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7681 commits

Author SHA1 Message Date
Tim
3da0ef048e
Remove the Component trait implementation from Handle (#15796)
# Objective

- Closes #15716
- Closes #15718

## Solution

- Replace `Handle<MeshletMesh>` with a new `MeshletMesh3d` component
- As expected there were some random things that needed fixing:
- A couple tests were storing handles just to prevent them from being
dropped I believe, which seems to have been unnecessary in some.
- The `SpriteBundle` still had a `Handle<Image>` field. I've removed
this.
- Tests in `bevy_sprite` incorrectly added a `Handle<Image>` field
outside of the `Sprite` component.
- A few examples were still inserting `Handle`s, switched those to their
corresponding wrappers.
- 2 examples that were still querying for `Handle<Image>` were changed
to query `Sprite`

## Testing

- I've verified that the changed example work now

## Migration Guide

`Handle` can no longer be used as a `Component`. All existing Bevy types
using this pattern have been wrapped in their own semantically
meaningful type. You should do the same for any custom `Handle`
components your project needs.

The `Handle<MeshletMesh>` component is now `MeshletMesh3d`.

The `WithMeshletMesh` type alias has been removed. Use
`With<MeshletMesh3d>` instead.
2024-10-09 21:10:01 +00:00
UkoeHB
a6be9b4ccd
Rename TextBlock to TextLayout (#15797)
# Objective

- Improve clarity when spawning a text block. See [this
discussion](https://github.com/bevyengine/bevy/pull/15591/#discussion_r1787083571).

## Solution

- Rename `TextBlock` to `TextLayout`.
2024-10-09 20:58:27 +00:00
Christian Hughes
b4071ca370
Add World::get_resource_or_init as an alternative to World::get_resource_or_insert_with (#15758)
# Objective

If a `Resource` implements `FromWorld` or `Default`, it's nicer to be
able to write:

```rust
let foo = world.get_resource_or_init::<Foo>();
```

Rather than:

```rust
let foo = world.get_resource_or_insert_with(Foo::default);
```

The latter is also not possible if a type implements `FromWorld` only,
and not `Default`.

## Solution

Added:

```rust
impl World {
    pub fn get_resource_or_init<R: Resource + FromWorld>(&mut self) -> Mut<'_, R>;
}
```

Turns out all current in-engine uses of `get_resource_or_insert_with`
are exactly the above, so they've also been replaced.

## Testing

- Added a doc-test.
- Also added a doc-test for `World::get_resource_or_insert_with`.
2024-10-09 20:56:26 +00:00
Brandon Reinhart
88d9ead7f8
promote atlas sources texture_ids to pub visibility (#15795)
In order to create texture atlases from other systems (custom game
solutions) that are compatible with the ones generated by the bevy
builders, it would be nice to have the interface be fully public. This
field is pub(crate). Unless there's a good reason, can we promote this
to pub?

Alternatives:
- Don't do it.
2024-10-09 18:37:26 +00:00
UkoeHB
c2c19e5ae4
Text rework (#15591)
**Ready for review. Examples migration progress: 100%.**

# Objective

- Implement https://github.com/bevyengine/bevy/discussions/15014

## Solution

This implements [cart's
proposal](https://github.com/bevyengine/bevy/discussions/15014#discussioncomment-10574459)
faithfully except for one change. I separated `TextSpan` from
`TextSpan2d` because `TextSpan` needs to require the `GhostNode`
component, which is a `bevy_ui` component only usable by UI.

Extra changes:
- Added `EntityCommands::commands_mut` that returns a mutable reference.
This is a blocker for extension methods that return something other than
`self`. Note that `sickle_ui`'s `UiBuilder::commands` returns a mutable
reference for this reason.

## Testing

- [x] Text examples all work.

---

## Showcase

TODO: showcase-worthy

## Migration Guide

TODO: very breaking

### Accessing text spans by index

Text sections are now text sections on different entities in a
hierarchy, Use the new `TextReader` and `TextWriter` system parameters
to access spans by index.

Before:
```rust
fn refresh_text(mut query: Query<&mut Text, With<TimeText>>, time: Res<Time>) {
    let text = query.single_mut();
    text.sections[1].value = format_time(time.elapsed());
}
```

After:
```rust
fn refresh_text(
    query: Query<Entity, With<TimeText>>,
    mut writer: UiTextWriter,
    time: Res<Time>
) {
    let entity = query.single();
    *writer.text(entity, 1) = format_time(time.elapsed());
}
```

### Iterating text spans

Text spans are now entities in a hierarchy, so the new `UiTextReader`
and `UiTextWriter` system parameters provide ways to iterate that
hierarchy. The `UiTextReader::iter` method will give you a normal
iterator over spans, and `UiTextWriter::for_each` lets you visit each of
the spans.

---------

Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-10-09 18:35:36 +00:00
Nathan Lilienthal
0b2e0cfaca
bevy_reflect: Add crate level functions feature docs (#15086)
Adds the missing section for the `functions` cargo feature of the
`bevy_reflect` crate.
2024-10-09 18:06:56 +00:00
Tim
e19c53ebbd
Remove Handle<T> trait implementations that are dependent on Component (#15749)
# Objective

- Another step towards #15716
- Remove trait implementations that are dependent on `Handle<T>` being a
`Component`

## Solution

- Remove unused `ExtractComponent` trait implementation for `Handle<T>`
- Remove unused `ExtractInstance` trait implementation for `AssetId`
- Although the `ExtractInstance` trait wasn't used, the `AssetId`s were
being stored inside of `ExtractedInstances` which has an
`ExtractInstance` trait bound on its contents.
I've upgraded the `RenderMaterialInstances` type alias to be its own
resource, identical to `ExtractedInstances<AssetId<M>>` to get around
that with minimal breakage.
## Testing

Tested `many_cubes`, rendering did not explode
2024-10-09 17:12:27 +00:00
Matty
123a19afa9
Put curve-related stuff behind a feature (#15790)
# Objective

A bunch of code is used only if you care about the `Curve` trait. Put it
behind a feature so it can be ignored if wanted.

## Solution

Added a default feature `curve` to `bevy_math` which feature-gates the
`curve` module and internal integrations.

## Testing

Tested compiling with the feature enabled and disabled.
2024-10-09 16:38:23 +00:00
Emerson Coskey
7d40e3ec87
Migrate bevy_sprite to required components (#15489)
# Objective

Continue migration of bevy APIs to required components, following
guidance of https://hackmd.io/@bevy/required_components/

## Solution

- Make `Sprite` require `Transform` and `Visibility` and
`SyncToRenderWorld`
- move image and texture atlas handles into `Sprite`
- deprecate `SpriteBundle`
- remove engine uses of `SpriteBundle`

## Testing

ran cargo tests on bevy_sprite and tested several sprite examples.

---

## Migration Guide

Replace all uses of `SpriteBundle` with `Sprite`. There are several new
convenience constructors: `Sprite::from_image`,
`Sprite::from_atlas_image`, `Sprite::from_color`.

WARNING: use of `Handle<Image>` and `TextureAtlas` as components on
sprite entities will NO LONGER WORK. Use the fields on `Sprite` instead.
I would have removed the `Component` impls from `TextureAtlas` and
`Handle<Image>` except it is still used within ui. We should fix this
moving forward with the migration.
2024-10-09 16:17:26 +00:00
Christian Hughes
219b5930f1
Rename App/World::observe to add_observer, EntityWorldMut::observe_entity to observe. (#15754)
# Objective

- Closes #15752

Calling the functions `App::observe` and `World::observe` doesn't make
sense because you're not "observing" the `App` or `World`, you're adding
an observer that listens for an event that occurs *within* the `World`.
We should rename them to better fit this.

## Solution

Renames:
- `App::observe` -> `App::add_observer`
- `World::observe` -> `World::add_observer`
- `Commands::observe` -> `Commands::add_observer`
- `EntityWorldMut::observe_entity` -> `EntityWorldMut::observe`

(Note this isn't a breaking change as the original rename was introduced
earlier this cycle.)

## Testing

Reusing current tests.
2024-10-09 15:39:29 +00:00
Joona Aalto
a2b53d46e7
Fix meshlet materials (#15755)
# Objective

After #15524, there are these bunny-shaped holes in rendering in the
meshlet example!


![broken](https://github.com/user-attachments/assets/9e9f20ec-b820-44df-b961-68a1dee44002)

This is because (1) they're using a raw asset handle instead of
`MeshMaterial3d`, and (2) the system that extracts mesh materials into
the render world has an unnecessary `With<Mesh3d>` filter, which makes
it not account for meshlets.

## Solution

Remove the redundant filter and use `MeshMaterial3d`. The bunnies got
some paint!


![fixed](https://github.com/user-attachments/assets/adb42556-fd4b-4000-8ca8-1356250dd532)
2024-10-09 15:39:10 +00:00
Zachary Harrold
35edb256ab
Remove thiserror from bevy_asset (#15778)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_asset`
2024-10-09 14:30:46 +00:00
Zachary Harrold
ecd04c1b72
Remove thiserror from bevy_sprite (#15763)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_sprite`
2024-10-09 14:29:26 +00:00
Zachary Harrold
b50f2ec334
Remove thiserror from bevy_scene (#15764)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_scene`
2024-10-09 14:29:10 +00:00
Zachary Harrold
c9e41ef552
Remove thiserror from bevy_ui (#15760)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_ui`
2024-10-09 14:27:53 +00:00
Zachary Harrold
bdc649a2d1
Remove thiserror from bevy_transform (#15761)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_transform`
2024-10-09 14:27:30 +00:00
Zachary Harrold
8fd3d54e48
Remove thiserror from bevy_text (#15762)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_text`
2024-10-09 14:27:09 +00:00
Zachary Harrold
8718adc74f
Remove thiserror from bevy_render (#15765)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_render`
2024-10-09 14:26:28 +00:00
Zachary Harrold
3cc1527e9e
Remove thiserror from bevy_reflect (#15766)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_reflect`
2024-10-09 14:25:41 +00:00
Zachary Harrold
46ad0b7513
Remove thiserror from bevy_pbr (#15767)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_pbr`
2024-10-09 14:25:16 +00:00
Zachary Harrold
80fe269349
Remove thiserror from bevy_mesh (#15768)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_mesh`
2024-10-09 14:24:54 +00:00
Zachary Harrold
1f4adec7df
Remove thiserror from bevy_image (#15771)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_image`
2024-10-09 14:23:53 +00:00
Zachary Harrold
9366b95006
Remove thiserror from bevy_math (#15769)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_math`
2024-10-09 14:23:23 +00:00
Zachary Harrold
5e89acacb4
Remove thiserror from bevy_input (#15770)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_input`
2024-10-09 14:23:01 +00:00
Zachary Harrold
f88c6820f0
Remove thiserror from bevy_gltf (#15772)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_gltf`
2024-10-09 14:22:00 +00:00
Zachary Harrold
c6a2411e90
Remove thiserror from bevy_gilrs (#15773)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_gilrs`
2024-10-09 14:21:25 +00:00
Zachary Harrold
0a61f04d9b
Remove thiserror from bevy_ecs (#15774)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_ecs`
2024-10-09 14:20:58 +00:00
Zachary Harrold
4c76ea7a5a
Remove thiserror from bevy_core_pipeline (#15775)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_core_pipeline`
2024-10-09 14:20:16 +00:00
Zachary Harrold
284e36af5e
Remove thiserror from bevy_color (#15777)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_color`
2024-10-09 14:18:41 +00:00
Zachary Harrold
1be0ed33fc
Remove thiserror from bevy_app (#15779)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_app`
2024-10-09 14:17:52 +00:00
Zachary Harrold
814f8ec039
Remove thiserror from bevy_animation (#15780)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_animation`
2024-10-09 14:16:21 +00:00
Rob Parrett
6f8f70b56d
Remove eprintln from 2d_screen_shake example (#15786)
# Objective

Remove debug print

## Solution

Remove it

## Testing

`cargo run --example 2d_screen_shake`
2024-10-09 14:15:24 +00:00
Jiří Švejda
3f683c728a
Fix missing Msaa::Off in scrolling_fog example (#15787)
# Objective

- The `scrolling_fog` example has a camera with the
`TemporalAntiAliasing` component, but it's missing the `Msaa::Off`
component, which leads to this warning being printed on current `main`:

```
WARN bevy_core_pipeline::taa: Temporal anti-aliasing requires MSAA to be disabled
```

## Solution

- This PR adds the `Msaa::Off` component to the example to explicitly
disable MSAA in favor of TAA.
2024-10-09 14:15:24 +00:00
Zachary Harrold
6cc2322fa3
Remove thiserror from bevy_time (#15759)
# Objective

- Contributes to #15460

## Solution

- Removed `thiserror` from `bevy_time`

## Notes

`thiserror` actually wasn't even used in this crate.
2024-10-09 14:13:28 +00:00
ickshonpe
a7ed13ad17
Add register_type for UiAntiAlias (#15783)
# Objective

Add `register_type` for `UiAntiAlias`
2024-10-09 14:04:26 +00:00
Tim
57c297becc
Add register_type for UiMaterialHandle and AnimationGraphHandle (#15784) 2024-10-09 14:04:06 +00:00
Gino Valente
05b0f28ebf
bevy_scene: Use FromReflect on extracted resources (#15753)
# Objective

Fixes #15726

The extraction logic for components makes use of `FromReflect` to try
and ensure we have a concrete type for serialization. However, we did
not do the same for resources.

The reason we're seeing this for the glam types is that #15174 also made
a change to rely on the glam type's `Serialize` and `Deserialize` impls,
which I don't think should have been merged (I'll put up a PR addressing
this specifically soon).

## Solution

Use `FromReflect` on extracted resources.

## Testing

You can test locally by running:

```
cargo test --package bevy_scene
```
2024-10-09 02:56:35 +00:00
Joona Aalto
bc352561c9
Migrate reflection probes to required components (#15737)
# Objective

Getting closer to the end! Another part of the required components
migration: reflection probes.

## Solution

As per the [proposal added by
Cart](https://hackmd.io/@bevy/required_components/%2FNmpIh0tGSiayGlswbfcEzw)
(Proposal 2), make `LightProbe` require `Transform` and `Visibility`,
and deprecate `ReflectionProbeBundle`.

Note that this proposal wasn't officially blessed yet, but it is the
only existing one that really works, so I implemented it here for
consideration.

## Testing

I ran the reflection probe example, and it appears to work.

---

## Migration Guide

`ReflectionProbeBundle` has been deprecated in favor of inserting the
`LightProbe` and `EnvironmentMapLight` components directly. Inserting
them will now automatically insert `Transform` and `Visibility`
components.

---------

Co-authored-by: Tim Blackbird <justthecooldude@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-10-08 23:59:27 +00:00
Shoyu Vanilla (Flint)
a89ae8e9d9
fix: Skip some rendering logics when the viewport width or height is zero (#15654)
# Objective

- Fixes #15285

## Solution

`winit` sends resized to zero events when the window is minimized only
on Windows OS(rust-windowing/winit#2015).
This makes updating window viewport size to `(0, 0)` and panicking when
calculating aspect ratio.

~~So, just skip these kinds of events - resizing to (0, 0) when the
window is minimized - on Windows OS~~

Idially, the camera extraction excludes the cameras whose target size
width or height is zero here;


25bfa80e60/crates/bevy_render/src/camera/camera.rs (L1060-L1074)

but it seems that winit event loop sends resize events after extraction
and before post update schedule, so they might panics before the
extraction filters them out.

Alternatively, it might be possible to change event loop evaluating
order or defer them to the right schedule but I'm afraid that it might
cause some breaking changes, so just skip rendering logics for such
windows and they will be all filtered out by the extractions on the next
frame and thereafter.

## Testing

Running the example in the original issue and minimizing causes panic,
or just running `tests/window/minimising.rs` with `cargo run --example
minimising` panics without this PR and doesn't panics with this PR.

I think that we should run it in CI on Windows OS btw
2024-10-08 22:52:19 +00:00
Antony
0837ade0fc
Ensure Bevy's rendering byte usage is little-endian (#15750)
# Objective

- Fixes (partially) #15701.

## Solution

- Use little-endian bytes over native-endian bytes where applicable.

## Testing

- Ran CI.

## Open Questions

- Should we config-gate these for big-endian targets? It looks like
there are [very few
targets](https://doc.rust-lang.org/nightly/rustc/platform-support.html)
that use big-endian.
2024-10-08 22:43:35 +00:00
Tim
700123ec64
Replace Handle<AnimationGraph> component with a wrapper (#15742)
# Objective

- Closes #15717 

## Solution

- Wrap the handle in a new wrapper component: `AnimationGraphHandle`.

## Testing

Searched for all instances of `AnimationGraph` in the examples and
updated and tested those

## Migration Guide

`Handle<AnimationGraph>` is no longer a component. Instead, use the
`AnimationGraphHandle` component which contains a
`Handle<AnimationGraph>`.
2024-10-08 22:41:24 +00:00
papow65
01b37d67fc
Fix failing cargo check with only the bevy_dev_tools feature (#15743)
# Objective
Fixes #15741

## Solution

- Copied the feature gates of a type to where the type is used.

## Testing

- `cargo check` works now using only the bevy_dev_tools feature
2024-10-08 22:41:04 +00:00
François Mockers
26813d9732
easing_functions example: draw point closer to its curve (#15744)
# Objective

- After #15711 which added a column to the example, the point of a curve
was too close to the next curve

## Solution

- Make it closer to its own
2024-10-08 22:40:40 +00:00
IceSentry
dec52a0c8f
Use shader_def for oit resolve layer count (#15747)
# Objective

- Size is currently hardcoded in the shader which means it will break if
a user uses anything higher than that.

## Solution

- Use a shader_def to define the size

## Testing

Tested with the OIT example
2024-10-08 22:40:17 +00:00
ickshonpe
675f8ad403
Improved text batching (#14848)
# Objective

The UI text rendering is really slow because it extracts each glyph as a
separate ui node even though all the glyphs in a text section have the
same texture, color and clipping rects.

## Solution

Store the glyphs in a seperate contiguous array, queue one transparent
ui item per text section which has indices into the glyph array.

## Testing

```cargo run --example many_glyphs --release```

Runs at about 22fps on main and 95fps with this PR on my computer.

I'll do some proper comparisons once I work out why tracy 11 is refusing to run.

---------

Co-authored-by: Kristoffer Søholm <k.soeholm@gmail.com>
2024-10-08 22:24:27 +00:00
Kristoffer Søholm
2d1b4939d2
Synchronize removed components with the render world (#15582)
# Objective

Fixes #15560
Fixes (most of) #15570

Currently a lot of examples (and presumably some user code) depend on
toggling certain render features by adding/removing a single component
to an entity, e.g. `SpotLight` to toggle a light. Because of the
retained render world this no longer works: Extract will add any new
components, but when it is removed the entity persists unchanged in the
render world.

## Solution

Add `SyncComponentPlugin<C: Component>` that registers
`SyncToRenderWorld` as a required component for `C`, and adds a
component hook that will clear all components from the render world
entity when `C` is removed. We add this plugin to
`ExtractComponentPlugin` which fixes most instances of the problem. For
custom extraction logic we can manually add `SyncComponentPlugin` for
that component.

We also rename `WorldSyncPlugin` to `SyncWorldPlugin` so we start a
naming convention like all the `Extract` plugins.

In this PR I also fixed a bunch of breakage related to the retained
render world, stemming from old code that assumed that `Entity` would be
the same in both worlds.

I found that using the `RenderEntity` wrapper instead of `Entity` in
data structures when referring to render world entities makes intent
much clearer, so I propose we make this an official pattern.

## Testing

Run examples like

```
cargo run --features pbr_multi_layer_material_textures --example clearcoat
cargo run --example volumetric_fog
```

and see that they work, and that toggles work correctly. But really we
should test every single example, as we might not even have caught all
the breakage yet.

---

## Migration Guide

The retained render world notes should be updated to explain this edge
case and `SyncComponentPlugin`

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Trashtalk217 <trashtalk217@gmail.com>
2024-10-08 22:23:17 +00:00
François Mockers
45eff09213
remove the interpolation dependency from bevy_math (#15748)
# Objective

- `interpolation` crates provides all the curves functions, but some of
them were wrong
- We have a partial solution where some functions comes from the
external crate, some from bevy_math

## Solution

- Move them all to bevy_math
- Remove the dependency on `interpolation`

## Testing

Playing the `easing_functions` example

![easing-functions](https://github.com/user-attachments/assets/88832f34-4bb3-4dc2-85af-7b9e4fa23e52)
2024-10-08 22:18:25 +00:00
mrgzi
e995f71a9b
Improve fps_overlay example (#15739)
This PR improves the `fps_overlay` example by adding:

1. The ability to increase the overlay font size (previously, only
decreasing the size was supported).
2. A toggle for overlay color between red and green (previously, it only
changed from green to red without toggling back).
2024-10-08 22:17:55 +00:00
Alice Cecile
2f63ebc9c9
Remove warning for children in UI hierarchies without Style (#15736)
# Objective

As discussed in #15591, this warning prevents us from storing leaf nodes
without a `Style` component. Because text sections (as distinct
entities) should not be laid out using `taffy`, this warning is
incorrect.

Users may also have other uses for doing this, and this should generally
increase flexibility without posing particularly serious correctness
concerns.

## Solution

- removed warning about non-UI children with UI parents
- improved the warning about UI parents with non-UI parents
- this warning should stay, for now, as it results in a genuine failure
to perform `taffy` layout
- that said, we should be clearer about the cause and potentially
harmful results of this!
   
## Testing

I inserted an empty entity into the hierarchy in the `button` example as
a leaf node, and it ran with no warnings.
2024-10-08 19:51:47 +00:00
Matty
e563f86a1d
Simplified easing curves (#15711)
# Objective

Simplify the API surrounding easing curves. Broaden the base of types
that support easing.

## Solution

There is now a single library function, `easing_curve`, which constructs
a unit-parametrized easing curve between two values based on an
`EaseFunction`:
```rust
/// Given a `start` and `end` value, create a curve parametrized over [the unit interval]
/// that connects them, using the given [ease function] to determine the form of the
/// curve in between.
///
/// [the unit interval]: Interval::UNIT
/// [ease function]: EaseFunction
pub fn easing_curve<T: Ease>(start: T, end: T, ease_fn: EaseFunction) -> EasingCurve<T> { //... }
```

As this shows, the type of the output curve is generic only in `T`. In
particular, as long as `T` is `Reflect` (and `FromReflect` etc. — i.e.,
a standard "well-behaved" reflectable type), `EasingCurve<T>` is also
`Reflect`, and there is no special field handling nonsense. Therefore,
`EasingCurve` is the kind of thing that would be able to be easily
changed in an editor. This is made possible by storing the actual
`EaseFunction` on `EasingCurve<T>` instead of indirecting through some
kind of function type (which generally leads to issues with reflection).

The types that can be eased are those that implement a trait `Ease`:
```rust
/// A type whose values can be eased between.
///
/// This requires the construction of an interpolation curve that actually extends
/// beyond the curve segment that connects two values, because an easing curve may
/// extrapolate before the starting value and after the ending value. This is
/// especially common in easing functions that mimic elastic or springlike behavior.
pub trait Ease: Sized {
    /// Given `start` and `end` values, produce a curve with [unlimited domain]
    /// that:
    /// - takes a value equivalent to `start` at `t = 0`
    /// - takes a value equivalent to `end` at `t = 1`
    /// - has constant speed everywhere, including outside of `[0, 1]`
    ///
    /// [unlimited domain]: Interval::EVERYWHERE
    fn interpolating_curve_unbounded(start: &Self, end: &Self) -> impl Curve<Self>;
}
```

(I know, I know, yet *another* interpolation trait. See 'Future
direction'.)

The other existing easing functions from the previous version of this
module have also become new members of `EaseFunction`: `Linear`,
`Steps`, and `Elastic` (which maybe needs a different name). The latter
two are parametrized.

## Testing

Tested using the `easing_functions` example. I also axed the
`cubic_curve` example which was of questionable value and replaced it
with `eased_motion`, which uses this API in the context of animation:


https://github.com/user-attachments/assets/3c802992-6b9b-4b56-aeb1-a47501c29ce2


---

## Future direction

Morally speaking, `Ease` is incredibly similar to `StableInterpolate`.
Probably, we should just merge `StableInterpolate` into `Ease`, and then
make `SmoothNudge` an automatic extension trait of `Ease`. The reason I
didn't do that is that `StableInterpolate` is not implemented for
`VectorSpace` because of concerns about the `Color` types, and I wanted
to avoid controversy. I think that may be a good idea though.

As Alice mentioned before, we should also probably get rid of the
`interpolation` dependency.

The parametrized `Elastic` variant probably also needs some additional
work (e.g. renaming, in/out/in-out variants, etc.) if we want to keep
it.
2024-10-08 19:45:13 +00:00