_copy-pasted from my doc comment in the code_
# Objective
This example shows how to properly handle player input, advance a
physics simulation in a fixed timestep, and display the results.
The classic source for how and why this is done is Glenn Fiedler's
article [Fix Your
Timestep!](https://gafferongames.com/post/fix_your_timestep/).
## Motivation
The naive way of moving a player is to just update their position like
so:
```rust
transform.translation += velocity;
```
The issue here is that the player's movement speed will be tied to the
frame rate.
Faster machines will move the player faster, and slower machines will
move the player slower.
In fact, you can observe this today when running some old games that did
it this way on modern hardware!
The player will move at a breakneck pace.
The more sophisticated way is to update the player's position based on
the time that has passed:
```rust
transform.translation += velocity * time.delta_seconds();
```
This way, velocity represents a speed in units per second, and the
player will move at the same speed regardless of the frame rate.
However, this can still be problematic if the frame rate is very low or
very high. If the frame rate is very low, the player will move in large
jumps. This may lead to a player moving in such large jumps that they
pass through walls or other obstacles. In general, you cannot expect a
physics simulation to behave nicely with *any* delta time. Ideally, we
want to have some stability in what kinds of delta times we feed into
our physics simulation.
The solution is using a fixed timestep. This means that we advance the
physics simulation by a fixed amount at a time. If the real time that
passed between two frames is less than the fixed timestep, we simply
don't advance the physics simulation at all.
If it is more, we advance the physics simulation multiple times until we
catch up. You can read more about how Bevy implements this in the
documentation for
[`bevy::time::Fixed`](https://docs.rs/bevy/latest/bevy/time/struct.Fixed.html).
This leaves us with a last problem, however. If our physics simulation
may advance zero or multiple times per frame, there may be frames in
which the player's position did not need to be updated at all, and some
where it is updated by a large amount that resulted from running the
physics simulation multiple times. This is physically correct, but
visually jarring. Imagine a player moving in a straight line, but
depending on the frame rate, they may sometimes advance by a large
amount and sometimes not at all. Visually, we want the player to move
smoothly. This is why we need to separate the player's position in the
physics simulation from the player's position in the visual
representation. The visual representation can then be interpolated
smoothly based on the last and current actual player position in the
physics simulation.
This is a tradeoff: every visual frame is now slightly lagging behind
the actual physical frame, but in return, the player's movement will
appear smooth. There are other ways to compute the visual representation
of the player, such as extrapolation. See the [documentation of the
lightyear
crate](https://cbournhonesque.github.io/lightyear/book/concepts/advanced_replication/visual_interpolation.html)
for a nice overview of the different methods and their tradeoffs.
## Implementation
- The player's velocity is stored in a `Velocity` component. This is the
speed in units per second.
- The player's current position in the physics simulation is stored in a
`PhysicalTranslation` component.
- The player's previous position in the physics simulation is stored in
a `PreviousPhysicalTranslation` component.
- The player's visual representation is stored in Bevy's regular
`Transform` component.
- Every frame, we go through the following steps:
- Advance the physics simulation by one fixed timestep in the
`advance_physics` system.
This is run in the `FixedUpdate` schedule, which runs before the
`Update` schedule.
- Update the player's visual representation in the
`update_displayed_transform` system.
This interpolates between the player's previous and current position in
the physics simulation.
- Update the player's velocity based on the player's input in the
`handle_input` system.
## Relevant Issues
Related to #1259.
I'm also fairly sure I've seen an issue somewhere made by
@alice-i-cecile about showing how to move a character correctly in a
fixed timestep, but I cannot find it.
# Objective
Fixes#14221
## Solution
Add indentation as suggested.
## Testing
Confirmed that
- This makes Clippy happy with rust beta
- Built docs visually look the same before/after
# Objective
- Often in games you will want to create chains of systems that modify
some event. For example, a chain of damage systems that handle a
DamageEvent and modify the underlying value before the health system
finally consumes the event. Right now this requires either:
* Using a component added to the entity
* Consuming and refiring events
Neither is ideal when really all we want to do is read the events value,
modify it, and write it back.
## Solution
- Create an EventMutator class similar to EventReader but with ResMut<T>
and iterators that return &mut so that events can be mutated.
## Testing
- I replicated all the existing tests for EventReader to make sure
behavior was the same (I believe) and added a number of tests specific
to testing that 1) events can actually be mutated, and that 2)
EventReader sees changes from EventMutator for events it hasn't already
seen.
## Migration Guide
Users currently using `ManualEventReader` should use `EventCursor`
instead. `ManualEventReader` will be removed in Bevy 0.16. Additionally,
`Events::get_reader` has been replaced by `Events::get_cursor`.
Users currently directly accessing the `Events` resource for mutation
should move to `EventMutator` if possible.
---------
Co-authored-by: poopy <gonesbird@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Bump version after release
This PR has been auto-generated
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François Mockers <mockersf@gmail.com>
Bumps [crate-ci/typos](https://github.com/crate-ci/typos) from 1.22.9 to
1.23.1.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/crate-ci/typos/releases">crate-ci/typos's
releases</a>.</em></p>
<blockquote>
<h2>v1.23.1</h2>
<h2>[1.23.1] - 2024-07-05</h2>
<h3>Fixes</h3>
<ul>
<li>Add missing <a
href="https://redirect.github.com/crate-ci/typos/issues/1024">June
2024</a> changes</li>
</ul>
<h2>v1.23.0</h2>
<h2>[1.23.0] - 2024-07-05</h2>
<h3>Fixes</h3>
<ul>
<li>Updated the dictionary with the <a
href="https://redirect.github.com/crate-ci/typos/issues/1024">June
2024</a> changes</li>
</ul>
</blockquote>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/crate-ci/typos/blob/master/CHANGELOG.md">crate-ci/typos's
changelog</a>.</em></p>
<blockquote>
<h2>[1.23.1] - 2024-07-05</h2>
<h3>Fixes</h3>
<ul>
<li>Add missing <a
href="https://redirect.github.com/crate-ci/typos/issues/1024">June
2024</a> changes</li>
</ul>
<h2>[1.23.0] - 2024-07-05</h2>
<h3>Fixes</h3>
<ul>
<li>Updated the dictionary with the <a
href="https://redirect.github.com/crate-ci/typos/issues/1024">June
2024</a> changes</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="81a34f1ca2"><code>81a34f1</code></a>
chore: Release</li>
<li><a
href="1aa7c985e4"><code>1aa7c98</code></a>
docs: Update changelog</li>
<li><a
href="4d4121ea86"><code>4d4121e</code></a>
chore: Release</li>
<li><a
href="4edcc6aa95"><code>4edcc6a</code></a>
Merge pull request <a
href="https://redirect.github.com/crate-ci/typos/issues/1053">#1053</a>
from epage/june</li>
<li><a
href="fa7786ec69"><code>fa7786e</code></a>
fix(dict): Add more june typos</li>
<li><a
href="04eea79695"><code>04eea79</code></a>
chore: Release</li>
<li><a
href="d3b2a6eb90"><code>d3b2a6e</code></a>
docs: Update changelog</li>
<li><a
href="494a98f93e"><code>494a98f</code></a>
chore: Release</li>
<li><a
href="bdc571d921"><code>bdc571d</code></a>
Merge pull request <a
href="https://redirect.github.com/crate-ci/typos/issues/1052">#1052</a>
from epage/june</li>
<li><a
href="eac884cf3b"><code>eac884c</code></a>
fix(dict): June updates</li>
<li>Additional commits viewable in <a
href="https://github.com/crate-ci/typos/compare/v1.22.9...v1.23.1">compare
view</a></li>
</ul>
</details>
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Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
- The post release version bump job failed:
https://github.com/bevyengine/bevy/actions/runs/9799332118
- This is because main didn't update to 0.14 as that happened in a
branch
## Solution
- Update the regexes to work with the -dev suffix
---------
Co-authored-by: Jan Hohenheim <jan@hohenheim.ch>
# Objective
Oftentimes I find myself reading through a PR and not quite
understanding what's going on. Even if it's super detailed, it can
sometimes be difficult to imagine what the end result of the PR might
look like.
For example, #10756 clearly communicates its goals and contains a
descriptive Changelog. However, I was still a bit lost as to what a user
might see from the change until I saw the dedicated example in the diff.
## Solution
At the risk of giving contributors more work, I think a dedicated
`Showcase` section could be really nice.
Along with providing reviewers stumbling on the PR with a "tangible
summary" of the change, it should also help out when working on the
release post. Sometimes someone other than the PR's author has to write
up a blog section on the PR. This can be somewhat daunting to people
wanting to contribute in that effort as they have to rely on the
Migration Guide giving a decent example (assuming it's a breaking
change), piecing together the other sections into a sensible example
themselves, or manually reading through the diff.
Theoretically, this new `Showcase` section would be more of an
encouragement than a strict requirement. And it's probably only going to
be useful where there is something to showcase (e.g. visual changes, API
changes, new features, etc.).
### Bikeshedding
- **Naming.** I also considered `Demo` and `Example`, but there may be
others we prefer. I chose `Showcase` to communicate the feeling of fun
and appreciation for the work contributors put in.
- **Position.** I placed the section right above the `Changelog` section
since I felt it made sense to move from the details in `Solution` to a
brief example in `Showcase` to a tl;dr of the changes in `Changelog`
- **Phrasing.** We can also bikeshed the bullet points and phrasing of
each as well.
## Explanation
I got kind of lost on this earlier (the Tracy docs are not very helpful)
and required some assistance, so I thought it might be helpful to add
this somewhere in the profiling docs. The way it's presently inserted is
kind of awkward, but I don't know enough about the other operating
systems to make similar sections for them, which I think would be
helpful, since it's going to be different on each one.
---------
Co-authored-by: Jerome Humbert <djeedai@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Jan Hohenheim <jan@hohenheim.ch>
# Objective
Allow use of `bevy_input` types without needing `bevy_reflect`.
## Solution
Make `bevy_reflect` within `bevy_input` optional. It's compiled in by
default.
Turn on reflect in dependencies as well when this feature is on.
## Testing
- Did you test these changes? If so, how?
I did a `cargo hack -p bevy_input --each-feature build`.
Signed-off-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
Co-authored-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
# Objective
Allow use of `bevy_core` types without needing `bevy_reflect`.
## Solution
Make `bevy_reflect` within `bevy_core` optional. It's compiled in by
default.
Turn on reflect in dependencies as well when this feature is on.
## Testing
- Did you test these changes? If so, how?
I did a `cargo hack -p bevy_core--each-feature build`.
Similar PR: https://github.com/bevyengine/bevy/pull/14167
Discord context starts here:
https://discord.com/channels/691052431525675048/768253008416342076/1258814534651482163
Signed-off-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
Co-authored-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
# Objective
Fix#14146
## Solution
Expansion of #13323 , excluded Adreno 730 and earlier.
## Testing
Tested on android device(Adreno 730) that used to crash
# Objective
- There was a new warning added about having an unstyled child in the ui
hierarchy. Debugging the new error is pretty hard without any info about
which entity is.
## Solution
- Add the entity id to the warning.
```text
// Before
2024-07-05T19:40:59.904014Z WARN bevy_ui::layout::ui_surface: Unstyled child in a UI entity hierarchy. You are using an entity without UI components as a child of an entity with UI components, results may be unexpected.
//After
2024-07-05T19:40:59.904014Z WARN bevy_ui::layout::ui_surface: Unstyled child `3v1` in a UI entity hierarchy. You are using an entity without UI components as a child of an entity with UI components, results may be unexpected.
```
## Changelog
- add entity id to ui surface warning
# Objective
- Expand the flexibilty of StateScoped by adding Reflect and Clone
- This lets StateScoped be used in Clone Bundles, for example
```rust
#[derive(Component, Reflect, Clone)]
pub struct StateScoped<S: States>(pub S);
```
Notes:
- States are already Clone.
- Type registration is up to the user, but this is commonly the case
with reflected generic types.
## Testing
- Ran the examples.
# Objective
This PR fixes a crash that happens when an asset failure event is
processed after the asset has already been dropped.
```
2024-07-03T17:12:16.847178Z ERROR bevy_asset::server: Encountered HTTP status 404 when loading asset
thread 'main' panicked at bevy/crates/bevy_asset/src/server/info.rs:593:18:
```
## Solution
- Update `process_asset_fail` to match the graceful behavior in
`process_asset_load` (it does not assume the state still exists).
---
## Changelog
- Fixed a rare crash that happens when an asset failed event is
processed after the asset has been dropped.
# Objective
Allow random sampling from the surfaces of triangle meshes.
## Solution
This has two parts.
Firstly, rendering meshes can now yield their collections of triangles
through a method `Mesh::triangles`. This has signature
```rust
pub fn triangles(&self) -> Result<Vec<Triangle3d>, MeshTrianglesError> { //... }
```
and fails in a variety of cases — the most obvious of these is that the
mesh must have either the `TriangleList` or `TriangleStrip` topology,
and the others correspond to malformed vertex or triangle-index data.
With that in hand, we have the second piece, which is
`UniformMeshSampler`, which is a `Vec3`-valued
[distribution](https://docs.rs/rand/latest/rand/distributions/trait.Distribution.html)
that samples uniformly from collections of triangles. It caches the
triangles' distribution of areas so that after its initial setup,
sampling is allocation-free. It is constructed via
`UniformMeshSampler::try_new`, which looks like this:
```rust
pub fn try_new<T: Into<Vec<Triangle3d>>>(triangles: T) -> Result<Self, ZeroAreaMeshError> { //... }
```
It fails if the collection of triangles has zero area.
The sum of these parts means that you can sample random points from a
mesh as follows:
```rust
let triangles = my_mesh.triangles().unwrap();
let mut rng = StdRng::seed_from_u64(8765309);
let distribution = UniformMeshSampler::try_new(triangles).unwrap();
// 10000 random points from the surface of my_mesh:
let sample_points: Vec<Vec3> = distribution.sample_iter(&mut rng).take(10000).collect();
```
## Testing
Tested by instantiating meshes and sampling as demonstrated above.
---
## Changelog
- Added `Mesh::triangles` method to get a collection of triangles from a
mesh.
- Added `UniformMeshSampler` to `bevy_math::sampling`. This is a
distribution which allows random sampling over collections of triangles
(such as those provided through meshes).
---
## Discussion
### Design decisions
The main thing here was making sure to have a good separation between
the parts of this in `bevy_render` and in `bevy_math`. Getting the
triangles from a mesh seems like a reasonable step after adding
`Triangle3d` to `bevy_math`, so I decided to make all of the random
sampling operate at that level, with the fallible conversion to
triangles doing most of the work.
Notably, the sampler could be called something else that reflects that
its input is a collection of triangles, but if/when we add other kinds
of meshes to `bevy_math` (e.g. half-edge meshes), the fact that
`try_new` takes an `impl Into<Vec<Triangle3d>>` means that those meshes
just need to satisfy that trait bound in order to work immediately with
this sampling functionality. In that case, the result would just be
something like this:
```rust
let dist = UniformMeshSampler::try_new(mesh).unwrap();
```
I think this highlights that most of the friction is really just from
extracting data from `Mesh`.
It's maybe worth mentioning also that "collection of triangles"
(`Vec<Triangle3d>`) sits downstream of any other kind of triangle mesh,
since the topology connecting the triangles has been effectively erased,
which makes an `Into<Vec<Triangle3d>>` trait bound seem all the more
natural to me.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes https://github.com/bevyengine/bevy/issues/13972
## Solution
Added 3 new attributes to the `Component` macro.
## Testing
Added `component_hook_order_spawn_despawn_with_macro_hooks`, that makes
the same as `component_hook_order_spawn_despawn` but uses a struct, that
defines it's hooks with the `Component` macro.
---
---------
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
# Objective
- Rustdoc doesn't seem to follow cargo's `linker` setting
- Improves the situation in #12207
## Solution
- Explicitly set the linker in rustdoc flags
## Testing
- I tested this change on Windows and it significantly improves testing
performances (can't give an exact estimate since they got stuck before
this change)
---
Note: I avoided changing the settings on Linux and MacOS because I can't
test on those platforms. It would be nice if someone could test similar
changes there and report so they can be done on all major platforms.
# Objective
- `EmptyPathStream` is only used in android and wasm32
- This now makes rust nightly warn
## Solution
- flag the struct to only be present when needed
- also change how `MorphTargetNames` is used because that makes rust
happier?
# Objective
- Emit an event regardless of scene type (`Scene` and `DynamicScene`).
- Also send the `InstanceId` along.
Follow-up to #11002.
Fixes#2218.
## Solution
- Send `SceneInstanceReady` regardless of scene type.
- Make `SceneInstanceReady::parent` `Option`al.
- Add `SceneInstanceReady::id`.
---
## Changelog
### Changed
- `SceneInstanceReady` is now sent for `Scene` as well.
`SceneInstanceReady::parent` is an `Option` and
`SceneInstanceReady::id`, an `InstanceId`, is added to identify the
corresponding `Scene`.
## Migration Guide
- `SceneInstanceReady { parent: Entity }` is now `SceneInstanceReady {
id: InstanceId, parent: Option<Entity> }`.
# Objective
- `Parallel::drain()` has an unused type parameter `B` than can be
removed.
- Caught [on
Discord](https://discord.com/channels/691052431525675048/692572690833473578/1259004180560085003)
by Andrew, thanks!
## Solution
- Remove it! :)
## Testing
- `Parallel::drain()` should still function exactly the same.
---
## Changelog
- Removed unused type parameter in `Parallel::drain()`.
## Migration Guide
The type parameter of `Parallel::drain()` was unused, so it is now
removed. If you were manually specifying it, you can remove the bounds.
```rust
// 0.14
// Create a `Parallel` and give it a value.
let mut parallel: Parallel<Vec<u8>> = Parallel::default();
*parallel.borrow_local_mut() = vec![1, 2, 3];
for v in parallel.drain::<u8>() {
// ...
}
// 0.15
let mut parallel: Parallel<Vec<u8>> = Parallel::default();
*parallel.borrow_local_mut() = vec![1, 2, 3];
// Remove the type parameter.
for v in parallel.drain() {
// ...
}
```
# Objective
Looks like I accidentally disabled the reflection compile fail tests in
#13152. These should be re-enabled.
## Solution
Re-enable reflection compile fail tests.
## Testing
CI should pass. You can also test locally by navigating to
`crates/bevy_reflect/compile_fail/` and running:
```
cargo test --target-dir ../../../target
```
# Objective
Both `Material` and `MaterialExtension` (base and extension) can derive
Debug, so there's no reason to not allow `ExtendedMaterial` to derive it
## Solution
- Describe the solution used to achieve the objective above.
Add `Debug` to the list of derived traits
## Testing
- Did you test these changes? If so, how?
I compiled my test project on latest commit, making sure it actually
compiles
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
Create an ExtendedMaterial instance, try to `println!("{:?}",
material);`
Co-authored-by: NWPlayer123 <NWPlayer123@users.noreply.github.com>
# Replace ab_glyph with the more capable cosmic-text
Fixes#7616.
Cosmic-text is a more mature text-rendering library that handles scripts
and ligatures better than ab_glyph, it can also handle system fonts
which can be implemented in bevy in the future
Rebase of https://github.com/bevyengine/bevy/pull/8808
## Changelog
Replaces text renderer ab_glyph with cosmic-text
The definition of the font size has changed with the migration to cosmic
text. The behavior is now consistent with other platforms (e.g. the
web), where the font size in pixels measures the height of the font (the
distance between the top of the highest ascender and the bottom of the
lowest descender). Font sizes in your app need to be rescaled to
approximately 1.2x smaller; for example, if you were using a font size
of 60.0, you should now use a font size of 50.0.
## Migration guide
- `Text2dBounds` has been replaced with `TextBounds`, and it now accepts
`Option`s to the bounds, instead of using `f32::INFINITY` to inidicate
lack of bounds
- Textsizes should be changed, dividing the current size with 1.2 will
result in the same size as before.
- `TextSettings` struct is removed
- Feature `subpixel_alignment` has been removed since cosmic-text
already does this automatically
- TextBundles and things rendering texts requires the `CosmicBuffer`
Component on them as well
## Suggested followups:
- TextPipeline: reconstruct byte indices for keeping track of eventual
cursors in text input
- TextPipeline: (future work) split text entities into section entities
- TextPipeline: (future work) text editing
- Support line height as an option. Unitless `1.2` is the default used
in browsers (1.2x font size).
- Support System Fonts and font families
- Example showing of animated text styles. Eg. throbbing hyperlinks
---------
Co-authored-by: tigregalis <anak.harimau@gmail.com>
Co-authored-by: Nico Burns <nico@nicoburns.com>
Co-authored-by: sam edelsten <samedelsten1@gmail.com>
Co-authored-by: Dimchikkk <velo.app1@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Rob Parrett <robparrett@gmail.com>
# Objective
- After #14017 , I noticed that the drawcall increased 10x in the
`many_buttons`, causing the `UIPassNode `to increase from 1.5ms to 6ms.
This is because our UI batching is very fragile.
## Solution
- skip extract UiImage when its texture is default
## Performance
many_buttons UiPassNode
# Objective
Fixes#14120
`ui_texture_slice` and `ui_texture_atlas_slice` were working as
intended, so undo the changes.
## Solution
Partially revert https://github.com/bevyengine/bevy/pull/14115 for
`ui_texture_slice` and `ui_texture_atlas_slice`.
## Testing
Ran those two examples, confirmed the border color is the thing that
changes when buttons are hovered.
# Objective
- Standard Material is starting to run out of samplers (currently uses
13 with no additional features off, I think in 0.13 it was 12).
- This change adds a new feature switch, modelled on the other ones
which add features to Standard Material, to turn off the new anisotropy
feature by default.
## Solution
- feature + texture define
## Testing
- Anisotropy example still works fine
- Other samples work fine
- Standard Material now takes 12 samplers by default on my Mac instead
of 13
## Migration Guide
- Add feature pbr_anisotropy_texture if you are using that texture in
any standard materials.
---------
Co-authored-by: John Payne <20407779+johngpayne@users.noreply.github.com>
# Objective
The bounds for query iterators are quite intimidating.
## Solution
With Rust 1.79, [associated type
bounds](https://github.com/rust-lang/rust/pull/122055/) stabilized,
which can simplify the bounds slightly.
# Objective
- https://github.com/bevyengine/bevy/pull/13136 changed the default
value of `-Zshare-generics=n` to `-Zshare-generics=y` on Windows
- New users are encouraged to use dynamic builds and LLD when setting up
Bevy
- New users are also encouraged to check out `fast_config.toml`
- https://github.com/bevyengine/bevy/issues/1126 means that running
dynamic builds, using LLD and sharing generics on Windows results in a
cryptic error message
As a result, a new Windows user following all recommendations for better
compiles is actually not able to compile Bevy at all.
## Solution
- Set `-Zshare-generics=n` on Windows with a comment saying this is for
dynamic linking
## Testing
I verified that https://github.com/bevyengine/bevy/issues/1126 is still
in place on the current nightly (1.80)
## Additional Info
Maybe the website should mention this as well? The relevant snippet
there looks like this:
```toml
# /path/to/project/.cargo/config.toml
[target.x86_64-unknown-linux-gnu]
rustflags = [
# (Nightly) Make the current crate share its generic instantiations
"-Zshare-generics=y",
]
```
so it kinda implies it's only for Linux? Which is not quite true, this
setting works on macOS as well AFAIK
# Objective
The Bevy API around manipulating hierarchies removes `Children` if the
operation results in an entity having no children. This means that
`Children` is guaranteed to hold actual children. However, the following
code unexpectedly inserts empty `Children`:
```rust
commands.entity(entity).with_children(|_| {});
```
This was discovered by @Jondolf:
https://discord.com/channels/691052431525675048/1124043933886976171/1257660865625325800
## Solution
- `with_children` is now a noop when no children were passed
## Testing
- Added a regression test
# Objective
The `AssetReader` trait allows customizing the behavior of fetching
bytes for an `AssetPath`, and expects implementors to return `dyn
AsyncRead + AsyncSeek`. This gives implementors of `AssetLoader` great
flexibility to tightly integrate their asset loading behavior with the
asynchronous task system.
However, almost all implementors of `AssetLoader` don't use the async
functionality at all, and just call `AsyncReadExt::read_to_end(&mut
Vec<u8>)`. This is incredibly inefficient, as this method repeatedly
calls `poll_read` on the trait object, filling the vector 32 bytes at a
time. At my work we have assets that are hundreds of megabytes which
makes this a meaningful overhead.
## Solution
Turn the `Reader` type alias into an actual trait, with a provided
method `read_to_end`. This provided method should be more efficient than
the existing extension method, as the compiler will know the underlying
type of `Reader` when generating this function, which removes the
repeated dynamic dispatches and allows the compiler to make further
optimizations after inlining. Individual implementors are able to
override the provided implementation -- for simple asset readers that
just copy bytes from one buffer to another, this allows removing a large
amount of overhead from the provided implementation.
Now that `Reader` is an actual trait, I also improved the ergonomics for
implementing `AssetReader`. Currently, implementors are expected to box
their reader and return it as a trait object, which adds unnecessary
boilerplate to implementations. This PR changes that trait method to
return a pseudo trait alias, which allows implementors to return `impl
Reader` instead of `Box<dyn Reader>`. Now, the boilerplate for boxing
occurs in `ErasedAssetReader`.
## Testing
I made identical changes to my company's fork of bevy. Our app, which
makes heavy use of `read_to_end` for asset loading, still worked
properly after this. I am not aware if we have a more systematic way of
testing asset loading for correctness.
---
## Migration Guide
The trait method `bevy_asset::io::AssetReader::read` (and `read_meta`)
now return an opaque type instead of a boxed trait object. Implementors
of these methods should change the type signatures appropriately
```rust
impl AssetReader for MyReader {
// Before
async fn read<'a>(&'a self, path: &'a Path) -> Result<Box<Reader<'a>>, AssetReaderError> {
let reader = // construct a reader
Box::new(reader) as Box<Reader<'a>>
}
// After
async fn read<'a>(&'a self, path: &'a Path) -> Result<impl Reader + 'a, AssetReaderError> {
// create a reader
}
}
```
`bevy::asset::io::Reader` is now a trait, rather than a type alias for a
trait object. Implementors of `AssetLoader::load` will need to adjust
the method signature accordingly
```rust
impl AssetLoader for MyLoader {
async fn load<'a>(
&'a self,
// Before:
reader: &'a mut bevy::asset::io::Reader,
// After:
reader: &'a mut dyn bevy::asset::io::Reader,
_: &'a Self::Settings,
load_context: &'a mut LoadContext<'_>,
) -> Result<Self::Asset, Self::Error> {
}
```
Additionally, implementors of `AssetReader` that return a type
implementing `futures_io::AsyncRead` and `AsyncSeek` might need to
explicitly implement `bevy::asset::io::Reader` for that type.
```rust
impl bevy::asset::io::Reader for MyAsyncReadAndSeek {}
```
# Objective
Add ability to de-register events from the EventRegistry (and the
associated World).
The initial reasoning relates to retaining support for Event hot
reloading in `dexterous_developer`.
## Solution
Add a `deregister_events<T: Event>(&mut world)` method to the
`EventRegistry` struct.
## Testing
Added an automated test that verifies the event registry adds and
removes `Events<T>` from the world.
---------
Co-authored-by: BD103 <59022059+BD103@users.noreply.github.com>
# Objective
It's not always obvious what the default value for `RenderLayers`
represents. It is documented, but since it's an implementation of a
trait method the documentation may or may not be shown depending on the
IDE.
## Solution
Add documentation to the `none` method that explicitly calls out the
difference.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Also bumps `accesskit_winit` to 0.22 and fixes one breaking change.
# Objective
- `accesskit` has been updated recently to 0.16!
## Solution
- Update `accesskit`, as well as `accesskit_winit`.
- [`accesskit`
changelog](552032c839/common/CHANGELOG.md (0160-2024-06-29))
- [`accesskit_winit`
changelog](552032c839/platforms/winit/CHANGELOG.md (0220-2024-06-29))
- Fix one breaking change where `Role::StaticText` has been renamed to
`Role::Label`.
## Testing
- The test suite should cover most things.
- It would be good to test this with an example, but I don't know how.
---
## Changelog
- Update `accesskit` to 0.16 and `accesskit_winit` to 0.22.
## Migration Guide
`accesskit`'s `Role::StaticText` variant has been renamed to
`Role::Label`.
# Objective
- Though Rodio will eventually be replaced with Kira for `bevy_audio`,
we should not let it languish.
## Solution
- Bump Rodio to 0.19.
- This is [the
changelog](27f2b42406/CHANGELOG.md (version-0190-2024-06-29)).
No apparent breaking changes, only 1 feature and 1 fix.
## Testing
- Run an example that uses audio, on both native and WASM.
---
## Changelog
- Bumped Rodio to 0.19.
# Objective
The `BuildChildren` and `BuildWorldChildren` traits are mostly
identical, so I decided to try and merge them. I'm not sure of the
history, maybe they were added before GATs existed.
## Solution
- Add an associated type to `BuildChildren` which reflects the prior
differences between the `BuildChildren` and `BuildWorldChildren` traits.
- Add `ChildBuild` trait that is the bounds for
`BuildChildren::Builder`, with impls for `ChildBuilder` and
`WorldChildBuilder`.
- Remove `BuildWorldChildren` trait and replace it with an impl of
`BuildChildren` for `EntityWorldMut`.
## Testing
I ran several of the examples that use entity hierarchies, mainly UI.
---
## Changelog
n/a
## Migration Guide
n/a
# Objective
- Add the `AccumulatedMouseMotion` and `AccumulatedMouseScroll`
resources to make it simpler to track mouse motion/scroll changes
- Closes#13915
## Solution
- Created two resources, `AccumulatedMouseMotion` and
`AccumulatedMouseScroll`, and a method that tracks the `MouseMotion` and
`MouseWheel` events and accumulates their deltas every frame.
- Also modified the mouse input example to show how to use the
resources.
## Testing
- Tested the changes by modifying an existing example to use the newly
added resources, and moving/scrolling my trackpad around a ton.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
# Objective
Fixes#13995.
## Solution
Override the default `Ctrl+C` handler with one that sends `AppExit`
event to every app with `TerminalCtrlCHandlerPlugin`.
## Testing
Tested by running the `3d_scene` example and hitting `Ctrl+C` in the
terminal.
---
## Changelog
Handles `Ctrl+C` in the terminal gracefully.
## Migration Guide
If you are overriding the `Ctrl+C` handler then you should call
`TerminalCtrlCHandlerPlugin::gracefully_exit` from your handler. It will
tell the app to exit.
Part of #13681
# Objective
gLTF Assets shouldn't be duplicated between Assets resource and node
children.
Also changed `asset_label` to be a method as [per previous PR
comment](https://github.com/bevyengine/bevy/pull/13558).
## Solution
- Made GltfNode children be Handles instead of asset copies.
## Testing
- Added tests that actually test loading and hierarchy as previous ones
unit tested only one function and that makes little sense.
- Made circular nodes an actual loading failure instead of a warning
no-op. You [_MUST NOT_ have cycles in
gLTF](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#nodes-and-hierarchy)
according to the spec.
- IMO this is a bugfix, not a breaking change. But in an extremely
unlikely event in which you relied on invalid behavior for loading gLTF
with cyclic children, you will not be able to do that anymore. You
should fix your gLTF file as it's not valid according to gLTF spec. For
it to for work someone, it had to be bevy with bevy_animation flag off.
---
## Changelog
### Changed
- `GltfNode.children` are now `Vec<Handle<GltfNode>>` instead of
`Vec<GltfNode>`
- Having children cycles between gLTF nodes in a gLTF document is now an
explicit asset loading failure.
## Migration Guide
If accessing children, use `Assets<GltfNode>` resource to get the actual
child object.
#### Before
```rs
fn gltf_print_first_node_children_system(gltf_component_query: Query<Handle<Gltf>>, gltf_assets: Res<Assets<Gltf>>, gltf_nodes: Res<Assets<GltfNode>>) {
for gltf_handle in gltf_component_query.iter() {
let gltf_root = gltf_assets.get(gltf_handle).unwrap();
let first_node_handle = gltf_root.nodes.get(0).unwrap();
let first_node = gltf_nodes.get(first_node_handle).unwrap();
let first_child = first_node.children.get(0).unwrap();
println!("First nodes child node name is {:?)", first_child.name);
}
}
```
#### After
```rs
fn gltf_print_first_node_children_system(gltf_component_query: Query<Handle<Gltf>>, gltf_assets: Res<Assets<Gltf>>, gltf_nodes: Res<Assets<GltfNode>>) {
for gltf_handle in gltf_component_query.iter() {
let gltf_root = gltf_assets.get(gltf_handle).unwrap();
let first_node_handle = gltf_root.nodes.get(0).unwrap();
let first_node = gltf_nodes.get(first_node_handle).unwrap();
let first_child_handle = first_node.children.get(0).unwrap();
let first_child = gltf_nodes.get(first_child_handle).unwrap();
println!("First nodes child node name is {:?)", first_child.name);
}
}
```
