b9123e74b6
6 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Zachary Harrold
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a35811d088
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Add Immutable Component Support (#16372)
# Objective - Fixes #16208 ## Solution - Added an associated type to `Component`, `Mutability`, which flags whether a component is mutable, or immutable. If `Mutability= Mutable`, the component is mutable. If `Mutability= Immutable`, the component is immutable. - Updated `derive_component` to default to mutable unless an `#[component(immutable)]` attribute is added. - Updated `ReflectComponent` to check if a component is mutable and, if not, panic when attempting to mutate. ## Testing - CI - `immutable_components` example. --- ## Showcase Users can now mark a component as `#[component(immutable)]` to prevent safe mutation of a component while it is attached to an entity: ```rust #[derive(Component)] #[component(immutable)] struct Foo { // ... } ``` This prevents creating an exclusive reference to the component while it is attached to an entity. This is particularly powerful when combined with component hooks, as you can now fully track a component's value, ensuring whatever invariants you desire are upheld. Before this would be done my making a component private, and manually creating a `QueryData` implementation which only permitted read access. <details> <summary>Using immutable components as an index</summary> ```rust /// This is an example of a component like [`Name`](bevy::prelude::Name), but immutable. #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Component)] #[component( immutable, on_insert = on_insert_name, on_replace = on_replace_name, )] pub struct Name(pub &'static str); /// This index allows for O(1) lookups of an [`Entity`] by its [`Name`]. #[derive(Resource, Default)] struct NameIndex { name_to_entity: HashMap<Name, Entity>, } impl NameIndex { fn get_entity(&self, name: &'static str) -> Option<Entity> { self.name_to_entity.get(&Name(name)).copied() } } fn on_insert_name(mut world: DeferredWorld<'_>, entity: Entity, _component: ComponentId) { let Some(&name) = world.entity(entity).get::<Name>() else { unreachable!() }; let Some(mut index) = world.get_resource_mut::<NameIndex>() else { return; }; index.name_to_entity.insert(name, entity); } fn on_replace_name(mut world: DeferredWorld<'_>, entity: Entity, _component: ComponentId) { let Some(&name) = world.entity(entity).get::<Name>() else { unreachable!() }; let Some(mut index) = world.get_resource_mut::<NameIndex>() else { return; }; index.name_to_entity.remove(&name); } // Setup our name index world.init_resource::<NameIndex>(); // Spawn some entities! let alyssa = world.spawn(Name("Alyssa")).id(); let javier = world.spawn(Name("Javier")).id(); // Check our index let index = world.resource::<NameIndex>(); assert_eq!(index.get_entity("Alyssa"), Some(alyssa)); assert_eq!(index.get_entity("Javier"), Some(javier)); // Changing the name of an entity is also fully capture by our index world.entity_mut(javier).insert(Name("Steven")); // Javier changed their name to Steven let steven = javier; // Check our index let index = world.resource::<NameIndex>(); assert_eq!(index.get_entity("Javier"), None); assert_eq!(index.get_entity("Steven"), Some(steven)); ``` </details> Additionally, users can use `Component<Mutability = ...>` in trait bounds to enforce that a component _is_ mutable or _is_ immutable. When using `Component` as a trait bound without specifying `Mutability`, any component is applicable. However, methods which only work on mutable or immutable components are unavailable, since the compiler must be pessimistic about the type. ## Migration Guide - When implementing `Component` manually, you must now provide a type for `Mutability`. The type `Mutable` provides equivalent behaviour to earlier versions of `Component`: ```rust impl Component for Foo { type Mutability = Mutable; // ... } ``` - When working with generic components, you may need to specify that your generic parameter implements `Component<Mutability = Mutable>` rather than `Component` if you require mutable access to said component. - The entity entry API has had to have some changes made to minimise friction when working with immutable components. Methods which previously returned a `Mut<T>` will now typically return an `OccupiedEntry<T>` instead, requiring you to add an `into_mut()` to get the `Mut<T>` item again. ## Draft Release Notes Components can now be made immutable while stored within the ECS. Components are the fundamental unit of data within an ECS, and Bevy provides a number of ways to work with them that align with Rust's rules around ownership and borrowing. One part of this is hooks, which allow for defining custom behavior at key points in a component's lifecycle, such as addition and removal. However, there is currently no way to respond to _mutation_ of a component using hooks. The reasons for this are quite technical, but to summarize, their addition poses a significant challenge to Bevy's core promises around performance. Without mutation hooks, it's relatively trivial to modify a component in such a way that breaks invariants it intends to uphold. For example, you can use `core::mem::swap` to swap the components of two entities, bypassing the insertion and removal hooks. This means the only way to react to this modification is via change detection in a system, which then begs the question of what happens _between_ that alteration and the next run of that system? Alternatively, you could make your component private to prevent mutation, but now you need to provide commands and a custom `QueryData` implementation to allow users to interact with your component at all. Immutable components solve this problem by preventing the creation of an exclusive reference to the component entirely. Without an exclusive reference, the only way to modify an immutable component is via removal or replacement, which is fully captured by component hooks. To make a component immutable, simply add `#[component(immutable)]`: ```rust #[derive(Component)] #[component(immutable)] struct Foo { // ... } ``` When implementing `Component` manually, there is an associated type `Mutability` which controls this behavior: ```rust impl Component for Foo { type Mutability = Mutable; // ... } ``` Note that this means when working with generic components, you may need to specify that a component is mutable to gain access to certain methods: ```rust // Before fn bar<C: Component>() { // ... } // After fn bar<C: Component<Mutability = Mutable>>() { // ... } ``` With this new tool, creating index components, or caching data on an entity should be more user friendly, allowing libraries to provide APIs relying on components and hooks to uphold their invariants. ## Notes - ~~I've done my best to implement this feature, but I'm not happy with how reflection has turned out. If any reflection SMEs know a way to improve this situation I'd greatly appreciate it.~~ There is an outstanding issue around the fallibility of mutable methods on `ReflectComponent`, but the DX is largely unchanged from `main` now. - I've attempted to prevent all safe mutable access to a component that does not implement `Component<Mutability = Mutable>`, but there may still be some methods I have missed. Please indicate so and I will address them, as they are bugs. - Unsafe is an escape hatch I am _not_ attempting to prevent. Whatever you do with unsafe is between you and your compiler. - I am marking this PR as ready, but I suspect it will undergo fairly major revisions based on SME feedback. - I've marked this PR as _Uncontroversial_ based on the feature, not the implementation. --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> Co-authored-by: Benjamin Brienen <benjamin.brienen@outlook.com> Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com> Co-authored-by: Nuutti Kotivuori <naked@iki.fi> |
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Carter Anderson
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015f2c69ca
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Merge Style properties into Node. Use ComputedNode for computed properties. (#15975)
# Objective Continue improving the user experience of our UI Node API in the direction specified by [Bevy's Next Generation Scene / UI System](https://github.com/bevyengine/bevy/discussions/14437) ## Solution As specified in the document above, merge `Style` fields into `Node`, and move "computed Node fields" into `ComputedNode` (I chose this name over something like `ComputedNodeLayout` because it currently contains more than just layout info. If we want to break this up / rename these concepts, lets do that in a separate PR). `Style` has been removed. This accomplishes a number of goals: ## Ergonomics wins Specifying both `Node` and `Style` is now no longer required for non-default styles Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` ## Conceptual clarity `Style` was never a comprehensive "style sheet". It only defined "core" style properties that all `Nodes` shared. Any "styled property" that couldn't fit that mold had to be in a separate component. A "real" style system would style properties _across_ components (`Node`, `Button`, etc). We have plans to build a true style system (see the doc linked above). By moving the `Style` fields to `Node`, we fully embrace `Node` as the driving concept and remove the "style system" confusion. ## Next Steps * Consider identifying and splitting out "style properties that aren't core to Node". This should not happen for Bevy 0.15. --- ## Migration Guide Move any fields set on `Style` into `Node` and replace all `Style` component usage with `Node`. Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` For any usage of the "computed node properties" that used to live on `Node`, use `ComputedNode` instead: Before: ```rust fn system(nodes: Query<&Node>) { for node in &nodes { let computed_size = node.size(); } } ``` After: ```rust fn system(computed_nodes: Query<&ComputedNode>) { for computed_node in &computed_nodes { let computed_size = computed_node.size(); } } ``` |
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MiniaczQ
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f602edad09
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Text Rework cleanup (#15887)
# Objective Cleanup naming and docs, add missing migration guide after #15591 All text root nodes now use `Text` (UI) / `Text2d`. All text readers/writers use `Text<Type>Reader`/`Text<Type>Writer` convention. --- ## Migration Guide Doubles as #15591 migration guide. Text bundles (`TextBundle` and `Text2dBundle`) were removed in favor of `Text` and `Text2d`. Shared configuration fields were replaced with `TextLayout`, `TextFont` and `TextColor` components. Just `TextBundle`'s additional field turned into `TextNodeFlags` component, while `Text2dBundle`'s additional fields turned into `TextBounds` and `Anchor` components. Text sections were removed in favor of hierarchy-based approach. For root text entities with `Text` or `Text2d` components, child entities with `TextSpan` will act as additional text sections. To still access text spans by index, use the new `TextUiReader`, `Text2dReader` and `TextUiWriter`, `Text2dWriter` system parameters. |
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ickshonpe
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6f7d0e5725
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split up TextStyle (#15857)
# Objective
Currently text is recomputed unnecessarily on any changes to its color,
which is extremely expensive.
## Solution
Split up `TextStyle` into two separate components `TextFont` and
`TextColor`.
## Testing
I added this system to `many_buttons`:
```rust
fn set_text_colors_changed(mut colors: Query<&mut TextColor>) {
for mut text_color in colors.iter_mut() {
text_color.set_changed();
}
}
```
reports ~4fps on main, ~50fps with this PR.
## Migration Guide
`TextStyle` has been renamed to `TextFont` and its `color` field has
been moved to a separate component named `TextColor` which newtypes
`Color`.
|
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UkoeHB
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a6be9b4ccd
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Rename TextBlock to TextLayout (#15797)
# Objective - Improve clarity when spawning a text block. See [this discussion](https://github.com/bevyengine/bevy/pull/15591/#discussion_r1787083571). ## Solution - Rename `TextBlock` to `TextLayout`. |
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UkoeHB
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c2c19e5ae4
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Text rework (#15591)
**Ready for review. Examples migration progress: 100%.** # Objective - Implement https://github.com/bevyengine/bevy/discussions/15014 ## Solution This implements [cart's proposal](https://github.com/bevyengine/bevy/discussions/15014#discussioncomment-10574459) faithfully except for one change. I separated `TextSpan` from `TextSpan2d` because `TextSpan` needs to require the `GhostNode` component, which is a `bevy_ui` component only usable by UI. Extra changes: - Added `EntityCommands::commands_mut` that returns a mutable reference. This is a blocker for extension methods that return something other than `self`. Note that `sickle_ui`'s `UiBuilder::commands` returns a mutable reference for this reason. ## Testing - [x] Text examples all work. --- ## Showcase TODO: showcase-worthy ## Migration Guide TODO: very breaking ### Accessing text spans by index Text sections are now text sections on different entities in a hierarchy, Use the new `TextReader` and `TextWriter` system parameters to access spans by index. Before: ```rust fn refresh_text(mut query: Query<&mut Text, With<TimeText>>, time: Res<Time>) { let text = query.single_mut(); text.sections[1].value = format_time(time.elapsed()); } ``` After: ```rust fn refresh_text( query: Query<Entity, With<TimeText>>, mut writer: UiTextWriter, time: Res<Time> ) { let entity = query.single(); *writer.text(entity, 1) = format_time(time.elapsed()); } ``` ### Iterating text spans Text spans are now entities in a hierarchy, so the new `UiTextReader` and `UiTextWriter` system parameters provide ways to iterate that hierarchy. The `UiTextReader::iter` method will give you a normal iterator over spans, and `UiTextWriter::for_each` lets you visit each of the spans. --------- Co-authored-by: ickshonpe <david.curthoys@googlemail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com> |