Fixes#17856.
## Migration Guide
- `EventWriter::send` has been renamed to `EventWriter::write`.
- `EventWriter::send_batch` has been renamed to
`EventWriter::write_batch`.
- `EventWriter::send_default` has been renamed to
`EventWriter::write_default`.
---------
Co-authored-by: François Mockers <mockersf@gmail.com>
## Objective
A major critique of Bevy at the moment is how boilerplatey it is to
compose (and read) entity hierarchies:
```rust
commands
.spawn(Foo)
.with_children(|p| {
p.spawn(Bar).with_children(|p| {
p.spawn(Baz);
});
p.spawn(Bar).with_children(|p| {
p.spawn(Baz);
});
});
```
There is also currently no good way to statically define and return an
entity hierarchy from a function. Instead, people often do this
"internally" with a Commands function that returns nothing, making it
impossible to spawn the hierarchy in other cases (direct World spawns,
ChildSpawner, etc).
Additionally, because this style of API results in creating the
hierarchy bits _after_ the initial spawn of a bundle, it causes ECS
archetype changes (and often expensive table moves).
Because children are initialized after the fact, we also can't count
them to pre-allocate space. This means each time a child inserts itself,
it has a high chance of overflowing the currently allocated capacity in
the `RelationshipTarget` collection, causing literal worst-case
reallocations.
We can do better!
## Solution
The Bundle trait has been extended to support an optional
`BundleEffect`. This is applied directly to World immediately _after_
the Bundle has fully inserted. Note that this is
[intentionally](https://github.com/bevyengine/bevy/discussions/16920)
_not done via a deferred Command_, which would require repeatedly
copying each remaining subtree of the hierarchy to a new command as we
walk down the tree (_not_ good performance).
This allows us to implement the new `SpawnRelated` trait for all
`RelationshipTarget` impls, which looks like this in practice:
```rust
world.spawn((
Foo,
Children::spawn((
Spawn((
Bar,
Children::spawn(Spawn(Baz)),
)),
Spawn((
Bar,
Children::spawn(Spawn(Baz)),
)),
))
))
```
`Children::spawn` returns `SpawnRelatedBundle<Children, L:
SpawnableList>`, which is a `Bundle` that inserts `Children`
(preallocated to the size of the `SpawnableList::size_hint()`).
`Spawn<B: Bundle>(pub B)` implements `SpawnableList` with a size of 1.
`SpawnableList` is also implemented for tuples of `SpawnableList` (same
general pattern as the Bundle impl).
There are currently three built-in `SpawnableList` implementations:
```rust
world.spawn((
Foo,
Children::spawn((
Spawn(Name::new("Child1")),
SpawnIter(["Child2", "Child3"].into_iter().map(Name::new),
SpawnWith(|parent: &mut ChildSpawner| {
parent.spawn(Name::new("Child4"));
parent.spawn(Name::new("Child5"));
})
)),
))
```
We get the benefits of "structured init", but we have nice flexibility
where it is required!
Some readers' first instinct might be to try to remove the need for the
`Spawn` wrapper. This is impossible in the Rust type system, as a tuple
of "child Bundles to be spawned" and a "tuple of Components to be added
via a single Bundle" is ambiguous in the Rust type system. There are two
ways to resolve that ambiguity:
1. By adding support for variadics to the Rust type system (removing the
need for nested bundles). This is out of scope for this PR :)
2. Using wrapper types to resolve the ambiguity (this is what I did in
this PR).
For the single-entity spawn cases, `Children::spawn_one` does also
exist, which removes the need for the wrapper:
```rust
world.spawn((
Foo,
Children::spawn_one(Bar),
))
```
## This works for all Relationships
This API isn't just for `Children` / `ChildOf` relationships. It works
for any relationship type, and they can be mixed and matched!
```rust
world.spawn((
Foo,
Observers::spawn((
Spawn(Observer::new(|trigger: Trigger<FuseLit>| {})),
Spawn(Observer::new(|trigger: Trigger<Exploded>| {})),
)),
OwnerOf::spawn(Spawn(Bar))
Children::spawn(Spawn(Baz))
))
```
## Macros
While `Spawn` is necessary to satisfy the type system, we _can_ remove
the need to express it via macros. The example above can be expressed
more succinctly using the new `children![X]` macro, which internally
produces `Children::spawn(Spawn(X))`:
```rust
world.spawn((
Foo,
children![
(
Bar,
children![Baz],
),
(
Bar,
children![Baz],
),
]
))
```
There is also a `related!` macro, which is a generic version of the
`children!` macro that supports any relationship type:
```rust
world.spawn((
Foo,
related!(Children[
(
Bar,
related!(Children[Baz]),
),
(
Bar,
related!(Children[Baz]),
),
])
))
```
## Returning Hierarchies from Functions
Thanks to these changes, the following pattern is now possible:
```rust
fn button(text: &str, color: Color) -> impl Bundle {
(
Node {
width: Val::Px(300.),
height: Val::Px(100.),
..default()
},
BackgroundColor(color),
children![
Text::new(text),
]
)
}
fn ui() -> impl Bundle {
(
Node {
width: Val::Percent(100.0),
height: Val::Percent(100.0),
..default(),
},
children![
button("hello", BLUE),
button("world", RED),
]
)
}
// spawn from a system
fn system(mut commands: Commands) {
commands.spawn(ui());
}
// spawn directly on World
world.spawn(ui());
```
## Additional Changes and Notes
* `Bundle::from_components` has been split out into
`BundleFromComponents::from_components`, enabling us to implement
`Bundle` for types that cannot be "taken" from the ECS (such as the new
`SpawnRelatedBundle`).
* The `NoBundleEffect` trait (which implements `BundleEffect`) is
implemented for empty tuples (and tuples of empty tuples), which allows
us to constrain APIs to only accept bundles that do not have effects.
This is critical because the current batch spawn APIs cannot efficiently
apply BundleEffects in their current form (as doing so in-place could
invalidate the cached raw pointers). We could consider allocating a
buffer of the effects to be applied later, but that does have
performance implications that could offset the balance and value of the
batched APIs (and would likely require some refactors to the underlying
code). I've decided to be conservative here. We can consider relaxing
that requirement on those APIs later, but that should be done in a
followup imo.
* I've ported a few examples to illustrate real-world usage. I think in
a followup we should port all examples to the `children!` form whenever
possible (and for cases that require things like SpawnIter, use the raw
APIs).
* Some may ask "why not use the `Relationship` to spawn (ex:
`ChildOf::spawn(Foo)`) instead of the `RelationshipTarget` (ex:
`Children::spawn(Spawn(Foo))`)?". That _would_ allow us to remove the
`Spawn` wrapper. I've explicitly chosen to disallow this pattern.
`Bundle::Effect` has the ability to create _significant_ weirdness.
Things in `Bundle` position look like components. For example
`world.spawn((Foo, ChildOf::spawn(Bar)))` _looks and reads_ like Foo is
a child of Bar. `ChildOf` is in Foo's "component position" but it is not
a component on Foo. This is a huge problem. Now that `Bundle::Effect`
exists, we should be _very_ principled about keeping the "weird and
unintuitive behavior" to a minimum. Things that read like components
_should be the components they appear to be".
## Remaining Work
* The macros are currently trivially implemented using macro_rules and
are currently limited to the max tuple length. They will require a
proc_macro implementation to work around the tuple length limit.
## Next Steps
* Port the remaining examples to use `children!` where possible and raw
`Spawn` / `SpawnIter` / `SpawnWith` where the flexibility of the raw API
is required.
## Migration Guide
Existing spawn patterns will continue to work as expected.
Manual Bundle implementations now require a `BundleEffect` associated
type. Exisiting bundles would have no bundle effect, so use `()`.
Additionally `Bundle::from_components` has been moved to the new
`BundleFromComponents` trait.
```rust
// Before
unsafe impl Bundle for X {
unsafe fn from_components<T, F>(ctx: &mut T, func: &mut F) -> Self {
}
/* remaining bundle impl here */
}
// After
unsafe impl Bundle for X {
type Effect = ();
/* remaining bundle impl here */
}
unsafe impl BundleFromComponents for X {
unsafe fn from_components<T, F>(ctx: &mut T, func: &mut F) -> Self {
}
}
```
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
Co-authored-by: Emerson Coskey <emerson@coskey.dev>
This adds support for one-to-many non-fragmenting relationships (with
planned paths for fragmenting and non-fragmenting many-to-many
relationships). "Non-fragmenting" means that entities with the same
relationship type, but different relationship targets, are not forced
into separate tables (which would cause "table fragmentation").
Functionally, this fills a similar niche as the current Parent/Children
system. The biggest differences are:
1. Relationships have simpler internals and significantly improved
performance and UX. Commands and specialized APIs are no longer
necessary to keep everything in sync. Just spawn entities with the
relationship components you want and everything "just works".
2. Relationships are generalized. Bevy can provide additional built in
relationships, and users can define their own.
**REQUEST TO REVIEWERS**: _please don't leave top level comments and
instead comment on specific lines of code. That way we can take
advantage of threaded discussions. Also dont leave comments simply
pointing out CI failures as I can read those just fine._
## Built on top of what we have
Relationships are implemented on top of the Bevy ECS features we already
have: components, immutability, and hooks. This makes them immediately
compatible with all of our existing (and future) APIs for querying,
spawning, removing, scenes, reflection, etc. The fewer specialized APIs
we need to build, maintain, and teach, the better.
## Why focus on one-to-many non-fragmenting first?
1. This allows us to improve Parent/Children relationships immediately,
in a way that is reasonably uncontroversial. Switching our hierarchy to
fragmenting relationships would have significant performance
implications. ~~Flecs is heavily considering a switch to non-fragmenting
relations after careful considerations of the performance tradeoffs.~~
_(Correction from @SanderMertens: Flecs is implementing non-fragmenting
storage specialized for asset hierarchies, where asset hierarchies are
many instances of small trees that have a well defined structure)_
2. Adding generalized one-to-many relationships is currently a priority
for the [Next Generation Scene / UI
effort](https://github.com/bevyengine/bevy/discussions/14437).
Specifically, we're interested in building reactions and observers on
top.
## The changes
This PR does the following:
1. Adds a generic one-to-many Relationship system
3. Ports the existing Parent/Children system to Relationships, which now
lives in `bevy_ecs::hierarchy`. The old `bevy_hierarchy` crate has been
removed.
4. Adds on_despawn component hooks
5. Relationships can opt-in to "despawn descendants" behavior, meaning
that the entire relationship hierarchy is despawned when
`entity.despawn()` is called. The built in Parent/Children hierarchies
enable this behavior, and `entity.despawn_recursive()` has been removed.
6. `world.spawn` now applies commands after spawning. This ensures that
relationship bookkeeping happens immediately and removes the need to
manually flush. This is in line with the equivalent behaviors recently
added to the other APIs (ex: insert).
7. Removes the ValidParentCheckPlugin (system-driven / poll based) in
favor of a `validate_parent_has_component` hook.
## Using Relationships
The `Relationship` trait looks like this:
```rust
pub trait Relationship: Component + Sized {
type RelationshipSources: RelationshipSources<Relationship = Self>;
fn get(&self) -> Entity;
fn from(entity: Entity) -> Self;
}
```
A relationship is a component that:
1. Is a simple wrapper over a "target" Entity.
2. Has a corresponding `RelationshipSources` component, which is a
simple wrapper over a collection of entities. Every "target entity"
targeted by a "source entity" with a `Relationship` has a
`RelationshipSources` component, which contains every "source entity"
that targets it.
For example, the `Parent` component (as it currently exists in Bevy) is
the `Relationship` component and the entity containing the Parent is the
"source entity". The entity _inside_ the `Parent(Entity)` component is
the "target entity". And that target entity has a `Children` component
(which implements `RelationshipSources`).
In practice, the Parent/Children relationship looks like this:
```rust
#[derive(Relationship)]
#[relationship(relationship_sources = Children)]
pub struct Parent(pub Entity);
#[derive(RelationshipSources)]
#[relationship_sources(relationship = Parent)]
pub struct Children(Vec<Entity>);
```
The Relationship and RelationshipSources derives automatically implement
Component with the relevant configuration (namely, the hooks necessary
to keep everything in sync).
The most direct way to add relationships is to spawn entities with
relationship components:
```rust
let a = world.spawn_empty().id();
let b = world.spawn(Parent(a)).id();
assert_eq!(world.entity(a).get::<Children>().unwrap(), &[b]);
```
There are also convenience APIs for spawning more than one entity with
the same relationship:
```rust
world.spawn_empty().with_related::<Children>(|s| {
s.spawn_empty();
s.spawn_empty();
})
```
The existing `with_children` API is now a simpler wrapper over
`with_related`. This makes this change largely non-breaking for existing
spawn patterns.
```rust
world.spawn_empty().with_children(|s| {
s.spawn_empty();
s.spawn_empty();
})
```
There are also other relationship APIs, such as `add_related` and
`despawn_related`.
## Automatic recursive despawn via the new on_despawn hook
`RelationshipSources` can opt-in to "despawn descendants" behavior,
which will despawn all related entities in the relationship hierarchy:
```rust
#[derive(RelationshipSources)]
#[relationship_sources(relationship = Parent, despawn_descendants)]
pub struct Children(Vec<Entity>);
```
This means that `entity.despawn_recursive()` is no longer required.
Instead, just use `entity.despawn()` and the relevant related entities
will also be despawned.
To despawn an entity _without_ despawning its parent/child descendants,
you should remove the `Children` component first, which will also remove
the related `Parent` components:
```rust
entity
.remove::<Children>()
.despawn()
```
This builds on the on_despawn hook introduced in this PR, which is fired
when an entity is despawned (before other hooks).
## Relationships are the source of truth
`Relationship` is the _single_ source of truth component.
`RelationshipSources` is merely a reflection of what all the
`Relationship` components say. By embracing this, we are able to
significantly improve the performance of the system as a whole. We can
rely on component lifecycles to protect us against duplicates, rather
than needing to scan at runtime to ensure entities don't already exist
(which results in quadratic runtime). A single source of truth gives us
constant-time inserts. This does mean that we cannot directly spawn
populated `Children` components (or directly add or remove entities from
those components). I personally think this is a worthwhile tradeoff,
both because it makes the performance much better _and_ because it means
theres exactly one way to do things (which is a philosophy we try to
employ for Bevy APIs).
As an aside: treating both sides of the relationship as "equivalent
source of truth relations" does enable building simple and flexible
many-to-many relationships. But this introduces an _inherent_ need to
scan (or hash) to protect against duplicates.
[`evergreen_relations`](https://github.com/EvergreenNest/evergreen_relations)
has a very nice implementation of the "symmetrical many-to-many"
approach. Unfortunately I think the performance issues inherent to that
approach make it a poor choice for Bevy's default relationship system.
## Followup Work
* Discuss renaming `Parent` to `ChildOf`. I refrained from doing that in
this PR to keep the diff reasonable, but I'm personally biased toward
this change (and using that naming pattern generally for relationships).
* [Improved spawning
ergonomics](https://github.com/bevyengine/bevy/discussions/16920)
* Consider adding relationship observers/triggers for "relationship
targets" whenever a source is added or removed. This would replace the
current "hierarchy events" system, which is unused upstream but may have
existing users downstream. I think triggers are the better fit for this
than a buffered event queue, and would prefer not to add that back.
* Fragmenting relations: My current idea hinges on the introduction of
"value components" (aka: components whose type _and_ value determines
their ComponentId, via something like Hashing / PartialEq). By labeling
a Relationship component such as `ChildOf(Entity)` as a "value
component", `ChildOf(e1)` and `ChildOf(e2)` would be considered
"different components". This makes the transition between fragmenting
and non-fragmenting a single flag, and everything else continues to work
as expected.
* Many-to-many support
* Non-fragmenting: We can expand Relationship to be a list of entities
instead of a single entity. I have largely already written the code for
this.
* Fragmenting: With the "value component" impl mentioned above, we get
many-to-many support "for free", as it would allow inserting multiple
copies of a Relationship component with different target entities.
Fixes#3742 (If this PR is merged, I think we should open more targeted
followup issues for the work above, with a fresh tracking issue free of
the large amount of less-directed historical context)
Fixes#17301Fixes#12235Fixes#15299Fixes#15308
## Migration Guide
* Replace `ChildBuilder` with `ChildSpawnerCommands`.
* Replace calls to `.set_parent(parent_id)` with
`.insert(Parent(parent_id))`.
* Replace calls to `.replace_children()` with `.remove::<Children>()`
followed by `.add_children()`. Note that you'll need to manually despawn
any children that are not carried over.
* Replace calls to `.despawn_recursive()` with `.despawn()`.
* Replace calls to `.despawn_descendants()` with
`.despawn_related::<Children>()`.
* If you have any calls to `.despawn()` which depend on the children
being preserved, you'll need to remove the `Children` component first.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Continue improving the user experience of our UI Node API in the
direction specified by [Bevy's Next Generation Scene / UI
System](https://github.com/bevyengine/bevy/discussions/14437)
## Solution
As specified in the document above, merge `Style` fields into `Node`,
and move "computed Node fields" into `ComputedNode` (I chose this name
over something like `ComputedNodeLayout` because it currently contains
more than just layout info. If we want to break this up / rename these
concepts, lets do that in a separate PR). `Style` has been removed.
This accomplishes a number of goals:
## Ergonomics wins
Specifying both `Node` and `Style` is now no longer required for
non-default styles
Before:
```rust
commands.spawn((
Node::default(),
Style {
width: Val::Px(100.),
..default()
},
));
```
After:
```rust
commands.spawn(Node {
width: Val::Px(100.),
..default()
});
```
## Conceptual clarity
`Style` was never a comprehensive "style sheet". It only defined "core"
style properties that all `Nodes` shared. Any "styled property" that
couldn't fit that mold had to be in a separate component. A "real" style
system would style properties _across_ components (`Node`, `Button`,
etc). We have plans to build a true style system (see the doc linked
above).
By moving the `Style` fields to `Node`, we fully embrace `Node` as the
driving concept and remove the "style system" confusion.
## Next Steps
* Consider identifying and splitting out "style properties that aren't
core to Node". This should not happen for Bevy 0.15.
---
## Migration Guide
Move any fields set on `Style` into `Node` and replace all `Style`
component usage with `Node`.
Before:
```rust
commands.spawn((
Node::default(),
Style {
width: Val::Px(100.),
..default()
},
));
```
After:
```rust
commands.spawn(Node {
width: Val::Px(100.),
..default()
});
```
For any usage of the "computed node properties" that used to live on
`Node`, use `ComputedNode` instead:
Before:
```rust
fn system(nodes: Query<&Node>) {
for node in &nodes {
let computed_size = node.size();
}
}
```
After:
```rust
fn system(computed_nodes: Query<&ComputedNode>) {
for computed_node in &computed_nodes {
let computed_size = computed_node.size();
}
}
```
# Objective
- closes#15866
## Solution
- Simply migrate where possible.
## Testing
- Expect that CI will do most of the work. Examples is another way of
testing this, as most of the work is in that area.
---
## Notes
For now, this PR doesn't migrate `QueryState::single` and friends as for
now, this look like another issue. So for example, QueryBuilders that
used single or `World::query` that used single wasn't migrated. If there
is a easy way to migrate those, please let me know.
Most of the uses of `Query::single` were removed, the only other uses
that I found was related to tests of said methods, so will probably be
removed when we remove `Query::single`.
# Objective
Currently text is recomputed unnecessarily on any changes to its color,
which is extremely expensive.
## Solution
Split up `TextStyle` into two separate components `TextFont` and
`TextColor`.
## Testing
I added this system to `many_buttons`:
```rust
fn set_text_colors_changed(mut colors: Query<&mut TextColor>) {
for mut text_color in colors.iter_mut() {
text_color.set_changed();
}
}
```
reports ~4fps on main, ~50fps with this PR.
## Migration Guide
`TextStyle` has been renamed to `TextFont` and its `color` field has
been moved to a separate component named `TextColor` which newtypes
`Color`.
**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>
# Objective
Yet another PR for migrating stuff to required components. This time,
cameras!
## Solution
As per the [selected
proposal](https://hackmd.io/tsYID4CGRiWxzsgawzxG_g#Combined-Proposal-1-Selected),
deprecate `Camera2dBundle` and `Camera3dBundle` in favor of `Camera2d`
and `Camera3d`.
Adding a `Camera` without `Camera2d` or `Camera3d` now logs a warning,
as suggested by Cart [on
Discord](https://discord.com/channels/691052431525675048/1264881140007702558/1291506402832945273).
I would personally like cameras to work a bit differently and be split
into a few more components, to avoid some footguns and confusing
semantics, but that is more controversial, and shouldn't block this core
migration.
## Testing
I ran a few 2D and 3D examples, and tried cameras with and without
render graphs.
---
## Migration Guide
`Camera2dBundle` and `Camera3dBundle` have been deprecated in favor of
`Camera2d` and `Camera3d`. Inserting them will now also insert the other
components required by them automatically.
As discussed in #15521
- Partial revert of #14897, reverting the change to the methods to
consume `self`
- The `insert_if` method is kept
The migration guide of #14897 should be removed
Closes#15521
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes#15079 , repairing the `game_menu` example
## Solution
- Changed the target component for the color updates from `UiImage` to
`BackgroundColor`.
- Changed the width of the `button_style` to `300px` to prevent overlap
with the text.
## Testing
Checked that buttons now correctly update their background color on
hover/exit/press.
---
## Showcase
https://github.com/user-attachments/assets/8f7ede9b-c271-4b59-91f9-27d9e3db1429
# Objective
Fixes#14883
## Solution
Pretty simple update to `EntityCommands` methods to consume `self` and
return it rather than taking `&mut self`. The things probably worth
noting:
* I added `#[allow(clippy::should_implement_trait)]` to the `add` method
because it causes a linting conflict with `std::ops::Add`.
* `despawn` and `log_components` now return `Self`. I'm not sure if
that's exactly the desired behavior so I'm happy to adjust if that seems
wrong.
## Testing
Tested with `cargo run -p ci`. I think that should be sufficient to call
things good.
## Migration Guide
The most likely migration needed is changing code from this:
```
let mut entity = commands.get_or_spawn(entity);
if depth_prepass {
entity.insert(DepthPrepass);
}
if normal_prepass {
entity.insert(NormalPrepass);
}
if motion_vector_prepass {
entity.insert(MotionVectorPrepass);
}
if deferred_prepass {
entity.insert(DeferredPrepass);
}
```
to this:
```
let mut entity = commands.get_or_spawn(entity);
if depth_prepass {
entity = entity.insert(DepthPrepass);
}
if normal_prepass {
entity = entity.insert(NormalPrepass);
}
if motion_vector_prepass {
entity = entity.insert(MotionVectorPrepass);
}
if deferred_prepass {
entity.insert(DeferredPrepass);
}
```
as can be seen in several of the example code updates here. There will
probably also be instances where mutable `EntityCommands` vars no longer
need to be mutable.
# Objective
In Bevy 0.13, `BackgroundColor` simply tinted the image of any
`UiImage`. This was confusing: in every other case (e.g. Text), this
added a solid square behind the element. #11165 changed this, but
removed `BackgroundColor` from `ImageBundle` to avoid confusion, since
the semantic meaning had changed.
However, this resulted in a serious UX downgrade / inconsistency, as
this behavior was no longer part of the bundle (unlike for `TextBundle`
or `NodeBundle`), leaving users with a relatively frustrating upgrade
path.
Additionally, adding both `BackgroundColor` and `UiImage` resulted in a
bizarre effect, where the background color was seemingly ignored as it
was covered by a solid white placeholder image.
Fixes#13969.
## Solution
Per @viridia's design:
> - if you don't specify a background color, it's transparent.
> - if you don't specify an image color, it's white (because it's a
multiplier).
> - if you don't specify an image, no image is drawn.
> - if you specify both a background color and an image color, they are
independent.
> - the background color is drawn behind the image (in whatever pixels
are transparent)
As laid out by @benfrankel, this involves:
1. Changing the default `UiImage` to use a transparent texture but a
pure white tint.
2. Adding `UiImage::solid_color` to quickly set placeholder images.
3. Changing the default `BorderColor` and `BackgroundColor` to
transparent.
4. Removing the default overrides for these values in the other assorted
UI bundles.
5. Adding `BackgroundColor` back to `ImageBundle` and `ButtonBundle`.
6. Adding a 1x1 `Image::transparent`, which can be accessed from
`Assets<Image>` via the `TRANSPARENT_IMAGE_HANDLE` constant.
Huge thanks to everyone who helped out with the design in the linked
issue and [the Discord
thread](https://discord.com/channels/691052431525675048/1255209923890118697/1255209999278280844):
this was very much a joint design.
@cart helped me figure out how to set the UiImage's default texture to a
transparent 1x1 image, which is a much nicer fix.
## Testing
I've checked the examples modified by this PR, and the `ui` example as
well just to be sure.
## Migration Guide
- `BackgroundColor` no longer tints the color of images in `ImageBundle`
or `ButtonBundle`. Set `UiImage::color` to tint images instead.
- The default texture for `UiImage` is now a transparent white square.
Use `UiImage::solid_color` to quickly draw debug images.
- The default value for `BackgroundColor` and `BorderColor` is now
transparent. Set the color to white manually to return to previous
behavior.
# Objective
Closes#13017.
## Solution
- Make `AppExit` a enum with a `Success` and `Error` variant.
- Make `App::run()` return a `AppExit` if it ever returns.
- Make app runners return a `AppExit` to signal if they encountered a
error.
---
## Changelog
### Added
- [`App::should_exit`](https://example.org/)
- [`AppExit`](https://docs.rs/bevy/latest/bevy/app/struct.AppExit.html)
to the `bevy` and `bevy_app` preludes,
### Changed
- [`AppExit`](https://docs.rs/bevy/latest/bevy/app/struct.AppExit.html)
is now a enum with 2 variants (`Success` and `Error`).
- The app's [runner
function](https://docs.rs/bevy/latest/bevy/app/struct.App.html#method.set_runner)
now has to return a `AppExit`.
-
[`App::run()`](https://docs.rs/bevy/latest/bevy/app/struct.App.html#method.run)
now also returns the `AppExit` produced by the runner function.
## Migration Guide
- Replace all usages of
[`AppExit`](https://docs.rs/bevy/latest/bevy/app/struct.AppExit.html)
with `AppExit::Success` or `AppExit::Failure`.
- Any custom app runners now need to return a `AppExit`. We suggest you
return a `AppExit::Error` if any `AppExit` raised was a Error. You can
use the new [`App::should_exit`](https://example.org/) method.
- If not exiting from `main` any other way. You should return the
`AppExit` from `App::run()` so the app correctly returns a error code if
anything fails e.g.
```rust
fn main() -> AppExit {
App::new()
//Your setup here...
.run()
}
```
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes#12225
Prior to the `bevy_color` port, `GREEN` used to mean "full green." But
it is now a much darker color matching the css1 spec.
## Solution
Change usages of `basic::GREEN` or `css::GREEN` to `LIME` to restore the
examples to their former colors.
This also removes the duplicate definition of `GREEN` from `css`. (it
was already re-exported from `basic`)
## Note
A lot of these examples could use nicer colors. I'm not trying to do
that here.
"Dark Grey" will be tackled separately and has its own tracking issue.
# Objective
Fixes https://github.com/bevyengine/bevy/issues/11157.
## Solution
Stop using `BackgroundColor` as a color tint for `UiImage`. Add a
`UiImage::color` field for color tint instead. Allow a UI node to
simultaneously include a solid-color background and an image, with the
image rendered on top of the background (this is already how it works
for e.g. text).
---
## Changelog
- The `BackgroundColor` component now renders a solid-color background
behind `UiImage` instead of tinting its color.
- Removed `BackgroundColor` from `ImageBundle`, `AtlasImageBundle`, and
`ButtonBundle`.
- Added `UiImage::color`.
- Expanded `RenderUiSystem` variants.
- Renamed `bevy_ui::extract_text_uinodes` to `extract_uinodes_text` for
consistency.
## Migration Guide
- `BackgroundColor` no longer tints the color of UI images. Use
`UiImage::color` for that instead.
- For solid color buttons, replace `ButtonBundle { background_color:
my_color.into(), ... }` with `ButtonBundle { image:
UiImage::default().with_color(my_color), ... }`, and update button
interaction systems to use `UiImage::color` instead of `BackgroundColor`
as well.
- `bevy_ui::RenderUiSystem::ExtractNode` has been split into
`ExtractBackgrounds`, `ExtractImages`, `ExtractBorders`, and
`ExtractText`.
- `bevy_ui::extract_uinodes` has been split into
`bevy_ui::extract_uinode_background_colors` and
`bevy_ui::extract_uinode_images`.
- `bevy_ui::extract_text_uinodes` has been renamed to
`extract_uinode_text`.
# Objective
- As part of the migration process we need to a) see the end effect of
the migration on user ergonomics b) check for serious perf regressions
c) actually migrate the code
- To accomplish this, I'm going to attempt to migrate all of the
remaining user-facing usages of `LegacyColor` in one PR, being careful
to keep a clean commit history.
- Fixes#12056.
## Solution
I've chosen to use the polymorphic `Color` type as our standard
user-facing API.
- [x] Migrate `bevy_gizmos`.
- [x] Take `impl Into<Color>` in all `bevy_gizmos` APIs
- [x] Migrate sprites
- [x] Migrate UI
- [x] Migrate `ColorMaterial`
- [x] Migrate `MaterialMesh2D`
- [x] Migrate fog
- [x] Migrate lights
- [x] Migrate StandardMaterial
- [x] Migrate wireframes
- [x] Migrate clear color
- [x] Migrate text
- [x] Migrate gltf loader
- [x] Register color types for reflection
- [x] Remove `LegacyColor`
- [x] Make sure CI passes
Incidental improvements to ease migration:
- added `Color::srgba_u8`, `Color::srgba_from_array` and friends
- added `set_alpha`, `is_fully_transparent` and `is_fully_opaque` to the
`Alpha` trait
- add and immediately deprecate (lol) `Color::rgb` and friends in favor
of more explicit and consistent `Color::srgb`
- standardized on white and black for most example text colors
- added vector field traits to `LinearRgba`: ~~`Add`, `Sub`,
`AddAssign`, `SubAssign`,~~ `Mul<f32>` and `Div<f32>`. Multiplications
and divisions do not scale alpha. `Add` and `Sub` have been cut from
this PR.
- added `LinearRgba` and `Srgba` `RED/GREEN/BLUE`
- added `LinearRgba_to_f32_array` and `LinearRgba::to_u32`
## Migration Guide
Bevy's color types have changed! Wherever you used a
`bevy::render::Color`, a `bevy::color::Color` is used instead.
These are quite similar! Both are enums storing a color in a specific
color space (or to be more precise, using a specific color model).
However, each of the different color models now has its own type.
TODO...
- `Color::rgba`, `Color::rgb`, `Color::rbga_u8`, `Color::rgb_u8`,
`Color::rgb_from_array` are now `Color::srgba`, `Color::srgb`,
`Color::srgba_u8`, `Color::srgb_u8` and `Color::srgb_from_array`.
- `Color::set_a` and `Color::a` is now `Color::set_alpha` and
`Color::alpha`. These are part of the `Alpha` trait in `bevy_color`.
- `Color::is_fully_transparent` is now part of the `Alpha` trait in
`bevy_color`
- `Color::r`, `Color::set_r`, `Color::with_r` and the equivalents for
`g`, `b` `h`, `s` and `l` have been removed due to causing silent
relatively expensive conversions. Convert your `Color` into the desired
color space, perform your operations there, and then convert it back
into a polymorphic `Color` enum.
- `Color::hex` is now `Srgba::hex`. Call `.into` or construct a
`Color::Srgba` variant manually to convert it.
- `WireframeMaterial`, `ExtractedUiNode`, `ExtractedDirectionalLight`,
`ExtractedPointLight`, `ExtractedSpotLight` and `ExtractedSprite` now
store a `LinearRgba`, rather than a polymorphic `Color`
- `Color::rgb_linear` and `Color::rgba_linear` are now
`Color::linear_rgb` and `Color::linear_rgba`
- The various CSS color constants are no longer stored directly on
`Color`. Instead, they're defined in the `Srgba` color space, and
accessed via `bevy::color::palettes::css`. Call `.into()` on them to
convert them into a `Color` for quick debugging use, and consider using
the much prettier `tailwind` palette for prototyping.
- The `LIME_GREEN` color has been renamed to `LIMEGREEN` to comply with
the standard naming.
- Vector field arithmetic operations on `Color` (add, subtract, multiply
and divide by a f32) have been removed. Instead, convert your colors
into `LinearRgba` space, and perform your operations explicitly there.
This is particularly relevant when working with emissive or HDR colors,
whose color channel values are routinely outside of the ordinary 0 to 1
range.
- `Color::as_linear_rgba_f32` has been removed. Call
`LinearRgba::to_f32_array` instead, converting if needed.
- `Color::as_linear_rgba_u32` has been removed. Call
`LinearRgba::to_u32` instead, converting if needed.
- Several other color conversion methods to transform LCH or HSL colors
into float arrays or `Vec` types have been removed. Please reimplement
these externally or open a PR to re-add them if you found them
particularly useful.
- Various methods on `Color` such as `rgb` or `hsl` to convert the color
into a specific color space have been removed. Convert into
`LinearRgba`, then to the color space of your choice.
- Various implicitly-converting color value methods on `Color` such as
`r`, `g`, `b` or `h` have been removed. Please convert it into the color
space of your choice, then check these properties.
- `Color` no longer implements `AsBindGroup`. Store a `LinearRgba`
internally instead to avoid conversion costs.
---------
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
Co-authored-by: Afonso Lage <lage.afonso@gmail.com>
Co-authored-by: Rob Parrett <robparrett@gmail.com>
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
The migration process for `bevy_color` (#12013) will be fairly involved:
there will be hundreds of affected files, and a large number of APIs.
## Solution
To allow us to proceed granularly, we're going to keep both
`bevy_color::Color` (new) and `bevy_render::Color` (old) around until
the migration is complete.
However, simply doing this directly is confusing! They're both called
`Color`, making it very hard to tell when a portion of the code has been
ported.
As discussed in #12056, by renaming the old `Color` type, we can make it
easier to gradually migrate over, one API at a time.
## Migration Guide
THIS MIGRATION GUIDE INTENTIONALLY LEFT BLANK.
This change should not be shipped to end users: delete this section in
the final migration guide!
---------
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
# Objective
Plugins are an incredible tool for encapsulating functionality. They are
low-key one of Bevy's best features. Combined with rust's module and
privacy system, it's a match made in heaven.
The one downside is that they can be a little too verbose to define. 90%
of all plugin definitions look something like this:
```rust
pub struct MyPlugin;
impl Plugin for MyPlugin {
fn build(&self, app: &mut App) {
app.init_resource::<CameraAssets>()
.add_event::<SetCamera>()
.add_systems(Update, (collect_set_camera_events, drive_camera).chain());
}
}
```
Every so often it gets a little spicier:
```rust
pub struct MyGenericPlugin<T>(PhantomData<T>);
impl<T> Default for MyGenericPlugin<T> {
fn default() -> Self { ... }
}
impl<T> Plugin for MyGenericPlugin<T> { ... }
```
This is an annoying amount of boilerplate. Ideally, plugins should be
focused and small in scope, which means any app is going to have a *lot*
of them. Writing a plugin should be as easy as possible, and the *only*
part of this process that carries any meaning is the body of `fn build`.
## Solution
Implement `Plugin` for functions that take `&mut App` as a parameter.
The two examples above now look like this:
```rust
pub fn my_plugin(app: &mut App) {
app.init_resource::<CameraAssets>()
.add_event::<SetCamera>()
.add_systems(Update, (collect_set_camera_events, drive_camera).chain());
}
pub fn my_generic_plugin<T>(app: &mut App) {
// No need for PhantomData, it just works.
}
```
Almost all plugins can be written this way, which I believe will make
bevy code much more attractive. Less boilerplate and less meaningless
indentation. More plugins with smaller scopes.
---
## Changelog
The `Plugin` trait is now implemented for all functions that take `&mut
App` as their only parameter. This is an abbreviated way of defining
plugins with less boilerplate than manually implementing the trait.
---------
Co-authored-by: Federico Rinaldi <gisquerin@gmail.com>
# Objective
Fix#10731.
## Solution
Rename `App::add_state<T>(&mut self)` to `init_state`, and add
`App::insert_state<T>(&mut self, state: T)`. I decided on these names
because they are more similar to `init_resource` and `insert_resource`.
I also removed the `States` trait's requirement for `Default`. Instead,
`init_state` requires `FromWorld`.
---
## Changelog
- Renamed `App::add_state` to `init_state`.
- Added `App::insert_state`.
- Removed the `States` trait's requirement for `Default`.
## Migration Guide
- Renamed `App::add_state` to `init_state`.
# Objective
- Fix adding `#![allow(clippy::type_complexity)]` everywhere. like #9796
## Solution
- Use the new [lints] table that will land in 1.74
(https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#lints)
- inherit lint to the workspace, crates and examples.
```
[lints]
workspace = true
```
## Changelog
- Bump rust version to 1.74
- Enable lints table for the workspace
```toml
[workspace.lints.clippy]
type_complexity = "allow"
```
- Allow type complexity for all crates and examples
```toml
[lints]
workspace = true
```
---------
Co-authored-by: Martín Maita <47983254+mnmaita@users.noreply.github.com>
# Objective
- Fixes#10532
## Solution
I've updated the various `Event` send methods to return the sent
`EventId`(s). Since these methods previously returned nothing, and this
information is cheap to copy, there should be minimal negative
consequences to providing this additional information. In the case of
`send_batch`, an iterator is returned built from `Range` and `Map`,
which only consumes 16 bytes on the stack with no heap allocations for
all batch sizes. As such, the cost of this information is negligible.
These changes are reflected for `EventWriter` and `World`. For `World`,
the return types are optional to account for the possible lack of an
`Events` resource. Again, these methods previously returned no
information, so its inclusion should only be a benefit.
## Usage
Now when sending events, the IDs of those events is available for
immediate use:
```rust
// Example of a request-response system where the requester can track handled requests.
/// A system which can make and track requests
fn requester(
mut requests: EventWriter<Request>,
mut handled: EventReader<Handled>,
mut pending: Local<HashSet<EventId<Request>>>,
) {
// Check status of previous requests
for Handled(id) in handled.read() {
pending.remove(&id);
}
if !pending.is_empty() {
error!("Not all my requests were handled on the previous frame!");
pending.clear();
}
// Send a new request and remember its ID for later
let request_id = requests.send(Request::MyRequest { /* ... */ });
pending.insert(request_id);
}
/// A system which handles requests
fn responder(
mut requests: EventReader<Request>,
mut handled: EventWriter<Handled>,
) {
for (request, id) in requests.read_with_id() {
if handle(request).is_ok() {
handled.send(Handled(id));
}
}
}
```
In the above example, a `requester` system can send request events, and
keep track of which ones are currently pending by `EventId`. Then, a
`responder` system can act on that event, providing the ID as a
reference that the `requester` can use. Before this PR, it was not
trivial for a system sending events to keep track of events by ID. This
is unfortunate, since for a system reading events, it is trivial to
access the ID of a event.
---
## Changelog
- Updated `Events`:
- Added `send_batch`
- Modified `send` to return the sent `EventId`
- Modified `send_default` to return the sent `EventId`
- Updated `EventWriter`
- Modified `send_batch` to return all sent `EventId`s
- Modified `send` to return the sent `EventId`
- Modified `send_default` to return the sent `EventId`
- Updated `World`
- Modified `send_event` to return the sent `EventId` if sent, otherwise
`None`.
- Modified `send_event_default` to return the sent `EventId` if sent,
otherwise `None`.
- Modified `send_event_batch` to return all sent `EventId`s if sent,
otherwise `None`.
- Added unit test `test_send_events_ids` to ensure returned `EventId`s
match the sent `Event`s
- Updated uses of modified methods.
## Migration Guide
### `send` / `send_default` / `send_batch`
For the following methods:
- `Events::send`
- `Events::send_default`
- `Events::send_batch`
- `EventWriter::send`
- `EventWriter::send_default`
- `EventWriter::send_batch`
- `World::send_event`
- `World::send_event_default`
- `World::send_event_batch`
Ensure calls to these methods either handle the returned value, or
suppress the result with `;`.
```rust
// Now fails to compile due to mismatched return type
fn send_my_event(mut events: EventWriter<MyEvent>) {
events.send_default()
}
// Fix
fn send_my_event(mut events: EventWriter<MyEvent>) {
events.send_default();
}
```
This will most likely be noticed within `match` statements:
```rust
// Before
match is_pressed {
true => events.send(PlayerAction::Fire),
// ^--^ No longer returns ()
false => {}
}
// After
match is_pressed {
true => {
events.send(PlayerAction::Fire);
},
false => {}
}
```
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
- See fewer warnings when running `cargo clippy` locally.
## Solution
- allow `clippy::type_complexity` in more places, which also signals to
users they should do the same.
# Objective
Make `bevy_ui` "root" nodes more intuitive to use/style by:
- Removing the implicit flexbox styling (such as stretch alignment) that
is applied to them, and replacing it with more intuitive CSS Grid
styling (notably with stretch alignment disabled in both axes).
- Making root nodes layout independently of each other. Instead of there
being a single implicit "viewport" node that all root nodes are children
of, there is now an implicit "viewport" node *per root node*. And layout
of each tree is computed separately.
## Solution
- Remove the global implicit viewport node, and instead create an
implicit viewport node for each user-specified root node.
- Keep track of both the user-specified root nodes and the implicit
viewport nodes in a separate `Vec`.
- Use the window's size as the `available_space` parameter to
`Taffy.compute_layout` rather than setting it on the implicit viewport
node (and set the viewport to `height: 100%; width: 100%` to make this
"just work").
---
## Changelog
- Bevy UI now lays out root nodes independently of each other in
separate layout contexts.
- The implicit viewport node (which contains each user-specified root
node) is now `Display::Grid` with `align_items` and `justify_items` both
set to `Start`.
## Migration Guide
- Bevy UI now lays out root nodes independently of each other in
separate layout contexts. If you were relying on your root nodes being
able to affect each other's layouts, then you may need to wrap them in a
single root node.
- The implicit viewport node (which contains each user-specified root
node) is now `Display::Grid` with `align_items` and `justify_items` both
set to `Start`. You may need to add `height: Val::Percent(100.)` to your
root nodes if you were previously relying on being implicitly set.
# Objective
Fix a few issues with some of the examples:
* Root UI nodes have an implicit parent with `FlexDirection::Row` and
`AlignItems::Stretch` set. Only a width constraint is needed to fill the
viewport. Specifying ```height: Val::Percent(100.)``` is unnecessary and
can cause confusing overflow behaviour.
* The default for position and size constraint properties is
`Val::Auto`. Setting `left: Val::Auto`, `max_height: Val::Auto`, etc
does nothing.
## Solution
Delete those lines. There should be no observable differences in the
behaviours of any of the examples.
Also changed a padding setting in the `flex_layout` example to use the
`axes` helper function.
# Objective
In the `game_menu` example:
```rust
let button_icon_style = Style {
width: Val::Px(30.0),
// This takes the icons out of the flexbox flow, to be positioned exactly
position_type: PositionType::Absolute,
// The icon will be close to the left border of the button
left: Val::Px(10.0),
right: Val::Auto,
..default()
};
```
The default value for `right` is `Val::Auto` so that line is unnecessary
and can be removed.
# Objective
- Better consistency with `add_systems`.
- Deprecating `add_plugin` in favor of a more powerful `add_plugins`.
- Allow passing `Plugin` to `add_plugins`.
- Allow passing tuples to `add_plugins`.
## Solution
- `App::add_plugins` now takes an `impl Plugins` parameter.
- `App::add_plugin` is deprecated.
- `Plugins` is a new sealed trait that is only implemented for `Plugin`,
`PluginGroup` and tuples over `Plugins`.
- All examples, benchmarks and tests are changed to use `add_plugins`,
using tuples where appropriate.
---
## Changelog
### Changed
- `App::add_plugins` now accepts all types that implement `Plugins`,
which is implemented for:
- Types that implement `Plugin`.
- Types that implement `PluginGroup`.
- Tuples (up to 16 elements) over types that implement `Plugins`.
- Deprecated `App::add_plugin` in favor of `App::add_plugins`.
## Migration Guide
- Replace `app.add_plugin(plugin)` calls with `app.add_plugins(plugin)`.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Simplify API and make authoring styles easier
See:
https://github.com/bevyengine/bevy/issues/8540#issuecomment-1536177102
## Solution
- The `size`, `min_size`, `max_size`, and `gap` properties have been
replaced by `width`, `height`, `min_width`, `min_height`, `max_width`,
`max_height`, `row_gap`, and `column_gap` properties
---
## Changelog
- Flattened `Style` properties that have a `Size` value directly into
`Style`
## Migration Guide
- The `size`, `min_size`, `max_size`, and `gap` properties have been
replaced by the `width`, `height`, `min_width`, `min_height`,
`max_width`, `max_height`, `row_gap`, and `column_gap` properties. Use
the new properties instead.
---------
Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
# Objective
- Have a default font
## Solution
- Add a font based on FiraMono containing only ASCII characters and use
it as the default font
- It is behind a feature `default_font` enabled by default
- I also updated examples to use it, but not UI examples to still show
how to use a custom font
---
## Changelog
* If you display text without using the default handle provided by
`TextStyle`, the text will be displayed
Fixes issue mentioned in PR #8285.
_Note: By mistake, this is currently dependent on #8285_
# Objective
Ensure consistency in the spelling of the documentation.
Exceptions:
`crates/bevy_mikktspace/src/generated.rs` - Has not been changed from
licence to license as it is part of a licensing agreement.
Maybe for further consistency,
https://github.com/bevyengine/bevy-website should also be given a look.
## Solution
### Changed the spelling of the current words (UK/CN/AU -> US) :
cancelled -> canceled (Breaking API changes in #8285)
behaviour -> behavior (Breaking API changes in #8285)
neighbour -> neighbor
grey -> gray
recognise -> recognize
centre -> center
metres -> meters
colour -> color
### ~~Update [`engine_style_guide.md`]~~ Moved to #8324
---
## Changelog
Changed UK spellings in documentation to US
## Migration Guide
Non-breaking changes*
\* If merged after #8285
# Objective
Support the following syntax for adding systems:
```rust
App::new()
.add_system(setup.on_startup())
.add_systems((
show_menu.in_schedule(OnEnter(GameState::Paused)),
menu_ssytem.in_set(OnUpdate(GameState::Paused)),
hide_menu.in_schedule(OnExit(GameState::Paused)),
))
```
## Solution
Add the traits `IntoSystemAppConfig{s}`, which provide the extension methods necessary for configuring which schedule a system belongs to. These extension methods return `IntoSystemAppConfig{s}`, which `App::add_system{s}` uses to choose which schedule to add systems to.
---
## Changelog
+ Added the extension methods `in_schedule(label)` and `on_startup()` for configuring the schedule a system belongs to.
## Future Work
* Replace all uses of `add_startup_system` in the engine.
* Deprecate this method
# Objective
Fixes#7632.
As discussed in #7634, it can be quite challenging for users to intuit the mental model of how states now work.
## Solution
Rather than change the behavior of the `OnUpdate` system set, instead work on making sure it's easy to understand what's going on.
Two things have been done:
1. Remove the `.on_update` method from our bevy of system building traits. This was special-cased and made states feel much more magical than they need to.
2. Improve the docs for the `OnUpdate` system set.
# Objective
Implementing `States` manually is repetitive, so let's not.
One thing I'm unsure of is whether the macro import statement is in the right place.
Huge thanks to @maniwani, @devil-ira, @hymm, @cart, @superdump and @jakobhellermann for the help with this PR.
# Objective
- Followup #6587.
- Minimal integration for the Stageless Scheduling RFC: https://github.com/bevyengine/rfcs/pull/45
## Solution
- [x] Remove old scheduling module
- [x] Migrate new methods to no longer use extension methods
- [x] Fix compiler errors
- [x] Fix benchmarks
- [x] Fix examples
- [x] Fix docs
- [x] Fix tests
## Changelog
### Added
- a large number of methods on `App` to work with schedules ergonomically
- the `CoreSchedule` enum
- `App::add_extract_system` via the `RenderingAppExtension` trait extension method
- the private `prepare_view_uniforms` system now has a public system set for scheduling purposes, called `ViewSet::PrepareUniforms`
### Removed
- stages, and all code that mentions stages
- states have been dramatically simplified, and no longer use a stack
- `RunCriteriaLabel`
- `AsSystemLabel` trait
- `on_hierarchy_reports_enabled` run criteria (now just uses an ad hoc resource checking run condition)
- systems in `RenderSet/Stage::Extract` no longer warn when they do not read data from the main world
- `RunCriteriaLabel`
- `transform_propagate_system_set`: this was a nonstandard pattern that didn't actually provide enough control. The systems are already `pub`: the docs have been updated to ensure that the third-party usage is clear.
### Changed
- `System::default_labels` is now `System::default_system_sets`.
- `App::add_default_labels` is now `App::add_default_sets`
- `CoreStage` and `StartupStage` enums are now `CoreSet` and `StartupSet`
- `App::add_system_set` was renamed to `App::add_systems`
- The `StartupSchedule` label is now defined as part of the `CoreSchedules` enum
- `.label(SystemLabel)` is now referred to as `.in_set(SystemSet)`
- `SystemLabel` trait was replaced by `SystemSet`
- `SystemTypeIdLabel<T>` was replaced by `SystemSetType<T>`
- The `ReportHierarchyIssue` resource now has a public constructor (`new`), and implements `PartialEq`
- Fixed time steps now use a schedule (`CoreSchedule::FixedTimeStep`) rather than a run criteria.
- Adding rendering extraction systems now panics rather than silently failing if no subapp with the `RenderApp` label is found.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied.
- `SceneSpawnerSystem` now runs under `CoreSet::Update`, rather than `CoreStage::PreUpdate.at_end()`.
- `bevy_pbr::add_clusters` is no longer an exclusive system
- the top level `bevy_ecs::schedule` module was replaced with `bevy_ecs::scheduling`
- `tick_global_task_pools_on_main_thread` is no longer run as an exclusive system. Instead, it has been replaced by `tick_global_task_pools`, which uses a `NonSend` resource to force running on the main thread.
## Migration Guide
- Calls to `.label(MyLabel)` should be replaced with `.in_set(MySet)`
- Stages have been removed. Replace these with system sets, and then add command flushes using the `apply_system_buffers` exclusive system where needed.
- The `CoreStage`, `StartupStage, `RenderStage` and `AssetStage` enums have been replaced with `CoreSet`, `StartupSet, `RenderSet` and `AssetSet`. The same scheduling guarantees have been preserved.
- Systems are no longer added to `CoreSet::Update` by default. Add systems manually if this behavior is needed, although you should consider adding your game logic systems to `CoreSchedule::FixedTimestep` instead for more reliable framerate-independent behavior.
- Similarly, startup systems are no longer part of `StartupSet::Startup` by default. In most cases, this won't matter to you.
- For example, `add_system_to_stage(CoreStage::PostUpdate, my_system)` should be replaced with
- `add_system(my_system.in_set(CoreSet::PostUpdate)`
- When testing systems or otherwise running them in a headless fashion, simply construct and run a schedule using `Schedule::new()` and `World::run_schedule` rather than constructing stages
- Run criteria have been renamed to run conditions. These can now be combined with each other and with states.
- Looping run criteria and state stacks have been removed. Use an exclusive system that runs a schedule if you need this level of control over system control flow.
- For app-level control flow over which schedules get run when (such as for rollback networking), create your own schedule and insert it under the `CoreSchedule::Outer` label.
- Fixed timesteps are now evaluated in a schedule, rather than controlled via run criteria. The `run_fixed_timestep` system runs this schedule between `CoreSet::First` and `CoreSet::PreUpdate` by default.
- Command flush points introduced by `AssetStage` have been removed. If you were relying on these, add them back manually.
- Adding extract systems is now typically done directly on the main app. Make sure the `RenderingAppExtension` trait is in scope, then call `app.add_extract_system(my_system)`.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. You may need to order your movement systems to occur before this system in order to avoid system order ambiguities in culling behavior.
- the `RenderLabel` `AppLabel` was renamed to `RenderApp` for clarity
- `App::add_state` now takes 0 arguments: the starting state is set based on the `Default` impl.
- Instead of creating `SystemSet` containers for systems that run in stages, simply use `.on_enter::<State::Variant>()` or its `on_exit` or `on_update` siblings.
- `SystemLabel` derives should be replaced with `SystemSet`. You will also need to add the `Debug`, `PartialEq`, `Eq`, and `Hash` traits to satisfy the new trait bounds.
- `with_run_criteria` has been renamed to `run_if`. Run criteria have been renamed to run conditions for clarity, and should now simply return a bool.
- States have been dramatically simplified: there is no longer a "state stack". To queue a transition to the next state, call `NextState::set`
## TODO
- [x] remove dead methods on App and World
- [x] add `App::add_system_to_schedule` and `App::add_systems_to_schedule`
- [x] avoid adding the default system set at inappropriate times
- [x] remove any accidental cycles in the default plugins schedule
- [x] migrate benchmarks
- [x] expose explicit labels for the built-in command flush points
- [x] migrate engine code
- [x] remove all mentions of stages from the docs
- [x] verify docs for States
- [x] fix uses of exclusive systems that use .end / .at_start / .before_commands
- [x] migrate RenderStage and AssetStage
- [x] migrate examples
- [x] ensure that transform propagation is exported in a sufficiently public way (the systems are already pub)
- [x] ensure that on_enter schedules are run at least once before the main app
- [x] re-enable opt-in to execution order ambiguities
- [x] revert change to `update_bounds` to ensure it runs in `PostUpdate`
- [x] test all examples
- [x] unbreak directional lights
- [x] unbreak shadows (see 3d_scene, 3d_shape, lighting, transparaency_3d examples)
- [x] game menu example shows loading screen and menu simultaneously
- [x] display settings menu is a blank screen
- [x] `without_winit` example panics
- [x] ensure all tests pass
- [x] SubApp doc test fails
- [x] runs_spawn_local tasks fails
- [x] [Fix panic_when_hierachy_cycle test hanging](https://github.com/alice-i-cecile/bevy/pull/120)
## Points of Difficulty and Controversy
**Reviewers, please give feedback on these and look closely**
1. Default sets, from the RFC, have been removed. These added a tremendous amount of implicit complexity and result in hard to debug scheduling errors. They're going to be tackled in the form of "base sets" by @cart in a followup.
2. The outer schedule controls which schedule is run when `App::update` is called.
3. I implemented `Label for `Box<dyn Label>` for our label types. This enables us to store schedule labels in concrete form, and then later run them. I ran into the same set of problems when working with one-shot systems. We've previously investigated this pattern in depth, and it does not appear to lead to extra indirection with nested boxes.
4. `SubApp::update` simply runs the default schedule once. This sucks, but this whole API is incomplete and this was the minimal changeset.
5. `time_system` and `tick_global_task_pools_on_main_thread` no longer use exclusive systems to attempt to force scheduling order
6. Implemetnation strategy for fixed timesteps
7. `AssetStage` was migrated to `AssetSet` without reintroducing command flush points. These did not appear to be used, and it's nice to remove these bottlenecks.
8. Migration of `bevy_render/lib.rs` and pipelined rendering. The logic here is unusually tricky, as we have complex scheduling requirements.
## Future Work (ideally before 0.10)
- Rename schedule_v3 module to schedule or scheduling
- Add a derive macro to states, and likely a `EnumIter` trait of some form
- Figure out what exactly to do with the "systems added should basically work by default" problem
- Improve ergonomics for working with fixed timesteps and states
- Polish FixedTime API to match Time
- Rebase and merge #7415
- Resolve all internal ambiguities (blocked on better tools, especially #7442)
- Add "base sets" to replace the removed default sets.
# Objective
I found several words in code and docs are incorrect. This should be fixed.
## Solution
- Fix several minor typos
Co-authored-by: Chris Ohk <utilforever@gmail.com>
# Objective
Fixes#6498.
## Solution
Adding a parent node with properties AlignItems::Center and JustifyContent::Center to centered child nodes and removing their auto-margin properties.
# Objective
Fixes #3225, Allow for flippable UI Images
## Solution
Add flip_x and flip_y fields to UiImage, and swap the UV coordinates accordingly in ui_prepare_nodes.
## Changelog
* Changes UiImage to a struct with texture, flip_x, and flip_y fields.
* Adds flip_x and flip_y fields to ExtractedUiNode.
* Changes extract_uinodes to extract the flip_x and flip_y values from UiImage.
* Changes prepare_uinodes to swap the UV coordinates as required.
* Changes UiImage derefs to texture field accesses.
As mentioned in #2926, it's better to have an explicit type that clearly communicates the intent of the timer mode rather than an opaque boolean, which can be only understood when knowing the signature or having to look up the documentation.
This also opens up a way to merge different timers, such as `Stopwatch`, and possibly future ones, such as `DiscreteStopwatch` and `DiscreteTimer` from #2683, into one struct.
Signed-off-by: Lena Milizé <me@lvmn.org>
# Objective
Fixes#2926.
## Solution
Introduce `TimerMode` which replaces the `bool` argument of `Timer` constructors. A `Default` value for `TimerMode` is `Once`.
---
## Changelog
### Added
- `TimerMode` enum, along with variants `TimerMode::Once` and `TimerMode::Repeating`
### Changed
- Replace `bool` argument of `Timer::new` and `Timer::from_seconds` with `TimerMode`
- Change `repeating: bool` field of `Timer` with `mode: TimerMode`
## Migration Guide
- Replace `Timer::new(duration, false)` with `Timer::new(duration, TimerMode::Once)`.
- Replace `Timer::new(duration, true)` with `Timer::new(duration, TimerMode::Repeating)`.
- Replace `Timer::from_seconds(seconds, false)` with `Timer::from_seconds(seconds, TimerMode::Once)`.
- Replace `Timer::from_seconds(seconds, true)` with `Timer::from_seconds(seconds, TimerMode::Repeating)`.
- Change `timer.repeating()` to `timer.mode() == TimerMode::Repeating`.
# Objective
Fixes#6078. The `UiColor` component is unhelpfully named: it is unclear, ambiguous with border color and
## Solution
Rename the `UiColor` component (and associated fields) to `BackgroundColor` / `background_colorl`.
## Migration Guide
`UiColor` has been renamed to `BackgroundColor`. This change affects `NodeBundle`, `ButtonBundle` and `ImageBundle`. In addition, the corresponding field on `ExtractedUiNode` has been renamed to `background_color` for consistency.
# Objective
Now that we can consolidate Bundles and Components under a single insert (thanks to #2975 and #6039), almost 100% of world spawns now look like `world.spawn().insert((Some, Tuple, Here))`. Spawning an entity without any components is an extremely uncommon pattern, so it makes sense to give spawn the "first class" ergonomic api. This consolidated api should be made consistent across all spawn apis (such as World and Commands).
## Solution
All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input:
```rust
// before:
commands
.spawn()
.insert((A, B, C));
world
.spawn()
.insert((A, B, C);
// after
commands.spawn((A, B, C));
world.spawn((A, B, C));
```
All existing instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api. A new `spawn_empty` has been added, replacing the old `spawn` api.
By allowing `world.spawn(some_bundle)` to replace `world.spawn().insert(some_bundle)`, this opened the door to removing the initial entity allocation in the "empty" archetype / table done in `spawn()` (and subsequent move to the actual archetype in `.insert(some_bundle)`).
This improves spawn performance by over 10%:
To take this measurement, I added a new `world_spawn` benchmark.
Unfortunately, optimizing `Commands::spawn` is slightly less trivial, as Commands expose the Entity id of spawned entities prior to actually spawning. Doing the optimization would (naively) require assurances that the `spawn(some_bundle)` command is applied before all other commands involving the entity (which would not necessarily be true, if memory serves). Optimizing `Commands::spawn` this way does feel possible, but it will require careful thought (and maybe some additional checks), which deserves its own PR. For now, it has the same performance characteristics of the current `Commands::spawn_bundle` on main.
**Note that 99% of this PR is simple renames and refactors. The only code that needs careful scrutiny is the new `World::spawn()` impl, which is relatively straightforward, but it has some new unsafe code (which re-uses battle tested BundlerSpawner code path).**
---
## Changelog
- All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input
- All instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api
- World and Commands now have `spawn_empty()`, which is equivalent to the old `spawn()` behavior.
## Migration Guide
```rust
// Old (0.8):
commands
.spawn()
.insert_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));
// Old (0.8):
commands.spawn_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));
// Old (0.8):
let entity = commands.spawn().id();
// New (0.9)
let entity = commands.spawn_empty().id();
// Old (0.8)
let entity = world.spawn().id();
// New (0.9)
let entity = world.spawn_empty();
```
*This PR description is an edited copy of #5007, written by @alice-i-cecile.*
# Objective
Follow-up to https://github.com/bevyengine/bevy/pull/2254. The `Resource` trait currently has a blanket implementation for all types that meet its bounds.
While ergonomic, this results in several drawbacks:
* it is possible to make confusing, silent mistakes such as inserting a function pointer (Foo) rather than a value (Foo::Bar) as a resource
* it is challenging to discover if a type is intended to be used as a resource
* we cannot later add customization options (see the [RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/27-derive-component.md) for the equivalent choice for Component).
* dependencies can use the same Rust type as a resource in invisibly conflicting ways
* raw Rust types used as resources cannot preserve privacy appropriately, as anyone able to access that type can read and write to internal values
* we cannot capture a definitive list of possible resources to display to users in an editor
## Notes to reviewers
* Review this commit-by-commit; there's effectively no back-tracking and there's a lot of churn in some of these commits.
*ira: My commits are not as well organized :')*
* I've relaxed the bound on Local to Send + Sync + 'static: I don't think these concerns apply there, so this can keep things simple. Storing e.g. a u32 in a Local is fine, because there's a variable name attached explaining what it does.
* I think this is a bad place for the Resource trait to live, but I've left it in place to make reviewing easier. IMO that's best tackled with https://github.com/bevyengine/bevy/issues/4981.
## Changelog
`Resource` is no longer automatically implemented for all matching types. Instead, use the new `#[derive(Resource)]` macro.
## Migration Guide
Add `#[derive(Resource)]` to all types you are using as a resource.
If you are using a third party type as a resource, wrap it in a tuple struct to bypass orphan rules. Consider deriving `Deref` and `DerefMut` to improve ergonomics.
`ClearColor` no longer implements `Component`. Using `ClearColor` as a component in 0.8 did nothing.
Use the `ClearColorConfig` in the `Camera3d` and `Camera2d` components instead.
Co-authored-by: Alice <alice.i.cecile@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
