mirror of
https://github.com/bevyengine/bevy
synced 2024-12-23 11:33:06 +00:00
d26b63a04d
# Objective
One pattern to increase parallelism is deferred mutation: instead of directly mutating the world (and preventing other systems from running at the same time), you queue up operations to be applied to the world at the end of the stage. The most common example of this pattern uses the `Commands` SystemParam.
In order to avoid the overhead associated with commands, some power users may want to add their own deferred mutation behavior. To do this, you must implement the unsafe trait `SystemParam`, which interfaces with engine internals in a way that we'd like users to be able to avoid.
## Solution
Add the `Deferred<T>` primitive `SystemParam`, which encapsulates the deferred mutation pattern.
This can be combined with other types of `SystemParam` to safely and ergonomically create powerful custom types.
Essentially, this is just a variant of `Local<T>` which can run code at the end of the stage.
This type is used in the engine to derive `Commands` and `ParallelCommands`, which removes a bunch of unsafe boilerplate.
### Example
```rust
use bevy_ecs::system::{Deferred, SystemBuffer};
/// Sends events with a delay, but may run in parallel with other event writers.
#[derive(SystemParam)]
pub struct BufferedEventWriter<'s, E: Event> {
queue: Deferred<'s, EventQueue<E>>,
}
struct EventQueue<E>(Vec<E>);
impl<'s, E: Event> BufferedEventWriter<'s, E> {
/// Queues up an event to be sent at the end of this stage.
pub fn send(&mut self, event: E) {
self.queue.0.push(event);
}
}
// The `SystemBuffer` trait controls how [`Deferred`] gets applied at the end of the stage.
impl<E: Event> SystemBuffer for EventQueue<E> {
fn apply(&mut self, world: &mut World) {
let mut events = world.resource_mut::<Events<E>>();
for e in self.0.drain(..) {
events.send(e);
}
}
}
```
---
## Changelog
+ Added the `SystemParam` type `Deferred<T>`, which can be used to defer `World` mutations. Powered by the new trait `SystemBuffer`.
1167 lines
35 KiB
Rust
1167 lines
35 KiB
Rust
mod command_queue;
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mod parallel_scope;
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use crate::{
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self as bevy_ecs,
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bundle::Bundle,
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entity::{Entities, Entity},
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world::{FromWorld, World},
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};
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use bevy_ecs_macros::SystemParam;
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use bevy_utils::tracing::{error, info};
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pub use command_queue::CommandQueue;
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pub use parallel_scope::*;
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use std::marker::PhantomData;
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use super::{Deferred, Resource, SystemBuffer, SystemMeta};
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/// A [`World`] mutation.
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///
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/// Should be used with [`Commands::add`].
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///
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/// # Usage
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///
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/// ```
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/// # use bevy_ecs::prelude::*;
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/// # use bevy_ecs::system::Command;
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/// // Our world resource
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/// #[derive(Resource, Default)]
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/// struct Counter(u64);
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///
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/// // Our custom command
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/// struct AddToCounter(u64);
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///
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/// impl Command for AddToCounter {
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/// fn write(self, world: &mut World) {
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/// let mut counter = world.get_resource_or_insert_with(Counter::default);
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/// counter.0 += self.0;
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/// }
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/// }
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///
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/// fn some_system(mut commands: Commands) {
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/// commands.add(AddToCounter(42));
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/// }
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/// ```
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pub trait Command: Send + 'static {
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fn write(self, world: &mut World);
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}
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/// A [`Command`] queue to perform impactful changes to the [`World`].
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///
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/// Since each command requires exclusive access to the `World`,
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/// all queued commands are automatically applied in sequence
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/// when the [`apply_system_buffers`] system runs.
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///
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/// The command queue of an individual system can also be manually applied
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/// by calling [`System::apply_buffers`].
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/// Similarly, the command queue of a schedule can be manually applied via [`Schedule::apply_system_buffers`].
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///
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/// Each command can be used to modify the [`World`] in arbitrary ways:
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/// * spawning or despawning entities
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/// * inserting components on new or existing entities
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/// * inserting resources
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/// * etc.
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///
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/// # Usage
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///
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/// Add `mut commands: Commands` as a function argument to your system to get a copy of this struct that will be applied the next time a copy of [`apply_system_buffers`] runs.
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/// Commands are almost always used as a [`SystemParam`](crate::system::SystemParam).
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///
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/// ```
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/// # use bevy_ecs::prelude::*;
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/// #
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/// fn my_system(mut commands: Commands) {
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/// // ...
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/// }
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/// # bevy_ecs::system::assert_is_system(my_system);
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/// ```
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///
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/// # Implementing
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///
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/// Each built-in command is implemented as a separate method, e.g. [`spawn`](#method.spawn).
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/// In addition to the pre-defined command methods, you can add commands with any arbitrary
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/// behavior using [`Commands::add`](#method.add), which accepts any type implementing [`Command`].
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///
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/// Since closures and other functions implement this trait automatically, this allows one-shot,
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/// anonymous custom commands.
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///
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/// ```
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/// # use bevy_ecs::prelude::*;
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/// # fn foo(mut commands: Commands) {
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/// // NOTE: type inference fails here, so annotations are required on the closure.
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/// commands.add(|w: &mut World| {
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/// // Mutate the world however you want...
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/// # todo!();
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/// });
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/// # }
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/// ```
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///
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/// [`System::apply_buffers`]: crate::system::System::apply_buffers
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/// [`apply_system_buffers`]: crate::schedule::apply_system_buffers
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/// [`Schedule::apply_system_buffers`]: crate::schedule::Schedule::apply_system_buffers
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#[derive(SystemParam)]
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pub struct Commands<'w, 's> {
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queue: Deferred<'s, CommandQueue>,
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entities: &'w Entities,
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}
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impl SystemBuffer for CommandQueue {
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#[inline]
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fn apply(&mut self, _system_meta: &SystemMeta, world: &mut World) {
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#[cfg(feature = "trace")]
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let _system_span =
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bevy_utils::tracing::info_span!("system_commands", name = _system_meta.name())
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.entered();
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self.apply(world);
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}
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}
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impl<'w, 's> Commands<'w, 's> {
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/// Returns a new `Commands` instance from a [`CommandQueue`] and a [`World`].
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///
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/// It is not required to call this constructor when using `Commands` as a [system parameter].
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///
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/// [system parameter]: crate::system::SystemParam
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pub fn new(queue: &'s mut CommandQueue, world: &'w World) -> Self {
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Self::new_from_entities(queue, world.entities())
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}
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/// Returns a new `Commands` instance from a [`CommandQueue`] and an [`Entities`] reference.
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///
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/// It is not required to call this constructor when using `Commands` as a [system parameter].
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///
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/// [system parameter]: crate::system::SystemParam
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pub fn new_from_entities(queue: &'s mut CommandQueue, entities: &'w Entities) -> Self {
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Self {
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queue: Deferred(queue),
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entities,
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}
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}
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/// Pushes a [`Command`] to the queue for creating a new empty [`Entity`],
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/// and returns its corresponding [`EntityCommands`].
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///
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/// See [`World::spawn_empty`] for more details.
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///
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/// # Example
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///
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/// ```
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/// # use bevy_ecs::prelude::*;
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///
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/// #[derive(Component)]
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/// struct Label(&'static str);
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/// #[derive(Component)]
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/// struct Strength(u32);
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/// #[derive(Component)]
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/// struct Agility(u32);
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///
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/// fn example_system(mut commands: Commands) {
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/// // Create a new empty entity and retrieve its id.
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/// let empty_entity = commands.spawn_empty().id();
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///
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/// // Create another empty entity, then add some component to it
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/// commands.spawn_empty()
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/// // adds a new component bundle to the entity
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/// .insert((Strength(1), Agility(2)))
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/// // adds a single component to the entity
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/// .insert(Label("hello world"));
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/// }
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/// # bevy_ecs::system::assert_is_system(example_system);
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/// ```
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///
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/// # See also
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///
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/// - [`spawn`](Self::spawn) to spawn an entity with a bundle.
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/// - [`spawn_batch`](Self::spawn_batch) to spawn entities with a bundle each.
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pub fn spawn_empty<'a>(&'a mut self) -> EntityCommands<'w, 's, 'a> {
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let entity = self.entities.reserve_entity();
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EntityCommands {
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entity,
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commands: self,
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}
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}
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/// Pushes a [`Command`] to the queue for creating a new [`Entity`] if the given one does not exists,
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/// and returns its corresponding [`EntityCommands`].
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///
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/// This method silently fails by returning `EntityCommands`
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/// even if the given `Entity` cannot be spawned.
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///
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/// See [`World::get_or_spawn`] for more details.
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///
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/// # Note
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///
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/// Spawning a specific `entity` value is rarely the right choice. Most apps should favor
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/// [`Commands::spawn`]. This method should generally only be used for sharing entities across
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/// apps, and only when they have a scheme worked out to share an ID space (which doesn't happen
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/// by default).
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pub fn get_or_spawn<'a>(&'a mut self, entity: Entity) -> EntityCommands<'w, 's, 'a> {
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self.add(GetOrSpawn { entity });
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EntityCommands {
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entity,
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commands: self,
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}
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}
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/// Pushes a [`Command`] to the queue for creating a new entity with the given [`Bundle`]'s components,
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/// and returns its corresponding [`EntityCommands`].
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///
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/// # Example
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///
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/// ```
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/// use bevy_ecs::prelude::*;
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///
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/// #[derive(Component)]
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/// struct Component1;
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/// #[derive(Component)]
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/// struct Component2;
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/// #[derive(Component)]
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/// struct Label(&'static str);
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/// #[derive(Component)]
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/// struct Strength(u32);
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/// #[derive(Component)]
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/// struct Agility(u32);
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///
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/// #[derive(Bundle)]
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/// struct ExampleBundle {
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/// a: Component1,
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/// b: Component2,
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/// }
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///
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/// fn example_system(mut commands: Commands) {
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/// // Create a new entity with a single component.
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/// commands.spawn(Component1);
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///
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/// // Create a new entity with a component bundle.
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/// commands.spawn(ExampleBundle {
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/// a: Component1,
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/// b: Component2,
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/// });
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///
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/// commands
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/// // Create a new entity with two components using a "tuple bundle".
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/// .spawn((Component1, Component2))
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/// // `spawn returns a builder, so you can insert more bundles like this:
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/// .insert((Strength(1), Agility(2)))
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/// // or insert single components like this:
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/// .insert(Label("hello world"));
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/// }
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/// # bevy_ecs::system::assert_is_system(example_system);
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/// ```
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///
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/// # See also
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///
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/// - [`spawn_empty`](Self::spawn_empty) to spawn an entity without any components.
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/// - [`spawn_batch`](Self::spawn_batch) to spawn entities with a bundle each.
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pub fn spawn<'a, T: Bundle>(&'a mut self, bundle: T) -> EntityCommands<'w, 's, 'a> {
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let mut e = self.spawn_empty();
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e.insert(bundle);
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e
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}
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/// Returns the [`EntityCommands`] for the requested [`Entity`].
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///
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/// # Panics
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///
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/// This method panics if the requested entity does not exist.
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///
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/// # Example
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///
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/// ```
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/// use bevy_ecs::prelude::*;
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///
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/// #[derive(Component)]
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/// struct Label(&'static str);
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/// #[derive(Component)]
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/// struct Strength(u32);
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/// #[derive(Component)]
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/// struct Agility(u32);
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///
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/// fn example_system(mut commands: Commands) {
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/// // Create a new, empty entity
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/// let entity = commands.spawn_empty().id();
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///
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/// commands.entity(entity)
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/// // adds a new component bundle to the entity
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/// .insert((Strength(1), Agility(2)))
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/// // adds a single component to the entity
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/// .insert(Label("hello world"));
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/// }
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/// # bevy_ecs::system::assert_is_system(example_system);
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/// ```
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///
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/// # See also
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///
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/// - [`get_entity`](Self::get_entity) for the fallible version.
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#[inline]
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#[track_caller]
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pub fn entity<'a>(&'a mut self, entity: Entity) -> EntityCommands<'w, 's, 'a> {
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self.get_entity(entity).unwrap_or_else(|| {
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panic!(
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"Attempting to create an EntityCommands for entity {entity:?}, which doesn't exist.",
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)
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})
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}
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/// Returns the [`EntityCommands`] for the requested [`Entity`], if it exists.
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///
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/// Returns `None` if the entity does not exist.
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///
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/// This method does not guarantee that `EntityCommands` will be successfully applied,
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/// since another command in the queue may delete the entity before them.
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///
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/// # Example
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///
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/// ```
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/// use bevy_ecs::prelude::*;
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///
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/// #[derive(Component)]
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/// struct Label(&'static str);
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/// fn example_system(mut commands: Commands) {
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/// // Create a new, empty entity
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/// let entity = commands.spawn_empty().id();
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///
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/// // Get the entity if it still exists, which it will in this case
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/// if let Some(mut entity_commands) = commands.get_entity(entity) {
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/// // adds a single component to the entity
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/// entity_commands.insert(Label("hello world"));
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/// }
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/// }
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/// # bevy_ecs::system::assert_is_system(example_system);
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/// ```
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///
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/// # See also
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///
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/// - [`entity`](Self::entity) for the panicking version.
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#[inline]
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#[track_caller]
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pub fn get_entity<'a>(&'a mut self, entity: Entity) -> Option<EntityCommands<'w, 's, 'a>> {
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self.entities.contains(entity).then_some(EntityCommands {
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entity,
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commands: self,
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})
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}
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/// Pushes a [`Command`] to the queue for creating entities with a particular [`Bundle`] type.
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///
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/// `bundles_iter` is a type that can be converted into a `Bundle` iterator
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/// (it can also be a collection).
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///
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/// This method is equivalent to iterating `bundles_iter`
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/// and calling [`spawn`](Self::spawn) on each bundle,
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/// but it is faster due to memory pre-allocation.
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///
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/// # Example
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///
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/// ```
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/// # use bevy_ecs::prelude::*;
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/// #
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/// # #[derive(Component)]
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/// # struct Name(String);
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/// # #[derive(Component)]
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/// # struct Score(u32);
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/// #
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/// # fn system(mut commands: Commands) {
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/// commands.spawn_batch(vec![
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/// (
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/// Name("Alice".to_string()),
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/// Score(0),
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/// ),
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/// (
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/// Name("Bob".to_string()),
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/// Score(0),
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/// ),
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/// ]);
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/// # }
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/// # bevy_ecs::system::assert_is_system(system);
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/// ```
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///
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/// # See also
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///
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/// - [`spawn`](Self::spawn) to spawn an entity with a bundle.
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/// - [`spawn_empty`](Self::spawn_empty) to spawn an entity without any components.
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pub fn spawn_batch<I>(&mut self, bundles_iter: I)
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where
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I: IntoIterator + Send + Sync + 'static,
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I::Item: Bundle,
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{
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self.queue.push(SpawnBatch { bundles_iter });
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}
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/// Pushes a [`Command`] to the queue for creating entities, if needed,
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/// and for adding a bundle to each entity.
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///
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/// `bundles_iter` is a type that can be converted into an ([`Entity`], [`Bundle`]) iterator
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/// (it can also be a collection).
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///
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/// When the command is applied,
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/// for each (`Entity`, `Bundle`) pair in the given `bundles_iter`,
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/// the `Entity` is spawned, if it does not exist already.
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/// Then, the `Bundle` is added to the entity.
|
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///
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/// This method is equivalent to iterating `bundles_iter`,
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/// calling [`get_or_spawn`](Self::get_or_spawn) for each bundle,
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/// and passing it to [`insert`](EntityCommands::insert),
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/// but it is faster due to memory pre-allocation.
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///
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/// # Note
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///
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/// Spawning a specific `entity` value is rarely the right choice. Most apps should use [`Commands::spawn_batch`].
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/// This method should generally only be used for sharing entities across apps, and only when they have a scheme
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/// worked out to share an ID space (which doesn't happen by default).
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pub fn insert_or_spawn_batch<I, B>(&mut self, bundles_iter: I)
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where
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I: IntoIterator + Send + Sync + 'static,
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I::IntoIter: Iterator<Item = (Entity, B)>,
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B: Bundle,
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{
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self.queue.push(InsertOrSpawnBatch { bundles_iter });
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}
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|
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/// Pushes a [`Command`] to the queue for inserting a [`Resource`] in the [`World`] with an inferred value.
|
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///
|
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/// The inferred value is determined by the [`FromWorld`] trait of the resource.
|
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/// When the command is applied,
|
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/// if the resource already exists, nothing happens.
|
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///
|
|
/// See [`World::init_resource`] for more details.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
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|
/// #
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/// # #[derive(Resource, Default)]
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/// # struct Scoreboard {
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/// # current_score: u32,
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/// # high_score: u32,
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/// # }
|
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/// #
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/// # fn initialise_scoreboard(mut commands: Commands) {
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/// commands.init_resource::<Scoreboard>();
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/// # }
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/// # bevy_ecs::system::assert_is_system(initialise_scoreboard);
|
|
/// ```
|
|
pub fn init_resource<R: Resource + FromWorld>(&mut self) {
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self.queue.push(InitResource::<R> {
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_phantom: PhantomData::<R>::default(),
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|
});
|
|
}
|
|
|
|
/// Pushes a [`Command`] to the queue for inserting a [`Resource`] in the [`World`] with a specific value.
|
|
///
|
|
/// This will overwrite any previous value of the same resource type.
|
|
///
|
|
/// See [`World::insert_resource`] for more details.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// #
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|
/// # #[derive(Resource)]
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|
/// # struct Scoreboard {
|
|
/// # current_score: u32,
|
|
/// # high_score: u32,
|
|
/// # }
|
|
/// #
|
|
/// # fn system(mut commands: Commands) {
|
|
/// commands.insert_resource(Scoreboard {
|
|
/// current_score: 0,
|
|
/// high_score: 0,
|
|
/// });
|
|
/// # }
|
|
/// # bevy_ecs::system::assert_is_system(system);
|
|
/// ```
|
|
pub fn insert_resource<R: Resource>(&mut self, resource: R) {
|
|
self.queue.push(InsertResource { resource });
|
|
}
|
|
|
|
/// Pushes a [`Command`] to the queue for removing a [`Resource`] from the [`World`].
|
|
///
|
|
/// See [`World::remove_resource`] for more details.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// #
|
|
/// # #[derive(Resource)]
|
|
/// # struct Scoreboard {
|
|
/// # current_score: u32,
|
|
/// # high_score: u32,
|
|
/// # }
|
|
/// #
|
|
/// # fn system(mut commands: Commands) {
|
|
/// commands.remove_resource::<Scoreboard>();
|
|
/// # }
|
|
/// # bevy_ecs::system::assert_is_system(system);
|
|
/// ```
|
|
pub fn remove_resource<R: Resource>(&mut self) {
|
|
self.queue.push(RemoveResource::<R> {
|
|
phantom: PhantomData,
|
|
});
|
|
}
|
|
|
|
/// Pushes a generic [`Command`] to the command queue.
|
|
///
|
|
/// `command` can be a built-in command, custom struct that implements [`Command`] or a closure
|
|
/// that takes [`&mut World`](World) as an argument.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::{system::Command, prelude::*};
|
|
/// #[derive(Resource, Default)]
|
|
/// struct Counter(u64);
|
|
///
|
|
/// struct AddToCounter(u64);
|
|
///
|
|
/// impl Command for AddToCounter {
|
|
/// fn write(self, world: &mut World) {
|
|
/// let mut counter = world.get_resource_or_insert_with(Counter::default);
|
|
/// counter.0 += self.0;
|
|
/// }
|
|
/// }
|
|
///
|
|
/// fn add_three_to_counter_system(mut commands: Commands) {
|
|
/// commands.add(AddToCounter(3));
|
|
/// }
|
|
/// fn add_twenty_five_to_counter_system(mut commands: Commands) {
|
|
/// commands.add(|world: &mut World| {
|
|
/// let mut counter = world.get_resource_or_insert_with(Counter::default);
|
|
/// counter.0 += 25;
|
|
/// });
|
|
/// }
|
|
|
|
/// # bevy_ecs::system::assert_is_system(add_three_to_counter_system);
|
|
/// # bevy_ecs::system::assert_is_system(add_twenty_five_to_counter_system);
|
|
/// ```
|
|
pub fn add<C: Command>(&mut self, command: C) {
|
|
self.queue.push(command);
|
|
}
|
|
}
|
|
|
|
/// A [`Command`] which gets executed for a given [`Entity`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # use std::collections::HashSet;
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// use bevy_ecs::system::EntityCommand;
|
|
/// #
|
|
/// # #[derive(Component, PartialEq)]
|
|
/// # struct Name(String);
|
|
/// # impl Name {
|
|
/// # fn new(s: String) -> Self { Name(s) }
|
|
/// # fn as_str(&self) -> &str { &self.0 }
|
|
/// # }
|
|
///
|
|
/// #[derive(Resource, Default)]
|
|
/// struct Counter(i64);
|
|
///
|
|
/// /// A `Command` which names an entity based on a global counter.
|
|
/// struct CountName;
|
|
///
|
|
/// impl EntityCommand for CountName {
|
|
/// fn write(self, id: Entity, world: &mut World) {
|
|
/// // Get the current value of the counter, and increment it for next time.
|
|
/// let mut counter = world.resource_mut::<Counter>();
|
|
/// let i = counter.0;
|
|
/// counter.0 += 1;
|
|
///
|
|
/// // Name the entity after the value of the counter.
|
|
/// world.entity_mut(id).insert(Name::new(format!("Entity #{i}")));
|
|
/// }
|
|
/// }
|
|
///
|
|
/// // App creation boilerplate omitted...
|
|
/// # let mut world = World::new();
|
|
/// # world.init_resource::<Counter>();
|
|
/// #
|
|
/// # let mut setup_schedule = Schedule::new();
|
|
/// # setup_schedule.add_system(setup);
|
|
/// # let mut assert_schedule = Schedule::new();
|
|
/// # assert_schedule.add_system(assert_names);
|
|
/// #
|
|
/// # setup_schedule.run(&mut world);
|
|
/// # assert_schedule.run(&mut world);
|
|
///
|
|
/// fn setup(mut commands: Commands) {
|
|
/// commands.spawn_empty().add(CountName);
|
|
/// commands.spawn_empty().add(CountName);
|
|
/// }
|
|
///
|
|
/// fn assert_names(named: Query<&Name>) {
|
|
/// // We use a HashSet because we do not care about the order.
|
|
/// let names: HashSet<_> = named.iter().map(Name::as_str).collect();
|
|
/// assert_eq!(names, HashSet::from_iter(["Entity #0", "Entity #1"]));
|
|
/// }
|
|
/// ```
|
|
pub trait EntityCommand: Send + 'static {
|
|
fn write(self, id: Entity, world: &mut World);
|
|
/// Returns a [`Command`] which executes this [`EntityCommand`] for the given [`Entity`].
|
|
fn with_entity(self, id: Entity) -> WithEntity<Self>
|
|
where
|
|
Self: Sized,
|
|
{
|
|
WithEntity { cmd: self, id }
|
|
}
|
|
}
|
|
|
|
/// Turns an [`EntityCommand`] type into a [`Command`] type.
|
|
pub struct WithEntity<C: EntityCommand> {
|
|
cmd: C,
|
|
id: Entity,
|
|
}
|
|
|
|
impl<C: EntityCommand> Command for WithEntity<C> {
|
|
#[inline]
|
|
fn write(self, world: &mut World) {
|
|
self.cmd.write(self.id, world);
|
|
}
|
|
}
|
|
|
|
/// A list of commands that will be run to modify an [entity](crate::entity).
|
|
pub struct EntityCommands<'w, 's, 'a> {
|
|
entity: Entity,
|
|
commands: &'a mut Commands<'w, 's>,
|
|
}
|
|
|
|
impl<'w, 's, 'a> EntityCommands<'w, 's, 'a> {
|
|
/// Returns the [`Entity`] id of the entity.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// #
|
|
/// fn my_system(mut commands: Commands) {
|
|
/// let entity_id = commands.spawn_empty().id();
|
|
/// }
|
|
/// # bevy_ecs::system::assert_is_system(my_system);
|
|
/// ```
|
|
#[inline]
|
|
#[must_use = "Omit the .id() call if you do not need to store the `Entity` identifier."]
|
|
pub fn id(&self) -> Entity {
|
|
self.entity
|
|
}
|
|
|
|
/// Adds a [`Bundle`] of components to the entity.
|
|
///
|
|
/// This will overwrite any previous value(s) of the same component type.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// The command will panic when applied if the associated entity does not exist.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// # #[derive(Resource)]
|
|
/// # struct PlayerEntity { entity: Entity }
|
|
/// #[derive(Component)]
|
|
/// struct Health(u32);
|
|
/// #[derive(Component)]
|
|
/// struct Strength(u32);
|
|
/// #[derive(Component)]
|
|
/// struct Defense(u32);
|
|
///
|
|
/// #[derive(Bundle)]
|
|
/// struct CombatBundle {
|
|
/// health: Health,
|
|
/// strength: Strength,
|
|
/// }
|
|
///
|
|
/// fn add_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
|
|
/// commands
|
|
/// .entity(player.entity)
|
|
/// // You can insert individual components:
|
|
/// .insert(Defense(10))
|
|
/// // You can also insert pre-defined bundles of components:
|
|
/// .insert(CombatBundle {
|
|
/// health: Health(100),
|
|
/// strength: Strength(40),
|
|
/// })
|
|
/// // You can also insert tuples of components and bundles.
|
|
/// // This is equivalent to the calls above:
|
|
/// .insert((
|
|
/// Defense(10),
|
|
/// CombatBundle {
|
|
/// health: Health(100),
|
|
/// strength: Strength(40),
|
|
/// },
|
|
/// ));
|
|
/// }
|
|
/// # bevy_ecs::system::assert_is_system(add_combat_stats_system);
|
|
/// ```
|
|
pub fn insert(&mut self, bundle: impl Bundle) -> &mut Self {
|
|
self.commands.add(Insert {
|
|
entity: self.entity,
|
|
bundle,
|
|
});
|
|
self
|
|
}
|
|
|
|
/// Removes a [`Bundle`] of components from the entity.
|
|
///
|
|
/// See [`EntityMut::remove`](crate::world::EntityMut::remove) for more
|
|
/// details.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// #
|
|
/// # #[derive(Resource)]
|
|
/// # struct PlayerEntity { entity: Entity }
|
|
/// #[derive(Component)]
|
|
/// struct Health(u32);
|
|
/// #[derive(Component)]
|
|
/// struct Strength(u32);
|
|
/// #[derive(Component)]
|
|
/// struct Defense(u32);
|
|
///
|
|
/// #[derive(Bundle)]
|
|
/// struct CombatBundle {
|
|
/// health: Health,
|
|
/// strength: Strength,
|
|
/// }
|
|
///
|
|
/// fn remove_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
|
|
/// commands
|
|
/// .entity(player.entity)
|
|
/// // You can remove individual components:
|
|
/// .remove::<Defense>()
|
|
/// // You can also remove pre-defined Bundles of components:
|
|
/// .remove::<CombatBundle>()
|
|
/// // You can also remove tuples of components and bundles.
|
|
/// // This is equivalent to the calls above:
|
|
/// .remove::<(Defense, CombatBundle)>();
|
|
/// }
|
|
/// # bevy_ecs::system::assert_is_system(remove_combat_stats_system);
|
|
/// ```
|
|
pub fn remove<T>(&mut self) -> &mut Self
|
|
where
|
|
T: Bundle,
|
|
{
|
|
self.commands.add(Remove::<T> {
|
|
entity: self.entity,
|
|
phantom: PhantomData,
|
|
});
|
|
self
|
|
}
|
|
|
|
/// Despawns the entity.
|
|
///
|
|
/// See [`World::despawn`] for more details.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// The command will panic when applied if the associated entity does not exist.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// #
|
|
/// # #[derive(Resource)]
|
|
/// # struct CharacterToRemove { entity: Entity }
|
|
/// #
|
|
/// fn remove_character_system(
|
|
/// mut commands: Commands,
|
|
/// character_to_remove: Res<CharacterToRemove>
|
|
/// )
|
|
/// {
|
|
/// commands.entity(character_to_remove.entity).despawn();
|
|
/// }
|
|
/// # bevy_ecs::system::assert_is_system(remove_character_system);
|
|
/// ```
|
|
pub fn despawn(&mut self) {
|
|
self.commands.add(Despawn {
|
|
entity: self.entity,
|
|
});
|
|
}
|
|
|
|
/// Pushes an [`EntityCommand`] to the queue, which will get executed for the current [`Entity`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # use bevy_ecs::prelude::*;
|
|
/// # fn my_system(mut commands: Commands) {
|
|
/// commands
|
|
/// .spawn_empty()
|
|
/// // Closures with this signature implement `EntityCommand`.
|
|
/// .add(|id: Entity, world: &mut World| {
|
|
/// println!("Executed an EntityCommand for {id:?}");
|
|
/// });
|
|
/// # }
|
|
/// # bevy_ecs::system::assert_is_system(my_system);
|
|
/// ```
|
|
pub fn add<C: EntityCommand>(&mut self, command: C) -> &mut Self {
|
|
self.commands.add(command.with_entity(self.entity));
|
|
self
|
|
}
|
|
|
|
/// Logs the components of the entity at the info level.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// The command will panic when applied if the associated entity does not exist.
|
|
pub fn log_components(&mut self) {
|
|
self.commands.add(LogComponents {
|
|
entity: self.entity,
|
|
});
|
|
}
|
|
|
|
/// Returns the underlying [`Commands`].
|
|
pub fn commands(&mut self) -> &mut Commands<'w, 's> {
|
|
self.commands
|
|
}
|
|
}
|
|
|
|
impl<F> Command for F
|
|
where
|
|
F: FnOnce(&mut World) + Send + 'static,
|
|
{
|
|
fn write(self, world: &mut World) {
|
|
self(world);
|
|
}
|
|
}
|
|
|
|
impl<F> EntityCommand for F
|
|
where
|
|
F: FnOnce(Entity, &mut World) + Send + 'static,
|
|
{
|
|
fn write(self, id: Entity, world: &mut World) {
|
|
self(id, world);
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct Spawn<T> {
|
|
pub bundle: T,
|
|
}
|
|
|
|
impl<T> Command for Spawn<T>
|
|
where
|
|
T: Bundle,
|
|
{
|
|
fn write(self, world: &mut World) {
|
|
world.spawn(self.bundle);
|
|
}
|
|
}
|
|
|
|
pub struct GetOrSpawn {
|
|
entity: Entity,
|
|
}
|
|
|
|
impl Command for GetOrSpawn {
|
|
fn write(self, world: &mut World) {
|
|
world.get_or_spawn(self.entity);
|
|
}
|
|
}
|
|
|
|
pub struct SpawnBatch<I>
|
|
where
|
|
I: IntoIterator,
|
|
I::Item: Bundle,
|
|
{
|
|
pub bundles_iter: I,
|
|
}
|
|
|
|
impl<I> Command for SpawnBatch<I>
|
|
where
|
|
I: IntoIterator + Send + Sync + 'static,
|
|
I::Item: Bundle,
|
|
{
|
|
fn write(self, world: &mut World) {
|
|
world.spawn_batch(self.bundles_iter);
|
|
}
|
|
}
|
|
|
|
pub struct InsertOrSpawnBatch<I, B>
|
|
where
|
|
I: IntoIterator + Send + Sync + 'static,
|
|
B: Bundle,
|
|
I::IntoIter: Iterator<Item = (Entity, B)>,
|
|
{
|
|
pub bundles_iter: I,
|
|
}
|
|
|
|
impl<I, B> Command for InsertOrSpawnBatch<I, B>
|
|
where
|
|
I: IntoIterator + Send + Sync + 'static,
|
|
B: Bundle,
|
|
I::IntoIter: Iterator<Item = (Entity, B)>,
|
|
{
|
|
fn write(self, world: &mut World) {
|
|
if let Err(invalid_entities) = world.insert_or_spawn_batch(self.bundles_iter) {
|
|
error!(
|
|
"Failed to 'insert or spawn' bundle of type {} into the following invalid entities: {:?}",
|
|
std::any::type_name::<B>(),
|
|
invalid_entities
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct Despawn {
|
|
pub entity: Entity,
|
|
}
|
|
|
|
impl Command for Despawn {
|
|
fn write(self, world: &mut World) {
|
|
world.despawn(self.entity);
|
|
}
|
|
}
|
|
|
|
pub struct Insert<T> {
|
|
pub entity: Entity,
|
|
pub bundle: T,
|
|
}
|
|
|
|
impl<T> Command for Insert<T>
|
|
where
|
|
T: Bundle + 'static,
|
|
{
|
|
fn write(self, world: &mut World) {
|
|
if let Some(mut entity) = world.get_entity_mut(self.entity) {
|
|
entity.insert(self.bundle);
|
|
} else {
|
|
panic!("error[B0003]: Could not insert a bundle (of type `{}`) for entity {:?} because it doesn't exist in this World.", std::any::type_name::<T>(), self.entity);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct Remove<T> {
|
|
pub entity: Entity,
|
|
pub phantom: PhantomData<T>,
|
|
}
|
|
|
|
impl<T> Command for Remove<T>
|
|
where
|
|
T: Bundle,
|
|
{
|
|
fn write(self, world: &mut World) {
|
|
if let Some(mut entity_mut) = world.get_entity_mut(self.entity) {
|
|
// remove intersection to gracefully handle components that were removed before running
|
|
// this command
|
|
entity_mut.remove_intersection::<T>();
|
|
}
|
|
}
|
|
}
|
|
|
|
pub struct InitResource<R: Resource + FromWorld> {
|
|
_phantom: PhantomData<R>,
|
|
}
|
|
|
|
impl<R: Resource + FromWorld> Command for InitResource<R> {
|
|
fn write(self, world: &mut World) {
|
|
world.init_resource::<R>();
|
|
}
|
|
}
|
|
|
|
pub struct InsertResource<R: Resource> {
|
|
pub resource: R,
|
|
}
|
|
|
|
impl<R: Resource> Command for InsertResource<R> {
|
|
fn write(self, world: &mut World) {
|
|
world.insert_resource(self.resource);
|
|
}
|
|
}
|
|
|
|
pub struct RemoveResource<R: Resource> {
|
|
pub phantom: PhantomData<R>,
|
|
}
|
|
|
|
impl<R: Resource> Command for RemoveResource<R> {
|
|
fn write(self, world: &mut World) {
|
|
world.remove_resource::<R>();
|
|
}
|
|
}
|
|
|
|
/// [`Command`] to log the components of a given entity. See [`EntityCommands::log_components`].
|
|
pub struct LogComponents {
|
|
entity: Entity,
|
|
}
|
|
|
|
impl Command for LogComponents {
|
|
fn write(self, world: &mut World) {
|
|
let debug_infos: Vec<_> = world
|
|
.inspect_entity(self.entity)
|
|
.into_iter()
|
|
.map(|component_info| component_info.name())
|
|
.collect();
|
|
info!("Entity {:?}: {:?}", self.entity, debug_infos);
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
#[allow(clippy::float_cmp, clippy::approx_constant)]
|
|
mod tests {
|
|
use crate::{
|
|
self as bevy_ecs,
|
|
component::Component,
|
|
system::{CommandQueue, Commands, Resource},
|
|
world::World,
|
|
};
|
|
use std::sync::{
|
|
atomic::{AtomicUsize, Ordering},
|
|
Arc,
|
|
};
|
|
|
|
#[derive(Component)]
|
|
#[component(storage = "SparseSet")]
|
|
struct SparseDropCk(DropCk);
|
|
|
|
#[derive(Component)]
|
|
struct DropCk(Arc<AtomicUsize>);
|
|
impl DropCk {
|
|
fn new_pair() -> (Self, Arc<AtomicUsize>) {
|
|
let atomic = Arc::new(AtomicUsize::new(0));
|
|
(DropCk(atomic.clone()), atomic)
|
|
}
|
|
}
|
|
|
|
impl Drop for DropCk {
|
|
fn drop(&mut self) {
|
|
self.0.as_ref().fetch_add(1, Ordering::Relaxed);
|
|
}
|
|
}
|
|
|
|
#[derive(Component, Resource)]
|
|
struct W<T>(T);
|
|
|
|
fn simple_command(world: &mut World) {
|
|
world.spawn((W(0u32), W(42u64)));
|
|
}
|
|
|
|
#[test]
|
|
fn commands() {
|
|
let mut world = World::default();
|
|
let mut command_queue = CommandQueue::default();
|
|
let entity = Commands::new(&mut command_queue, &world)
|
|
.spawn((W(1u32), W(2u64)))
|
|
.id();
|
|
command_queue.apply(&mut world);
|
|
assert!(world.entities().len() == 1);
|
|
let results = world
|
|
.query::<(&W<u32>, &W<u64>)>()
|
|
.iter(&world)
|
|
.map(|(a, b)| (a.0, b.0))
|
|
.collect::<Vec<_>>();
|
|
assert_eq!(results, vec![(1u32, 2u64)]);
|
|
// test entity despawn
|
|
{
|
|
let mut commands = Commands::new(&mut command_queue, &world);
|
|
commands.entity(entity).despawn();
|
|
commands.entity(entity).despawn(); // double despawn shouldn't panic
|
|
}
|
|
command_queue.apply(&mut world);
|
|
let results2 = world
|
|
.query::<(&W<u32>, &W<u64>)>()
|
|
.iter(&world)
|
|
.map(|(a, b)| (a.0, b.0))
|
|
.collect::<Vec<_>>();
|
|
assert_eq!(results2, vec![]);
|
|
|
|
// test adding simple (FnOnce) commands
|
|
{
|
|
let mut commands = Commands::new(&mut command_queue, &world);
|
|
|
|
// set up a simple command using a closure that adds one additional entity
|
|
commands.add(|world: &mut World| {
|
|
world.spawn((W(42u32), W(0u64)));
|
|
});
|
|
|
|
// set up a simple command using a function that adds one additional entity
|
|
commands.add(simple_command);
|
|
}
|
|
command_queue.apply(&mut world);
|
|
let results3 = world
|
|
.query::<(&W<u32>, &W<u64>)>()
|
|
.iter(&world)
|
|
.map(|(a, b)| (a.0, b.0))
|
|
.collect::<Vec<_>>();
|
|
|
|
assert_eq!(results3, vec![(42u32, 0u64), (0u32, 42u64)]);
|
|
}
|
|
|
|
#[test]
|
|
fn remove_components() {
|
|
let mut world = World::default();
|
|
|
|
let mut command_queue = CommandQueue::default();
|
|
let (dense_dropck, dense_is_dropped) = DropCk::new_pair();
|
|
let (sparse_dropck, sparse_is_dropped) = DropCk::new_pair();
|
|
let sparse_dropck = SparseDropCk(sparse_dropck);
|
|
|
|
let entity = Commands::new(&mut command_queue, &world)
|
|
.spawn((W(1u32), W(2u64), dense_dropck, sparse_dropck))
|
|
.id();
|
|
command_queue.apply(&mut world);
|
|
let results_before = world
|
|
.query::<(&W<u32>, &W<u64>)>()
|
|
.iter(&world)
|
|
.map(|(a, b)| (a.0, b.0))
|
|
.collect::<Vec<_>>();
|
|
assert_eq!(results_before, vec![(1u32, 2u64)]);
|
|
|
|
// test component removal
|
|
Commands::new(&mut command_queue, &world)
|
|
.entity(entity)
|
|
.remove::<W<u32>>()
|
|
.remove::<(W<u32>, W<u64>, SparseDropCk, DropCk)>();
|
|
|
|
assert_eq!(dense_is_dropped.load(Ordering::Relaxed), 0);
|
|
assert_eq!(sparse_is_dropped.load(Ordering::Relaxed), 0);
|
|
command_queue.apply(&mut world);
|
|
assert_eq!(dense_is_dropped.load(Ordering::Relaxed), 1);
|
|
assert_eq!(sparse_is_dropped.load(Ordering::Relaxed), 1);
|
|
|
|
let results_after = world
|
|
.query::<(&W<u32>, &W<u64>)>()
|
|
.iter(&world)
|
|
.map(|(a, b)| (a.0, b.0))
|
|
.collect::<Vec<_>>();
|
|
assert_eq!(results_after, vec![]);
|
|
let results_after_u64 = world
|
|
.query::<&W<u64>>()
|
|
.iter(&world)
|
|
.map(|v| v.0)
|
|
.collect::<Vec<_>>();
|
|
assert_eq!(results_after_u64, vec![]);
|
|
}
|
|
|
|
#[test]
|
|
fn remove_resources() {
|
|
let mut world = World::default();
|
|
let mut queue = CommandQueue::default();
|
|
{
|
|
let mut commands = Commands::new(&mut queue, &world);
|
|
commands.insert_resource(W(123i32));
|
|
commands.insert_resource(W(456.0f64));
|
|
}
|
|
|
|
queue.apply(&mut world);
|
|
assert!(world.contains_resource::<W<i32>>());
|
|
assert!(world.contains_resource::<W<f64>>());
|
|
|
|
{
|
|
let mut commands = Commands::new(&mut queue, &world);
|
|
// test resource removal
|
|
commands.remove_resource::<W<i32>>();
|
|
}
|
|
queue.apply(&mut world);
|
|
assert!(!world.contains_resource::<W<i32>>());
|
|
assert!(world.contains_resource::<W<f64>>());
|
|
}
|
|
}
|