns the amount of time the animation has been playing.
pub fn elapsed(&self) -> f32 {
self.elapsed
}
/// Returns the seek time of the animation.
///
/// This is nonnegative and no more than the clip duration.
pub fn seek_time(&self) -> f32 {
self.seek_time
}
/// Seeks to a specific time in the animation.
pub fn seek_to(&mut self, seek_time: f32) -> &mut Self {
self.seek_time = seek_time;
self
}
/// Seeks to the beginning of the animation.
pub fn rewind(&mut self) -> &mut Self {
self.seek_time = 0.0;
self
}
}
/// Animation controls.
///
/// Automatically added to any root animations of a `SceneBundle` when it is
/// spawned.
#[derive(Component, Default, Reflect)]
#[reflect(Component, Default)]
pub struct AnimationPlayer {
/// We use a `BTreeMap` instead of a `HashMap` here to ensure a consistent
/// ordering when applying the animations.
active_animations: BTreeMap<AnimationNodeIndex, ActiveAnimation>,
blend_weights: HashMap<AnimationNodeIndex, f32>,
}
// This is needed since `#[derive(Clone)]` does not generate optimized `clone_from`.
impl Clone for AnimationPlayer {
fn clone(&self) -> Self {
Self {
active_animations: self.active_animations.clone(),
blend_weights: self.blend_weights.clone(),
}
}
fn clone_from(&mut self, source: &Self) {
self.active_animations.clone_from(&source.active_animations);
self.blend_weights.clone_from(&source.blend_weights);
}
}
/// Information needed during the traversal of the animation graph in
/// [`advance_animations`].
#[derive(Default)]
pub struct AnimationGraphEvaluator {
/// The stack used for the depth-first search of the graph.
dfs_stack: Vec<NodeIndex>,
/// The list of visited nodes during the depth-first traversal.
dfs_visited: FixedBitSet,
/// Accumulated weights and masks for each node.
nodes: Vec<EvaluatedAnimationGraphNode>,
}
/// The accumulated weight and computed mask for a single node.
#[derive(Clone, Copy, Default, Debug)]
struct EvaluatedAnimationGraphNode {
/// The weight that has been accumulated for this node, taking its
/// ancestors' weights into account.
weight: f32,
/// The mask that has been computed for this node, taking its ancestors'
/// masks into account.
mask: AnimationMask,
}
impl AnimationPlayer {
/// Start playing an animation, restarting it if necessary.
pub fn start(&mut self, animation: AnimationNodeIndex) -> &mut ActiveAnimation {
let playing_animation = self.active_animations.entry(animation).or_default();
playing_animation.replay();
playing_animation
}
/// Start playing an animation, unless the requested animation is already playing.
pub fn play(&mut self, animation: AnimationNodeIndex) -> &mut ActiveAnimation {
self.active_animations.entry(animation).or_default()
}
/// Stops playing the given animation, removing it from the list of playing
/// animations.
pub fn stop(&mut self, animation: AnimationNodeIndex) -> &mut Self {
self.active_animations.remove(&animation);
self
}
/// Stops all currently-playing animations.
pub fn stop_all(&mut self) -> &mut Self {
self.active_animations.clear();
self
}
/// Iterates through all animations that this [`AnimationPlayer`] is
/// currently playing.
pub fn playing_animations(
&self,
) -> impl Iterator<Item = (&AnimationNodeIndex, &ActiveAnimation)> {
self.active_animations.iter()
}
/// Iterates through all animations that this [`AnimationPlayer`] is
/// currently playing, mutably.
pub fn playing_animations_mut(
&mut self,
) -> impl Iterator<Item = (&AnimationNodeIndex, &mut ActiveAnimation)> {
self.active_animations.iter_mut()
}
#[deprecated = "Use `animation_is_playing` instead"]
/// Check if the given animation node is being played.
pub fn is_playing_animation(&self, animation: AnimationNodeIndex) -> bool {
self.active_animations.contains_key(&animation)
}
/// Check if all playing animations have finished, according to the repetition behavior.
pub fn all_finished(&self) -> bool {
self.active_animations
.values()
.all(ActiveAnimation::is_finished)
}
/// Check if all playing animations are paused.
#[doc(alias = "is_paused")]
pub fn all_paused(&self) -> bool {
self.active_animations
.values()
.all(ActiveAnimation::is_paused)
}
/// Resume all playing animations.
#[doc(alias = "pause")]
pub fn pause_all(&mut self) -> &mut Self {
for (_, playing_animation) in self.playing_animations_mut() {
playing_animation.pause();
}
self
}
/// Resume all active animations.
#[doc(alias = "resume")]
pub fn resume_all(&mut self) -> &mut Self {
for (_, playing_animation) in self.playing_animations_mut() {
playing_animation.resume();
}
self
}
/// Rewinds all active animations.
#[doc(alias = "rewind")]
pub fn rewind_all(&mut self) -> &mut Self {
for (_, playing_animation) in self.playing_animations_mut() {
playing_animation.rewind();
}
self
}
/// Multiplies the speed of all active animations by the given factor.
#[doc(alias = "set_speed")]
pub fn adjust_speeds(&mut self, factor: f32) -> &mut Self {
for (_, playing_animation) in self.playing_animations_mut() {
let new_speed = playing_animation.speed() * factor;
playing_animation.set_speed(new_speed);
}
self
}
/// Seeks all active animations forward or backward by the same amount.
///
/// To seek forward, pass a positive value; to seek negative, pass a
/// negative value. Values below 0.0 or beyond the end of the animation clip
/// are clamped appropriately.
#[doc(alias = "seek_to")]
pub fn seek_all_by(&mut self, amount: f32) -> &mut Self {
for (_, playing_animation) in self.playing_animations_mut() {
let new_time = playing_animation.seek_time();
playing_animation.seek_to(new_time + amount);
}
self
}
/// Returns the [`ActiveAnimation`] associated with the given animation
/// node if it's currently playing.
///
/// If the animation isn't currently active, returns `None`.
pub fn animation(&self, animation: AnimationNodeIndex) -> Option<&ActiveAnimation> {
self.active_animations.get(&animation)
}
/// Returns a mutable reference to the [`ActiveAnimation`] associated with
/// the given animation node if it's currently active.
///
/// If the animation isn't currently active, returns `None`.
pub fn animation_mut(&mut self, animation: AnimationNodeIndex) -> Option<&mut ActiveAnimation> {
self.active_animations.get_mut(&animation)
}
/// Returns true if the animation is currently playing or paused, or false
/// if the animation is stopped.
pub fn animation_is_playing(&self, animation: AnimationNodeIndex) -> bool {
self.active_animations.contains_key(&animation)
}
}
/// A system that advances the time for all playing animations.
pub fn advance_animations(
time: Res<Time>,
animation_clips: Res<Assets<AnimationClip>>,
animation_graphs: Res<Assets<AnimationGraph>>,
mut players: Query<(&mut AnimationPlayer, &Handle<AnimationGraph>)>,
animation_graph_evaluator: Local<ThreadLocal<RefCell<AnimationGraphEvaluator>>>,
) {
let delta_seconds = time.delta_seconds();
players
.par_iter_mut()
.for_each(|(mut player, graph_handle)| {
let Some(animation_graph) = animation_graphs.get(graph_handle) else {
return;
};
// Tick animations, and schedule them.
//
// We use a thread-local here so we can reuse allocations across
// frames.
let mut evaluator = animation_graph_evaluator.get_or_default().borrow_mut();
let AnimationPlayer {
ref mut active_animations,
ref blend_weights,
..
} = *player;
// Reset our state.
evaluator.reset(animation_graph.root, animation_graph.graph.node_count());
while let Some(node_index) = evaluator.dfs_stack.pop() {
// Skip if we've already visited this node.
if evaluator.dfs_visited.put(node_index.index()) {
continue;
}
let node = &animation_graph[node_index];
// Calculate weight and mask from the graph.
let (mut weight, mut mask) = (node.weight, node.mask);
for parent_index in animation_graph
.graph
.neighbors_directed(node_index, Direction::Incoming)
{
let evaluated_parent = &evaluator.nodes[parent_index.index()];
weight *= evaluated_parent.weight;
mask |= evaluated_parent.mask;
}
evaluator.nodes[node_index.index()] = EvaluatedAnimationGraphNode { weight, mask };
if let Some(active_animation) = active_animations.get_mut(&node_index) {
// Tick the animation if necessary.
if !active_animation.paused {
if let Some(ref clip_handle) = node.clip {
if let Some(clip) = animation_clips.get(clip_handle) {
active_animation.update(delta_seconds, clip.duration);
}
}
}
weight *= active_animation.weight;
} else if let Some(&blend_weight) = blend_weights.get(&node_index) {
weight *= blend_weight;
}
// Write in the computed weight and mask for this node.
if let Some(active_animation) = active_animations.get_mut(&node_index) {
active_animation.computed_weight = weight;
active_animation.computed_mask = mask;
}
// Push children.
evaluator.dfs_stack.extend(
animation_graph
.graph
.neighbors_directed(node_index, Direction::Outgoing),
);
}
});
}
/// A system that modifies animation targets (e.g. bones in a skinned mesh)
/// according to the currently-playing animations.
pub fn animate_targets(
clips: Res<Assets<AnimationClip>>,
graphs: Res<Assets<AnimationGraph>>,
players: Query<(&AnimationPlayer, &Handle<AnimationGraph>)>,
mut targets: Query<(
Option<&mut Transform>,
EntityMutExcept<(Transform, AnimationPlayer, Handle<AnimationGraph>)>,
)>,
) {
// Evaluate all animation targets in parallel.
targets
.par_iter_mut()
.for_each(|(mut transform, mut entity_mut)| {
let Some(&AnimationTarget {
id: target_id,
player: player_id,
}) = entity_mut.get::<AnimationTarget>()
else {
return;
};
let (animation_player, animation_graph_id) =
if let Ok((player, graph_handle)) = players.get(player_id) {
(player, graph_handle.id())
} else {
trace!(
"Either an animation player {:?} or a graph was missing for the target \
entity {:?} ({:?}); no animations will play this frame",
player_id,
entity_mut.id(),
entity_mut.get::<Name>(),
);
return;
};
// The graph might not have loaded yet. Safely bail.
let Some(animation_graph) = graphs.get(animation_graph_id) else {
return;
};
// Determine which mask groups this animation target belongs to.
let target_mask = animation_graph
.mask_groups
.get(&target_id)
.cloned()
.unwrap_or_default();
// Apply the animations one after another. The way we accumulate
// weights ensures that the order we apply them in doesn't matter.
//
// Proof: Consider three animations A₀, A₁, A₂, … with weights w₀,
// w₁, w₂, … respectively. We seek the value:
//
// A₀w₀ + A₁w₁ + A₂w₂ + ⋯
//
// Defining lerp(a, b, t) = a + t(b - a), we have:
//
// ⎛ ⎛ w₁ ⎞ w₂ ⎞
// A₀w₀ + A₁w₁ + A₂w₂ + ⋯ = ⋯ lerp⎜lerp⎜A₀, A₁, ⎯⎯⎯⎯⎯⎯⎯⎯⎟, A₂, ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎟ ⋯
// ⎝ ⎝ w₀ + w₁⎠ w₀ + w₁ + w₂⎠
//
// Each step of the following loop corresponds to one of the lerp
// operations above.
let mut total_weight = 0.0;
for (&animation_graph_node_index, active_animation) in
animation_player.active_animations.iter()
{
// If the weight is zero or the current animation target is
// masked out, stop here.
if active_animation.weight == 0.0
|| (target_mask & active_animation.computed_mask) != 0
{
continue;
}
let Some(clip) = animation_graph
.get(animation_graph_node_index)
.and_then(|animation_graph_node| animation_graph_node.clip.as_ref())
.and_then(|animation_clip_handle| clips.get(animation_clip_handle))
else {
continue;
};
let Some(curves) = clip.curves_for_target(target_id) else {
continue;
};
let weight = active_animation.computed_weight;
total_weight += weight;
let weight = weight / total_weight;
let seek_time = active_animation.seek_time;
for curve in curves {
// Some curves have only one keyframe used to set a transform
if curve.keyframe_timestamps.len() == 1 {
if let Err(err) = curve.keyframes.apply_single_keyframe(
transform.as_mut().map(|transform| transform.reborrow()),
entity_mut.reborrow(),
weight,
) {
warn!("Animation application failed: {:?}", err);
}
continue;
}
// Find the best keyframe to interpolate from
let step_start = curve.find_interpolation_start_keyframe(seek_time);
let timestamp_start = curve.keyframe_timestamps[step_start];
let timestamp_end = curve.keyframe_timestamps[step_start + 1];
// Compute how far we are through the keyframe, normalized to [0, 1]
let lerp = f32::inverse_lerp(timestamp_start, timestamp_end, seek_time)
.clamp(0.0, 1.0);
if let Err(err) = curve.keyframes.apply_tweened_keyframes(
transform.as_mut().map(|transform| transform.reborrow()),
entity_mut.reborrow(),
curve.interpolation,
step_start,
lerp,
weight,
timestamp_end - timestamp_start,
) {
warn!("Animation application failed: {:?}", err);
}
}
}
});
}
/// Adds animation support to an app
#[derive(Default)]
pub struct AnimationPlugin;
impl Plugin for AnimationPlugin {
fn build(&self, app: &mut App) {
app.init_asset::<AnimationClip>()
.init_asset::<AnimationGraph>()
.init_asset_loader::<AnimationGraphAssetLoader>()
.register_asset_reflect::<AnimationClip>()
.register_asset_reflect::<AnimationGraph>()
.register_type::<AnimationPlayer>()
.register_type::<AnimationTarget>()
.register_type::<AnimationTransitions>()
.register_type::<NodeIndex>()
.add_systems(
PostUpdate,
(
advance_transitions,
advance_animations,
// TODO: `animate_targets` can animate anything, so
// ambiguity testing currently considers it ambiguous with
// every other system in `PostUpdate`. We may want to move
// it to its own system set after `Update` but before
// `PostUpdate`. For now, we just disable ambiguity testing
// for this system.
animate_targets
.after(bevy_render::mesh::morph::inherit_weights)
.ambiguous_with_all(),
expire_completed_transitions,
)
.chain()
.before(TransformSystem::TransformPropagate)
.before(UiSystem::Prepare),
);
}
}
impl AnimationTargetId {
/// Creates a new [`AnimationTargetId`] by hashing a list of names.
///
/// Typically, this will be the path from the animation root to the
/// animation target (e.g. bone) that is to be animated.
pub fn from_names<'a>(names: impl Iterator<Item = &'a Name>) -> Self {
let mut blake3 = blake3::Hasher::new();
blake3.update(ANIMATION_TARGET_NAMESPACE.as_bytes());
for name in names {
blake3.update(name.as_bytes());
}
let hash = blake3.finalize().as_bytes()[0..16].try_into().unwrap();
Self(*uuid::Builder::from_sha1_bytes(hash).as_uuid())
}
/// Creates a new [`AnimationTargetId`] by hashing a single name.
pub fn from_name(name: &Name) -> Self {
Self::from_names(iter::once(name))
}
}
impl From<&Name> for AnimationTargetId {
fn from(name: &Name) -> Self {
AnimationTargetId::from_name(name)
}
}
impl MapEntities for AnimationTarget {
fn map_entities<M: EntityMapper>(&mut self, entity_mapper: &mut M) {
self.player = entity_mapper.map_entity(self.player);
}
}
impl AnimationGraphEvaluator {
// Starts a new depth-first search.
fn reset(&mut self, root: AnimationNodeIndex, node_count: usize) {
self.dfs_stack.clear();
self.dfs_stack.push(root);
self.dfs_visited.grow(node_count);
self.dfs_visited.clear();
self.nodes.clear();
self.nodes
.extend(iter::repeat(EvaluatedAnimationGraphNode::default()).take(node_count));
}
}
#[cfg(test)]
mod tests {
use crate::{prelude::TranslationKeyframes, VariableCurve};
use bevy_math::Vec3;
// Returns the curve and the keyframe count.
fn test_variable_curve() -> (VariableCurve, usize) {
let keyframe_timestamps = vec![1.0, 2.0, 3.0, 4.0];
let keyframes = vec![
Vec3::ONE * 0.0,
Vec3::ONE * 3.0,
Vec3::ONE * 6.0,
Vec3::ONE * 9.0,
];
let interpolation = crate::Interpolation::Linear;
assert_eq!(keyframe_timestamps.len(), keyframes.len());
let keyframe_count = keyframes.len();
let variable_curve = VariableCurve::new::<TranslationKeyframes>(
keyframe_timestamps,
keyframes,
interpolation,
);
// f32 doesn't impl Ord so we can't easily sort it
let mut maybe_last_timestamp = None;
for current_timestamp in &variable_curve.keyframe_timestamps {
assert!(current_timestamp.is_finite());
if let Some(last_timestamp) = maybe_last_timestamp {
assert!(current_timestamp > last_timestamp);
}
maybe_last_timestamp = Some(current_timestamp);
}
(variable_curve, keyframe_count)
}
#[test]
fn find_current_keyframe_is_in_bounds() {
let curve = test_variable_curve().0;
let min_time = *curve.keyframe_timestamps.first().unwrap();
// We will always get none at times at or past the second last keyframe
let second_last_keyframe = curve.keyframe_timestamps.len() - 2;
let max_time = curve.keyframe_timestamps[second_last_keyframe];
let elapsed_time = max_time - min_time;
let n_keyframes = curve.keyframe_timestamps.len();
let n_test_points = 5;
for i in 0..=n_test_points {
// Get a value between 0 and 1
let normalized_time = i as f32 / n_test_points as f32;
let seek_time = min_time + normalized_time * elapsed_time;
assert!(seek_time >= min_time);
assert!(seek_time <= max_time);
let maybe_current_keyframe = curve.find_current_keyframe(seek_time);
assert!(
maybe_current_keyframe.is_some(),
"Seek time: {seek_time}, Min time: {min_time}, Max time: {max_time}"
);
// We cannot return the last keyframe,
// because we want to interpolate between the current and next keyframe
assert!(maybe_current_keyframe.unwrap() < n_keyframes);
}
}
#[test]
fn find_current_keyframe_returns_none_on_unstarted_animations() {
let curve = test_variable_curve().0;
let min_time = *curve.keyframe_timestamps.first().unwrap();
let seek_time = 0.0;
assert!(seek_time < min_time);
let maybe_keyframe = curve.find_current_keyframe(seek_time);
assert!(
maybe_keyframe.is_none(),
"Seek time: {seek_time}, Minimum time: {min_time}"
);
}
#[test]
fn find_current_keyframe_returns_none_on_finished_animation() {
let curve = test_variable_curve().0;
let max_time = *curve.keyframe_timestamps.last().unwrap();
assert!(max_time < f32::INFINITY);
let maybe_keyframe = curve.find_current_keyframe(f32::INFINITY);
assert!(maybe_keyframe.is_none());
let maybe_keyframe = curve.find_current_keyframe(max_time);
assert!(maybe_keyframe.is_none());
}
#[test]
fn second_last_keyframe_is_found_correctly() {
let curve = test_variable_curve().0;
// Exact time match
let second_last_keyframe = curve.keyframe_timestamps.len() - 2;
let second_last_time = curve.keyframe_timestamps[second_last_keyframe];
let maybe_keyframe = curve.find_current_keyframe(second_last_time);
assert!(maybe_keyframe.unwrap() == second_last_keyframe);
// Inexact match, between the last and second last frames
let seek_time = second_last_time + 0.001;
let last_time = curve.keyframe_timestamps[second_last_keyframe + 1];
assert!(seek_time < last_time);
let maybe_keyframe = curve.find_current_keyframe(seek_time);
assert!(maybe_keyframe.unwrap() == second_last_keyframe);
}
#[test]
fn exact_keyframe_matches_are_found_correctly() {
let (curve, keyframe_count) = test_variable_curve();
let second_last_keyframe = keyframe_count - 2;
for i in 0..=second_last_keyframe {
let seek_time = curve.keyframe_timestamps[i];
let keyframe = curve.find_current_keyframe(seek_time).unwrap();
assert!(keyframe == i);
}
}
#[test]
fn exact_and_inexact_keyframes_correspond() {
let (curve, keyframe_count) = test_variable_curve();
let second_last_keyframe = keyframe_count - 2;
for i in 0..=second_last_keyframe {
let seek_time = curve.keyframe_timestamps[i];
let exact_keyframe = curve.find_current_keyframe(seek_time).unwrap();
let inexact_seek_time = seek_time + 0.0001;
let final_time = *curve.keyframe_timestamps.last().unwrap();
assert!(inexact_seek_time < final_time);
let inexact_keyframe = curve.find_current_keyframe(inexact_seek_time).unwrap();
assert!(exact_keyframe == inexact_keyframe);
}
}
}