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116 commits

Author SHA1 Message Date
Mantas
5af2f022d8
Rename WorldQueryData & WorldQueryFilter to QueryData & QueryFilter (#10779)
# Rename `WorldQueryData` & `WorldQueryFilter` to `QueryData` &
`QueryFilter`

Fixes #10776 

## Solution

Traits `WorldQueryData` & `WorldQueryFilter` were renamed to `QueryData`
and `QueryFilter`, respectively. Related Trait types were also renamed.

---

## Changelog

- Trait `WorldQueryData` has been renamed to `QueryData`. Derive macro's
`QueryData` attribute `world_query_data` has been renamed to
`query_data`.
- Trait `WorldQueryFilter` has been renamed to `QueryFilter`. Derive
macro's `QueryFilter` attribute `world_query_filter` has been renamed to
`query_filter`.
- Trait's `ExtractComponent` type `Query` has been renamed to `Data`.
- Trait's `GetBatchData` types `Query` & `QueryFilter` has been renamed
to `Data` & `Filter`, respectively.
- Trait's `ExtractInstance` type `Query` has been renamed to `Data`.
- Trait's `ViewNode` type `ViewQuery` has been renamed to `ViewData`.
- Trait's `RenderCommand` types `ViewWorldQuery` & `ItemWorldQuery` has
been renamed to `ViewData` & `ItemData`, respectively.

## Migration Guide

Note: if merged before 0.13 is released, this should instead modify the
migration guide of #10776 with the updated names.

- Rename `WorldQueryData` & `WorldQueryFilter` trait usages to
`QueryData` & `QueryFilter` and their respective derive macro attributes
`world_query_data` & `world_query_filter` to `query_data` &
`query_filter`.
- Rename the following trait type usages:
  - Trait's `ExtractComponent` type `Query` to `Data`.
  - Trait's `GetBatchData` type `Query` to `Data`.
  - Trait's `ExtractInstance` type `Query` to `Data`.
  - Trait's `ViewNode` type `ViewQuery` to `ViewData`'
- Trait's `RenderCommand` types `ViewWolrdQuery` & `ItemWorldQuery` to
`ViewData` & `ItemData`, respectively.

```rust
// Before
#[derive(WorldQueryData)]
#[world_query_data(derive(Debug))]
struct EmptyQuery {
    empty: (),
}

// After
#[derive(QueryData)]
#[query_data(derive(Debug))]
struct EmptyQuery {
    empty: (),
}

// Before
#[derive(WorldQueryFilter)]
struct CustomQueryFilter<T: Component, P: Component> {
    _c: With<ComponentC>,
    _d: With<ComponentD>,
    _or: Or<(Added<ComponentC>, Changed<ComponentD>, Without<ComponentZ>)>,
    _generic_tuple: (With<T>, With<P>),
}

// After
#[derive(QueryFilter)]
struct CustomQueryFilter<T: Component, P: Component> {
    _c: With<ComponentC>,
    _d: With<ComponentD>,
    _or: Or<(Added<ComponentC>, Changed<ComponentD>, Without<ComponentZ>)>,
    _generic_tuple: (With<T>, With<P>),
}

// Before
impl ExtractComponent for ContrastAdaptiveSharpeningSettings {
    type Query = &'static Self;
    type Filter = With<Camera>;
    type Out = (DenoiseCAS, CASUniform);

    fn extract_component(item: QueryItem<Self::Query>) -> Option<Self::Out> {
        //...
    }
}

// After
impl ExtractComponent for ContrastAdaptiveSharpeningSettings {
    type Data = &'static Self;
    type Filter = With<Camera>;
    type Out = (DenoiseCAS, CASUniform);

    fn extract_component(item: QueryItem<Self::Data>) -> Option<Self::Out> {
        //...
    }
}

// Before
impl GetBatchData for MeshPipeline {
    type Param = SRes<RenderMeshInstances>;
    type Query = Entity;
    type QueryFilter = With<Mesh3d>;
    type CompareData = (MaterialBindGroupId, AssetId<Mesh>);
    type BufferData = MeshUniform;

    fn get_batch_data(
        mesh_instances: &SystemParamItem<Self::Param>,
        entity: &QueryItem<Self::Query>,
    ) -> (Self::BufferData, Option<Self::CompareData>) {
        // ....
    }
}

// After
impl GetBatchData for MeshPipeline {
    type Param = SRes<RenderMeshInstances>;
    type Data = Entity;
    type Filter = With<Mesh3d>;
    type CompareData = (MaterialBindGroupId, AssetId<Mesh>);
    type BufferData = MeshUniform;

    fn get_batch_data(
        mesh_instances: &SystemParamItem<Self::Param>,
        entity: &QueryItem<Self::Data>,
    ) -> (Self::BufferData, Option<Self::CompareData>) {
        // ....
    }
}

// Before
impl<A> ExtractInstance for AssetId<A>
where
    A: Asset,
{
    type Query = Read<Handle<A>>;
    type Filter = ();

    fn extract(item: QueryItem<'_, Self::Query>) -> Option<Self> {
        Some(item.id())
    }
}

// After
impl<A> ExtractInstance for AssetId<A>
where
    A: Asset,
{
    type Data = Read<Handle<A>>;
    type Filter = ();

    fn extract(item: QueryItem<'_, Self::Data>) -> Option<Self> {
        Some(item.id())
    }
}

// Before
impl ViewNode for PostProcessNode {
    type ViewQuery = (
        &'static ViewTarget,
        &'static PostProcessSettings,
    );

    fn run(
        &self,
        _graph: &mut RenderGraphContext,
        render_context: &mut RenderContext,
        (view_target, _post_process_settings): QueryItem<Self::ViewQuery>,
        world: &World,
    ) -> Result<(), NodeRunError> {
        // ...
    }
}

// After
impl ViewNode for PostProcessNode {
    type ViewData = (
        &'static ViewTarget,
        &'static PostProcessSettings,
    );

    fn run(
        &self,
        _graph: &mut RenderGraphContext,
        render_context: &mut RenderContext,
        (view_target, _post_process_settings): QueryItem<Self::ViewData>,
        world: &World,
    ) -> Result<(), NodeRunError> {
        // ...
    }
}

// Before
impl<P: CachedRenderPipelinePhaseItem> RenderCommand<P> for SetItemPipeline {
    type Param = SRes<PipelineCache>;
    type ViewWorldQuery = ();
    type ItemWorldQuery = ();
    #[inline]
    fn render<'w>(
        item: &P,
        _view: (),
        _entity: (),
        pipeline_cache: SystemParamItem<'w, '_, Self::Param>,
        pass: &mut TrackedRenderPass<'w>,
    ) -> RenderCommandResult {
        // ...
    }
}

// After
impl<P: CachedRenderPipelinePhaseItem> RenderCommand<P> for SetItemPipeline {
    type Param = SRes<PipelineCache>;
    type ViewData = ();
    type ItemData = ();
    #[inline]
    fn render<'w>(
        item: &P,
        _view: (),
        _entity: (),
        pipeline_cache: SystemParamItem<'w, '_, Self::Param>,
        pass: &mut TrackedRenderPass<'w>,
    ) -> RenderCommandResult {
        // ...
    }
}
```
2023-12-12 19:45:50 +00:00
Mark Wainwright
f0a8994f55
Split WorldQuery into WorldQueryData and WorldQueryFilter (#9918)
# Objective

- Fixes #7680
- This is an updated for https://github.com/bevyengine/bevy/pull/8899
which had the same objective but fell a long way behind the latest
changes


## Solution

The traits `WorldQueryData : WorldQuery` and `WorldQueryFilter :
WorldQuery` have been added and some of the types and functions from
`WorldQuery` has been moved into them.

`ReadOnlyWorldQuery` has been replaced with `ReadOnlyWorldQueryData`. 

`WorldQueryFilter` is safe (as long as `WorldQuery` is implemented
safely).

`WorldQueryData` is unsafe - safely implementing it requires that
`Self::ReadOnly` is a readonly version of `Self` (this used to be a
safety requirement of `WorldQuery`)

The type parameters `Q` and `F` of `Query` must now implement
`WorldQueryData` and `WorldQueryFilter` respectively.

This makes it impossible to accidentally use a filter in the data
position or vice versa which was something that could lead to bugs.
~~Compile failure tests have been added to check this.~~

It was previously sometimes useful to use `Option<With<T>>` in the data
position. Use `Has<T>` instead in these cases.

The `WorldQuery` derive macro has been split into separate derive macros
for `WorldQueryData` and `WorldQueryFilter`.

Previously it was possible to derive both `WorldQuery` for a struct that
had a mixture of data and filter items. This would not work correctly in
some cases but could be a useful pattern in others. *This is no longer
possible.*

---

## Notes

- The changes outside of `bevy_ecs` are all changing type parameters to
the new types, updating the macro use, or replacing `Option<With<T>>`
with `Has<T>`.

- All `WorldQueryData` types always returned `true` for `IS_ARCHETYPAL`
so I moved it to `WorldQueryFilter` and
replaced all calls to it with `true`. That should be the only logic
change outside of the macro generation code.

- `Changed<T>` and `Added<T>` were being generated by a macro that I
have expanded. Happy to revert that if desired.

- The two derive macros share some functions for implementing
`WorldQuery` but the tidiest way I could find to implement them was to
give them a ton of arguments and ask clippy to ignore that.

## Changelog

### Changed
- Split `WorldQuery` into `WorldQueryData` and `WorldQueryFilter` which
now have separate derive macros. It is not possible to derive both for
the same type.
- `Query` now requires that the first type argument implements
`WorldQueryData` and the second implements `WorldQueryFilter`

## Migration Guide

- Update derives

```rust
// old
#[derive(WorldQuery)]
#[world_query(mutable, derive(Debug))]
struct CustomQuery {
    entity: Entity,
    a: &'static mut ComponentA
}

#[derive(WorldQuery)]
struct QueryFilter {
    _c: With<ComponentC>
}

// new 
#[derive(WorldQueryData)]
#[world_query_data(mutable, derive(Debug))]
struct CustomQuery {
    entity: Entity,
    a: &'static mut ComponentA,
}

#[derive(WorldQueryFilter)]
struct QueryFilter {
    _c: With<ComponentC>
}
```
- Replace `Option<With<T>>` with `Has<T>`

```rust
/// old
fn my_system(query: Query<(Entity, Option<With<ComponentA>>)>)
{
  for (entity, has_a_option) in query.iter(){
    let has_a:bool = has_a_option.is_some();
    //todo!()
  }
}

/// new
fn my_system(query: Query<(Entity, Has<ComponentA>)>)
{
  for (entity, has_a) in query.iter(){
    //todo!()
  }
}
```

- Fix queries which had filters in the data position or vice versa.

```rust
// old
fn my_system(query: Query<(Entity, With<ComponentA>)>)
{
  for (entity, _) in query.iter(){
  //todo!()
  }
}

// new
fn my_system(query: Query<Entity, With<ComponentA>>)
{
  for entity in query.iter(){
  //todo!()
  }
}

// old
fn my_system(query: Query<AnyOf<(&ComponentA, With<ComponentB>)>>)
{
  for (entity, _) in query.iter(){
  //todo!()
  }
}

// new
fn my_system(query: Query<Option<&ComponentA>, Or<(With<ComponentA>, With<ComponentB>)>>)
{
  for entity in query.iter(){
  //todo!()
  }
}

```

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-11-28 03:56:07 +00:00
Mincong Lu
c33bacd5fd
Make bevy_app and reflect opt-out for bevy_hierarchy. (#10721)
# Objective

Bevy_hierarchy is very useful for ECS only usages of bevy_ecs, but it
currently pulls in bevy_reflect, bevy_app and bevy_core with no way to
opt out.

## Solution

This PR provides features `bevy_app` and `reflect` that are enabled by
default. If disabled, they should remove these dependencies from
bevy_hierarchy.

---

## Changelog

Added features `bevy_app` and `reflect` to bevy_hierarchy.
2023-11-25 03:05:38 +00:00
Stepan Koltsov
1da0afa3aa
bevy_hierarchy: add some docs (#10598)
Just adding comments to code I did not understand before and I hope
understand now.

---------

Co-authored-by: Kristoffer Søholm <k.soeholm@gmail.com>
2023-11-21 01:11:20 +00:00
Ame
951c9bb1a2
Add [lints] table, fix adding #![allow(clippy::type_complexity)] everywhere (#10011)
# Objective

- Fix adding `#![allow(clippy::type_complexity)]` everywhere. like #9796

## Solution

- Use the new [lints] table that will land in 1.74
(https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#lints)
- inherit lint to the workspace, crates and examples.
```
[lints]
workspace = true
```

## Changelog

- Bump rust version to 1.74
- Enable lints table for the workspace
```toml
[workspace.lints.clippy]
type_complexity = "allow"
```
- Allow type complexity for all crates and examples
```toml
[lints]
workspace = true
```

---------

Co-authored-by: Martín Maita <47983254+mnmaita@users.noreply.github.com>
2023-11-18 20:58:48 +00:00
Talin
d2c754c816
Added 'clear_children' and 'replace_children' methods to BuildWorldChildren to be consistent with BuildChildren. (#10311)
# Objective

The `BuildWorldChildren` API was missing several methods that exist in
`BuildChildren`.

## Solution

Added the methods (and tests) for consistency.
2023-10-31 23:55:33 +00:00
Ame :]
7541bf862c
Fix some warnings shown in nightly (#10012)
# Objective

Fix warnings:
- #[warn(clippy::needless_pass_by_ref_mut)]
- #[warn(elided_lifetimes_in_associated_constant)]

## Solution

- Remove mut
- add &'static

## Errors

```rust
warning: this argument is a mutable reference, but not used mutably
   --> crates/bevy_hierarchy/src/child_builder.rs:672:31
    |
672 |     fn assert_children(world: &mut World, parent: Entity, children: Option<&[Entity]>) {
    |                               ^^^^^^^^^^ help: consider changing to: `&World`
    |
    = note: this is cfg-gated and may require further changes
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
    = note: `#[warn(clippy::needless_pass_by_ref_mut)]` on by default
```


```rust
warning: `&` without an explicit lifetime name cannot be used here
   --> examples/shader/post_processing.rs:120:21
    |
120 |     pub const NAME: &str = "post_process";
    |                     ^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #115010 <https://github.com/rust-lang/rust/issues/115010>
    = note: `#[warn(elided_lifetimes_in_associated_constant)]` on by default
help: use the `'static` lifetime
    |
120 |     pub const NAME: &'static str = "post_process";
    |                      +++++++


```
2023-10-05 05:41:09 +00:00
SADIK KUZU
483f2464a8
Fix typos (#9965)
# Objective

- There were a few typos in the project.
- This PR fixes these typos.

## Solution

- Fixing the typos.

Signed-off-by: SADIK KUZU <sadikkuzu@hotmail.com>
2023-09-29 12:26:41 +00:00
iiYese
0181d40d83
Add as_slice to parent (#9871)
# Objective
- Make it possible to write APIs that require a type or homogenous
storage for both `Children` & `Parent` that is agnostic to edge
direction.

## Solution
- Add a way to get the `Entity` from `Parent` as a slice.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Joseph <21144246+JoJoJet@users.noreply.github.com>
2023-09-22 06:27:58 +00:00
Joseph
8eb6ccdd87
Remove useless single tuples and trailing commas (#9720)
# Objective

Title
2023-09-08 21:46:54 +00:00
Joseph
02b520b4e8
Split ComputedVisibility into two components to allow for accurate change detection and speed up visibility propagation (#9497)
# Objective

Fix #8267.
Fixes half of #7840.

The `ComputedVisibility` component contains two flags: hierarchy
visibility, and view visibility (whether its visible to any cameras).
Due to the modular and open-ended way that view visibility is computed,
it triggers change detection every single frame, even when the value
does not change. Since hierarchy visibility is stored in the same
component as view visibility, this means that change detection for
inherited visibility is completely broken.

At the company I work for, this has become a real issue. We are using
change detection to only re-render scenes when necessary. The broken
state of change detection for computed visibility means that we have to
to rely on the non-inherited `Visibility` component for now. This is
workable in the early stages of our project, but since we will
inevitably want to use the hierarchy, we will have to either:

1. Roll our own solution for computed visibility.
2. Fix the issue for everyone.

## Solution

Split the `ComputedVisibility` component into two: `InheritedVisibilty`
and `ViewVisibility`.
This allows change detection to behave properly for
`InheritedVisibility`.
View visiblity is still erratic, although it is less useful to be able
to detect changes
for this flavor of visibility.

Overall, this actually simplifies the API. Since the visibility system
consists of
self-explaining components, it is much easier to document the behavior
and usage.
This approach is more modular and "ECS-like" -- one could
strip out the `ViewVisibility` component entirely if it's not needed,
and rely only on inherited visibility.

---

## Changelog

- `ComputedVisibility` has been removed in favor of:
`InheritedVisibility` and `ViewVisiblity`.

## Migration Guide

The `ComputedVisibilty` component has been split into
`InheritedVisiblity` and
`ViewVisibility`. Replace any usages of
`ComputedVisibility::is_visible_in_hierarchy`
with `InheritedVisibility::get`, and replace
`ComputedVisibility::is_visible_in_view`
 with `ViewVisibility::get`.
 
 ```rust
 // Before:
 commands.spawn(VisibilityBundle {
     visibility: Visibility::Inherited,
     computed_visibility: ComputedVisibility::default(),
 });
 
 // After:
 commands.spawn(VisibilityBundle {
     visibility: Visibility::Inherited,
     inherited_visibility: InheritedVisibility::default(),
     view_visibility: ViewVisibility::default(),
 });
 ```
 
 ```rust
 // Before:
 fn my_system(q: Query<&ComputedVisibilty>) {
     for vis in &q {
         if vis.is_visible_in_hierarchy() {
     
 // After:
 fn my_system(q: Query<&InheritedVisibility>) {
     for inherited_visibility in &q {
         if inherited_visibility.get() {
 ```
 
 ```rust
 // Before:
 fn my_system(q: Query<&ComputedVisibilty>) {
     for vis in &q {
         if vis.is_visible_in_view() {
     
 // After:
 fn my_system(q: Query<&ViewVisibility>) {
     for view_visibility in &q {
         if view_visibility.get() {
 ```
 
 ```rust
 // Before:
 fn my_system(mut q: Query<&mut ComputedVisibilty>) {
     for vis in &mut q {
         vis.set_visible_in_view();
     
 // After:
 fn my_system(mut q: Query<&mut ViewVisibility>) {
     for view_visibility in &mut q {
         view_visibility.set();
 ```

---------

Co-authored-by: Robert Swain <robert.swain@gmail.com>
2023-09-01 13:00:18 +00:00
Joseph
bc8bf34818
Allow disjoint mutable world access via EntityMut (#9419)
# Objective

Fix #4278
Fix #5504
Fix #9422

Provide safe ways to borrow an entire entity, while allowing disjoint
mutable access. `EntityRef` and `EntityMut` are not suitable for this,
since they provide access to the entire world -- they are just helper
types for working with `&World`/`&mut World`.

This has potential uses for reflection and serialization

## Solution

Remove `EntityRef::world`, which allows it to soundly be used within
queries.

`EntityMut` no longer supports structural world mutations, which allows
multiple instances of it to exist for different entities at once.
Structural world mutations are performed using the new type
`EntityWorldMut`.

```rust
fn disjoint_system(
     q2: Query<&mut A>,
     q1: Query<EntityMut, Without<A>>,
) { ... }

let [entity1, entity2] = world.many_entities_mut([id1, id2]);
*entity1.get_mut::<T>().unwrap() = *entity2.get().unwrap();

for entity in world.iter_entities_mut() {
    ...
}
```

---

## Changelog

- Removed `EntityRef::world`, to fix a soundness issue with queries.
+ Removed the ability to structurally mutate the world using
`EntityMut`, which allows it to be used in queries.
+ Added `EntityWorldMut`, which is used to perform structural mutations
that are no longer allowed using `EntityMut`.

## Migration Guide

**Note for maintainers: ensure that the guide for #9604 is updated
accordingly.**

Removed the method `EntityRef::world`, to fix a soundness issue with
queries. If you need access to `&World` while using an `EntityRef`,
consider passing the world as a separate parameter.

`EntityMut` can no longer perform 'structural' world mutations, such as
adding or removing components, or despawning the entity. Additionally,
`EntityMut::world`, `EntityMut::world_mut` , and
`EntityMut::world_scope` have been removed.
Instead, use the newly-added type `EntityWorldMut`, which is a helper
type for working with `&mut World`.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-08-28 23:30:59 +00:00
张林伟
7ccb203b37
Prevent setting parent as itself (#8980)
# Objective

- Fixes https://github.com/bevyengine/bevy/issues/8979.

## Solution

- Panic when parent and child are same entity.
- Add checks into EntityCommands and EntityMut methods
2023-08-07 23:00:48 +00:00
ClayenKitten
ffc572728f
Fix typos throughout the project (#9090)
# Objective

Fix typos throughout the project.

## Solution

[`typos`](https://github.com/crate-ci/typos) project was used for
scanning, but no automatic corrections were applied. I checked
everything by hand before fixing.

Most of the changes are documentation/comments corrections. Also, there
are few trivial changes to code (variable name, pub(crate) function name
and a few error/panic messages).

## Unsolved

`bevy_reflect_derive` has
[typo](1b51053f19/crates/bevy_reflect/bevy_reflect_derive/src/type_path.rs (L76))
in enum variant name that I didn't fix. Enum is `pub(crate)`, so there
shouldn't be any trouble if fixed. However, code is tightly coupled with
macro usage, so I decided to leave it for more experienced contributor
just in case.
2023-07-10 00:11:51 +00:00
Gino Valente
aeeb20ec4c
bevy_reflect: FromReflect Ergonomics Implementation (#6056)
# Objective

**This implementation is based on
https://github.com/bevyengine/rfcs/pull/59.**

---

Resolves #4597

Full details and motivation can be found in the RFC, but here's a brief
summary.

`FromReflect` is a very powerful and important trait within the
reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to
be formed into Real ones (e.g., `Vec<i32>`, etc.).

This mainly comes into play concerning deserialization, where the
reflection deserializers both return a `Box<dyn Reflect>` that almost
always contain one of these Dynamic representations of a Real type. To
convert this to our Real type, we need to use `FromReflect`.

It also sneaks up in other ways. For example, it's a required bound for
`T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`.
It's also required by all fields of an enum as it's used as part of the
`Reflect::apply` implementation.

So in other words, much like `GetTypeRegistration` and `Typed`, it is
very much a core reflection trait.

The problem is that it is not currently treated like a core trait and is
not automatically derived alongside `Reflect`. This makes using it a bit
cumbersome and easy to forget.

## Solution

Automatically derive `FromReflect` when deriving `Reflect`.

Users can then choose to opt-out if needed using the
`#[reflect(from_reflect = false)]` attribute.

```rust
#[derive(Reflect)]
struct Foo;

#[derive(Reflect)]
#[reflect(from_reflect = false)]
struct Bar;

fn test<T: FromReflect>(value: T) {}

test(Foo); // <-- OK
test(Bar); // <-- Panic! Bar does not implement trait `FromReflect`
```

#### `ReflectFromReflect`

This PR also automatically adds the `ReflectFromReflect` (introduced in
#6245) registration to the derived `GetTypeRegistration` impl— if the
type hasn't opted out of `FromReflect` of course.

<details>
<summary><h4>Improved Deserialization</h4></summary>

> **Warning**
> This section includes changes that have since been descoped from this
PR. They will likely be implemented again in a followup PR. I am mainly
leaving these details in for archival purposes, as well as for reference
when implementing this logic again.

And since we can do all the above, we might as well improve
deserialization. We can now choose to deserialize into a Dynamic type or
automatically convert it using `FromReflect` under the hood.

`[Un]TypedReflectDeserializer::new` will now perform the conversion and
return the `Box`'d Real type.

`[Un]TypedReflectDeserializer::new_dynamic` will work like what we have
now and simply return the `Box`'d Dynamic type.

```rust
// Returns the Real type
let reflect_deserializer = UntypedReflectDeserializer::new(&registry);
let mut deserializer = ron:🇩🇪:Deserializer::from_str(input)?;

let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?;

// Returns the Dynamic type
let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry);
let mut deserializer = ron:🇩🇪:Deserializer::from_str(input)?;

let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?;
```

</details>

---

## Changelog

* `FromReflect` is now automatically derived within the `Reflect` derive
macro
* This includes auto-registering `ReflectFromReflect` in the derived
`GetTypeRegistration` impl
* ~~Renamed `TypedReflectDeserializer::new` and
`UntypedReflectDeserializer::new` to
`TypedReflectDeserializer::new_dynamic` and
`UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped**
* ~~Changed `TypedReflectDeserializer::new` and
`UntypedReflectDeserializer::new` to automatically convert the
deserialized output using `FromReflect`~~ **Descoped**

## Migration Guide

* `FromReflect` is now automatically derived within the `Reflect` derive
macro. Items with both derives will need to remove the `FromReflect`
one.

  ```rust
  // OLD
  #[derive(Reflect, FromReflect)]
  struct Foo;
  
  // NEW
  #[derive(Reflect)]
  struct Foo;
  ```

If using a manual implementation of `FromReflect` and the `Reflect`
derive, users will need to opt-out of the automatic implementation.

  ```rust
  // OLD
  #[derive(Reflect)]
  struct Foo;
  
  impl FromReflect for Foo {/* ... */}
  
  // NEW
  #[derive(Reflect)]
  #[reflect(from_reflect = false)]
  struct Foo;
  
  impl FromReflect for Foo {/* ... */}
  ```

<details>
<summary><h4>Removed Migrations</h4></summary>

> **Warning**
> This section includes changes that have since been descoped from this
PR. They will likely be implemented again in a followup PR. I am mainly
leaving these details in for archival purposes, as well as for reference
when implementing this logic again.

* The reflect deserializers now perform a `FromReflect` conversion
internally. The expected output of `TypedReflectDeserializer::new` and
`UntypedReflectDeserializer::new` is no longer a Dynamic (e.g.,
`DynamicList`), but its Real counterpart (e.g., `Vec<i32>`).

  ```rust
let reflect_deserializer =
UntypedReflectDeserializer::new_dynamic(&registry);
  let mut deserializer = ron:🇩🇪:Deserializer::from_str(input)?;
  
  // OLD
let output: DynamicStruct = reflect_deserializer.deserialize(&mut
deserializer)?.take()?;
  
  // NEW
let output: SomeStruct = reflect_deserializer.deserialize(&mut
deserializer)?.take()?;
  ```

Alternatively, if this behavior isn't desired, use the
`TypedReflectDeserializer::new_dynamic` and
`UntypedReflectDeserializer::new_dynamic` methods instead:

  ```rust
  // OLD
  let reflect_deserializer = UntypedReflectDeserializer::new(&registry);
  
  // NEW
let reflect_deserializer =
UntypedReflectDeserializer::new_dynamic(&registry);
  ```

</details>

---------

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
Anby
29f7293e30
Change despawn_descendants to return &mut Self (#8928)
# Objective

- Change despawn descendants to return self (#8883).

## Solution

- Change function signature `despawn_descendants` under trait
`DespawnRecursiveExt`.
- Add single extra test `spawn_children_after_despawn_descendants` (May
be unnecessary)

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-06-23 02:08:13 +00:00
Raffaele Ragni
7fc6db32ce
Add FromReflect where Reflect is used (#8776)
# Objective

Discovered that PointLight did not implement FromReflect. Adding
FromReflect where Reflect is used. I overreached and applied this rule
everywhere there was a Reflect without a FromReflect, except from where
the compiler wouldn't allow me.

Based from question: https://github.com/bevyengine/bevy/discussions/8774

## Solution

- Adding FromReflect where Reflect was already derived

## Notes

First PR I do in this ecosystem, so not sure if this is the usual
approach, that is, to touch many files at once.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-06-19 16:18:17 +00:00
Natanael Mojica
f135535cd6
Rename Command's "write" method to "apply" (#8814)
# Objective

- Fixes #8811 .

## Solution

- Rename "write" method to "apply" in Command trait definition.
- Rename other implementations of command trait throughout bevy's code
base.

---

## Changelog

- Changed: `Command::write` has been changed to `Command::apply`
- Changed: `EntityCommand::write` has been changed to
`EntityCommand::apply`

## Migration Guide

- `Command::write` implementations need to be changed to implement
`Command::apply` instead. This is a mere name change, with no further
actions needed.
- `EntityCommand::write` implementations need to be changed to implement
`EntityCommand::apply` instead. This is a mere name change, with no
further actions needed.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-06-12 17:53:47 +00:00
CatThingy
89cbc78d3d
Require #[derive(Event)] on all Events (#7086)
# Objective

Be consistent with `Resource`s and `Components` and have `Event` types
be more self-documenting.
Although not susceptible to accidentally using a function instead of a
value due to `Event`s only being initialized by their type, much of the
same reasoning for removing the blanket impl on `Resource` also applies
here.

* Not immediately obvious if a type is intended to be an event
* Prevent invisible conflicts if the same third-party or primitive types
are used as events
* Allows for further extensions (e.g. opt-in warning for missed events)

## Solution

Remove the blanket impl for the `Event` trait. Add a derive macro for
it.

---

## Changelog

- `Event` is no longer implemented for all applicable types. Add the
`#[derive(Event)]` macro for events.

## Migration Guide

* Add the `#[derive(Event)]` macro for events. Third-party types used as
events should be wrapped in a newtype.
2023-06-06 14:44:32 +00:00
Marco Buono
5288be7c6e
Expose sorting methods in Children (#8522)
# 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)
2023-05-01 15:57:25 +00:00
Illiux
eebc92a7d4
Make scene handling of entity references robust (#7335)
# 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>
2023-05-01 15:49:27 +00:00
ira
5dec3236ac
Remove Children component when calling despawn_descendants (#8476)
# Objective

Fix #8474
2023-04-24 14:14:52 +00:00
Wybe Westra
abf12f3b3b
Fixed several missing links in docs. (#8117)
Links in the api docs are nice. I noticed that there were several places
where structs / functions and other things were referenced in the docs,
but weren't linked. I added the links where possible / logical.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
2023-04-23 17:28:36 +00:00
JohnTheCoolingFan
15a96adc01
ChildBuilder docs improvement (#8371)
# Objective

Fixes #7230 

## Solution

Documented some side-effects

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2023-04-22 20:43:13 +00:00
Bruce Reif (Buswolley)
7604464438
fix panic when moving child (#8346)
# Objective
When changing an Entity's `Parent` to a new one from an old `Parent`
that doesn't exist, Bevy panics. Fixes #8337.

## Solution

Use `get_entity_mut` instead of `entity_mut` in `remove_from_children`.

---------

Co-authored-by: James Liu <contact@jamessliu.com>
2023-04-17 18:03:47 +00:00
JoJoJet
3ead10a3e0
Suppress the clippy::type_complexity lint (#8313)
# Objective

The clippy lint `type_complexity` is known not to play well with bevy.
It frequently triggers when writing complex queries, and taking the
lint's advice of using a type alias almost always just obfuscates the
code with no benefit. Because of this, this lint is currently ignored in
CI, but unfortunately it still shows up when viewing bevy code in an
IDE.

As someone who's made a fair amount of pull requests to this repo, I
will say that this issue has been a consistent thorn in my side. Since
bevy code is filled with spurious, ignorable warnings, it can be very
difficult to spot the *real* warnings that must be fixed -- most of the
time I just ignore all warnings, only to later find out that one of them
was real after I'm done when CI runs.

## Solution

Suppress this lint in all bevy crates. This was previously attempted in
#7050, but the review process ended up making it more complicated than
it needs to be and landed on a subpar solution.

The discussion in https://github.com/rust-lang/rust-clippy/pull/10571
explores some better long-term solutions to this problem. Since there is
no timeline on when these solutions may land, we should resolve this
issue in the meantime by locally suppressing these lints.

### Unresolved issues

Currently, these lints are not suppressed in our examples, since that
would require suppressing the lint in every single source file. They are
still ignored in CI.
2023-04-06 21:27:36 +00:00
Carter Anderson
aefe1f0739
Schedule-First: the new and improved add_systems (#8079)
Co-authored-by: Mike <mike.hsu@gmail.com>
2023-03-18 01:45:34 +00:00
Cameron
be22569db7 EntityMut: rename remove_intersection to remove and remove to take (#7810)
# Objective

- A more intuitive distinction between the two. `remove_intersection` is verbose and unclear.
- `EntityMut::remove` and `Commands::remove` should match.


## Solution

- What the title says.

---

## Migration Guide

Before
```rust
fn clear_children(parent: Entity, world: &mut World) {
    if let Some(children) = world.entity_mut(parent).remove::<Children>() {
        for &child in &children.0 {
            world.entity_mut(child).remove_intersection::<Parent>();
        }
    }
}
```

After
```rust
fn clear_children(parent: Entity, world: &mut World) {
    if let Some(children) = world.entity_mut(parent).take::<Children>() {
        for &child in &children.0 {
            world.entity_mut(child).remove::<Parent>();
        }
    }
}
```
2023-02-26 00:09:19 +00:00
Carter Anderson
dcc03724a5 Base Sets (#7466)
# 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
2023-02-06 03:10:08 +00:00
Alice Cecile
206c7ce219 Migrate engine to Schedule v3 (#7267)
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.
2023-02-06 02:04:50 +00:00
ld000
e44990a48d Add ReplaceChildren and ClearChildren EntityCommands (#6035)
# Objective

Fixes #5859 

## Solution

- Add `ClearChildren` and `ReplaceChildren` commands in the `crates/bevy_hierarchy/src/child_builder.rs`

---

## Changelog

  - Added `ClearChildren` and `ReplaceChildren` struct
  - Added `clear_children(&mut self) -> &mut Self` and `replace_children(&mut self, children: &[Entity]) -> &mut Self` function in `BuildChildren` trait
  - Changed `PushChildren` `write` function body to a `push_children ` function to reused in `ReplaceChildren`
  - Added `clear_children` function
  - Added `push_and_replace_children_commands` and `push_and_clear_children_commands` test



Co-authored-by: ld000 <lidong9144@163.com>
Co-authored-by: lidong63 <lidong63@meituan.com>
2023-01-16 21:24:15 +00:00
Nicola Papale
689eab6fb7 Add an extension trait to EntityCommands to update hierarchy while preserving GlobalTransform (#7024)
# Objective

It is often necessary  to update an entity's parent
while keeping its GlobalTransform static. Currently
it is cumbersome and error-prone (two questions in
the discord `#help` channel in the past week)

- Part 2, resolves #5475
- Builds on: #7020.

## Solution

- Added the `BuildChildrenTransformExt` trait, it is part
  of `bevy::prelude` and adds the following methods to `EntityCommands`:
  - `set_parent_in_place`: Change the parent of an entity and
    update its `Transform` in order to preserve its `GlobalTransform` after the parent change
  - `remove_parent_in_place`: Remove an entity from a hierarchy,
    while preserving its `GlobalTransform`.

---

## Changelog


- Added the `BuildChildrenTransformExt` trait, it is part
  of `bevy::prelude` and adds the following methods to `EntityCommands`:
  - `set_parent_in_place`: Change the parent of an entity and
    update its `Transform` in order to preserve its `GlobalTransform` after the parent change
  - `remove_parent_in_place`: Remove an entity from a hierarchy,
    while preserving its `GlobalTransform`.

Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2023-01-12 18:46:11 +00:00
Rob Parrett
3dd8b42f72 Fix various typos (#7096)
I stumbled across a typo in some docs. Fixed some more while I was in there.
2023-01-06 00:43:30 +00:00
François
f1a21db250 don't error when sending HierarchyEvents when Event type not registered (#7031)
# Objective

- Loading a gltf files prints many errors
```
ERROR bevy_ecs::world: Unable to send event `bevy_hierarchy::events::HierarchyEvent`
	Event must be added to the app with `add_event()`
	https://docs.rs/bevy/*/bevy/app/struct.App.html#method.add_event
```
- Loading a gltf file create a world for a scene where events are not registered. Executing hierarchy commands on that world should not print error

## Solution

- Revert part of #6921 
- don't use `world.send_event` / `world.send_event_batch` from commands
2022-12-26 16:39:17 +00:00
ira
b39817a27c Add add_child, set_parent and remove_parent to EntityMut (#6926)
# Objective
Align the hierarchy API between `EntityCommands` and `EntityMut`.

Added missing methods to `EntityMut`.
Replaced the duplicate `Command` implementations with the ones on `EntityMut` (e.g. The `AddChild` command is now just `world.entity_mut(..).add_child(..)`)

Fixed `update_old_parents` not sending `ChildAdded` events.

This PR does not add `add_children` to `EntityMut` as I would like to remove it from `EntityCommands` instead in #6942.

## Changelog
* Added `add_child`, `set_parent` and `remove_parent` to `EntityMut`
* Fixed missing `ChildAdded` events


Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-12-25 00:23:12 +00:00
ira
0761594dd8 Use World helper methods for sending HierarchyEvents (#6921)
A code-quality PR

Also cleans up the helper methods by just importing the `Event` type

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-12-20 16:17:07 +00:00
ira
0d606030a2 Remove EntityCommands::add_children (#6942)
# Objective
Remove a method with an unfortunate name and questionable usefulness.
Added in #4708

It doesn't make sense to me for us to provide a method to work around a limitation of closures when we can simply, *not* use a closure.
The limitation in this case is not being able to initialize a variable from inside a closure:

```rust
let child_id;
commands.spawn_empty().with_children(|parent| {
    // Error: passing uninitalized variable to a closure.
    child_id = parent.spawn_empty().id();
});

// Do something with child_id
```
The docs for `add_children` suggest the following:
```rust
let child_id = commands
    .spawn_empty()
    .add_children(|parent| parent.spawn_empty().id());
```
I would instead suggest using the following snippet.
```rust
let parent_id = commands.spawn_empty().id();
let child_id = commands.spawn_empty().set_parent(parent_id).id();

// To be fair, at the time of #4708 this would have been a bit more cumbersome since `set_parent` did not exist.
```

Using `add_children` gets more unwieldy when you also want the `parent_id`.
```rust
let parent_commands = commands.spawn_empty();
let parent_id = parent_commands.id();
let child_id = parent_commands.add_children(|parent| parent.spawn_empty().id());
```
### The name
I see why `add_children` is named that way, it's the non-builder variant of `with_children` so it kinda makes sense,
but now the method name situation for `add_child`, `add_children` and `push_children` is *rather* unfortunate.

Removing `add_children` and renaming `push_children` to `add_children` in one go is kinda bleh, but that way we end up with the matching methods `add_child` and `add_children`. 

Another reason to rename `push_children` is that it's trying to mimick the `Vec` api naming but fails because `push` is for single elements. I guess it should have been `extend_children_from_slice`, but lets not name it that :)

### Questions
~~Should `push_children` be renamed in this PR? This would make the migration guide easier to deal with.~~
Let's do that later.

Does anyone know of a way to do a simple text/regex search through all the github repos for usage of `add_children`?
That way we can have a better idea of how this will affect users. My guess is that usage of `add_children` is quite rare.

## Migration Guide
The method `add_children` on `EntityCommands` was removed.
If you were using `add_children` over `with_children` to return data out of the closure you can use `set_parent` or `add_child` to avoid the closure instead.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-12-16 19:53:23 +00:00
James Liu
17480b2d89 Remove APIs deprecated in 0.9 (#6801)
# Objective
These functions were deprecated in 0.9. They should be removed in 0.10.

## Solution
Remove them.
2022-12-05 22:49:04 +00:00
JoJoJet
70d7f80564 Make adding children idempotent (#6763)
# Objective

* Fix #6668
* There is no need to panic when a parenting operation is redundant, as no invalid state is entered.

## Solution

Make `push_children` idempotent.
2022-11-28 13:40:14 +00:00
JoJoJet
416a33e613 Add const Entity::PLACEHOLDER (#6761)
# Objective

One of the use-cases for the function `Entity::from_raw` is creating placeholder entity ids, which are meant to be overwritten later. If we use a constant for this instead of `from_raw`, it is more ergonomic and self-documenting.

## Solution

Add a constant that returns an entity ID with an index of `u32::MAX` and a generation of zero. Users are instructed to overwrite this value before using it.
2022-11-28 13:40:10 +00:00
ira
7d57d7ac0c Remove BuildWorldChildren impl from WorldChildBuilder (#6727)
# Objective
Remove an obscure and inconsistent bit of API.
Simplify the `WorldChildBuilder` code.

No idea why this even exists.

An example of the removed API:
```rust
world.spawn_empty().with_children(|parent| {
    parent.spawn_empty();
    parent.push_children(&[some_entity]); // Does *not* add children to the parent.
    // It's actually identical to:
    parent.spawn_empty().push_children(&[some_entity]);
});

world.spawn_empty().with_children(|parent| {
    // This just panics.
    parent.push_children(&[some_entity]);
});
```
This exists only on `WorldChildBuilder`; `ChildBuilder` does not have this API.

Yeet.

## Migration Guide
Hierarchy editing methods such as `with_children` and `push_children` have been removed from `WorldChildBuilder`.
You can edit the hierarchy via `EntityMut` instead.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-11-23 00:27:28 +00:00
Gino Valente
1f8cc9dd67 bevy_scene: Add missing registration for SmallVec<[Entity; 8]> (#6578)
# Objective

> Part of #6573

`Children` was not being properly deserialized in scenes. This was due to a missing registration on `SmallVec<[Entity; 8]>`, which is used by `Children`.

## Solution

Register `SmallVec<[Entity; 8]>`.

---

## Changelog

- Registered `SmallVec<[Entity; 8]>`
2022-11-14 23:08:23 +00:00
Lixou
e48c05c734 Fix Link in valid_parent_check_plugin.rs (#6584)
# Objective

Link doesn't get to right segment

## Solution

Fix link
2022-11-13 15:35:48 +00:00
ira
b0bd8722f3 Fix unsound EntityMut::remove_children. Add EntityMut::world_scope (#6464)
`EntityMut::remove_children` does not call `self.update_location()` which is unsound.
Verified by adding the following assertion, which fails when running the tests.
```rust
let before = self.location();
self.update_location();
assert_eq!(before, self.location());
```

I also removed incorrect messages like "parent entity is not modified" and the unhelpful "Inserting a bundle in the children entities may change the parent entity's location if they were of the same archetype" which might lead people to think that's the *only* thing that can change the entity's location.

# Changelog
Added `EntityMut::world_scope`.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-11-04 17:30:40 +00:00
Boxy
30e35764a1 Replace WorldQueryGats trait with actual gats (#6319)
# Objective

Replace `WorldQueryGats` trait with actual gats

## Solution

Replace `WorldQueryGats` trait with actual gats

---

## Changelog

- Replaced `WorldQueryGats` trait with actual gats

## Migration Guide

- Replace usage of `WorldQueryGats` assoc types with the actual gats on `WorldQuery` trait
2022-11-03 16:33:05 +00:00
Alice Cecile
334e09892b Revert "Show prelude re-exports in docs (#6448)" (#6449)
This reverts commit 53d387f340.

# Objective

Reverts #6448. This didn't have the intended effect: we're now getting bevy::prelude shown in the docs again.

Co-authored-by: Alejandro Pascual <alejandro.pascual.pozo@gmail.com>
2022-11-02 20:40:45 +00:00
Alejandro Pascual
53d387f340 Show prelude re-exports in docs (#6448)
# Objective

- Right now re-exports are completely hidden in prelude docs.
- Fixes #6433

## Solution

- We could show the re-exports without inlining their documentation.
2022-11-02 19:35:06 +00:00
ira
13da481bea Add methods to Query<&Children> and Query<&Parent> to iterate over descendants and ancestors (#6185)
# Objective
Add methods to `Query<&Children>` and `Query<&Parent>` to iterate over descendants and ancestors, respectively.

## Changelog

* Added extension trait for `Query` in `bevy_hierarchy`, `HierarchyQueryExt`
* Added method `iter_descendants` to `Query<&Children>` via `HierarchyQueryExt` for iterating over the descendants of an entity.
* Added method `iter_ancestors` to `Query<&Parent>` via `HierarchyQueryExt` for iterating over the ancestors of an entity.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-10-31 15:57:50 +00:00
JoJoJet
336049da68 Remove outdated uses of single-tuple bundles (#6406)
# Objective

Bevy still has many instances of using single-tuples `(T,)` to create a bundle. Due to #2975, this is no longer necessary.

## Solution

Search for regex `\(.+\s*,\)`. This should have found every instance.
2022-10-29 18:15:28 +00:00
ira
c9ec5c771a Add set_parent and remove_parent to EntityCommands (#6189)
I found myself doing
```rust
let child = commands.spawn(..).id();
commands.entity(parent).add_child(child);
```
When that could just be
```rust
commands.spawn(..).set_parent(parent);
```

Adding `set_parent` was trivial as it's just an `AddChild` command. Most of the changes are for `remove_parent`.
Also updated some outdated docs.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-10-24 14:33:49 +00:00
ira
1ca1c8c39e Fix RemoveChildren command (#6192)
# Objective

`RemoveChildren` could remove the `Parent` component from children belonging to a different parent, which breaks the hierarchy.

This change looks a little funny because I'm reusing the events to avoid needing to clone the parent's `Children`.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-10-10 23:40:32 +00:00
Gabriel Bourgeois
6b75589e2c Fix inconsistent children removal behavior (#6017)
# Objective

Fixes #6010

## Solution

As discussed in #6010, this makes it so the `Children` component is removed from the entity whenever all of its children are removed. The behavior is now consistent between all of the commands that may remove children from a parent, and this is tested via two new test functions (one for world functions and one for commands).

Documentation was also added to `insert_children`, `push_children`, `add_child` and `remove_children` commands to make this behavior clearer for users.

## Changelog

- Fixed `Children` component not getting removed from entity when all its children are moved to a new parent.

## Migration Guide

- Queries with `Changed<Children>` will no longer match entities that had all of their children removed using `remove_children`.
- `RemovedComponents<Children>` will now contain entities that had all of their children remove using `remove_children`.
2022-10-06 21:39:34 +00:00
ira
92e78a4bc5 Fix some grammatical errors in the docs (#6109)
Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-09-26 21:47:31 +00:00
Carter Anderson
01aedc8431 Spawn now takes a Bundle (#6054)
# 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%:
![image](https://user-images.githubusercontent.com/2694663/191627587-4ab2f949-4ccd-4231-80eb-80dd4d9ad6b9.png)

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();
```
2022-09-23 19:55:54 +00:00
Carter Anderson
cd15f0f5be Accept Bundles for insert and remove. Deprecate insert/remove_bundle (#6039)
# Objective

Take advantage of the "impl Bundle for Component" changes in #2975 / add the follow up changes discussed there.

## Solution

- Change `insert` and `remove` to accept a Bundle instead of a Component (for both Commands and World)
- Deprecate `insert_bundle`, `remove_bundle`, and `remove_bundle_intersection`
- Add `remove_intersection`

---

## Changelog

- Change `insert` and `remove` now accept a Bundle instead of a Component (for both Commands and World)
- `insert_bundle` and `remove_bundle` are deprecated
 

## Migration Guide

Replace `insert_bundle` with `insert`:
```rust
// Old (0.8)
commands.spawn().insert_bundle(SomeBundle::default());
// New (0.9)
commands.spawn().insert(SomeBundle::default());
```

Replace `remove_bundle` with `remove`:
```rust
// Old (0.8)
commands.entity(some_entity).remove_bundle::<SomeBundle>();
// New (0.9)
commands.entity(some_entity).remove::<SomeBundle>();
```

Replace `remove_bundle_intersection` with `remove_intersection`:
```rust
// Old (0.8)
world.entity_mut(some_entity).remove_bundle_intersection::<SomeBundle>();
// New (0.9)
world.entity_mut(some_entity).remove_intersection::<SomeBundle>();
```

Consider consolidating as many operations as possible to improve ergonomics and cut down on archetype moves:
```rust
// Old (0.8)
commands.spawn()
  .insert_bundle(SomeBundle::default())
  .insert(SomeComponent);

// New (0.9) - Option 1
commands.spawn().insert((
  SomeBundle::default(),
  SomeComponent,
))

// New (0.9) - Option 2
commands.spawn_bundle((
  SomeBundle::default(),
  SomeComponent,
))
```

## Next Steps

Consider changing `spawn` to accept a bundle and deprecate `spawn_bundle`.
2022-09-21 21:47:53 +00:00
Nicola Papale
6c5403cf47 Add warning when a hierarchy component is missing (#5590)
# Objective

A common pitfall since 0.8 is the requirement on `ComputedVisibility`
being present on all ancestors of an entity that itself has
`ComputedVisibility`, without which, the entity becomes invisible.

I myself hit the issue and got very confused, and saw a few people hit
it as well, so it makes sense to provide a hint of what to do when such
a situation is encountered.

- Fixes #5849
- Closes #5616
- Closes #2277 
- Closes #5081

## Solution

We now check that all entities with both a `Parent` and a
`ComputedVisibility` component have parents that themselves have a
`ComputedVisibility` component.

Note that the warning is only printed once.

We also add a similar warning to `GlobalTransform`.

This only emits a warning. Because sometimes it could be an intended
behavior.

Alternatives:
- Do nothing and keep repeating to newcomers how to avoid recurring
  pitfalls
- Make the transform and visibility propagation tolerant to missing
  components (#5616)
- Probably archetype invariants, though the current draft would not
  allow detecting that kind of errors

---

## Changelog

- Add a warning when encountering dubious component hierarchy structure


Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2022-09-19 16:12:11 +00:00
Boutillier
a70b9c5969 Remove duplicate asserts in test (#5648)
# Objective

While poking around the hierarchy code, I wondered why some asserts in tests were duplicated.
Some git blame later, I found out that commit ( 8eb0440f1e ) added already existing asserts while removing others.

## Solution

Remove the duplicated asserts.
2022-08-15 23:03:42 +00:00
ira
c37939d322 Make Children constructor pub(crate). (#5532)
#4197 intended to remove all `pub` constructors of `Children` and `Parent` and it seems like this one was missed.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-08-05 03:49:12 +00:00
ira
4847f7e3ad Update codebase to use IntoIterator where possible. (#5269)
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>
2022-07-11 15:28:50 +00:00
James Liu
8eb0440f1e Hierarchy commandization (#4197)
## Objective
Implement absolute minimum viable product for the changes proposed in bevyengine/rfcs#53.

## Solution

 - Remove public mutative access to `Parent` (Children is already publicly read-only). This includes public construction methods like `Copy`, `Clone`, and `Default`.
 - Remove `PreviousParent`
 - Remove `parent_update_system`
 - Update all hierarchy related commands to immediately update both `Parent` and `Children` references.

## Remaining TODOs

 - [ ] Update documentation for both `Parent` and `Children`. Discourage using `EntityCommands::remove`
 - [x] Add `HierarchyEvent` to notify listeners of hierarchy updates. This is meant to replace listening on `PreviousParent`

## Followup

 - These changes should be best moved to the hooks mentioned in #3742.
 - Backing storage for both might be best moved to indexes mentioned in the same relations.
2022-07-10 20:29:06 +00:00
Jakob Hellermann
d38a8dfdd7 add more SAFETY comments and lint for missing ones in bevy_ecs (#4835)
# Objective

`SAFETY` comments are meant to be placed before `unsafe` blocks and should contain the reasoning of why in this case the usage of unsafe is okay. This is useful when reading the code because it makes it clear which assumptions are required for safety, and makes it easier to spot possible unsoundness holes. It also forces the code writer to think of something to write and maybe look at the safety contracts of any called unsafe methods again to double-check their correct usage.

There's a clippy lint called `undocumented_unsafe_blocks` which warns when using a block without such a comment. 

## Solution

- since clippy expects `SAFETY` instead of `SAFE`, rename those
- add `SAFETY` comments in more places
- for the last remaining 3 places, add an `#[allow()]` and `// TODO` since I wasn't comfortable enough with the code to justify their safety
- add ` #![warn(clippy::undocumented_unsafe_blocks)]` to `bevy_ecs`


### Note for reviewers

The first commit only renames `SAFETY` to `SAFE` so it doesn't need a thorough review.
cb042a416e..55cef2d6fa is the diff for all other changes.

### Safety comments where I'm not too familiar with the code

774012ece5/crates/bevy_ecs/src/entity/mod.rs (L540-L546)

774012ece5/crates/bevy_ecs/src/world/entity_ref.rs (L249-L252)

### Locations left undocumented with a `TODO` comment

5dde944a30/crates/bevy_ecs/src/schedule/executor_parallel.rs (L196-L199)

5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L287-L289)

5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L413-L415)

Co-authored-by: Jakob Hellermann <hellermann@sipgate.de>
2022-07-04 14:44:24 +00:00
François
c6958b3056 add a SceneBundle to spawn a scene (#2424)
# Objective

- Spawning a scene is handled as a special case with a command `spawn_scene` that takes an handle but doesn't let you specify anything else. This is the only handle that works that way.
- Workaround for this have been to add the `spawn_scene` on `ChildBuilder` to be able to specify transform of parent, or to make the `SceneSpawner` available to be able to select entities from a scene by their instance id

## Solution

Add a bundle
```rust
pub struct SceneBundle {
    pub scene: Handle<Scene>,
    pub transform: Transform,
    pub global_transform: GlobalTransform,
    pub instance_id: Option<InstanceId>,
}
```

and instead of 
```rust
commands.spawn_scene(asset_server.load("models/FlightHelmet/FlightHelmet.gltf#Scene0"));
```
you can do
```rust
commands.spawn_bundle(SceneBundle {
    scene: asset_server.load("models/FlightHelmet/FlightHelmet.gltf#Scene0"),
    ..Default::default()
});
```

The scene will be spawned as a child of the entity with the `SceneBundle`

~I would like to remove the command `spawn_scene` in favor of this bundle but didn't do it yet to get feedback first~

Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-06-09 20:34:09 +00:00
ira
92ddfe8ad4 Add methods for querying lists of entities. (#4879)
# Objective
Improve querying ergonomics around collections and iterators of entities.

Example how queries over Children might be done currently. 
```rust
fn system(foo_query: Query<(&Foo, &Children)>, bar_query: Query<(&Bar, &Children)>) {
    for (foo, children) in &foo_query {
        for child in children.iter() {
            if let Ok((bar, children)) = bar_query.get(*child) {
                for child in children.iter() {
                    if let Ok((foo, children)) = foo_query.get(*child) {
                        // D:
                    }
                }
            }
        }
    }
}
```
Answers #4868
Partially addresses #4864
Fixes #1470
## Solution
Based on the great work by @deontologician in #2563 

Added `iter_many` and `many_for_each_mut` to `Query`.
These take a list of entities (Anything that implements `IntoIterator<Item: Borrow<Entity>>`).

`iter_many` returns a `QueryManyIter` iterator over immutable results of a query (mutable data will be cast to an immutable form).

`many_for_each_mut` calls a closure for every result of the query, ensuring not aliased mutability. 
This iterator goes over the list of entities in order and returns the result from the query for it. Skipping over any entities that don't match the query.

Also added `unsafe fn iter_many_unsafe`.

### Examples
```rust
#[derive(Component)]
struct Counter {
    value: i32
}

#[derive(Component)]
struct Friends {
    list: Vec<Entity>,
}

fn system(
    friends_query: Query<&Friends>,
    mut counter_query: Query<&mut Counter>,
) {
    for friends in &friends_query {
        for counter in counter_query.iter_many(&friends.list) {
            println!("Friend's counter: {:?}", counter.value);
        }
        
        counter_query.many_for_each_mut(&friends.list, |mut counter| {
            counter.value += 1;
            println!("Friend's counter: {:?}", counter.value);
        });
    }
}

```

Here's how example in the Objective section can be written with this PR.
```rust
fn system(foo_query: Query<(&Foo, &Children)>, bar_query: Query<(&Bar, &Children)>) {
    for (foo, children) in &foo_query {
        for (bar, children) in bar_query.iter_many(children) {
            for (foo, children) in foo_query.iter_many(children) {
                // :D
            }
        }
    }
}
```
## Additional changes
Implemented `IntoIterator` for `&Children` because why not.
## Todo
- Bikeshed!

Co-authored-by: deontologician <deontologician@gmail.com>

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-06-06 16:09:16 +00:00
Alex Saveau
a0a14aa615 Support returning data out of with_children (#4708)
# Objective

Support returning data out of with_children to enable the use case of changing the parent commands with data created inside the child builder.

## Solution

Change the with_children closure to return T.

Closes https://github.com/bevyengine/bevy/pull/2817.

---

## Changelog

`BuildChildren::add_children` was added with the ability to return data to use outside the closure (for spawning a new child builder on a returned entity for example).
2022-05-17 22:37:51 +00:00
François
8630b194dc add more logs when despawning entities (#3851)
# Objective

- Provide more information when despawning an entity

## Solution

- Add a debug log when despawning an entity
- Add spans to the recursive ways of despawning an entity

```sh
RUST_LOG=debug cargo run --example panic --features trace
# RUST_LOG=debug needed to show debug logs from bevy_ecs
# --features trace needed to have the extra spans
...

DEBUG bevy_app:frame:stage{name=Update}:system_commands{name="panic::despawn_parent"}:command{name="DespawnRecursive" entity=0v0}: bevy_ecs::world: Despawning entity 1v0
DEBUG bevy_app:frame:stage{name=Update}:system_commands{name="panic::despawn_parent"}:command{name="DespawnRecursive" entity=0v0}: bevy_ecs::world: Despawning entity 0v0
```
2022-04-13 23:35:28 +00:00
Alice Cecile
a304fd9a99 Split bevy_hierarchy out from bevy_transform (#4168)
# Objective

- Hierarchy tools are not just used for `Transform`: they are also used for scenes.
- In the future there's interest in using them for other features, such as visiibility inheritance.
- The fact that these tools are found in `bevy_transform` causes a great deal of user and developer confusion
- Fixes #2758.

## Solution

- Split `bevy_transform` into two!
- Make everything work again.

Note that this is a very tightly scoped PR: I *know* there are code quality and docs issues that existed in bevy_transform that I've just moved around. We should fix those in a seperate PR and try to merge this ASAP to reduce the bitrot involved in splitting an entire crate.

## Frustrations

The API around `GlobalTransform` is a mess: we have massive code and docs duplication, no link between the two types and no clear way to extend this to other forms of inheritance.

In the medium-term, I feel pretty strongly that `GlobalTransform` should be replaced by something like `Inherited<Transform>`, which lives in `bevy_hierarchy`:

- avoids code duplication
- makes the inheritance pattern extensible
- links the types at the type-level
- allows us to remove all references to inheritance from `bevy_transform`, making it more useful as a standalone crate and cleaning up its docs

## Additional context

- double-blessed by @cart in https://github.com/bevyengine/bevy/issues/4141#issuecomment-1063592414 and https://github.com/bevyengine/bevy/issues/2758#issuecomment-913810963
- preparation for more advanced / cleaner hierarchy tools: go read https://github.com/bevyengine/rfcs/pull/53 !
- originally attempted by @finegeometer in #2789. It was a great idea, just needed more discussion!

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-03-15 01:54:05 +00:00