0094bcbc07
6 Commits
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0094bcbc07
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Implement additive blending for animation graphs. (#15631)
*Additive blending* is an ubiquitous feature in game engines that allows animations to be concatenated instead of blended. The canonical use case is to allow a character to hold a weapon while performing arbitrary poses. For example, if you had a character that needed to be able to walk or run while attacking with a weapon, the typical workflow is to have an additive blend node that combines walking and running animation clips with an animation clip of one of the limbs performing a weapon attack animation. This commit adds support for additive blending to Bevy. It builds on top of the flexible infrastructure in #15589 and introduces a new type of node, the *add node*. Like blend nodes, add nodes combine the animations of their children according to their weights. Unlike blend nodes, however, add nodes don't normalize the weights to 1.0. The `animation_masks` example has been overhauled to demonstrate the use of additive blending in combination with masks. There are now controls to choose an animation clip for every limb of the fox individually. This patch also fixes a bug whereby masks were incorrectly accumulated with `insert()` during the graph threading phase, which could cause corruption of computed masks in some cases. Note that the `clip` field has been replaced with an `AnimationNodeType` enum, which breaks `animgraph.ron` files. The `Fox.animgraph.ron` asset has been updated to the new format. Closes #14395. ## Showcase https://github.com/user-attachments/assets/52dfe05f-fdb3-477a-9462-ec150f93df33 ## Migration Guide * The `animgraph.ron` format has changed to accommodate the new *additive blending* feature. You'll need to change `clip` fields to instances of the new `AnimationNodeType` enum. |
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2530f262f5
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Remove bevy_animation dependency on bevy_text (#15642)
# Objective - Fixes #15640 ## Solution - Do it ## Testing - ran many_foxes |
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528ca4f95e
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Eliminate redundant clamping from sample-interpolated curves (#15620)
# Objective Currently, sample-interpolated curves (such as those used by the glTF loader for animations) do unnecessary extra work when `sample_clamped` is called, since their implementations of `sample_unchecked` are already clamped. Eliminating this redundant sampling is a small, easy performance win which doesn't compromise on the animation system's internal usage of `sample_clamped`, which guarantees that it never samples curves out-of-bounds. ## Solution For sample-interpolated curves, define `sample_clamped` in the way `sample_unchecked` is currently defined, and then redirect `sample_unchecked` to `sample_clamped`. This is arguably a more idiomatic way of using the `cores` as well, which is nice. ## Testing Ran `many_foxes` to make sure I didn't break anything. |
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ca8dd06146
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Impose a more sensible ordering for animation graph evaluation. (#15589)
This is an updated version of #15530. Review comments were addressed. This commit changes the animation graph evaluation to be operate in a more sensible order and updates the semantics of blend nodes to conform to [the animation composition RFC]. Prior to this patch, a node graph like this: ``` ┌─────┐ │ │ │ 1 │ │ │ └──┬──┘ │ ┌───────┴───────┐ │ │ ▼ ▼ ┌─────┐ ┌─────┐ │ │ │ │ │ 2 │ │ 3 │ │ │ │ │ └──┬──┘ └──┬──┘ │ │ ┌───┴───┐ ┌───┴───┐ │ │ │ │ ▼ ▼ ▼ ▼ ┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐ │ │ │ │ │ │ │ │ │ 4 │ │ 6 │ │ 5 │ │ 7 │ │ │ │ │ │ │ │ │ └─────┘ └─────┘ └─────┘ └─────┘ ``` Would be evaluated as (((4 ⊕ 5) ⊕ 6) ⊕ 7), with the blend (lerp/slerp) operation notated as ⊕. As quaternion multiplication isn't commutative, this is very counterintuitive and will especially lead to trouble with the forthcoming additive blending feature (#15198). This patch fixes the issue by changing the evaluation order to postorder, with children of a node evaluated in ascending order by node index. To do so, this patch revamps `AnimationCurve` to be based on an *evaluation stack* and a *blend register*. During target evaluation, the graph evaluator traverses the graph in postorder. When encountering a clip node, the evaluator pushes the possibly-interpolated value onto the evaluation stack. When encountering a blend node, the evaluator pops values off the stack into the blend register, accumulating weights as appropriate. When the graph is completely evaluated, the top element on the stack is *committed* to the property of the component. A new system, the *graph threading* system, is added in order to cache the sorted postorder traversal to avoid the overhead of sorting children at animation evaluation time. Mask evaluation has been moved to this system so that the graph only has to be traversed at most once per frame. Unlike the `ActiveAnimation` list, the *threaded graph* is cached from frame to frame and only has to be regenerated when the animation graph asset changes. This patch currently regresses the `animate_target` performance in `many_foxes` by around 50%, resulting in an FPS loss of about 2-3 FPS. I'd argue that this is an acceptable price to pay for a much more intuitive system. In the future, we can mitigate the regression with a fast path that avoids consulting the graph if only one animation is playing. However, in the interest of keeping this patch simple, I didn't do so here. [the animation composition RFC]: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md # Objective - Describe the objective or issue this PR addresses. - If you're fixing a specific issue, say "Fixes #X". ## Solution - Describe the solution used to achieve the objective above. ## Testing - Did you test these changes? If so, how? - Are there any parts that need more testing? - How can other people (reviewers) test your changes? Is there anything specific they need to know? - If relevant, what platforms did you test these changes on, and are there any important ones you can't test? --- ## Showcase > This section is optional. If this PR does not include a visual change or does not add a new feature, you can delete this section. - Help others understand the result of this PR by showcasing your awesome work! - If this PR adds a new feature or public API, consider adding a brief pseudo-code snippet of it in action - If this PR includes a visual change, consider adding a screenshot, GIF, or video - If you want, you could even include a before/after comparison! - If the Migration Guide adequately covers the changes, you can delete this section While a showcase should aim to be brief and digestible, you can use a toggleable section to save space on longer showcases: <details> <summary>Click to view showcase</summary> ```rust println!("My super cool code."); ``` </details> ## Migration Guide > This section is optional. If there are no breaking changes, you can delete this section. - If this PR is a breaking change (relative to the last release of Bevy), describe how a user might need to migrate their code to support these changes - Simply adding new functionality is not a breaking change. - Fixing behavior that was definitely a bug, rather than a questionable design choice is not a breaking change. --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> |
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587a508ef9
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Remove TransformCurve (#15598)
# Objective It is somewhat unlikely we will actually be able to support `TransformCurve` (introduced in #15434) after the `AnimationGraph` evaluation order changes in the immediate future. This is because correctly blending overlapping animation properties is nontrivial, and `Transform` overlaps with all of its own fields. We could still potentially create something like this in the future, but it's likely to require significant design and implementation work. By way of contrast, the single-property wrappers `TranslationCurve`, `ScaleCurve`, and `RotationCurve` should work perfectly fine, since they are non-overlapping. In this version release, creating `TransformCurve` in userspace is also quite easy if desired (see the deletions from this PR). ## Solution Delete `TransformCurve`. ## Migration Guide There is no released version that contains this, but we should make sure that `TransformCurve` is excluded from the release notes for #15434 if we merge this pull request. |
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429987ebf8
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Curve-based animation (#15434)
# Objective This PR extends and reworks the material from #15282 by allowing arbitrary curves to be used by the animation system to animate arbitrary properties. The goals of this work are to: - Allow far greater flexibility in how animations are allowed to be defined in order to be used with `bevy_animation`. - Delegate responsibility over keyframe interpolation to `bevy_math` and the `Curve` libraries and reduce reliance on keyframes in animation definitions generally. - Move away from allowing the glTF spec to completely define animations on a mechanical level. ## Solution ### Overview At a high level, curves have been incorporated into the animation system using the `AnimationCurve` trait (closely related to what was `Keyframes`). From the top down: 1. In `animate_targets`, animations are driven by `VariableCurve`, which is now a thin wrapper around a `Box<dyn AnimationCurve>`. 2. `AnimationCurve` is something built out of a `Curve`, and it tells the animation system how to use the curve's output to actually mutate component properties. The trait looks like this: ```rust /// A low-level trait that provides control over how curves are actually applied to entities /// by the animation system. /// /// Typically, this will not need to be implemented manually, since it is automatically /// implemented by [`AnimatableCurve`] and other curves used by the animation system /// (e.g. those that animate parts of transforms or morph weights). However, this can be /// implemented manually when `AnimatableCurve` is not sufficiently expressive. /// /// In many respects, this behaves like a type-erased form of [`Curve`], where the output /// type of the curve is remembered only in the components that are mutated in the /// implementation of [`apply`]. /// /// [`apply`]: AnimationCurve::apply pub trait AnimationCurve: Reflect + Debug + Send + Sync { /// Returns a boxed clone of this value. fn clone_value(&self) -> Box<dyn AnimationCurve>; /// The range of times for which this animation is defined. fn domain(&self) -> Interval; /// Write the value of sampling this curve at time `t` into `transform` or `entity`, /// as appropriate, interpolating between the existing value and the sampled value /// using the given `weight`. fn apply<'a>( &self, t: f32, transform: Option<Mut<'a, Transform>>, entity: EntityMutExcept<'a, (Transform, AnimationPlayer, Handle<AnimationGraph>)>, weight: f32, ) -> Result<(), AnimationEvaluationError>; } ``` 3. The conversion process from a `Curve` to an `AnimationCurve` involves using wrappers which communicate the intent to animate a particular property. For example, here is `TranslationCurve`, which wraps a `Curve<Vec3>` and uses it to animate `Transform::translation`: ```rust /// This type allows a curve valued in `Vec3` to become an [`AnimationCurve`] that animates /// the translation component of a transform. pub struct TranslationCurve<C>(pub C); ``` ### Animatable Properties The `AnimatableProperty` trait survives in the transition, and it can be used to allow curves to animate arbitrary component properties. The updated documentation for `AnimatableProperty` explains this process: <details> <summary>Expand AnimatableProperty example</summary An `AnimatableProperty` is a value on a component that Bevy can animate. You can implement this trait on a unit struct in order to support animating custom components other than transforms and morph weights. Use that type in conjunction with `AnimatableCurve` (and perhaps `AnimatableKeyframeCurve` to define the animation itself). For example, in order to animate font size of a text section from 24 pt. to 80 pt., you might use: ```rust #[derive(Reflect)] struct FontSizeProperty; impl AnimatableProperty for FontSizeProperty { type Component = Text; type Property = f32; fn get_mut(component: &mut Self::Component) -> Option<&mut Self::Property> { Some(&mut component.sections.get_mut(0)?.style.font_size) } } ``` You can then create an `AnimationClip` to animate this property like so: ```rust let mut animation_clip = AnimationClip::default(); animation_clip.add_curve_to_target( animation_target_id, AnimatableKeyframeCurve::new( [ (0.0, 24.0), (1.0, 80.0), ] ) .map(AnimatableCurve::<FontSizeProperty, _>::from_curve) .expect("Failed to create font size curve") ); ``` Here, the use of `AnimatableKeyframeCurve` creates a curve out of the given keyframe time-value pairs, using the `Animatable` implementation of `f32` to interpolate between them. The invocation of `AnimatableCurve::from_curve` with `FontSizeProperty` indicates that the `f32` output from that curve is to be used to animate the font size of a `Text` component (as configured above). </details> ### glTF Loading glTF animations are now loaded into `Curve` types of various kinds, depending on what is being animated and what interpolation mode is being used. Those types get wrapped into and converted into `Box<dyn AnimationCurve>` and shoved inside of a `VariableCurve` just like everybody else. ### Morph Weights There is an `IterableCurve` abstraction which allows sampling these from a contiguous buffer without allocating. Its only reason for existing is that Rust disallows you from naming function types, otherwise we would just use `Curve` with an iterator output type. (The iterator involves `Map`, and the name of the function type would have to be able to be named, but it is not.) A `WeightsCurve` adaptor turns an `IterableCurve` into an `AnimationCurve`, so it behaves like everything else in that regard. ## Testing Tested by running existing animation examples. Interpolation logic has had additional tests added within the `Curve` API to replace the tests in `bevy_animation`. Some kinds of out-of-bounds errors have become impossible. Performance testing on `many_foxes` (`animate_targets`) suggests that performance is very similar to the existing implementation. Here are a couple trace histograms across different runs (yellow is this branch, red is main). <img width="669" alt="Screenshot 2024-09-27 at 9 41 50 AM" src="https://github.com/user-attachments/assets/5ba4e9ac-3aea-452e-aaf8-1492acc2d7fc"> <img width="673" alt="Screenshot 2024-09-27 at 9 45 18 AM" src="https://github.com/user-attachments/assets/8982538b-04cf-46b5-97b2-164c6bc8162e"> --- ## Migration Guide Most user code that does not directly deal with `AnimationClip` and `VariableCurve` will not need to be changed. On the other hand, `VariableCurve` has been completely overhauled. If you were previously defining animation curves in code using keyframes, you will need to migrate that code to use curve constructors instead. For example, a rotation animation defined using keyframes and added to an animation clip like this: ```rust animation_clip.add_curve_to_target( animation_target_id, VariableCurve { keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0], keyframes: Keyframes::Rotation(vec![ Quat::IDENTITY, Quat::from_axis_angle(Vec3::Y, PI / 2.), Quat::from_axis_angle(Vec3::Y, PI / 2. * 2.), Quat::from_axis_angle(Vec3::Y, PI / 2. * 3.), Quat::IDENTITY, ]), interpolation: Interpolation::Linear, }, ); ``` would now be added like this: ```rust animation_clip.add_curve_to_target( animation_target_id, AnimatableKeyframeCurve::new([0.0, 1.0, 2.0, 3.0, 4.0].into_iter().zip([ Quat::IDENTITY, Quat::from_axis_angle(Vec3::Y, PI / 2.), Quat::from_axis_angle(Vec3::Y, PI / 2. * 2.), Quat::from_axis_angle(Vec3::Y, PI / 2. * 3.), Quat::IDENTITY, ])) .map(RotationCurve) .expect("Failed to build rotation curve"), ); ``` Note that the interface of `AnimationClip::add_curve_to_target` has also changed (as this example shows, if subtly), and now takes its curve input as an `impl AnimationCurve`. If you need to add a `VariableCurve` directly, a new method `add_variable_curve_to_target` accommodates that (and serves as a one-to-one migration in this regard). ### For reviewers The diff is pretty big, and the structure of some of the changes might not be super-obvious: - `keyframes.rs` became `animation_curves.rs`, and `AnimationCurve` is based heavily on `Keyframes`, with the adaptors also largely following suite. - The Curve API adaptor structs were moved from `bevy_math::curve::mod` into their own module `adaptors`. There are no functional changes to how these adaptors work; this is just to make room for the specialized reflection implementations since `mod.rs` was getting kind of cramped. - The new module `gltf_curves` holds the additional curve constructions that are needed by the glTF loader. Note that the loader uses a mix of these and off-the-shelf `bevy_math` curve stuff. - `animatable.rs` no longer holds logic related to keyframe interpolation, which is now delegated to the existing abstractions in `bevy_math::curve::cores`. --------- Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com> Co-authored-by: aecsocket <43144841+aecsocket@users.noreply.github.com> |