2440aa8475
This PR is part of a project aimed at improving the API documentation of `bevy_hierarchy`. Other PRs will be based on this. This PR in particular is also an experiment in providing a high level overview of the tools provided by a Bevy plugin/crate. It also provides general information about universal invariants, so statement repetition in crate items can be dramatically reduced. ## Other changes The other PRs of this project that expand on this one: - #10952 - #10953 - #10954 - #10955 - #10956 - #10957 --------- Co-authored-by: GitGhillie <jillisnoordhoek@gmail.com>
98 lines
3.1 KiB
Rust
98 lines
3.1 KiB
Rust
#![warn(missing_docs)]
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//! Parent-child relationships for Bevy entities.
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//!
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//! You should use the tools in this crate
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//! whenever you want to organize your entities in a hierarchical fashion,
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//! to make groups of entities more manageable,
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//! or to propagate properties throughout the entity hierarchy.
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//!
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//! This crate introduces various tools, including a [plugin]
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//! for managing parent-child relationships between entities.
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//! It provides two components, [`Parent`] and [`Children`],
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//! to store references to related entities.
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//! It also provides [command] and [world] API extensions
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//! to set and clear those relationships.
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//!
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//! More advanced users may also appreciate
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//! [query extension methods] to traverse hierarchies,
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//! and [events] to notify hierarchical changes.
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//! There is also a [diagnostic plugin] to validate property propagation.
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//!
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//! # Hierarchy management
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//!
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//! The methods defined in this crate fully manage
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//! the components responsible for defining the entity hierarchy.
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//! Mutating these components manually may result in hierarchy invalidation.
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//!
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//! Hierarchical relationships are always managed symmetrically.
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//! For example, assigning a child to an entity
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//! will always set the parent in the other,
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//! and vice versa.
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//! Similarly, unassigning a child in the parent
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//! will always unassign the parent in the child.
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//!
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//! ## Despawning entities
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//!
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//! The commands and methods provided by `bevy_ecs` to despawn entities
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//! are not capable of automatically despawning hierarchies of entities.
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//! In most cases, these operations will invalidate the hierarchy.
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//! Instead, you should use the provided [hierarchical despawn extension methods].
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//!
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//! [command]: BuildChildren
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//! [diagnostic plugin]: ValidParentCheckPlugin
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//! [events]: HierarchyEvent
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//! [hierarchical despawn extension methods]: DespawnRecursiveExt
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//! [plugin]: HierarchyPlugin
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//! [query extension methods]: HierarchyQueryExt
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//! [world]: BuildWorldChildren
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mod components;
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pub use components::*;
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mod hierarchy;
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pub use hierarchy::*;
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mod child_builder;
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pub use child_builder::*;
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mod events;
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pub use events::*;
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mod valid_parent_check_plugin;
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pub use valid_parent_check_plugin::*;
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mod query_extension;
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pub use query_extension::*;
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#[doc(hidden)]
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pub mod prelude {
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#[doc(hidden)]
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pub use crate::{child_builder::*, components::*, hierarchy::*, query_extension::*};
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#[doc(hidden)]
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#[cfg(feature = "bevy_app")]
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pub use crate::{HierarchyPlugin, ValidParentCheckPlugin};
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}
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#[cfg(feature = "bevy_app")]
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use bevy_app::prelude::*;
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/// Provides hierarchy functionality to a Bevy app.
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///
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/// Check the [crate-level documentation] for all the features.
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///
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/// [crate-level documentation]: crate
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#[derive(Default)]
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pub struct HierarchyPlugin;
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#[cfg(feature = "bevy_app")]
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use bevy_utils::smallvec::SmallVec;
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impl Plugin for HierarchyPlugin {
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fn build(&self, app: &mut App) {
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app.register_type::<Children>()
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.register_type::<Parent>()
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.register_type::<SmallVec<[bevy_ecs::entity::Entity; 8]>>()
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.add_event::<HierarchyEvent>();
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}
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}
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