Commit Graph

19 Commits

Author SHA1 Message Date
Greeble
9a3baa7dc0 Update AnimatableProperty documentation, reduce crate dependencies (#18543)
## Objective

- Remove the second to last `bevy_animation` dependency on
`bevy_render`.
- Update some older documentation to reflect later changes to the crate.

## Narrative

I'm trying to make `bevy_animation` independent of `bevy_render`. The
documentation for `bevy_animation::AnimatableProperty` is one of the
last few dependencies. It uses `bevy_render::Projection` to demonstrate
animating an arbitrary value, but I thought that could be easily swapped
for something else.

I then realised that the rest of the documentation was a bit out of
date. Originally `AnimatableProperty` was the only way to animate a
property and so the documentation was quite detailed. But over time the
crate has gained more documentation and other ways to hook up
properties, leaving parts of the docs stale or covered elsewhere. So
I've slimmed down the `AnimatableProperty` docs and added a link to the
main alternative (`animated_field`).

I've probably swung too far towards brevity, so I can build them back up
if preferred. Also the example is kinda contrived and doesn't show the
range of `AnimatableProperty`, like being able to choose different
components. And finally the memes might be a bit stale?

## Showcase


![image](https://github.com/user-attachments/assets/23f1c0bf-10ea-4602-a566-673abe5dace7)

## Testing

```
cargo doc -p bevy_animation --no-deps --all-features
cargo test -p bevy_animation --doc --all-features
```
2025-03-26 19:06:51 +01:00
Greeble
7e45e8635c Reduce dependencies on bevy_render by preferring bevy_mesh imports (#18437)
Reduce dependencies on `bevy_render` by preferring `bevy_mesh` imports
over `bevy_render` re-exports.

```diff
- use bevy_render::mesh::Mesh;
+ use bevy_mesh::Mesh;
```

This is intended to help with #18423 (render crate restructure). Affects
`bevy_gltf`, `bevy_animation` and `bevy_picking`.

As part of #18423, I'm assuming there'll be a push to make crates less
dependent on the big render crates. This PR seemed like a small and safe
step along that path - it only changes imports and makes the `bevy_mesh`
crate dependency explicit in `Cargo.toml`. Any remaining dependencies on
`bevy_render` are true dependencies.

```
cargo run --example testbed_3d
cargo run --example mesh_picking
```
2025-03-25 22:45:39 +01:00
Zachary Harrold
9bc0ae33c3
Move hashbrown and foldhash out of bevy_utils (#17460)
# Objective

- Contributes to #16877

## Solution

- Moved `hashbrown`, `foldhash`, and related types out of `bevy_utils`
and into `bevy_platform_support`
- Refactored the above to match the layout of these types in `std`.
- Updated crates as required.

## Testing

- CI

---

## Migration Guide

- The following items were moved out of `bevy_utils` and into
`bevy_platform_support::hash`:
  - `FixedState`
  - `DefaultHasher`
  - `RandomState`
  - `FixedHasher`
  - `Hashed`
  - `PassHash`
  - `PassHasher`
  - `NoOpHash`
- The following items were moved out of `bevy_utils` and into
`bevy_platform_support::collections`:
  - `HashMap`
  - `HashSet`
- `bevy_utils::hashbrown` has been removed. Instead, import from
`bevy_platform_support::collections` _or_ take a dependency on
`hashbrown` directly.
- `bevy_utils::Entry` has been removed. Instead, import from
`bevy_platform_support::collections::hash_map` or
`bevy_platform_support::collections::hash_set` as appropriate.
- All of the above equally apply to `bevy::utils` and
`bevy::platform_support`.

## Notes

- I left `PreHashMap`, `PreHashMapExt`, and `TypeIdMap` in `bevy_utils`
as they might be candidates for micro-crating. They can always be moved
into `bevy_platform_support` at a later date if desired.
2025-01-23 16:46:08 +00:00
Jakob Wolf
5f0674f6c3
Allow tuple structs in animated_field! macro (#17234)
# Objective

Allow tuple structs in the animated_field macro.
-  for example `animated_field!(MyTupleStruct::0)`.

Fixes #16736 
- This issue was partially fixed in #16747, where support for tuple
structs was added to `AnimatedField::new_unchecked`.

## Solution

Change the designator for `$field` in the macro from `ident` to `tt`.

## Testing

Expanded the doc test on `animated_field!` to include an example with a
tuple struct.
2025-01-08 19:04:32 +00:00
Aevyrie
bed9ddf3ce
Refactor and simplify custom projections (#17063)
# Objective

- Fixes https://github.com/bevyengine/bevy/issues/16556
- Closes https://github.com/bevyengine/bevy/issues/11807

## Solution

- Simplify custom projections by using a single source of truth -
`Projection`, removing all existing generic systems and types.
- Existing perspective and orthographic structs are no longer components
- I could dissolve these to simplify further, but keeping them around
was the fast way to implement this.
- Instead of generics, introduce a third variant, with a trait object.
- Do an object safety dance with an intermediate trait to allow cloning
boxed camera projections. This is a normal rust polymorphism papercut.
You can do this with a crate but a manual impl is short and sweet.

## Testing

- Added a custom projection example

---

## Showcase

- Custom projections and projection handling has been simplified.
- Projection systems are no longer generic, with the potential for many
different projection components on the same camera.
- Instead `Projection` is now the single source of truth for camera
projections, and is the only projection component.
- Custom projections are still supported, and can be constructed with
`Projection::custom()`.

## Migration Guide

- `PerspectiveProjection` and `OrthographicProjection` are no longer
components. Use `Projection` instead.
- Custom projections should no longer be inserted as a component.
Instead, simply set the custom projection as a value of `Projection`
with `Projection::custom()`.
2025-01-01 20:44:24 +00:00
Zachary Harrold
d4b07a5114
Move Name out of bevy_core (#16894)
# Objective

- Contributes to #16892

## Solution

- Moved `Name` and `NameOrEntity` into `bevy_ecs::name`, and added them
to the prelude.

## Testing

- CI

## Migration Guide

If you were importing `Name` or `NameOrEntity` from `bevy_core`, instead
import from `bevy_ecs::name`.

---------

Co-authored-by: Christian Hughes <9044780+ItsDoot@users.noreply.github.com>
2024-12-19 02:45:16 +00:00
yonzebu
2994e53d82
Support tuple structs in AnimatedField (#16747)
# Objective

Partially fixes #16736.

## Solution

`AnimatedField::new_unchecked` now supports tuple struct fields.
`animated_field!` is unchanged.

## Testing

Added a test to make sure common and simple uses of
`AnimatedField::new_unchecked` with tuple structs don't panic.

---------

Co-authored-by: yonzebu <yonzebu@gmail.com>
2024-12-11 17:06:08 +00:00
Zachary Harrold
a35811d088
Add Immutable Component Support (#16372)
# Objective

- Fixes #16208

## Solution

- Added an associated type to `Component`, `Mutability`, which flags
whether a component is mutable, or immutable. If `Mutability= Mutable`,
the component is mutable. If `Mutability= Immutable`, the component is
immutable.
- Updated `derive_component` to default to mutable unless an
`#[component(immutable)]` attribute is added.
- Updated `ReflectComponent` to check if a component is mutable and, if
not, panic when attempting to mutate.

## Testing

- CI
- `immutable_components` example.

---

## Showcase

Users can now mark a component as `#[component(immutable)]` to prevent
safe mutation of a component while it is attached to an entity:

```rust
#[derive(Component)]
#[component(immutable)]
struct Foo {
    // ...
}
```

This prevents creating an exclusive reference to the component while it
is attached to an entity. This is particularly powerful when combined
with component hooks, as you can now fully track a component's value,
ensuring whatever invariants you desire are upheld. Before this would be
done my making a component private, and manually creating a `QueryData`
implementation which only permitted read access.

<details>
  <summary>Using immutable components as an index</summary>
  
```rust
/// This is an example of a component like [`Name`](bevy::prelude::Name), but immutable.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Component)]
#[component(
    immutable,
    on_insert = on_insert_name,
    on_replace = on_replace_name,
)]
pub struct Name(pub &'static str);

/// This index allows for O(1) lookups of an [`Entity`] by its [`Name`].
#[derive(Resource, Default)]
struct NameIndex {
    name_to_entity: HashMap<Name, Entity>,
}

impl NameIndex {
    fn get_entity(&self, name: &'static str) -> Option<Entity> {
        self.name_to_entity.get(&Name(name)).copied()
    }
}

fn on_insert_name(mut world: DeferredWorld<'_>, entity: Entity, _component: ComponentId) {
    let Some(&name) = world.entity(entity).get::<Name>() else {
        unreachable!()
    };
    let Some(mut index) = world.get_resource_mut::<NameIndex>() else {
        return;
    };

    index.name_to_entity.insert(name, entity);
}

fn on_replace_name(mut world: DeferredWorld<'_>, entity: Entity, _component: ComponentId) {
    let Some(&name) = world.entity(entity).get::<Name>() else {
        unreachable!()
    };
    let Some(mut index) = world.get_resource_mut::<NameIndex>() else {
        return;
    };

    index.name_to_entity.remove(&name);
}

// Setup our name index
world.init_resource::<NameIndex>();

// Spawn some entities!
let alyssa = world.spawn(Name("Alyssa")).id();
let javier = world.spawn(Name("Javier")).id();

// Check our index
let index = world.resource::<NameIndex>();

assert_eq!(index.get_entity("Alyssa"), Some(alyssa));
assert_eq!(index.get_entity("Javier"), Some(javier));

// Changing the name of an entity is also fully capture by our index
world.entity_mut(javier).insert(Name("Steven"));

// Javier changed their name to Steven
let steven = javier;

// Check our index
let index = world.resource::<NameIndex>();

assert_eq!(index.get_entity("Javier"), None);
assert_eq!(index.get_entity("Steven"), Some(steven));
```
  
</details>

Additionally, users can use `Component<Mutability = ...>` in trait
bounds to enforce that a component _is_ mutable or _is_ immutable. When
using `Component` as a trait bound without specifying `Mutability`, any
component is applicable. However, methods which only work on mutable or
immutable components are unavailable, since the compiler must be
pessimistic about the type.

## Migration Guide

- When implementing `Component` manually, you must now provide a type
for `Mutability`. The type `Mutable` provides equivalent behaviour to
earlier versions of `Component`:
```rust
impl Component for Foo {
    type Mutability = Mutable;
    // ...
}
```
- When working with generic components, you may need to specify that
your generic parameter implements `Component<Mutability = Mutable>`
rather than `Component` if you require mutable access to said component.
- The entity entry API has had to have some changes made to minimise
friction when working with immutable components. Methods which
previously returned a `Mut<T>` will now typically return an
`OccupiedEntry<T>` instead, requiring you to add an `into_mut()` to get
the `Mut<T>` item again.

## Draft Release Notes

Components can now be made immutable while stored within the ECS.

Components are the fundamental unit of data within an ECS, and Bevy
provides a number of ways to work with them that align with Rust's rules
around ownership and borrowing. One part of this is hooks, which allow
for defining custom behavior at key points in a component's lifecycle,
such as addition and removal. However, there is currently no way to
respond to _mutation_ of a component using hooks. The reasons for this
are quite technical, but to summarize, their addition poses a
significant challenge to Bevy's core promises around performance.
Without mutation hooks, it's relatively trivial to modify a component in
such a way that breaks invariants it intends to uphold. For example, you
can use `core::mem::swap` to swap the components of two entities,
bypassing the insertion and removal hooks.

This means the only way to react to this modification is via change
detection in a system, which then begs the question of what happens
_between_ that alteration and the next run of that system?
Alternatively, you could make your component private to prevent
mutation, but now you need to provide commands and a custom `QueryData`
implementation to allow users to interact with your component at all.

Immutable components solve this problem by preventing the creation of an
exclusive reference to the component entirely. Without an exclusive
reference, the only way to modify an immutable component is via removal
or replacement, which is fully captured by component hooks. To make a
component immutable, simply add `#[component(immutable)]`:

```rust
#[derive(Component)]
#[component(immutable)]
struct Foo {
    // ...
}
```

When implementing `Component` manually, there is an associated type
`Mutability` which controls this behavior:

```rust
impl Component for Foo {
    type Mutability = Mutable;
    // ...
}
```

Note that this means when working with generic components, you may need
to specify that a component is mutable to gain access to certain
methods:

```rust
// Before
fn bar<C: Component>() {
    // ...
}

// After
fn bar<C: Component<Mutability = Mutable>>() {
    // ...
}
```

With this new tool, creating index components, or caching data on an
entity should be more user friendly, allowing libraries to provide APIs
relying on components and hooks to uphold their invariants.

## Notes

- ~~I've done my best to implement this feature, but I'm not happy with
how reflection has turned out. If any reflection SMEs know a way to
improve this situation I'd greatly appreciate it.~~ There is an
outstanding issue around the fallibility of mutable methods on
`ReflectComponent`, but the DX is largely unchanged from `main` now.
- I've attempted to prevent all safe mutable access to a component that
does not implement `Component<Mutability = Mutable>`, but there may
still be some methods I have missed. Please indicate so and I will
address them, as they are bugs.
- Unsafe is an escape hatch I am _not_ attempting to prevent. Whatever
you do with unsafe is between you and your compiler.
- I am marking this PR as ready, but I suspect it will undergo fairly
major revisions based on SME feedback.
- I've marked this PR as _Uncontroversial_ based on the feature, not the
implementation.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Benjamin Brienen <benjamin.brienen@outlook.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
Co-authored-by: Nuutti Kotivuori <naked@iki.fi>
2024-12-05 14:27:48 +00:00
Carter Anderson
af10aa38aa
AnimatedField and Rework Evaluators (#16484)
# Objective

Animating component fields requires too much boilerplate at the moment:

```rust
#[derive(Reflect)]
struct FontSizeProperty;

impl AnimatableProperty for FontSizeProperty {
    type Component = TextFont;

    type Property = f32;

    fn get_mut(component: &mut Self::Component) -> Option<&mut Self::Property> {
        Some(&mut component.font_size)
    }
}

animation_clip.add_curve_to_target(
    animation_target_id,
    AnimatableKeyframeCurve::new(
        [0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0]
            .into_iter()
            .zip([24.0, 80.0, 24.0, 80.0, 24.0, 80.0, 24.0]),
    )
    .map(AnimatableCurve::<FontSizeProperty, _>::from_curve)
    .expect("should be able to build translation curve because we pass in valid samples"),
);
```

## Solution

This adds `AnimatedField` and an `animated_field!` macro, enabling the
following:

```rust
animation_clip.add_curve_to_target(
    animation_target_id,
    AnimatableCurve::new(
        animated_field!(TextFont::font_size),
        AnimatableKeyframeCurve::new(
            [0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0]
                .into_iter()
                .zip([24.0, 80.0, 24.0, 80.0, 24.0, 80.0, 24.0]),
        )
        .expect(
            "should be able to build translation curve because we pass in valid samples",
        ),
    ),
);
```

This required reworking the internals a bit, namely stripping out a lot
of the `Reflect` usage, as that implementation was fundamentally
incompatible with the `AnimatedField` pattern. `Reflect` was being used
in this context just to downcast traits. But we can get downcasting
behavior without the `Reflect` requirement by implementing `Downcast`
for `AnimationCurveEvaluator`.

This also reworks "evaluator identity" to support either a (Component /
Field) pair, or a TypeId. This allows properties to reuse evaluators,
even if they have different accessor methods. The "contract" here is
that for a given (Component / Field) pair, the accessor will return the
same value. Fields are identified by their Reflect-ed field index. The
(TypeId, usize) is prehashed and cached to optimize for lookup speed.

This removes the built-in hard-coded TranslationCurve / RotationCurve /
ScaleCurve in favor of AnimatableField.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-11-27 22:19:55 +00:00
Carter Anderson
7477928f13
Use normal constructors for EasingCurve, FunctionCurve, ConstantCurve (#16367)
# Objective

We currently use special "floating" constructors for `EasingCurve`,
`FunctionCurve`, and `ConstantCurve` (ex: `easing_curve`). This erases
the type being created (and in general "what is happening"
structurally), for very minimal ergonomics improvements. With rare
exceptions, we prefer normal `X::new()` constructors over floating `x()`
constructors in Bevy. I don't think this use case merits special casing
here.

## Solution

Add `EasingCurve::new()`, use normal constructors everywhere, and remove
the floating constructors.

I think this should land in 0.15 in the interest of not breaking people
later.
2024-11-13 15:30:05 +00:00
Matty
9beb1d96e7
Incorporate all node weights in additive blending (#16279)
# Objective

In the existing implementation, additive blending effectively treats the
node with least index specially by basically forcing its weight to be
`1.0` regardless of what its computed weight would be (based on the
weights in the `AnimationGraph` and `AnimationPlayer`).

Arguably this makes some amount of sense, because the "base" animation
is often one which was not authored to be used additively, meaning that
its sampled values are interpreted absolutely rather than as deltas.
However, this also leads to strange behavior with respect to animation
masks: if the "base" animation is masked out on some target, then the
next node is treated as the "base" animation, despite the fact that it
would normally be interpreted additively, and the weight of that
animation is thrown away as a result.

This is all kind of weird and revolves around special treatment (if the
behavior is even really intentional in the first place). From a
mathematical standpoint, there is nothing special about how the "base"
animation must be treated other than having a weight of 1.0 under an
`Add` node, which is something that the user can do without relying on
some bizarre corner-case behavior of the animation system — this is the
only present situation under which weights are discarded.

This PR changes this behavior so that the weight of every node is
incorporated. In other words, for an animation graph that looks like
this:
```text
┌───────────────┐                                 
│Base clip      ┼──┐                              
│      0.5      │  │                              
└───────────────┘  │                              
┌───────────────┐  │  ┌───────────────┐     ┌────┐
│Additive clip 1┼──┼─►┤Additive blend ┼────►│Root│
│      0.1      │  │  │      1.0      │     └────┘
└───────────────┘  │  └───────────────┘           
┌───────────────┐  │                              
│Additive clip 2┼──┘                              
│      0.2      │                                 
└───────────────┘                                 
```

Previously, the result would have been
```text
base_clip + 0.1 * additive_clip_1 + 0.2 * additive_clip_2
```

whereas now it would be
```text
0.5 * base_clip + 0.1 * additive_clip_1 + 0.2 * additive_clip_2
```

and in the scenario where `base_clip` is masked out:
```text
additive_clip_1 + 0.2 * additive_clip_2
```
vs.
```text
0.1 * additive_clip_1 + 0.2 * additive_clip_2
```

## Solution

For background, the way that the additive blending procedure works is
something like this:
- During graph traversal, the node values and weights of the children
are pushed onto the evaluator `stack`. The traversal order guarantees
that the item with least node index will be on top.
- Once we reach the `Add` node itself, we start popping off the `stack`
and into the evaluator's `blend_register`, which is an accumulator
holding up to one weight-value pair:
- If the `blend_register` is empty, it is filled using data from the top
of the `stack`.
- Otherwise, the `blend_register` is combined with data popped from the
`stack` and updated.

In the example above, the additive blending steps would look like this
(with the pre-existing implementation):
1. The `blend_register` is empty, so we pop `(base_clip, 0.5)` from the
top of the `stack` and put it in. Now the value of the `blend_register`
is `(base_clip, 0.5)`.
2. The `blend_register` is non-empty: we pop `(additive_clip_1, 0.1)`
from the top of the `stack` and combine it additively with the value in
the `blend_register`, forming `(base_clip + 0.1 * additive_clip_1, 0.6)`
in the `blend_register` (the carried weight value goes unused).
3. The `blend_register` is non-empty: we pop `(additive_clip_2, 0.2)`
from the top of the `stack` and combine it additively with the value in
the `blend_register`, forming `(base_clip + 0.1 * additive_clip_1 + 0.2
* additive_clip_2, 0.8)` in the `blend_register`.

The solution in this PR changes step 1: the `base_clip` is multiplied by
its weight as it is added to the `blend_register` in the first place,
yielding `0.5 * base_clip + 0.1 * additive_clip_1 + 0.2 *
additive_clip_2` as the final result.

### Note for reviewers

It might be tempting to look at the code, which contains a segment that
looks like this:
```rust
if additive {
    current_value = A::blend(
        [
            BlendInput {
                weight: 1.0, // <--
                value: current_value,
                additive: true,
            },
            BlendInput {
                weight: weight_to_blend,
                value: value_to_blend,
                additive: true,
            },
        ]
        .into_iter(),
    );
} 
```
and conclude that the explicit value of `1.0` is responsible for
overwriting the weight of the base animation. This is incorrect.

Rather, this additive blend has to be written this way because it is
multiplying the *existing value in the blend register* by 1 (i.e. not
doing anything) before adding the next value to it. Changing this to
another quantity (e.g. the existing weight) would cause the value in the
blend register to be spuriously multiplied down.

## Testing

Tested on `animation_masks` example. Checked `morph_weights` example as
well.

## Migration Guide

I will write a migration guide later if this change is not included in
0.15.
2024-11-07 19:12:08 +00:00
Matty
a06802a66e
Make AnimatableCurve::curve public (#15831)
# Objective

The other `Curve -> AnimationCurve` wrappers allow public access to the
inner curve, so this one should as well.

## Solution

Made the field public. Instances will still need to be constructed using
the (more ergonomic) `from_curve` method, which infers the phantom type
for the user.
2024-10-10 18:51:17 +00:00
Matty
42e0771633
Fix additive blending of quaternions (#15662)
# Objective

Fixes #13832

## Solution

Additively blend quaternions like this:
```rust
rotation = Quat::slerp(Quat::IDENTITY, incoming_rotation, weight) * rotation;
```

## Testing

Ran `animation_masks`, which behaves the same as before. (In the context
of an animation being blended only onto the base pose, there is no
difference.)

We should create some examples that actually exercise more of the
capabilities of the `AnimationGraph` so that issues like this can become
more visible in general. (On the other hand, I'm quite certain this was
wrong before.)

## Migration Guide

This PR changes the implementation of `Quat: Animatable`, which was not
used internally by Bevy prior to this release version. If you relied on
the old behavior of additive quaternion blending in manual applications,
that code will have to be updated, as the old behavior was incorrect.
2024-10-05 20:03:10 +00:00
Patrick Walton
0094bcbc07
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.
2024-10-04 22:13:22 +00:00
vero
2530f262f5
Remove bevy_animation dependency on bevy_text (#15642)
# Objective

- Fixes #15640

## Solution

- Do it

## Testing

- ran many_foxes
2024-10-04 12:22:15 +00:00
Matty
528ca4f95e
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.
2024-10-03 18:26:41 +00:00
Patrick Walton
ca8dd06146
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>
2024-10-03 00:36:42 +00:00
Matty
587a508ef9
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.
2024-10-02 19:46:38 +00:00
Matty
429987ebf8
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>
2024-09-30 19:56:55 +00:00