# Objective
Bevy code tends to make heavy use of the [newtype](
https://doc.rust-lang.org/rust-by-example/generics/new_types.html)
pattern, which is why we have a dedicated derive for
[`Deref`](https://doc.rust-lang.org/std/ops/trait.Deref.html) and
[`DerefMut`](https://doc.rust-lang.org/std/ops/trait.DerefMut.html).
This derive works for any struct with a single field:
```rust
#[derive(Component, Deref, DerefMut)]
struct MyNewtype(usize);
```
One reason for the single-field limitation is to prevent confusion and
footguns related that would arise from allowing multi-field structs:
<table align="center">
<tr>
<th colspan="2">
Similar structs, different derefs
</th>
</tr>
<tr>
<td>
```rust
#[derive(Deref, DerefMut)]
struct MyStruct {
foo: usize, // <- Derefs usize
bar: String,
}
```
</td>
<td>
```rust
#[derive(Deref, DerefMut)]
struct MyStruct {
bar: String, // <- Derefs String
foo: usize,
}
```
</td>
</tr>
<tr>
<th colspan="2">
Why `.1`?
</th>
</tr>
<tr>
<td colspan="2">
```rust
#[derive(Deref, DerefMut)]
struct MyStruct(Vec<usize>, Vec<f32>);
let mut foo = MyStruct(vec![123], vec![1.23]);
// Why can we skip the `.0` here?
foo.push(456);
// But not here?
foo.1.push(4.56);
```
</td>
</tr>
</table>
However, there are certainly cases where it's useful to allow for
structs with multiple fields. Such as for structs with one "real" field
and one `PhantomData` to allow for generics:
```rust
#[derive(Deref, DerefMut)]
struct MyStruct<T>(
// We want use this field for the `Deref`/`DerefMut` impls
String,
// But we need this field so that we can make this struct generic
PhantomData<T>
);
// ERROR: Deref can only be derived for structs with a single field
// ERROR: DerefMut can only be derived for structs with a single field
```
Additionally, the possible confusion and footguns are mainly an issue
for newer Rust/Bevy users. Those familiar with `Deref` and `DerefMut`
understand what adding the derive really means and can anticipate its
behavior.
## Solution
Allow users to opt into multi-field `Deref`/`DerefMut` derives using a
`#[deref]` attribute:
```rust
#[derive(Deref, DerefMut)]
struct MyStruct<T>(
// Use this field for the `Deref`/`DerefMut` impls
#[deref] String,
// We can freely include any other field without a compile error
PhantomData<T>
);
```
This prevents the footgun pointed out in the first issue described in
the previous section, but it still leaves the possible confusion
surrounding `.0`-vs-`.#`. However, the idea is that by making this
behavior explicit with an attribute, users will be more aware of it and
can adapt appropriately.
---
## Changelog
- Added `#[deref]` attribute to `Deref` and `DerefMut` derives
# Objective
The unit test `chang_tick_wraparound` is meant to ensure that change
ticks correctly deal with wrapping by setting the world's
`last_change_tick` to `u32::MAX`. However, since systems don't use* the
value of `World::last_change_tick`, this test doesn't actually involve
any wrapping behavior.
*exclusive systems do use `World::last_change_tick`; however it gets
overwritten by the system's own last tick in `System::run`.
## Solution
Use `QueryState` instead of systems in the unit test. This approach
actually uses `World::last_change_tick`, so it properly tests that
change ticks deal with wrapping correctly.
# 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
- Fix#5631
## Solution
- Wait 50ms (configurable) after the last modification event before
reloading an asset.
---
## Changelog
- `AssetPlugin::watch_for_changes` is now a `ChangeWatcher` instead of a
`bool`
- Fixed https://github.com/bevyengine/bevy/issues/5631
## Migration Guide
- Replace `AssetPlugin::watch_for_changes: true` with e.g.
`ChangeWatcher::with_delay(Duration::from_millis(200))`
---------
Co-authored-by: François <mockersf@gmail.com>
# Objective
- Fix bad links in the WebGPU example page
## Solution
- Bevy website always add the trailing slash, keep the link relative by
removing the current folder from it
# Objective
- Cleanup file tree
## Solution
A mysterious mod.rs lies in the scene_viewer directory. It seems
completely useless, everything ignores it and it doesn't affect
anything.
We cruelly remove it, making the world a less whimsical place. A
dystopian drive for pure and complete order compels us to eliminate all
that is useless, for clarity and to prevent the wonder and beauty of
confusion.
# Objective
* `Node::physical_rect` divides the logical size of the node by the
scale factor, when it should multiply.
* Add a `physical_size` method to `Node` that calculates the physical
size of a node.
---
## Changelog
* Added a method `physical_size` to `Node` that calculates the physical
size of the `Node` based on the given scale factor.
* Fixed the `Node::physical_rect` method, the logical size should be
multiplied by the scale factor to get the physical size.
* Removed the `scale_value` function from the `text` widget module and
replaced its usage with `Node::physical_size`.
* Derived `Copy` for `Node` (since it's only a wrapped `Vec2`).
* Made `Node::size` const.
# Objective
`ScheduleGraph` currently stores run conditions in a
`Option<Vec<BoxedCondition>>`. The `Option` is unnecessary, since we can
just use an empty vector instead of `None`.
# Objective
The method `UnsafeWorldCell::world_mut` is a special case, since its
safety contract is more difficult to satisfy than the other methods on
`UnsafeWorldCell`. Rewrite its documentation to be specific about when
it can and cannot be used. Provide examples and emphasize that it is
unsound to call in most cases.
# Objective
The method `UnsafeWorldCell::read_change_tick` is longer than it needs
to be. `World` only has a method called this because it has two methods
for getting a change tick: one that takes `&self` and one that takes
`&mut self`. Since this distinction is not applicable to
`UnsafeWorldCell`, we should just call this method `change_tick`.
## Solution
Deprecate the current method and add a new one called `change_tick`.
---
## Changelog
- Renamed `UnsafeWorldCell::read_change_tick` to `change_tick`.
## Migration Guide
The `UnsafeWorldCell` method `read_change_tick` has been renamed to
`change_tick`.
# Objective
`ScheduleRunnerPlugin` was still configured via a resource, meaning
users would be able to change the settings while the app is running, but
the changes wouldn't have an effect.
## Solution
Configure plugin directly
---
## Changelog
- Changed: merged `ScheduleRunnerSettings` into `ScheduleRunnerPlugin`
## Migration Guide
- instead of inserting the `ScheduleRunnerSettings` resource, configure
the `ScheduleRunnerPlugin`
# Objective
- Fixes#3531
## Solution
- Added an append wrapper to BufferVec based on the function signature
for vec.append()
---
First PR to Bevy. I didn't see any tests for other BufferVec methods
(could have missed them) and currently this method is not used anywhere
in the project. Let me know if there are tests to add or if I should
find somewhere to use append so it is not dead code. The issue mentions
implementing `truncate` and `extend` which were already implemented and
merged
[here](https://github.com/bevyengine/bevy/pull/6833/files#diff-c8fb332382379e383f1811e30c31991b1e0feb38ca436c357971755368012ced)
# Objective
Frustum culling for 2D components has been enabled since #7885,
Fixes#8490
## Solution
Re-introduced the comments about frustum culling in the
many_animated_sprites.rs and many_sprites.rs examples.
---------
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
Co-authored-by: François <mockersf@gmail.com>
# Objective
Replace `Query<&T, Changed<T>>` style queries with the more efficient
`Query<Ref<T>>` form in two of the UI systems.
---
## Changelog
Replaced use of `Changed` with `Ref` in queries in the
`ui_layout_system` and `calc_bounds` UI systems.
# Objective
- When writing render nodes that need a view, you always need to define
a `Query` on the associated view and make sure to update it manually and
query it manually. This is verbose and error prone.
## Solution
- Introduce a new `ViewNode` trait and `ViewNodeRunner` `Node` that will
take care of managing the associated view query automatically.
- The trait is currently a passthrough of the `Node` trait. So it still
has the update/run with all the same data passed in.
- The `ViewNodeRunner` is the actual node that is added to the render
graph and it contains the custom node. This is necessary because it's
the one that takes care of updating the node.
---
## Changelog
- Add `ViewNode`
- Add `ViewNodeRunner`
## Notes
Currently, this only handles the view query, but it could probably have
a ReadOnlySystemState that would also simplify querying all the readonly
resources that most render nodes currently query manually. The issue is
that I don't know how to do that without a `&mut self`.
At first, I tried making this a default feature of all `Node`, but I
kept hitting errors related to traits and generics and stuff I'm not
super comfortable with. This implementations is much simpler and keeps
the default Node behaviour so isn't a breaking change
## Reviewer Notes
The PR looks quite big, but the core of the PR is the changes in
`render_graph/node.rs`. Every other change is simply updating existing
nodes to use this new feature.
## Open questions
~~- Naming is not final, I'm opened to anything. I named it
ViewQueryNode because it's a node with a managed Query on a View.~~
~~- What to do when the query fails? All nodes using this pattern
currently just `return Ok(())` when it fails, so I chose that, but
should it be more flexible?~~
~~- Is the ViewQueryFilter actually necessary? All view queries run on
the entity that is already guaranteed to be a view. Filtering won't do
much, but maybe someone wants to control an effect with the presence of
a component instead of a flag.~~
~~- What to do with Nodes that are empty struct? Implementing
`FromWorld` is pretty verbose but not implementing it means there's 2
ways to create a `ViewNodeRunner` which seems less ideal. This is an
issue now because most node simply existed to hold the query, but now
that they don't hold the query state we are left with a bunch of empty
structs.~~
- Should we have a `RenderGraphApp::add_render_graph_view_node()`, this
isn't necessary, but it could make the code a bit shorter.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Add Reflect and FromReflect for AssetPath
- Fixes#8458
## Solution
- Straightforward derive of `Reflect` and `FromReflect` for `AssetPath`
- Implement `Reflect` and `FromReflect` for `Cow<'static, Path>` as to
satisfy the 'static lifetime requierments of bevy_reflect.
Implementation is a direct copy of that for `Cow<'static, str>` so maybe
it begs the question that was already asked in #7429 - maybe it would be
benefitial to write a general implementation for `Reflect` for
`Cow<'static, T>`.
# Objective
- Replace the `example_showcase.sh` script
- Helper tool to prepare the example page on the website
## Solution
- Have a command to run all the examples: `cargo run -p example-showcase
-- run`
- Have a command to take screenshots of all examples: `cargo run -p
example-showcase -- run --screenshot`
- Have a command to build the markdown files for the website: `cargo run
-p example-showcase -- build-website-list --content-folder content`
- Have a command to build all the examples in wasm/WebGPU: `cargo run -p
example-showcase -- build-web-gpu-examples --content-folder webgpus`
(with `--website-hacks` to enable the hacks for the Bevy website: canvas
id, resizing and loading bar)
This is the first step to an improved example page (all examples marked
as wasm, uses the card layout, has screenshots, reuse name, category and
description from the metadata). As one of the goal is to have a page
with WebGPU examples before the official release, this is not touching
the example page for now but targeting a new one.
<img width="1912" alt="Screenshot 2023-05-06 at 17 16 25"
src="https://user-images.githubusercontent.com/8672791/236632744-4372c95f-c50a-4168-973f-349412548f33.png">
# Objective
Sometimes we might want to read from the depth texture in some custom
rendering features. We must then add `STORAGE_BINDING` or
`TEXTURE_BINDING` to the texture usage flags when creating them.
## Solution
This PR allows one to customize the usage flags in the `Camera3d`
component.
# Objective
- Fixes#8563
## Solution
~~- Implement From<Color> for [u8; 4]~~
~~- also implement From<[u8; 4]> for Color because why not.~~
- implement method `as_rgba_u8` in Color
---------
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
# Objective
`text_system` and `measure_text_system` both keep local queues to keep
track of text node entities that need recomputations/remeasurement,
which scales very badly with large numbers of text entities (O(n^2)) and
makes the code quite difficult to understand.
Also `text_system` filters for `Changed<Text>`, this isn't something
that it should do. When a text node entity fails to be processed by
`measure_text_system` because a font can't be found, the text node will
still be added to `text_system`'s local queue for recomputation. `Text`
should only ever be queued by `text_system` when a text node's geometry
is modified or a new measure is added.
## Solution
Remove the local text queues and use a component `TextFlags` to schedule
remeasurements and recomputations.
## Changelog
* Created a component `TextFlags` with fields `remeasure` and
`recompute`, which can be used to schedule a text `remeasure` or
`recomputation` respectively and added it to `TextBundle`.
* Removed the local text queues from `measure_text_system` and
`text_system` and instead use the `TextFlags` component to schedule
remeasurements and recomputations.
## Migration Guide
The component `TextFlags` has been added to `TextBundle`.
# Objective
Copy the `debug::print_tree` function from Taffy except display entity
ids instead of Taffy's node ids and indicate which ui nodes have a
measure func.
# Objective
Ensure future consistency between the two compare functions for all
types with manual `Ord` and `PartialOrd` implementations.
## Solution
Use `Self::cpm` in the implementation of `partial_cpm` for types
`Handle` and `Name`.
# Objective
there were typos in AxisSettings livezone/deadzone get/set function doc
comments.
## Solution
I changed the comments to be (hopefully) correct this time. I could be
wrong though.
# Objective
- Support WebGPU
- alternative to #5027 that doesn't need any async / await
- fixes#8315
- Surprise fix#7318
## Solution
### For async renderer initialisation
- Update the plugin lifecycle:
- app builds the plugin
- calls `plugin.build`
- registers the plugin
- app starts the event loop
- event loop waits for `ready` of all registered plugins in the same
order
- returns `true` by default
- then call all `finish` then all `cleanup` in the same order as
registered
- then execute the schedule
In the case of the renderer, to avoid anything async:
- building the renderer plugin creates a detached task that will send
back the initialised renderer through a mutex in a resource
- `ready` will wait for the renderer to be present in the resource
- `finish` will take that renderer and place it in the expected
resources by other plugins
- other plugins (that expect the renderer to be available) `finish` are
called and they are able to set up their pipelines
- `cleanup` is called, only custom one is still for pipeline rendering
### For WebGPU support
- update the `build-wasm-example` script to support passing `--api
webgpu` that will build the example with WebGPU support
- feature for webgl2 was always enabled when building for wasm. it's now
in the default feature list and enabled on all platforms, so check for
this feature must also check that the target_arch is `wasm32`
---
## Migration Guide
- `Plugin::setup` has been renamed `Plugin::cleanup`
- `Plugin::finish` has been added, and plugins adding pipelines should
do it in this function instead of `Plugin::build`
```rust
// Before
impl Plugin for MyPlugin {
fn build(&self, app: &mut App) {
app.insert_resource::<MyResource>
.add_systems(Update, my_system);
let render_app = match app.get_sub_app_mut(RenderApp) {
Ok(render_app) => render_app,
Err(_) => return,
};
render_app
.init_resource::<RenderResourceNeedingDevice>()
.init_resource::<OtherRenderResource>();
}
}
// After
impl Plugin for MyPlugin {
fn build(&self, app: &mut App) {
app.insert_resource::<MyResource>
.add_systems(Update, my_system);
let render_app = match app.get_sub_app_mut(RenderApp) {
Ok(render_app) => render_app,
Err(_) => return,
};
render_app
.init_resource::<OtherRenderResource>();
}
fn finish(&self, app: &mut App) {
let render_app = match app.get_sub_app_mut(RenderApp) {
Ok(render_app) => render_app,
Err(_) => return,
};
render_app
.init_resource::<RenderResourceNeedingDevice>();
}
}
```
# Objective
Fixes#8528
## Solution
Manually implement `PartialEq`, `Eq`, `PartialOrd`, `Ord`, and `Hash`
for `bevy_ecs::event::EventId`. These new implementations do not rely on
the `Event` implementing the same traits allowing `EventId` to be used
in more cases.
# Objective
there was a typo in AxisSettings. It said "Values that are higher than
`livezone_upperbound` will be rounded up to -1.0." which I'm pretty
confident should be "1.0".
## Solution
I removed the '-'
# Objective
After fixing dynamic scene to only map specific entities, we want
map_entities to default to the less error prone behavior and have the
previous behavior renamed to "map_all_entities." As this is a breaking
change, it could not be pushed out with the bug fix.
## Solution
Simple rename and refactor.
## Changelog
### Changed
- `map_entities` now accepts a list of entities to apply to, with
`map_all_entities` retaining previous behavior of applying to all
entities in the map.
## Migration Guide
- In `bevy_ecs`, `ReflectMapEntities::map_entites` now requires an
additional `entities` parameter to specify which entities it applies to.
To keep the old behavior, use the new
`ReflectMapEntities::map_all_entities`, but consider if passing the
entities in specifically might be better for your use case to avoid
bugs.
# Objective
- I want to take screenshots of examples in CI to help with validation
of changes
## Solution
- Can override how much time is updated per frame
- Can specify on which frame to take a screenshots
- Save screenshots in CI
I reused the `TimeUpdateStrategy::ManualDuration` to be able to set the
time update strategy to a fixed duration every frame. Its previous
meaning didn't make much sense to me. This change makes it possible to
have screenshots that are exactly the same across runs.
If this gets merged, I'll add visual comparison of screenshots between
runs to ensure nothing gets broken
## Migration Guide
* `TimeUpdateStrategy::ManualDuration` meaning has changed. Instead of
setting time to `Instant::now()` plus the given duration, it sets time
to last update plus the given duration.
# Objective
- For many UI use cases (e.g. tree views, lists), it is important to be
able to imperatively sort child nodes.
- This also enables us to eventually support something like the
[`order`](https://developer.mozilla.org/en-US/docs/Web/CSS/order) CSS
property, that declaratively re-orders flex box items by a numeric
value, similar to z-index, but in space.
## Solution
We removed the ability to directly construct `Children` from `&[Entity]`
some time ago (#4197#5532) to enforce consistent hierarchies ([RFC
53](https://github.com/bevyengine/rfcs/blob/main/rfcs/53-consistent-hierarchy.md)).
If I understand it correctly, it's currently possible to re-order
children by using `Children::swap()` or
`commands.entity(id).replace_children(...)`, however these are either
too cumbersome, needlessly inefficient, and/or don't take effect
immediately.
This PR exposes the in-place sorting methods from the `slice` primitive
in `Children`, enabling imperatively sorting children in place via `&mut
Children`, while still preserving consistent hierarchies.
---
## Changelog
### Added
- The sorting methods from the `slice` primitive are now exposed by the
`Children` component, allowing imperatively sorting children in place
(Useful for UI scenarios such as lists)
# Objective
- Handle dangling entity references inside scenes
- Handle references to entities with generation > 0 inside scenes
- Fix a latent bug in `Parent`'s `MapEntities` implementation, which
would, if the parent was outside the scene, cause the scene to be loaded
into the new world with a parent reference potentially pointing to some
random entity in that new world.
- Fixes#4793 and addresses #7235
## Solution
- DynamicScenes now identify entities with a `Entity` instead of a u32,
therefore including generation
- `World` exposes a new `reserve_generations` function that despawns an
entity and advances its generation by some extra amount.
- `MapEntities` implementations have a new `get_or_reserve` function
available that will always return an `Entity`, establishing a new
mapping to a dead entity when the entity they are called with is not in
the `EntityMap`. Subsequent calls with that same `Entity` will return
the same newly created dead entity reference, preserving equality
semantics.
- As a result, after loading a scene containing references to dead
entities (or entities otherwise outside the scene), those references
will all point to different generations on a single entity id in the new
world.
---
## Changelog
### Changed
- In serialized scenes, entities are now identified by a u64 instead of
a u32.
- In serialized scenes, components with entity references now have those
references serialize as u64s instead of structs.
### Fixed
- Scenes containing components with entity references will now
deserialize and add to a world reliably.
## Migration Guide
- `MapEntities` implementations must change from a `&EntityMap`
parameter to a `&mut EntityMapper` parameter and can no longer return a
`Result`. Finally, they should switch from calling `EntityMap::get` to
calling `EntityMapper::get_or_reserve`.
---------
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
fixes#8516
* Give `CalculatedSize` a more specific and intuitive name.
* `MeasureFunc`s should only be updated when their `CalculatedSize` is
modified by the systems managing their content.
For example, suppose that you have a UI displaying an image using an
`ImageNode`. When the window is resized, the node's `MeasureFunc` will
be updated even though the dimensions of the texture contained by the
node are unchanged.
* Fix the `CalculatedSize` API so that it no longer requires the extra
boxing and the `dyn_clone` method.
## Solution
* Rename `CalculatedSize` to `ContentSize`
* Only update `MeasureFunc`s on `CalculatedSize` changes.
* Remove the `dyn_clone` method from `Measure` and move the `Measure`
from the `ContentSize` component rather than cloning it.
* Change the measure_func field of `ContentSize` to type
`Option<taffy::node::MeasureFunc>`. Add a `set` method that wraps the
given measure appropriately.
---
## Changelog
* Renamed `CalculatedSize` to `ContentSize`.
* Replaced `upsert_leaf` with a function `update_measure` that only
updates the node's `MeasureFunc`.
* `MeasureFunc`s are only updated when the `ContentSize` changes and not
when the layout changes.
* Scale factor is no longer applied to the size values passed to the
`MeasureFunc`.
* Remove the `ContentSize` scaling in `text_system`.
* The `dyn_clone` method has been removed from the `Measure` trait.
* `Measure`s are moved from the `ContentSize` component instead of
cloning them.
* Added `set` method to `ContentSize` that replaces the `new` function.
## Migration Guide
* `CalculatedSize` has been renamed to `ContentSize`.
* The `upsert_leaf` function has been removed from `UiSurface` and
replaced with `update_measure` which updates the `MeasureFunc` without
node insertion.
* The `dyn_clone` method has been removed from the `Measure` trait.
* The new function of `CalculatedSize` has been replaced with the method
`set`.
# Objective
after calling `SceneSpawner::spawn_as_child`, the scene spawner system
will always try to attach the scene instance to the parent once it is
loaded, even if the parent has been deleted, causing a panic.
## Solution
check if the parent is still alive, and don't spawn the scene instance
if not.
# Objective
- Enable taking a screenshot in wasm
- Followup on #7163
## Solution
- Create a blob from the image data, generate a url to that blob, add an
`a` element to the document linking to that url, click on that element,
then revoke the url
- This will automatically trigger a download of the screenshot file in
the browser
# Objective
This is just an oversight on my part when I implemented this in
https://github.com/bevyengine/bevy/pull/7186, there isn't much reason to
print out the hash of a `Name` like it does currently:
```
Name { hash: 1608798714325729304, name: "Suzanne" } (7v0)
```
## Solution
Instead it would be better if we just printed out the string like so:
```
"Suzanne" (7v0)
```
As it conveys all of the information in a less cluttered and immediately
intuitive way which was the original purpose of `DebugName`. Which I
also think translates to `Name` as well since I mostly see it as a thin
wrapper around a string.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Standardize on screen instructions in examples:
- top left, bottom left when better
- white, black when better
- same margin (12px) and font size (20)
## Solution
- Started with a few examples, let's reach consensus then document and
open issues for the rest
# Objective
- Updated to wgpu 0.16.0 and wgpu-hal 0.16.0
---
## Changelog
1. Upgrade wgpu to 0.16.0 and wgpu-hal to 0.16.0
2. Fix the error in native when using a filterable
`TextureSampleType::Float` on a multisample `BindingType::Texture`.
([https://github.com/gfx-rs/wgpu/pull/3686](https://github.com/gfx-rs/wgpu/pull/3686))
---------
Co-authored-by: François <mockersf@gmail.com>
# Objective
> This PR is based on discussion from #6601
The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as
both:
1. Dynamic containers which may hold any arbitrary data
2. Proxy types which may represent any other type
Currently, the only way we can represent the proxy-ness of a Dynamic is
by giving it a name.
```rust
// This is just a dynamic container
let mut data = DynamicStruct::default();
// This is a "proxy"
data.set_name(std::any::type_name::<Foo>());
```
This type name is the only way we check that the given Dynamic is a
proxy of some other type. When we need to "assert the type" of a `dyn
Reflect`, we call `Reflect::type_name` on it. However, because we're
only using a string to denote the type, we run into a few gotchas and
limitations.
For example, hashing a Dynamic proxy may work differently than the type
it proxies:
```rust
#[derive(Reflect, Hash)]
#[reflect(Hash)]
struct Foo(i32);
let concrete = Foo(123);
let dynamic = concrete.clone_dynamic();
let concrete_hash = concrete.reflect_hash();
let dynamic_hash = dynamic.reflect_hash();
// The hashes are not equal because `concrete` uses its own `Hash` impl
// while `dynamic` uses a reflection-based hashing algorithm
assert_ne!(concrete_hash, dynamic_hash);
```
Because the Dynamic proxy only knows about the name of the type, it's
unaware of any other information about it. This means it also differs on
`Reflect::reflect_partial_eq`, and may include ignored or skipped fields
in places the concrete type wouldn't.
## Solution
Rather than having Dynamics pass along just the type name of proxied
types, we can instead have them pass around the `TypeInfo`.
Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than
a `String`:
```diff
pub struct DynamicTupleStruct {
- type_name: String,
+ represented_type: Option<&'static TypeInfo>,
fields: Vec<Box<dyn Reflect>>,
}
```
By changing `Reflect::get_type_info` to
`Reflect::represented_type_info`, hopefully we make this behavior a
little clearer. And to account for `None` values on these dynamic types,
`Reflect::represented_type_info` now returns `Option<&'static
TypeInfo>`.
```rust
let mut data = DynamicTupleStruct::default();
// Not proxying any specific type
assert!(dyn_tuple_struct.represented_type_info().is_none());
let type_info = <Foo as Typed>::type_info();
dyn_tuple_struct.set_represented_type(Some(type_info));
// Alternatively:
// let dyn_tuple_struct = foo.clone_dynamic();
// Now we're proxying `Foo`
assert!(dyn_tuple_struct.represented_type_info().is_some());
```
This means that we can have full access to all the static type
information for the proxied type. Future work would include
transitioning more static type information (trait impls, attributes,
etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic
proxies.
### Alternatives & Rationale
> **Note**
> These alternatives were written when this PR was first made using a
`Proxy` trait. This trait has since been removed.
<details>
<summary>View</summary>
#### Alternative: The `Proxy<T>` Approach
I had considered adding something like a `Proxy<T>` type where `T` would
be the Dynamic and would contain the proxied type information.
This was nice in that it allows us to explicitly determine whether
something is a proxy or not at a type level. `Proxy<DynamicStruct>`
proxies a struct. Makes sense.
The reason I didn't go with this approach is because (1) tuples, (2)
complexity, and (3) `PartialReflect`.
The `DynamicTuple` struct allows us to represent tuples at runtime. It
also allows us to do something you normally can't with tuples: add new
fields. Because of this, adding a field immediately invalidates the
proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32,
NewField)`). By going with this PR's approach, we can just remove the
type info on `DynamicTuple` when that happens. However, with the
`Proxy<T>` approach, it becomes difficult to represent this behavior—
we'd have to completely control how we access data for `T` for each `T`.
Secondly, it introduces some added complexities (aside from the manual
impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we
want to represent it as `dyn Reflect`. What `TypeInfo` do we give it?
How would we forward reflection methods to the inner type (remember, we
don't have specialization)? How do we separate this from Dynamic types?
And finally, how do all this in a way that's both logical and intuitive
for users?
Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is
actually more inline with the [Unique Reflect
RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy`
trait is really one part of the `PartialReflect` trait introduced in
that RFC (it's technically not in that RFC but it fits well with it),
where the `PartialReflect` serves as a way for proxies to work _like_
concrete types without having full access to everything a concrete
`Reflect` type can do. This would help bridge the gap between the
current state of the crate and the implementation of that RFC.
All that said, this is still a viable solution. If the community
believes this is the better path forward, then we can do that instead.
These were just my reasons for not initially going with it in this PR.
#### Alternative: The Type Registry Approach
The `Proxy` trait is great and all, but how does it solve the original
problem? Well, it doesn't— yet!
The goal would be to start moving information from the derive macro and
its attributes to the generated `TypeInfo` since these are known
statically and shouldn't change. For example, adding `ignored: bool` to
`[Un]NamedField` or a list of impls.
However, there is another way of storing this information. This is, of
course, one of the uses of the `TypeRegistry`. If we're worried about
Dynamic proxies not aligning with their concrete counterparts, we could
move more type information to the registry and require its usage.
For example, we could replace `Reflect::reflect_hash(&self)` with
`Reflect::reflect_hash(&self, registry: &TypeRegistry)`.
That's not the _worst_ thing in the world, but it is an ergonomics loss.
Additionally, other attributes may have their own requirements, further
restricting what's possible without the registry. The `Reflect::apply`
method will require the registry as well now. Why? Well because the
`map_apply` function used for the `Reflect::apply` impls on `Map` types
depends on `Map::insert_boxed`, which (at least for `DynamicMap`)
requires `Reflect::reflect_hash`. The same would apply when adding
support for reflection-based diffing, which will require
`Reflect::reflect_partial_eq`.
Again, this is a totally viable alternative. I just chose not to go with
it for the reasons above. If we want to go with it, then we can close
this PR and we can pursue this alternative instead.
#### Downsides
Just to highlight a quick potential downside (likely needs more
investigation): retrieving the `TypeInfo` requires acquiring a lock on
the `GenericTypeInfoCell` used by the `Typed` impls for generic types
(non-generic types use a `OnceBox which should be faster). I am not sure
how much of a performance hit that is and will need to run some
benchmarks to compare against.
</details>
### Open Questions
1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be
easier for modding? Perhaps, in that case, we need to update
`Typed::type_info` and friends as well?
2. Are the alternatives better than the approach this PR takes? Are
there other alternatives?
---
## Changelog
### Changed
- `Reflect::get_type_info` has been renamed to
`Reflect::represented_type_info`
- This method now returns `Option<&'static TypeInfo>` rather than just
`&'static TypeInfo`
### Added
- Added `Reflect::is_dynamic` method to indicate when a type is dynamic
- Added a `set_represented_type` method on all dynamic types
### Removed
- Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead)
- Removed `Typed` impls for all dynamic types
## Migration Guide
- The Dynamic types no longer take a string type name. Instead, they
require a static reference to `TypeInfo`:
```rust
#[derive(Reflect)]
struct MyTupleStruct(f32, f32);
let mut dyn_tuple_struct = DynamicTupleStruct::default();
dyn_tuple_struct.insert(1.23_f32);
dyn_tuple_struct.insert(3.21_f32);
// BEFORE:
let type_name = std::any::type_name::<MyTupleStruct>();
dyn_tuple_struct.set_name(type_name);
// AFTER:
let type_info = <MyTupleStruct as Typed>::type_info();
dyn_tuple_struct.set_represented_type(Some(type_info));
```
- `Reflect::get_type_info` has been renamed to
`Reflect::represented_type_info` and now also returns an
`Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`):
```rust
// BEFORE:
let info: &'static TypeInfo = value.get_type_info();
// AFTER:
let info: &'static TypeInfo = value.represented_type_info().unwrap();
```
- `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use
`Reflect::is_dynamic` instead:
```rust
// BEFORE:
if matches!(value.get_type_info(), TypeInfo::Dynamic) {
// ...
}
// AFTER:
if value.is_dynamic() {
// ...
}
```
---------
Co-authored-by: radiish <cb.setho@gmail.com>
# Objective
A lot of items in `bevy_ui` could be `FromReflect` but aren't. This
prevents users and library authors from being able to convert from a
`dyn Reflect` to one of these items.
## Solution
Derive `FromReflect` where possible. Also register the
`ReflectFromReflect` type data.
# Objective
Considering that `FromReflect` is a very common trait to derive, it
would make sense to include `ReflectFromReflect` in the `bevy_reflect`
prelude so users don't need to import it separately.
## Solution
Add `ReflectFromReflect` to the prelude.
# Objective
Currently, there isn't a clean way of getting an untyped handle to an
asset during asset loading. This is useful for when an asset needs to
reference other assets, but may not know the concrete type of each
asset.
We could "hack" this together by just using some random asset:
```rust
// We don't care what `bar.baz` is, so we "pretend" it's an `Image`
let handle: Handle<Image> = load_context.get_handle("foo/bar.baz");
```
This should work since we don't actually care about the underlying type
in this case. However, we can do better.
## Solution
Add the `LoadContext::get_handle_untyped` method to get untyped handles
to assets.
# Objective
- Reduce compilation time
## Solution
- Make `spirv` and `glsl` shader format support optional. They are not
needed for Bevy shaders.
- on my mac (where shaders are compiled to `msl`), this reduces the
total build time by 2 to 5 seconds, improvement should be even better
with less cores
There is a big reduction in compile time for `naga`, and small
improvements on `wgpu` and `bevy_render`
This PR with optional shader formats enabled timings:
<img width="1478" alt="current main"
src="https://user-images.githubusercontent.com/8672791/234347032-cbd5c276-a9b0-49c3-b793-481677391c18.png">
This PR:
<img width="1479" alt="this pr"
src="https://user-images.githubusercontent.com/8672791/234347059-a67412a9-da8d-4356-91d8-7b0ae84ca100.png">
---
## Migration Guide
- If you want to use shaders in `spirv`, enable the
`shader_format_spirv` feature
- If you want to use shaders in `glsl`, enable the `shader_format_glsl`
feature
