# Objective
- Provide an expressive way to register dynamic behavior in response to
ECS changes that is consistent with existing bevy types and traits as to
provide a smooth user experience.
- Provide a mechanism for immediate changes in response to events during
command application in order to facilitate improved query caching on the
path to relations.
## Solution
- A new fundamental ECS construct, the `Observer`; inspired by flec's
observers but adapted to better fit bevy's access patterns and rust's
type system.
---
## Examples
There are 3 main ways to register observers. The first is a "component
observer" that looks like this:
```rust
world.observe(|trigger: Trigger<OnAdd, Transform>, query: Query<&Transform>| {
let transform = query.get(trigger.entity()).unwrap();
});
```
The above code will spawn a new entity representing the observer that
will run it's callback whenever the `Transform` component is added to an
entity. This is a system-like function that supports dependency
injection for all the standard bevy types: `Query`, `Res`, `Commands`
etc. It also has a `Trigger` parameter that provides information about
the trigger such as the target entity, and the event being triggered.
Importantly these systems run during command application which is key
for their future use to keep ECS internals up to date. There are similar
events for `OnInsert` and `OnRemove`, and this will be expanded with
things such as `ArchetypeCreated`, `TableEmpty` etc. in follow up PRs.
Another way to register an observer is an "entity observer" that looks
like this:
```rust
world.entity_mut(entity).observe(|trigger: Trigger<Resize>| {
// ...
});
```
Entity observers run whenever an event of their type is triggered
targeting that specific entity. This type of observer will de-spawn
itself if the entity (or entities) it is observing is ever de-spawned so
as to not leave dangling observers.
Entity observers can also be spawned from deferred contexts such as
other observers, systems, or hooks using commands:
```rust
commands.entity(entity).observe(|trigger: Trigger<Resize>| {
// ...
});
```
Observers are not limited to in built event types, they can be used with
any type that implements `Event` (which has been extended to implement
Component). This means events can also carry data:
```rust
#[derive(Event)]
struct Resize { x: u32, y: u32 }
commands.entity(entity).observe(|trigger: Trigger<Resize>, query: Query<&mut Size>| {
let event = trigger.event();
// ...
});
// Will trigger the observer when commands are applied.
commands.trigger_targets(Resize { x: 10, y: 10 }, entity);
```
You can also trigger events that target more than one entity at a time:
```rust
commands.trigger_targets(Resize { x: 10, y: 10 }, [e1, e2]);
```
Additionally, Observers don't _need_ entity targets:
```rust
app.observe(|trigger: Trigger<Quit>| {
})
commands.trigger(Quit);
```
In these cases, `trigger.entity()` will be a placeholder.
Observers are actually just normal entities with an `ObserverState` and
`Observer` component! The `observe()` functions above are just shorthand
for:
```rust
world.spawn(Observer::new(|trigger: Trigger<Resize>| {});
```
This will spawn the `Observer` system and use an `on_add` hook to add
the `ObserverState` component.
Dynamic components and trigger types are also fully supported allowing
for runtime defined trigger types.
## Possible Follow-ups
1. Deprecate `RemovedComponents`, observers should fulfill all use cases
while being more flexible and performant.
2. Queries as entities: Swap queries to entities and begin using
observers listening to archetype creation triggers to keep their caches
in sync, this allows unification of `ObserverState` and `QueryState` as
well as unlocking several API improvements for `Query` and the
management of `QueryState`.
3. Trigger bubbling: For some UI use cases in particular users are
likely to want some form of bubbling for entity observers, this is
trivial to implement naively but ideally this includes an acceleration
structure to cache hierarchy traversals.
4. All kinds of other in-built trigger types.
5. Optimization; in order to not bloat the complexity of the PR I have
kept the implementation straightforward, there are several areas where
performance can be improved. The focus for this PR is to get the
behavior implemented and not incur a performance cost for users who
don't use observers.
I am leaving each of these to follow up PR's in order to keep each of
them reviewable as this already includes significant changes.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: MiniaczQ <xnetroidpl@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Fixes#13844
- Warn user when initializing state multiple times
## Solution
- `insert_state` will overwrite previously initialized state value,
reset transition events and re-insert it's own transition event.
- `init_state`, `add_sub_state`, `add_computed_state` are idempotent, so
calling them multiple times will emit a warning.
## Testing
- 2 tests confirming overwrite works.
- Given the example from #13844
```rs
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.insert_state(AppState::A)
.insert_state(AppState::B)
.add_systems(OnEnter(AppState::A), setup_a)
.add_systems(OnEnter(AppState::B), setup_b)
.add_systems(OnExit(AppState::A), cleanup_a)
.add_systems(OnExit(AppState::B), cleanup_b)
.run();
}
#[derive(States, Debug, Clone, PartialEq, Eq, Hash)]
enum AppState {
A,
B,
}
fn setup_a() {
info!("setting up A");
}
fn setup_b() {
info!("setting up B");
}
fn cleanup_a() {
info!("cleaning up A");
}
fn cleanup_b() {
info!("cleaning up B");
}
```
We get the following result:
```
INFO states: setting up B
```
which matches our expectations.
# Objective
Fixes#13815
## Solution
Move insertion of the plugin name to after build is called.
## Testing
I added a regression test
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: François Mockers <mockersf@gmail.com>
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
when a parent container is auto-sized, text alignments `Center` and
`Right` don't align to the center and right properly. fix it
## Solution
ab_glyph positions return +/- values from an anchor point. we currently
transform them to positive values from the min-x of the glyphs, and then
offset from the left of the bounds. instead, we can keep the negative
values as ab_glyph intended and offset from the left/middle/right of the
bounds as appropriate.
## Testing
texts with align left, center, right, all contained in the purple boxes:
before (0.14.0-rc.2):
after:
code:
```rs
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.run();
}
fn setup(mut commands: Commands) {
commands.spawn(Camera2dBundle::default());
for (left, justify) in [
(100.0, JustifyText::Left),
(500.0, JustifyText::Center),
(900.0, JustifyText::Right),
] {
commands
// container
.spawn(NodeBundle {
style: Style {
flex_direction: FlexDirection::Column,
position_type: PositionType::Absolute,
left: Val::Px(left),
top: Val::Px(100.0),
width: Val::Px(300.0),
..Default::default()
},
..Default::default()
})
.with_children(|commands| {
commands.spawn(NodeBundle{
style: Style {
flex_direction: FlexDirection::Row,
height: Val::Px(75.0),
..Default::default()
},
background_color: Color::srgb(1.0, 0.0, 1.0).into(),
..Default::default()
}).with_children(|commands| {
// a div that reduces the available size
commands.spawn(NodeBundle {
style: Style {
width: Val::Px(75.0),
..Default::default()
},
background_color: Color::srgb(0.0, 1.0, 0.0).into(),
..Default::default()
});
// text with width=auto, but actual size will not be what it expcets due to the sibling div above
commands.spawn(TextBundle {
text: Text::from_section("Some text that wraps onto a second line", Default::default()).with_justify(justify),
style: Style {
align_self: AlignSelf::Center,
..Default::default()
},
..Default::default()
});
});
});
}
}
```
Currently blocked on https://github.com/gfx-rs/wgpu/issues/5774
# Objective
Update to wgpu 0.20
## Solution
Update to wgpu 0.20 and naga_oil 0.14.
## Testing
Tested a few different examples on linux (vulkan, webgl2, webgpu) and
windows (dx12 + vulkan) and they worked.
---
## Changelog
- Updated to wgpu 0.20. Note that we don't currently support wgpu's new
pipeline overridable constants, as they don't work on web currently and
need some more changes to naga_oil (and are somewhat redundant with
naga_oil's shader defs). See wgpu's changelog for more
https://github.com/gfx-rs/wgpu/blob/trunk/CHANGELOG.md#v0200-2024-04-28
## Migration Guide
TODO
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
- Fixes#13807
## Solution
- Before this pr we antialiased between 0.5 and -0.5. This pr changes
things to antialias between 0.25 and -0.25. I tried slightly larger
ranges, but the edge between the boxes still showed. I'm not 100% sure
this is the correct solution, but from what I could find the range you
use is more art than science.
## Testing
- Ran rounded_borders example, the code in the linked issue, and the
testing example from #12702.
---
## Changelog
- reduce antialiasing in ui shader.
# Objective
While learning about shaders and pipelines, I found this example to be
misleading; it wasn't clear to me how the node knew what the correct
"instance" of `PostProcessSettings` we should send to the shader (as the
combination of `ExtractComponentPlugin` and `UniformComponentPlugin`
extracts + sends _all_ of our `PostProcessSetting` components to the
GPU).
The goal of this PR is to clarify how to target the view specific
`PostProcessSettings` in the shader when there are multiple cameras.
## Solution
To accomplish this, we can use a dynamic uniform buffer for
`PostProcessSettings`, querying for the relevant `DynamicUniformIndex`
in the `PostProcessNode` to get the relevant index to use with the bind
group.
While the example in its current state is _correct_, I believe that fact
that it's intended to showcase a per camera post processing effect
warrants a dynamic uniform buffer (even though in the context of this
example we have only one camera, and therefore no adverse behaviour).
## Testing
- Run the `post_processing` example before and after this change,
verifying they behave the same.
## Reviewer notes
This is my first PR to Bevy, and I'm by no means an expert in the world
of rendering (though I'm trying to learn all I can). If there's a better
way to do this / a reason not to take this route, I'd love to hear it!
Thanks in advance.
StatesPlugin and GizmoPlugin were missing from the doc comment of
DefaultPlugins. I am not sure whether this was for a reason, but i just
stumbled over it and it seemed off...
## Testing
I'm not sure how to test these changes?
# Objective
As discovered in
https://github.com/Leafwing-Studios/leafwing-input-manager/issues/538,
there appears to be some real weirdness going on in how event updates
are processed between Bevy 0.13 and Bevy 0.14.
To identify the cause and prevent regression, I've added tests to
validate the intended behavior.
My initial suspicion was that this would be fixed by
https://github.com/bevyengine/bevy/pull/13762, but that doesn't seem to
be the case.
Instead, events appear to never be updated at all when using `bevy_app`
by itself. This is part of the problem resolved by
https://github.com/bevyengine/bevy/pull/11528, and introduced by
https://github.com/bevyengine/bevy/pull/10077.
After some investigation, it appears that `signal_event_update_system`
is never added using a bare-bones `App`, and so event updates are always
skipped.
This can be worked around by adding your own copy to a
later-in-the-frame schedule, but that's not a very good fix.
## Solution
Ensure that if we're not using a `FixedUpdate` schedule, events are
always updated every frame.
To do this, I've modified the logic of `event_update_condition` and
`event_update_system` to clearly and correctly differentiate between the
two cases: where we're waiting for a "you should update now" signal and
where we simply don't care.
To encode this, I've added the `ShouldUpdateEvents` enum, replacing a
simple `bool` in `EventRegistry`'s `needs_update` field.
Now, both tests pass as expected, without having to manually add a
system!
## Testing
I've written two parallel unit tests to cover the intended behavior:
1. Test that `iter_current_update_events` works as expected in
`bevy_ecs`.
2. Test that `iter_current_update_events` works as expected in
`bevy_app`
I've also added a test to verify that event updating works correctly in
the presence of a fixed main schedule, and a second test to verify that
fixed updating works at all to help future authors narrow down failures.
## Outstanding
- [x] figure out why the `bevy_app` version of this test fails but the
`bevy_ecs` version does not
- [x] figure out why `EventRegistry::run_updates` isn't working properly
- [x] figure out why `EventRegistry::run_updates` is never getting
called
- [x] figure out why `event_update_condition` is always returning false
- [x] figure out why `EventRegistry::needs_update` is always false
- [x] verify that the problem is a missing `signal_events_update_system`
---------
Co-authored-by: Mike <mike.hsu@gmail.com>
…izer (#13442)"
This reverts commit 5cfb063d4a.
- This PR broke bevy-trait-query, which needs to be able to write a
resource in init_state. See #13798 for more details.
- Note this doesn't fix everything as transmutes for bevy-trait-query
will still be broken,. But the current usage in that crate is UB, so we
need to find another solution.
# Objective
- Split the bevy_ecs::events module so it's easier to work with
## Solution
- Split the event.rs file across multiple files, made sure all tests
passed, and exports from the module were the same as previous
## Testing
- All automated tests pass.
# Objective
Closes#13738
## Solution
Added `from_color` to materials that would support it. Didn't add
`from_color` to `WireframeMaterial` as it doesn't seem we expect users
to be constructing them themselves.
## Testing
None
---
## Changelog
### Added
- `from_color` to `StandardMaterial` so you can construct this material
from any color type.
- `from_color` to `ColorMaterial` so you can construct this material
from any color type.
# Objective
- Add a new example showcasing how to add custom primitives and what you
can do with them.
## Solution
- Added a new example `custom_primitives` with a 2D heart shape
primitive highlighting
- `Bounded2d` by implementing and visualising bounding shapes,
- `Measured2d` by implementing it,
- `Meshable` to show the shape on the screen
- The example also includes an `Extrusion<Heart>` implementing
- `Measured3d`,
- `Bounded3d` using the `BoundedExtrusion` trait and
- meshing using the `Extrudable` trait.
## Additional information
Here are two images of the heart and its extrusion:
---------
Co-authored-by: Jakub Marcowski <37378746+Chubercik@users.noreply.github.com>
# Objective
- Mikktspace requires that we normalize world normals/tangents _before_
interpolation across vertices, and then do _not_ normalize after. I had
it backwards.
- We do not (am not supposed to?) need a second set of barycentrics for
motion vectors. If you think about the typical raster pipeline, in the
vertex shader we calculate previous_world_position, and then it gets
interpolated using the current triangle's barycentrics.
## Solution
- Fix normal/tangent processing
- Reuse barycentrics for motion vector calculations
- Not implementing this for 0.14, but long term I aim to remove explicit
vertex tangents and calculate them in the shader on the fly.
## Testing
- I tested out some of the normal maps we have in repo. Didn't seem to
make a difference, but mikktspace is all about correctness across
various baking tools. I probably just didn't have any of the ones that
would cause it to break.
- Didn't test motion vectors as there's a known bug with the depth
buffer and meshlets that I'm waiting on the render graph rewrite to fix.
# Objective
Reading system information severely slows down the update loop.
Fixes#12848.
## Solution
Read system info in a separate thread.
## Testing
- Open the scene 3d example
- Add `FrameTimeDiagnosticsPlugin`, `SystemInformationDiagnosticsPlugin`
and `LogDiagnosticsPlugin` to the app.
- Add this system to the update schedule to disable Vsync on the main
window
```rust
fn change_window_mode(mut windows: Query<&mut Window, Added<Window>>) {
for mut window in &mut windows {
window.present_mode = PresentMode::AutoNoVsync;
}
}
```
- Read the fps values in the console before and after this PR.
On my PC I went from around 50 fps to around 1150 fps.
---
## Changelog
### Changed
- The `SystemInformationDiagnosticsPlugin` now reads system data
separate of the update cycle.
### Added
- The `EXPECTED_SYSTEM_INFORMATION_INTERVAL` constant which defines how
often we read system diagnostic data.
---------
Co-authored-by: IceSentry <IceSentry@users.noreply.github.com>
Fixes#13758.
# Objective
Calling `update` on the main app already calls `clear_trackers`. Calling
it again in `SubApps::update` caused RemovedCompenet Events to be
cleared earlier than they should be.
## Solution
- Don't call clear_trackers an extra time.
## Testing
I manually tested the fix with this unit test:
```
#[cfg(test)]
mod test {
use crate::core::{FrameCount, FrameCountPlugin};
use crate::prelude::*;
#[test]
fn test_next_frame_removal() {
#[derive(Component)]
struct Foo;
#[derive(Resource)]
struct RemovedCount(usize);
let mut app = App::new();
app.add_plugins(FrameCountPlugin);
app.add_systems(Startup, |mut commands: Commands| {
for _ in 0..100 {
commands.spawn(Foo);
}
commands.insert_resource(RemovedCount(0));
});
app.add_systems(First, |counter: Res<FrameCount>| {
println!("Frame {}:", counter.0)
});
fn detector_system(
mut removals: RemovedComponents<Foo>,
foos: Query<Entity, With<Foo>>,
mut removed_c: ResMut<RemovedCount>,
) {
for e in removals.read() {
println!(" Detected removed Foo component for {e:?}");
removed_c.0 += 1;
}
let c = foos.iter().count();
println!(" Total Foos: {}", c);
assert_eq!(c + removed_c.0, 100);
}
fn deleter_system(foos: Query<Entity, With<Foo>>, mut commands: Commands) {
foos.iter().next().map(|e| {
commands.entity(e).remove::<Foo>();
});
}
app.add_systems(Update, (detector_system, deleter_system).chain());
app.update();
app.update();
app.update();
app.update();
}
}
```
i based the design on @mgi388 in the discussion about the issue.
i added the illustration in such a way that it shows up when you hover
your mouse over the type, i hope this is what was meant by the issue
no unit tests were added bc obviously
Fixes#13664
# Objective
There were some issues with the `serialize` feature:
- `bevy_app` had a `serialize` feature and a dependency on `serde` even
there is no usage of serde at all inside `bevy_app`
- the `bevy_app/serialize` feature enabled `bevy_ecs/serde`, which is
strange
- `bevy_internal/serialize` did not enable `bevy_app/serialize` so there
was no way of serializing an Entity in bevy 0.14
## Solution
- Remove `serde` and `bevy_app/serialize`
- Add a `serialize` flag on `bevy_ecs` that enables `serde`
- ` bevy_internal/serialize` now enables `bevy_ecs/serialize`
# Objective
- My attempt at fulfilling #13629.
## Solution
Renames the `and_then` / `or_else` run condition methods to `and` /
`or`, respectively.
Extends the run conditions API to include a suite of binary logical
operators:
- `and`
- `or`
- `nand`
- `nor`
- `xor`
- `xnor`
## Testing
- Did you test these changes? If so, how?
- The test **run_condition_combinators** was extended to include the
added run condition combinators. A **double_counter** system was added
to test for combinators running on even count cycles.
- Are there any parts that need more testing?
- I'm not too sure how I feel about the "counter" style of testing but I
wanted to keep it consistent. If it's just a unit test I would prefer
simply to just assert `true` == _combinator output_ or `false` ==
_combinator output_ .
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Nothing too specific. The added methods should be equivalent to the
logical operators they are analogous to (`&&` , `||`, `^`, `!`).
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
- Should not be relevant, I'm using Windows.
## Changelog
- What changed as a result of this PR?
- The run conditions API.
- If applicable, organize changes under "Added", "Changed", or "Fixed"
sub-headings
- Changed:
- `and_then` run condition combinator renamed to simply `and`
- `or_else` run condition combinator renamed to simply `or`
- Added:
- `nand` run condition combinator.
- `nor` run condition combinator.
- `xor` run condition combinator.
- `xnor` run condition combinator.
## Migration Guide
- The `and_then` run condition method has been replaced with the `and`
run condition method.
- The `or_else` run condition method has been replaced with the `or` run
condition method.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Andres O. Vela <andresovela@users.noreply.github.com>
# Objective
- If the fog is disabled it still generates a useless branch which can
hurt performance
## Solution
- Make the flag a shader_def instead
## Testing
- I tested enabling/disabling fog works as expected per-material in the
fog example
- I also tested that scenes that don't add the FogSettings resource
still work correctly
## Review notes
I'm not sure how to handle the removed material flag. Right now I just
commented it out and added a not to reuse it instead of creating a new
one.
The documentation for the `State` resource still referenced the use of
`apply_state_transition` to manually force a state transition to occur,
and the question around how to force transitions had come up a few times
on discord.
This is a docs-only change, that does the following:
- Properly references `StateTransition` in the `MainSchedule` docs
- replace the explanations for applying `NextState` with ones that
explain the `StateTransition` schedule, and mentions the possibility of
calling it manually
- Add an example of calling `StateTransition` manually in the docs for
the state transition schedule itself.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
The error printed-out due to a missing shader file was confusing; This
PR changes the error message.
Fixes#13644
## Solution
I replaced the confusing wording (`... shader is not loaded yet`) with a
clear explanation (`... shader could not be loaded`)
## Testing
> Did you test these changes? If so, how?
removing `assets/shaders/game_of_life.wgsl` & running its associated
example now produces the following error:
```
thread '<unnamed>' panicked at examples/shader/compute_shader_game_of_life.rs:233:25:
Initializing assets/shaders/game_of_life.wgsl:
Pipeline could not be compiled because the following shader could not be loaded: AssetId<bevy_render::render_resource::shader::Shader>{ index: 0, generation: 0}
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Encountered a panic in system `bevy_render::renderer::render_system`!
```
I don't think there are any tests expecting the previous error message,
so this change should not break anything.
> Are there any parts that need more testing?
If there was an intent behind the original message, this might need more
attention.
> How can other people (reviewers) test your changes? Is there anything
specific they need to know?
One should be able to preview the changes by running any example after
deleting/renaming their associated shader(s).
> If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
N/A
# Objective
Fixes#13711
## Solution
Introduce smaller, generic system sets for each schedule variant, which
are ordered against other generic variants:
- `ExitSchedules<S>` - For `OnExit` schedules, runs from leaf states to
root states.
- `TransitionSchedules<S>` - For `OnTransition` schedules, runs in
arbitrary order.
- `EnterSchedules<S>` - For `OnEnter` schedules, runs from root states
to leaf states.
Also unified `ApplyStateTransition<S>` schedule which works in basically
the same way, just for internals.
## Testing
- One test that tests schedule execution order
---------
Co-authored-by: Lee-Orr <lee-orr@users.noreply.github.com>
# Objective
One thing missing from the new Color implementation in 0.14 is the
ability to easily convert to a u8 representation of the rgb color.
(note this is a redo of PR https://github.com/bevyengine/bevy/pull/13739
as I needed to move the source branch
## Solution
I have added to_u8_array and to_u8_array_no_alpha to a new trait called
ColorToPacked to mirror the f32 conversions in ColorToComponents and
implemented the new trait for Srgba and LinearRgba.
To go with those I also added matching from_u8... functions and
converted a couple of cases that used ad-hoc implementations of that
conversion to use these.
After discussion on Discord of the experience of using the API I renamed
Color::linear to Color::to_linear, as without that it looks like a
constructor (like Color::rgb).
I also added to_srgba which is the other commonly converted to type of
color (for UI and 2D) to match to_linear.
Removed a redundant extra implementation of to_f32_array for LinearColor
as it is also supplied in ColorToComponents (I'm surprised that's
allowed?)
## Testing
Ran all tests and manually tested.
Added to_and_from_u8 to linear_rgba::tests
## Changelog
visible change is Color::linear becomes Color::to_linear.
---------
Co-authored-by: John Payne <20407779+johngpayne@users.noreply.github.com>
# Objective
The method `AssetServer::add_async` (added in
https://github.com/bevyengine/bevy/pull/13700) requires a future that
returns an `AssetLoadError` error, which was a bit of an oversight on my
part, as that type of error only really makes sense in the context of
bevy's own asset loader -- returning it from user-defined futures isn't
very useful.
## Solution
Allow passing custom error types to `add_async`, which get cast into a
trait object matching the form of `AssetLoader::load`. If merged before
the next release this will not be a breaking change
# Objective
Partially address #13408
Rework of #13613
Unify the very nice forms of interpolation specifically present in
`bevy_math` under a shared trait upon which further behavior can be
based.
The ideas in this PR were prompted by [Lerp smoothing is broken by Freya
Holmer](https://www.youtube.com/watch?v=LSNQuFEDOyQ).
## Solution
There is a new trait `StableInterpolate` in `bevy_math::common_traits`
which enshrines a quite-specific notion of interpolation with a lot of
guarantees:
```rust
/// A type with a natural interpolation that provides strong subdivision guarantees.
///
/// Although the only required method is `interpolate_stable`, many things are expected of it:
///
/// 1. The notion of interpolation should follow naturally from the semantics of the type, so
/// that inferring the interpolation mode from the type alone is sensible.
///
/// 2. The interpolation recovers something equivalent to the starting value at `t = 0.0`
/// and likewise with the ending value at `t = 1.0`.
///
/// 3. Importantly, the interpolation must be *subdivision-stable*: for any interpolation curve
/// between two (unnamed) values and any parameter-value pairs `(t0, p)` and `(t1, q)`, the
/// interpolation curve between `p` and `q` must be the *linear* reparametrization of the original
/// interpolation curve restricted to the interval `[t0, t1]`.
///
/// The last of these conditions is very strong and indicates something like constant speed. It
/// is called "subdivision stability" because it guarantees that breaking up the interpolation
/// into segments and joining them back together has no effect.
///
/// Here is a diagram depicting it:
/// ```text
/// top curve = u.interpolate_stable(v, t)
///
/// t0 => p t1 => q
/// |-------------|---------|-------------|
/// 0 => u / \ 1 => v
/// / \
/// / \
/// / linear \
/// / reparametrization \
/// / t = t0 * (1 - s) + t1 * s \
/// / \
/// |-------------------------------------|
/// 0 => p 1 => q
///
/// bottom curve = p.interpolate_stable(q, s)
/// ```
///
/// Note that some common forms of interpolation do not satisfy this criterion. For example,
/// [`Quat::lerp`] and [`Rot2::nlerp`] are not subdivision-stable.
///
/// Furthermore, this is not to be used as a general trait for abstract interpolation.
/// Consumers rely on the strong guarantees in order for behavior based on this trait to be
/// well-behaved.
///
/// [`Quat::lerp`]: crate::Quat::lerp
/// [`Rot2::nlerp`]: crate::Rot2::nlerp
pub trait StableInterpolate: Clone {
/// Interpolate between this value and the `other` given value using the parameter `t`.
/// Note that the parameter `t` is not necessarily clamped to lie between `0` and `1`.
/// When `t = 0.0`, `self` is recovered, while `other` is recovered at `t = 1.0`,
/// with intermediate values lying between the two.
fn interpolate_stable(&self, other: &Self, t: f32) -> Self;
}
```
This trait has a blanket implementation over `NormedVectorSpace`, where
`lerp` is used, along with implementations for `Rot2`, `Quat`, and the
direction types using variants of `slerp`. Other areas may choose to
implement this trait in order to hook into its functionality, but the
stringent requirements must actually be met.
This trait bears no direct relationship with `bevy_animation`'s
`Animatable` trait, although they may choose to use `interpolate_stable`
in their trait implementations if they wish, as both traits involve
type-inferred interpolations of the same kind. `StableInterpolate` is
not a supertrait of `Animatable` for a couple reasons:
1. Notions of interpolation in animation are generally going to be much
more general than those allowed under these constraints.
2. Laying out these generalized interpolation notions is the domain of
`bevy_animation` rather than of `bevy_math`. (Consider also that
inferring interpolation from types is not universally desirable.)
Similarly, this is not implemented on `bevy_color`'s color types,
although their current mixing behavior does meet the conditions of the
trait.
As an aside, the subdivision-stability condition is of interest
specifically for the [Curve
RFC](https://github.com/bevyengine/rfcs/pull/80), where it also ensures
a kind of stability for subsampling.
Importantly, this trait ensures that the "smooth following" behavior
defined in this PR behaves predictably:
```rust
/// Smoothly nudge this value towards the `target` at a given decay rate. The `decay_rate`
/// parameter controls how fast the distance between `self` and `target` decays relative to
/// the units of `delta`; the intended usage is for `decay_rate` to generally remain fixed,
/// while `delta` is something like `delta_time` from an updating system. This produces a
/// smooth following of the target that is independent of framerate.
///
/// More specifically, when this is called repeatedly, the result is that the distance between
/// `self` and a fixed `target` attenuates exponentially, with the rate of this exponential
/// decay given by `decay_rate`.
///
/// For example, at `decay_rate = 0.0`, this has no effect.
/// At `decay_rate = f32::INFINITY`, `self` immediately snaps to `target`.
/// In general, higher rates mean that `self` moves more quickly towards `target`.
///
/// # Example
/// ```
/// # use bevy_math::{Vec3, StableInterpolate};
/// # let delta_time: f32 = 1.0 / 60.0;
/// let mut object_position: Vec3 = Vec3::ZERO;
/// let target_position: Vec3 = Vec3::new(2.0, 3.0, 5.0);
/// // Decay rate of ln(10) => after 1 second, remaining distance is 1/10th
/// let decay_rate = f32::ln(10.0);
/// // Calling this repeatedly will move `object_position` towards `target_position`:
/// object_position.smooth_nudge(&target_position, decay_rate, delta_time);
/// ```
fn smooth_nudge(&mut self, target: &Self, decay_rate: f32, delta: f32) {
self.interpolate_stable_assign(target, 1.0 - f32::exp(-decay_rate * delta));
}
```
As the documentation indicates, the intention is for this to be called
in game update systems, and `delta` would be something like
`Time::delta_seconds` in Bevy, allowing positions, orientations, and so
on to smoothly follow a target. A new example, `smooth_follow`,
demonstrates a basic implementation of this, with a sphere smoothly
following a sharply moving target:
https://github.com/bevyengine/bevy/assets/2975848/7124b28b-6361-47e3-acf7-d1578ebd0347
## Testing
Tested by running the example with various parameters.
# Objective
- Add support for `segments` for extrusion-meshes, akin to what is
possible with cylinders
## Solution
- Added a `.segments(segments: usize)` function to `ExtrusionBuilder`.
- Implemented support for segments in the meshing algorithm.
- If you set `.segments(0)`, the meshing will fail, just like it does
with cylinders.
## Additional information
Here is a wireframe of some extrusions with 1, 2, 3, etc. segments:
---------
Co-authored-by: Lynn Büttgenbach <62256001+solis-lumine-vorago@users.noreply.github.com>
# Objective
`Scene` and `DynamicScene` work with `InstanceInfo` at different levels
of abstraction
- `Scene::write_to_world_with` returns an `InstanceInfo` whereas
`DynamicScene::write_to_world_with` returns `()`. Instances are created
one level higher at the `SceneSpawner` API level.
- `DynamicScene::write_to_world_with` takes the `entity_map` as an
argument whereas the `Scene` version is less flexible and creates a new
one for you. No reason this needs to be the case.
## Solution
I propose changing `Scene::write_to_world_with` to match the API we have
for `DynamicScene`. Returning the `InstanceInfo` as we do today just
seems like a leaky abstraction - it's only used in
`spawn_sync_internal`. Being able to pass in an entity_map gives you
more flexibility with how you write entities to a world.
This also moves `InstanceInfo` out of `Scene` which is cleaner
conceptually. If someone wants to work with instances then they should
work with `SceneSpawner` - I see `write_to_world_with` as a lower-level
API to be used with exclusive world access.
## Testing
Code is just shifting things around.
## Changelog
Changed `Scene::write_to_world_with` to take `entity_map` as an argument
and no longer return an `InstanceInfo`
## Migration Guide
`Scene::write_to_world_with` no longer returns an `InstanceInfo`.
Before
```rust
scene.write_to_world_with(world, ®istry)
```
After
```rust
let mut entity_map = EntityHashMap::default();
scene.write_to_world_with(world, &mut entity_map, ®istry)
```
# Objective
This PR addresses the 2D part of #12658. I plan to separate the examples
and make one PR per camera example.
## Solution
Added a new top-down example composed of:
- [x] Player keyboard movements
- [x] UI for keyboard instructions
- [x] Colors and bloom effect to see the movement of the player
- [x] Camera smooth movement towards the player (lerp)
## Testing
```bash
cargo run --features="wayland,bevy/dynamic_linking" --example 2d_top_down_camera
```
https://github.com/bevyengine/bevy/assets/10638479/95db0587-e5e0-4f55-be11-97444b795793
# Objective
- Let `init_non_send_resource` take `FromWorld` values again, not only
`Default`
- This reverts an unintended breaking change introduced in #9202
## Solution
- The resource initialized with `init_non_send_resource` requires
`FromWorld` again
Bumps [crate-ci/typos](https://github.com/crate-ci/typos) from 1.21.0 to
1.22.3.
<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>v1.22.3</h2>
<h2>[1.22.3] - 2024-06-07</h2>
<h3>Fixes</h3>
<ul>
<li>Don't correct <code>arbitral</code></li>
</ul>
<h2>v1.22.2</h2>
<h2>[1.22.2] - 2024-06-07</h2>
<h2>v1.22.1</h2>
<h2>[1.22.1] - 2024-06-05</h2>
<ul>
<li>In golang, <code>flate</code> is a valid term from the stdlib</li>
</ul>
<h2>v1.22.0</h2>
<h2>[1.22.0] - 2024-06-03</h2>
<h3>Fixes</h3>
<ul>
<li>Updated the dictionary with the <a
href="https://redirect.github.com/crate-ci/typos/issues/1007">May
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>[1.22.3] - 2024-06-07</h2>
<h3>Fixes</h3>
<ul>
<li>Don't correct <code>arbitral</code></li>
</ul>
<h2>[1.22.2] - 2024-06-07</h2>
<h2>[1.22.1] - 2024-06-05</h2>
<ul>
<li>In golang, <code>flate</code> is a valid term from the stdlib</li>
</ul>
<h2>[1.22.0] - 2024-06-03</h2>
<h3>Fixes</h3>
<ul>
<li>Updated the dictionary with the <a
href="https://redirect.github.com/crate-ci/typos/issues/1007">May
2024</a> changes</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="8382594ee0"><code>8382594</code></a>
chore: Release</li>
<li><a
href="e1f52262c1"><code>e1f5226</code></a>
docs: Update changelog</li>
<li><a
href="372a352672"><code>372a352</code></a>
Merge pull request <a
href="https://redirect.github.com/crate-ci/typos/issues/1030">#1030</a>
from epage/arbitral</li>
<li><a
href="c94dbf9024"><code>c94dbf9</code></a>
fix(dict): Don't correct arbitral</li>
<li><a
href="e12da5495c"><code>e12da54</code></a>
chore: Release</li>
<li><a
href="49d37361a0"><code>49d3736</code></a>
chore: Release</li>
<li><a
href="32458c6289"><code>32458c6</code></a>
docs: Update changelog</li>
<li><a
href="8d0593d333"><code>8d0593d</code></a>
Merge pull request <a
href="https://redirect.github.com/crate-ci/typos/issues/1019">#1019</a>
from SOF3/go-flate</li>
<li><a
href="107f99d4c6"><code>107f99d</code></a>
fix(dict): Ignore flate for Go files</li>
<li><a
href="160c60dfce"><code>160c60d</code></a>
Merge pull request <a
href="https://redirect.github.com/crate-ci/typos/issues/1026">#1026</a>
from noahp/noahp/dotall</li>
<li>Additional commits viewable in <a
href="https://github.com/crate-ci/typos/compare/v1.21.0...v1.22.3">compare
view</a></li>
</ul>
</details>
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# Objective
The `EntityCommands::despawn` method was previously changed from
panicking behavior to a warning, but the docs continue to state that it
panics.
## Solution
- Removed panic section, copied warning blurb from `World::despawn`
- Adds a similar warning blurb to
`DespawnRecursiveExt::despawn_recursive` and
`DespawnRecursiveExt::despawn_descendants`
# Objective
- In #13649 additional method had been added to AppExitStates, but there
feature gate left for method in implementation for App at refactoring
stage.
- Fixes#13733 .
## Solution
- Removed the feature gate.
## Testing
- Ran reproducing example from #13733 with no compilation errors
# Objective
- Fixes#13703
## Solution
- Added `mappings` to the `EntityMapper` trait, which returns an
iterator over currently tracked `Entity` to `Entity` mappings.
- Added `DynEntityMapper` as an [object
safe](https://doc.rust-lang.org/reference/items/traits.html#object-safety)
alternative to `EntityMapper`.
- Added `assert_object_safe` as a helper for ensuring traits are object
safe.
## Testing
- Added new unit test `entity_mapper_iteration` which tests the
`SceneEntityMapper` implementation of `EntityMapper::mappings`.
- Added unit tests to ensure `DynEntityMapper`, `DynEq` and `DynHash`
are object safe.
- Passed CI on my Windows 10 development environment
---
## Changelog
- Added `mappings` to `EntityMapper` trait.
## Migration Guide
- If you are implementing `EntityMapper` yourself, you can use the below
as a stub implementation:
```rust
fn mappings(&self) -> impl Iterator<Item = (Entity, Entity)> {
unimplemented!()
}
```
- If you were using `EntityMapper` as a trait object (`dyn
EntityMapper`), instead use `dyn DynEntityMapper` and its associated
methods.
## Notes
- The original issue proposed returning a `Vec` from `EntityMapper`
instead of an `impl Iterator` to preserve its object safety. This is a
simpler option, but also forces an allocation where it isn't strictly
needed. I've opted for this split into `DynEntityMapper` and
`EntityMapper` as it's been done several times across Bevy already, and
provides maximum flexibility to users.
- `assert_object_safe` is an empty function, since the assertion
actually happens once you try to use a `dyn T` for some trait `T`. I
have still added this function to clearly document what object safety is
within Bevy, and to create a standard way to communicate that a given
trait must be object safe.
- Other traits should have tests added to ensure object safety, but I've
left those off to avoid cluttering this PR further.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Remove some unnecessary coupling between `DynamicTextureAtlasBuilder`
and `bevy_asset`.
## Solution
Remove the dependency of `DynamicTextureAtlasBuilder::add_texture` to
`bevy_asset`, by directly passing the `Image` of the atlas to mutate,
instead of passing separate `Assets<Image>` and `Handle<Image>` for the
function to do the lookup by itself. The lookup can be done from the
caller, and this allows using the builder in contexts where the `Image`
is not stored inside `Assets`.
Clean-up a bit the font atlas files by introducing a `PlacedGlyph` type
storing the `GlyphId` and its `SubpixelOffset`, which were otherwise
always both passed as function parameters and the pair used as key in
hash maps.
## Testing
There's no change in behavior.
---
## Changelog
- Added a `PlacedGlyph` type aggregating a `GlyphId` and a
`SubpixelOffset`. That type is now used as parameter in a few text atlas
APIs, instead of passing individual values.
## Migration Guide
- Replace the `glyph_id` and `subpixel_offset` of a few text atlas APIs
by a single `place_glyph: PlacedGlyph` parameter trivially combining the
two.
# Objective
Some use cases might require holding onto the previous state of the
animation player for change detection.
## Solution
Added `clone` and `copy` implementation to most animation types.
Added optimized `clone_from` implementations for the specific use case
of holding a `PreviousAnimationPlayer` component.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
previously I worked on fixing issue #13646, back when the error message
did not include the type at all.
But that error message had room for improvement, so I included the
feedback of @alice-i-cecile and @MrGVSV.
The error message will now read `the given key (of type
bevy_reflect::tests::Foo) does not support hashing` or 'the given key
(of type bevy_reflect::DynamicStruct) does not support hashing' in case
of a dynamic struct that represents a hashable struct
i also added a new unit test for this new behaviour
(`reflect_map_no_hash_dynamic`).
Fixes#13646 (again)
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
