# Objective
UIs created for Bevy cannot currently be made accessible. This PR aims to address that.
## Solution
Integrate AccessKit as a dependency, adding accessibility support to existing bevy_ui widgets.
## Changelog
### Added
* Integrate with and expose [AccessKit](https://accesskit.dev) for platform accessibility.
* Add `Label` for marking text specifically as a label for UI controls.
# Objective
This adds small comment to window fall through example that it won't work on specific platforms. This information is documented in `Cursor` api but I think it is worth to add it in example description for clarity sake.
# Objective
`Size::width` sets the `height` field to `Val::DEFAULT` which is `Val::Undefined`, but the default for `Size` `height` is `Val::Auto`.
`Size::height` has the same problem, but with the `width` field.
The UI examples specify numeric values in many places where they could either be elided or replaced by composition of the Flex enum properties.
related: https://github.com/bevyengine/bevy/pull/7468
fixes: https://github.com/bevyengine/bevy/issues/6498
## Solution
Change `Size::width` so it sets `height` to `Val::AUTO` and change `Size::height` so it sets `width` to `Val::AUTO`.
Added some tests so this doesn't happen again.
## Changelog
Changed `Size::width` so it sets the `height` to `Val::AUTO`.
Changed `Size::height` so it sets the `width` to `Val::AUTO`.
Added tests to `geometry.rs` for `Size` and `UiRect` to ensure correct behaviour.
Simplified the UI examples. Replaced numeric values with the Flex property enums or elided them where possible, and removed the remaining use of auto margins.
## Migration Guide
The `Size::width` constructor function now sets the `height` to `Val::Auto` instead of `Val::Undefined`.
The `Size::height` constructor function now sets the `width` to `Val::Auto` instead of `Val::Undefined`.
# Objective
NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267.
"Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365).
## Solution
This adds "base sets" as a variant of `SystemSet`:
A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive:
```rust
#[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)]
#[system_set(base)]
enum MyBaseSet {
A,
B,
}
```
**Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build.
**Base sets cannot belong to other sets**: this is where the word "base" comes from
Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set.
```rust
app.add_system(foo.in_base_set(MyBaseSet::A))
// X must be a normal set ... base sets cannot be added to base sets
.configure_set(X.in_base_set(MyBaseSet::A))
```
Base sets can still be configured like normal sets:
```rust
app.add_system(MyBaseSet::B.after(MyBaseSet::Ap))
```
The primary use case for base sets is enabling a "default base set":
```rust
schedule.set_default_base_set(CoreSet::Update)
// this will belong to CoreSet::Update by default
.add_system(foo)
// this will override the default base set with PostUpdate
.add_system(bar.in_base_set(CoreSet::PostUpdate))
```
This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides.
---
## Changelog
- Added "base sets" and ported CoreSet to use them.
## Migration Guide
TODO
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
- Update winit to 0.28
## Solution
- Small API change
- A security advisory has been added for a unmaintained crate used by a dependency of winit build script for wayland
I didn't do anything for Android support in this PR though it should be fixable, it should be done in a separate one, maybe https://github.com/bevyengine/bevy/pull/6830
---
## Changelog
- `window.always_on_top` has been removed, you can now use `window.window_level`
## Migration Guide
before:
```rust
app.new()
.add_plugins(DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
always_on_top: true,
..default()
}),
..default()
}));
```
after:
```rust
app.new()
.add_plugins(DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
window_level: bevy:🪟:WindowLevel::AlwaysOnTop,
..default()
}),
..default()
}));
```
## Objective
A common easy to miss mistake is to write something like:
``` rust
Size::new(Val::Percent(100.), Val::Px(100.));
```
`UiRect` has the `left`, `right`, `all`, `vertical`, etc constructor functions, `Size` is used a lot more frequently but lacks anything similar.
## Solution
Implement `all`, `width` and `height` functions for `Size`.
## Changelog
* Added `all`, `width` and `height` functions to `Size`.
# Objective
Fix https://github.com/bevyengine/bevy/issues/4530
- Make it easier to open/close/modify windows by setting them up as `Entity`s with a `Window` component.
- Make multiple windows very simple to set up. (just add a `Window` component to an entity and it should open)
## Solution
- Move all properties of window descriptor to ~components~ a component.
- Replace `WindowId` with `Entity`.
- ~Use change detection for components to update backend rather than events/commands. (The `CursorMoved`/`WindowResized`/... events are kept for user convenience.~
Check each field individually to see what we need to update, events are still kept for user convenience.
---
## Changelog
- `WindowDescriptor` renamed to `Window`.
- Width/height consolidated into a `WindowResolution` component.
- Requesting maximization/minimization is done on the [`Window::state`] field.
- `WindowId` is now `Entity`.
## Migration Guide
- Replace `WindowDescriptor` with `Window`.
- Change `width` and `height` fields in a `WindowResolution`, either by doing
```rust
WindowResolution::new(width, height) // Explicitly
// or using From<_> for tuples for convenience
(1920., 1080.).into()
```
- Replace any `WindowCommand` code to just modify the `Window`'s fields directly and creating/closing windows is now by spawning/despawning an entity with a `Window` component like so:
```rust
let window = commands.spawn(Window { ... }).id(); // open window
commands.entity(window).despawn(); // close window
```
## Unresolved
- ~How do we tell when a window is minimized by a user?~
~Currently using the `Resize(0, 0)` as an indicator of minimization.~
No longer attempting to tell given how finnicky this was across platforms, now the user can only request that a window be maximized/minimized.
## Future work
- Move `exit_on_close` functionality out from windowing and into app(?)
- https://github.com/bevyengine/bevy/issues/5621
- https://github.com/bevyengine/bevy/issues/7099
- https://github.com/bevyengine/bevy/issues/7098
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Remove the `VerticalAlign` enum.
Text's alignment field should only affect the text's internal text alignment, not its position. The only way to control a `TextBundle`'s position and bounds should be through the manipulation of the constraints in the `Style` components of the nodes in the Bevy UI's layout tree.
`Text2dBundle` should have a separate `Anchor` component that sets its position relative to its transform.
Related issues: #676, #1490, #5502, #5513, #5834, #6717, #6724, #6741, #6748
## Changelog
* Changed `TextAlignment` into an enum with `Left`, `Center`, and `Right` variants.
* Removed the `HorizontalAlign` and `VerticalAlign` types.
* Added an `Anchor` component to `Text2dBundle`
* Added `Component` derive to `Anchor`
* Use `f32::INFINITY` instead of `f32::MAX` to represent unbounded text in Text2dBounds
## Migration Guide
The `alignment` field of `Text` now only affects the text's internal alignment.
### Change `TextAlignment` to TextAlignment` which is now an enum. Replace:
* `TextAlignment::TOP_LEFT`, `TextAlignment::CENTER_LEFT`, `TextAlignment::BOTTOM_LEFT` with `TextAlignment::Left`
* `TextAlignment::TOP_CENTER`, `TextAlignment::CENTER_LEFT`, `TextAlignment::BOTTOM_CENTER` with `TextAlignment::Center`
* `TextAlignment::TOP_RIGHT`, `TextAlignment::CENTER_RIGHT`, `TextAlignment::BOTTOM_RIGHT` with `TextAlignment::Right`
### Changes for `Text2dBundle`
`Text2dBundle` has a new field 'text_anchor' that takes an `Anchor` component that controls its position relative to its transform.
# Objective
Add useful information about cursor position relative to a UI node. Fixes#7079.
## Solution
- Added a new `RelativeCursorPosition` component
---
## Changelog
- Added
- `RelativeCursorPosition`
- an example showcasing the new component
Co-authored-by: Dawid Piotrowski <41804418+Pietrek14@users.noreply.github.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
- Bevy should be usable to create 'overlay' type apps, where the input is not captured by Bevy, but passed down/into a target app, or to allow passive displays/widgets etc.
## Solution
- the `winit:🪟:Window` already has a `set_cursor_hittest()` which basically does this for mouse input events, so I've exposed it (trying to copy the style laid out in the existing wrappings, and added a simple demo.
---
## Changelog
- Added `hittest` to `WindowAttributes`
- Added the `hittest`'s setters/getters
- Modified the `WindowBuilder`
- Modifed the `WindowDescriptor`'s `Default` impl.
- Added an example `cargo run --example fallthrough`
# Objective
Fixes: https://github.com/bevyengine/bevy/issues/6466
Summary: The UI Scaling example dynamically scales the UI which will dynamically allocate fonts to the font atlas surpassing the protective limit, throwing a panic.
## Solution
- Set TextSettings.allow_dynamic_font_size = true for the UI Scaling example. This is the ideal solution since the dynamic changes to the UI are not continuous yet still discrete.
- Update the panic text to reflect ui scaling as a potential cause
# Objective
Add consistent UI rendering and interaction where deep nodes inside two different hierarchies will never render on top of one-another by default and offer an escape hatch (z-index) for nodes to change their depth.
## The problem with current implementation
The current implementation of UI rendering is broken in that regard, mainly because [it sets the Z value of the `Transform` component based on a "global Z" space](https://github.com/bevyengine/bevy/blob/main/crates/bevy_ui/src/update.rs#L43) shared by all nodes in the UI. This doesn't account for the fact that each node's final `GlobalTransform` value will be relative to its parent. This effectively makes the depth unpredictable when two deep trees are rendered on top of one-another.
At the moment, it's also up to each part of the UI code to sort all of the UI nodes. The solution that's offered here does the full sorting of UI node entities once and offers the result through a resource so that all systems can use it.
## Solution
### New ZIndex component
This adds a new optional `ZIndex` enum component for nodes which offers two mechanism:
- `ZIndex::Local(i32)`: Overrides the depth of the node relative to its siblings.
- `ZIndex::Global(i32)`: Overrides the depth of the node relative to the UI root. This basically allows any node in the tree to "escape" the parent and be ordered relative to the entire UI.
Note that in the current implementation, omitting `ZIndex` on a node has the same result as adding `ZIndex::Local(0)`. Additionally, the "global" stacking context is essentially a way to add your node to the root stacking context, so using `ZIndex::Local(n)` on a root node (one without parent) will share that space with all nodes using `Index::Global(n)`.
### New UiStack resource
This adds a new `UiStack` resource which is calculated from both hierarchy and `ZIndex` during UI update and contains a vector of all node entities in the UI, ordered by depth (from farthest from camera to closest). This is exposed publicly by the bevy_ui crate with the hope that it can be used for consistent ordering and to reduce the amount of sorting that needs to be done by UI systems (i.e. instead of sorting everything by `global_transform.z` in every system, this array can be iterated over).
### New z_index example
This also adds a new z_index example that showcases the new `ZIndex` component. It's also a good general demo of the new UI stack system, because making this kind of UI was very broken with the old system (e.g. nodes would render on top of each other, not respecting hierarchy or insert order at all).
---
## Changelog
- Added the `ZIndex` component to bevy_ui.
- Added the `UiStack` resource to bevy_ui, and added implementation in a new `stack.rs` module.
- Removed the previous Z updating system from bevy_ui, because it was replaced with the above.
- Changed bevy_ui rendering to use UiStack instead of z ordering.
- Changed bevy_ui focus/interaction system to use UiStack instead of z ordering.
- Added a new z_index example.
## ZIndex demo
Here's a demo I wrote to test these features
https://user-images.githubusercontent.com/1060971/188329295-d7beebd6-9aee-43ab-821e-d437df5dbe8a.mp4
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Following discussion on #3536 and #3522, `Handle::as_weak()` takes a type `U`, reinterpreting the handle as of another asset type while keeping the same ID. This is mainly used today in font atlas code. This PR does two things:
- Rename the method to `cast_weak()` to make its intent more clear
- Actually change the type uuid in the handle if it's not an asset path variant.
## Migration Guide
- Rename `Handle::as_weak` uses to `Handle::cast_weak`
The method now properly sets the associated type uuid if the handle is a direct reference (e.g. not a reference to an `AssetPath`), so adjust you code accordingly if you relied on the previous behavior.
# Objective
- fix new clippy lints before they get stable and break CI
## Solution
- run `clippy --fix` to auto-fix machine-applicable lints
- silence `clippy::should_implement_trait` for `fn HandleId::default<T: Asset>`
## Changes
- always prefer `format!("{inline}")` over `format!("{}", not_inline)`
- prefer `Box::default` (or `Box::<T>::default` if necessary) over `Box::new(T::default())`
# Objective
Fixes#5884#2879
Alternative to #2988#5885#2886
"Immutable" Plugin settings are currently represented as normal ECS resources, which are read as part of plugin init. This presents a number of problems:
1. If a user inserts the plugin settings resource after the plugin is initialized, it will be silently ignored (and use the defaults instead)
2. Users can modify the plugin settings resource after the plugin has been initialized. This creates a false sense of control over settings that can no longer be changed.
(1) and (2) are especially problematic and confusing for the `WindowDescriptor` resource, but this is a general problem.
## Solution
Immutable Plugin settings now live on each Plugin struct (ex: `WindowPlugin`). PluginGroups have been reworked to support overriding plugin values. This also removes the need for the `add_plugins_with` api, as the `add_plugins` api can use the builder pattern directly. Settings that can be used at runtime continue to be represented as ECS resources.
Plugins are now configured like this:
```rust
app.add_plugin(AssetPlugin {
watch_for_changes: true,
..default()
})
```
PluginGroups are now configured like this:
```rust
app.add_plugins(DefaultPlugins
.set(AssetPlugin {
watch_for_changes: true,
..default()
})
)
```
This is an alternative to #2988, which is similar. But I personally prefer this solution for a couple of reasons:
* ~~#2988 doesn't solve (1)~~ #2988 does solve (1) and will panic in that case. I was wrong!
* This PR directly ties plugin settings to Plugin types in a 1:1 relationship, rather than a loose "setup resource" <-> plugin coupling (where the setup resource is consumed by the first plugin that uses it).
* I'm not a huge fan of overloading the ECS resource concept and implementation for something that has very different use cases and constraints.
## Changelog
- PluginGroups can now be configured directly using the builder pattern. Individual plugin values can be overridden by using `plugin_group.set(SomePlugin {})`, which enables overriding default plugin values.
- `WindowDescriptor` plugin settings have been moved to `WindowPlugin` and `AssetServerSettings` have been moved to `AssetPlugin`
- `app.add_plugins_with` has been replaced by using `add_plugins` with the builder pattern.
## Migration Guide
The `WindowDescriptor` settings have been moved from a resource to `WindowPlugin::window`:
```rust
// Old (Bevy 0.8)
app
.insert_resource(WindowDescriptor {
width: 400.0,
..default()
})
.add_plugins(DefaultPlugins)
// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(WindowPlugin {
window: WindowDescriptor {
width: 400.0,
..default()
},
..default()
}))
```
The `AssetServerSettings` resource has been removed in favor of direct `AssetPlugin` configuration:
```rust
// Old (Bevy 0.8)
app
.insert_resource(AssetServerSettings {
watch_for_changes: true,
..default()
})
.add_plugins(DefaultPlugins)
// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(AssetPlugin {
watch_for_changes: true,
..default()
}))
```
`add_plugins_with` has been replaced by `add_plugins` in combination with the builder pattern:
```rust
// Old (Bevy 0.8)
app.add_plugins_with(DefaultPlugins, |group| group.disable::<AssetPlugin>());
// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.build().disable::<AssetPlugin>());
```
# Objective
- Add Time-Adjusted Rolling EMA-based smoothing to diagnostics.
- Closes#4983; see that issue for more more information.
## Terms
- EMA - [Exponential Moving Average](https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average)
- SMA - [Simple Moving Average](https://en.wikipedia.org/wiki/Moving_average#Simple_moving_average)
## Solution
- We use a fairly standard approximation of a true EMA where $EMA_{\text{frame}} = EMA_{\text{previous}} + \alpha \left( x_{\text{frame}} - EMA_{\text{previous}} \right)$ where $\alpha = \Delta t / \tau$ and $\tau$ is an arbitrary smoothness factor. (See #4983 for more discussion of the math.)
- The smoothness factor is here defaulted to $2 / 21$; this was chosen fairly arbitrarily as supposedly related to the existing 20-bucket SMA.
- The smoothness factor can be set on a per-diagnostic basis via `Diagnostic::with_smoothing_factor`.
---
## Changelog
### Added
- `Diagnostic::smoothed` - provides an exponentially smoothed view of a recorded diagnostic, to e.g. reduce jitter in frametime readings.
### Changed
- `LogDiagnosticsPlugin` now records the smoothed value rather than the raw value.
- For diagnostics recorded less often than every 0.1 seconds, this change to defaults will have no visible effect.
- For discrete diagnostics where this smoothing is not desirable, set a smoothing factor of 0 to disable smoothing.
- The average of the recent history is still shown when available.
# Objective
- Make `Time` API more consistent.
- Support time accel/decel/pause.
## Solution
This is just the `Time` half of #3002. I was told that part isn't controversial.
- Give the "delta time" and "total elapsed time" methods `f32`, `f64`, and `Duration` variants with consistent naming.
- Implement accelerating / decelerating the passage of time.
- Implement stopping time.
---
## Changelog
- Changed `time_since_startup` to `elapsed` because `time.time_*` is just silly.
- Added `relative_speed` and `set_relative_speed` methods.
- Added `is_paused`, `pause`, `unpause` , and methods. (I'd prefer `resume`, but `unpause` matches `Timer` API.)
- Added `raw_*` variants of the "delta time" and "total elapsed time" methods.
- Added `first_update` method because there's a non-zero duration between startup and the first update.
## Migration Guide
- `time.time_since_startup()` -> `time.elapsed()`
- `time.seconds_since_startup()` -> `time.elapsed_seconds_f64()`
- `time.seconds_since_startup_wrapped_f32()` -> `time.elapsed_seconds_wrapped()`
If you aren't sure which to use, most systems should continue to use "scaled" time (e.g. `time.delta_seconds()`). The realtime "unscaled" time measurements (e.g. `time.raw_delta_seconds()`) are mostly for debugging and profiling.
# Objective
To be consistent like other examples, it's better to keep file name and example name same, so we don't need to find correct example name in Cargo.toml.
## Solution
Rename example file scaling.rs to ui_scaling.rs.
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#5820
## Solution
Change field name and documentation from `bevy::ui::Node` struct
---
## Changelog
`bevy::ui::Node` `size` field has renamed to `calculated_size`
## Migration Guide
All references to the old `size` name has been changed, to access `bevy::ui::Node` `size` field use `calculated_size`
# Objective
Closes#6202.
The default background color for `NodeBundle` is currently white.
However, it's very rare that you actually want a white background color.
Instead, you often want a background color specific to the style of your game or a transparent background (e.g. for UI layout nodes).
## Solution
`Default` is not derived for `NodeBundle` anymore, but explicitly specified.
The default background color is now transparent (`Color::NONE.into()`) as this is the most common use-case, is familiar from the web and makes specifying a layout for your UI less tedious.
---
## Changelog
- Changed the default `NodeBundle.background_color` to be transparent (`Color::NONE.into()`).
## Migration Guide
If you want a `NodeBundle` with a white background color, you must explicitly specify it:
Before:
```rust
let node = NodeBundle {
..default()
}
```
After:
```rust
let node = NodeBundle {
background_color: Color::WHITE.into(),
..default()
}
```
# 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();
```
# Objective
- Allow users to change the scaling of the UI
- Adopted from #2808
## Solution
- This is an accessibility feature for fixed-size UI elements, allowing the developer to expose a range of UI scales for the player to set a scale that works for their needs.
> - The user can modify the UiScale struct to change the scaling at runtime. This multiplies the Px values by the scale given, while not touching any others.
> - The example showcases how this even allows for fluid transitions
> Here's how the example looks like:
https://user-images.githubusercontent.com/1631166/132979069-044161a9-8e85-45ab-9e93-fcf8e3852c2b.mp4
---
## Changelog
- Added a `UiScale` which can be used to scale all of UI
Co-authored-by: Andreas Weibye <13300393+Weibye@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Very small convenience constructors added to `Size`.
Does not change current examples too much but I'm working on a rather complex UI use-case where this cuts down on some extra typing :)
*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>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Change frametimediagnostic from seconds to milliseconds because this will always be less than one seconds and is the common diagnostic display unit for game engines.
## Solution
- multiplied the existing value by 1000
---
## Changelog
Frametimes are now reported in milliseconds
Co-authored-by: Syama Mishra <38512086+SyamaMishra@users.noreply.github.com>
Co-authored-by: McSpidey <mcspidey@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Creating UI elements is very boilerplate-y with lots of indentation.
This PR aims to reduce boilerplate around creating text elements.
## Changelog
* Renamed `Text::with_section` to `from_section`.
It no longer takes a `TextAlignment` as argument, as the vast majority of cases left it `Default::default()`.
* Added `Text::from_sections` which creates a `Text` from a list of `TextSections`.
Reduces line-count and reduces indentation by one level.
* Added `Text::with_alignment`.
A builder style method for setting the `TextAlignment` of a `Text`.
* Added `TextSection::new`.
Does not reduce line count, but reduces character count and made it easier to read. No more `.to_string()` calls!
* Added `TextSection::from_style` which creates an empty `TextSection` with a style.
No more empty strings! Reduces indentation.
* Added `TextAlignment::CENTER` and friends.
* Added methods to `TextBundle`. `from_section`, `from_sections`, `with_text_alignment` and `with_style`.
## Note for reviewers.
Because of the nature of these changes I recommend setting diff view to 'split'.
~~Look for the book icon~~ cog in the top-left of the Files changed tab.
Have fun reviewing ❤️
<sup> >:D </sup>
## Migration Guide
`Text::with_section` was renamed to `from_section` and no longer takes a `TextAlignment` as argument.
Use `with_alignment` to set the alignment instead.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Remove unnecessary calls to `iter()`/`iter_mut()`.
Mainly updates the use of queries in our code, docs, and examples.
```rust
// From
for _ in list.iter() {
for _ in list.iter_mut() {
// To
for _ in &list {
for _ in &mut list {
```
We already enable the pedantic lint [clippy::explicit_iter_loop](https://rust-lang.github.io/rust-clippy/stable/) inside of Bevy. However, this only warns for a few known types from the standard library.
## Note for reviewers
As you can see the additions and deletions are exactly equal.
Maybe give it a quick skim to check I didn't sneak in a crypto miner, but you don't have to torture yourself by reading every line.
I already experienced enough pain making this PR :)
Co-authored-by: devil-ira <justthecooldude@gmail.com>
This adds "high level camera driven rendering" to Bevy. The goal is to give users more control over what gets rendered (and where) without needing to deal with render logic. This will make scenarios like "render to texture", "multiple windows", "split screen", "2d on 3d", "3d on 2d", "pass layering", and more significantly easier.
Here is an [example of a 2d render sandwiched between two 3d renders (each from a different perspective)](https://gist.github.com/cart/4fe56874b2e53bc5594a182fc76f4915):
Users can now spawn a camera, point it at a RenderTarget (a texture or a window), and it will "just work".
Rendering to a second window is as simple as spawning a second camera and assigning it to a specific window id:
```rust
// main camera (main window)
commands.spawn_bundle(Camera2dBundle::default());
// second camera (other window)
commands.spawn_bundle(Camera2dBundle {
camera: Camera {
target: RenderTarget::Window(window_id),
..default()
},
..default()
});
```
Rendering to a texture is as simple as pointing the camera at a texture:
```rust
commands.spawn_bundle(Camera2dBundle {
camera: Camera {
target: RenderTarget::Texture(image_handle),
..default()
},
..default()
});
```
Cameras now have a "render priority", which controls the order they are drawn in. If you want to use a camera's output texture as a texture in the main pass, just set the priority to a number lower than the main pass camera (which defaults to `0`).
```rust
// main pass camera with a default priority of 0
commands.spawn_bundle(Camera2dBundle::default());
commands.spawn_bundle(Camera2dBundle {
camera: Camera {
target: RenderTarget::Texture(image_handle.clone()),
priority: -1,
..default()
},
..default()
});
commands.spawn_bundle(SpriteBundle {
texture: image_handle,
..default()
})
```
Priority can also be used to layer to cameras on top of each other for the same RenderTarget. This is what "2d on top of 3d" looks like in the new system:
```rust
commands.spawn_bundle(Camera3dBundle::default());
commands.spawn_bundle(Camera2dBundle {
camera: Camera {
// this will render 2d entities "on top" of the default 3d camera's render
priority: 1,
..default()
},
..default()
});
```
There is no longer the concept of a global "active camera". Resources like `ActiveCamera<Camera2d>` and `ActiveCamera<Camera3d>` have been replaced with the camera-specific `Camera::is_active` field. This does put the onus on users to manage which cameras should be active.
Cameras are now assigned a single render graph as an "entry point", which is configured on each camera entity using the new `CameraRenderGraph` component. The old `PerspectiveCameraBundle` and `OrthographicCameraBundle` (generic on camera marker components like Camera2d and Camera3d) have been replaced by `Camera3dBundle` and `Camera2dBundle`, which set 3d and 2d default values for the `CameraRenderGraph` and projections.
```rust
// old 3d perspective camera
commands.spawn_bundle(PerspectiveCameraBundle::default())
// new 3d perspective camera
commands.spawn_bundle(Camera3dBundle::default())
```
```rust
// old 2d orthographic camera
commands.spawn_bundle(OrthographicCameraBundle::new_2d())
// new 2d orthographic camera
commands.spawn_bundle(Camera2dBundle::default())
```
```rust
// old 3d orthographic camera
commands.spawn_bundle(OrthographicCameraBundle::new_3d())
// new 3d orthographic camera
commands.spawn_bundle(Camera3dBundle {
projection: OrthographicProjection {
scale: 3.0,
scaling_mode: ScalingMode::FixedVertical,
..default()
}.into(),
..default()
})
```
Note that `Camera3dBundle` now uses a new `Projection` enum instead of hard coding the projection into the type. There are a number of motivators for this change: the render graph is now a part of the bundle, the way "generic bundles" work in the rust type system prevents nice `..default()` syntax, and changing projections at runtime is much easier with an enum (ex for editor scenarios). I'm open to discussing this choice, but I'm relatively certain we will all come to the same conclusion here. Camera2dBundle and Camera3dBundle are much clearer than being generic on marker components / using non-default constructors.
If you want to run a custom render graph on a camera, just set the `CameraRenderGraph` component:
```rust
commands.spawn_bundle(Camera3dBundle {
camera_render_graph: CameraRenderGraph::new(some_render_graph_name),
..default()
})
```
Just note that if the graph requires data from specific components to work (such as `Camera3d` config, which is provided in the `Camera3dBundle`), make sure the relevant components have been added.
Speaking of using components to configure graphs / passes, there are a number of new configuration options:
```rust
commands.spawn_bundle(Camera3dBundle {
camera_3d: Camera3d {
// overrides the default global clear color
clear_color: ClearColorConfig::Custom(Color::RED),
..default()
},
..default()
})
commands.spawn_bundle(Camera3dBundle {
camera_3d: Camera3d {
// disables clearing
clear_color: ClearColorConfig::None,
..default()
},
..default()
})
```
Expect to see more of the "graph configuration Components on Cameras" pattern in the future.
By popular demand, UI no longer requires a dedicated camera. `UiCameraBundle` has been removed. `Camera2dBundle` and `Camera3dBundle` now both default to rendering UI as part of their own render graphs. To disable UI rendering for a camera, disable it using the CameraUi component:
```rust
commands
.spawn_bundle(Camera3dBundle::default())
.insert(CameraUi {
is_enabled: false,
..default()
})
```
## Other Changes
* The separate clear pass has been removed. We should revisit this for things like sky rendering, but I think this PR should "keep it simple" until we're ready to properly support that (for code complexity and performance reasons). We can come up with the right design for a modular clear pass in a followup pr.
* I reorganized bevy_core_pipeline into Core2dPlugin and Core3dPlugin (and core_2d / core_3d modules). Everything is pretty much the same as before, just logically separate. I've moved relevant types (like Camera2d, Camera3d, Camera3dBundle, Camera2dBundle) into their relevant modules, which is what motivated this reorganization.
* I adapted the `scene_viewer` example (which relied on the ActiveCameras behavior) to the new system. I also refactored bits and pieces to be a bit simpler.
* All of the examples have been ported to the new camera approach. `render_to_texture` and `multiple_windows` are now _much_ simpler. I removed `two_passes` because it is less relevant with the new approach. If someone wants to add a new "layered custom pass with CameraRenderGraph" example, that might fill a similar niche. But I don't feel much pressure to add that in this pr.
* Cameras now have `target_logical_size` and `target_physical_size` fields, which makes finding the size of a camera's render target _much_ simpler. As a result, the `Assets<Image>` and `Windows` parameters were removed from `Camera::world_to_screen`, making that operation much more ergonomic.
* Render order ambiguities between cameras with the same target and the same priority now produce a warning. This accomplishes two goals:
1. Now that there is no "global" active camera, by default spawning two cameras will result in two renders (one covering the other). This would be a silent performance killer that would be hard to detect after the fact. By detecting ambiguities, we can provide a helpful warning when this occurs.
2. Render order ambiguities could result in unexpected / unpredictable render results. Resolving them makes sense.
## Follow Up Work
* Per-Camera viewports, which will make it possible to render to a smaller area inside of a RenderTarget (great for something like splitscreen)
* Camera-specific MSAA config (should use the same "overriding" pattern used for ClearColor)
* Graph Based Camera Ordering: priorities are simple, but they make complicated ordering constraints harder to express. We should consider adopting a "graph based" camera ordering model with "before" and "after" relationships to other cameras (or build it "on top" of the priority system).
* Consider allowing graphs to run subgraphs from any nest level (aka a global namespace for graphs). Right now the 2d and 3d graphs each need their own UI subgraph, which feels "fine" in the short term. But being able to share subgraphs between other subgraphs seems valuable.
* Consider splitting `bevy_core_pipeline` into `bevy_core_2d` and `bevy_core_3d` packages. Theres a shared "clear color" dependency here, which would need a new home.
# Objective
Provide a starting point for #3951, or a partial solution.
Providing a few comment blocks to discuss, and hopefully find better one in the process.
## Solution
Since I am pretty new to pretty much anything in this context, I figured I'd just start with a draft for some file level doc blocks. For some of them I found more relevant details (or at least things I considered interessting), for some others there is less.
## Changelog
- Moved some existing comments from main() functions in the 2d examples to the file header level
- Wrote some more comment blocks for most other 2d examples
TODO:
- [x] 2d/sprite_sheet, wasnt able to come up with something good yet
- [x] all other example groups...
Also: Please let me know if the commit style is okay, or to verbose. I could certainly squash these things, or add more details if needed.
I also hope its okay to raise this PR this early, with just a few files changed. Took me long enough and I dont wanted to let it go to waste because I lost motivation to do the whole thing. Additionally I am somewhat uncertain over the style and contents of the commets. So let me know what you thing please.
# Objective
- Closes#335.
- Related #4285.
- Part of the splitting process of #3503.
## Solution
- Move `Rect` to `bevy_ui` and rename it to `UiRect`.
## Reasons
- `Rect` is only used in `bevy_ui` and therefore calling it `UiRect` makes the intent clearer.
- We have two types that are called `Rect` currently and it's missleading (see `bevy_sprite::Rect` and #335).
- Discussion in #3503.
## Changelog
### Changed
- The `Rect` type got moved from `bevy_math` to `bevy_ui` and renamed to `UiRect`.
## Migration Guide
- The `Rect` type got renamed to `UiRect`. To migrate you just have to change every occurrence of `Rect` to `UiRect`.
Co-authored-by: KDecay <KDecayMusic@protonmail.com>
# Objective
- Use the low power, reactive rendering settings for UI examples.
- Make the feature more discoverable by using it in an applicable context.
Adds a `default()` shorthand for `Default::default()` ... because life is too short to constantly type `Default::default()`.
```rust
use bevy::prelude::*;
#[derive(Default)]
struct Foo {
bar: usize,
baz: usize,
}
// Normally you would do this:
let foo = Foo {
bar: 10,
..Default::default()
};
// But now you can do this:
let foo = Foo {
bar: 10,
..default()
};
```
The examples have been adapted to use `..default()`. I've left internal crates as-is for now because they don't pull in the bevy prelude, and the ergonomics of each case should be considered individually.
# Objective
Enable the user to specify any presentation modes (including `Mailbox`).
Fixes#3807
## Solution
I've added a new `PresentMode` enum in `bevy_window` that mirrors the `wgpu` enum 1:1. Alternatively, I could add a new dependency on `wgpu-types` if that would be preferred.
#3457 adds the `doc_markdown` clippy lint, which checks doc comments to make sure code identifiers are escaped with backticks. This causes a lot of lint errors, so this is one of a number of PR's that will fix those lint errors one crate at a time.
This PR fixes lints in the `examples` folder.
# Objective
This PR implements the `overflow` style property in `bevy_ui`. When set to `Overflow::Hidden`, the children of that node are clipped so that overflowing parts are not rendered. This is an important building block for UI widgets.
## Solution
Clipping is done on the CPU so that it does not break batching.
The clip regions update was implemented as a separate system for clarity, but it could be merged with the other UI systems to avoid doing an additional tree traversal. (I don't think it's important until we fix the layout performance issues though).
A scrolling list was added to the `ui_pipelined` example to showcase `Overflow::Hidden`. For the sake of simplicity, it can only be scrolled with a mouse.
