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use crate::{CoreStage, Events, Plugin, PluginGroup, PluginGroupBuilder, StartupStage};
pub use bevy_derive::AppLabel;
use bevy_ecs::{
prelude::{FromWorld, IntoExclusiveSystem},
schedule::{
IntoSystemDescriptor, RunOnce, Schedule, Stage, StageLabel, State, StateData, SystemSet,
SystemStage,
},
system::Resource,
world::World,
};
use bevy_utils::{tracing::debug, HashMap};
use std::fmt::Debug;
#[cfg(feature = "trace")]
use bevy_utils::tracing::info_span;
bevy_utils::define_label!(AppLabel);
#[allow(clippy::needless_doctest_main)]
/// Containers of app logic and data
///
/// Bundles together the necessary elements, like [`World`] and [`Schedule`], to create
/// an ECS-based application. It also stores a pointer to a
/// [runner function](Self::set_runner). The runner is responsible for managing the application's
/// event loop and applying the [`Schedule`] to the [`World`] to drive application logic.
/// Apps are constructed with the builder pattern.
///
/// ## Example
/// Here is a simple "Hello World" Bevy app:
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
///
/// fn main() {
/// App::new()
/// .add_system(hello_world_system)
/// .run();
/// }
///
/// fn hello_world_system() {
/// println!("hello world");
/// }
/// ```
pub struct App {
/// The main ECS [`World`] of the [`App`].
/// This stores and provides access to all the main data of the application.
/// The systems of the [`App`] will run using this [`World`].
/// If additional separate [`World`]-[`Schedule`] pairs are needed, you can use [`sub_app`][App::add_sub_app]s.
pub world: World,
/// The [runner function](Self::set_runner) is primarily responsible for managing
/// the application's event loop and advancing the [`Schedule`].
/// Typically, it is not configured manually, but set by one of Bevy's built-in plugins.
/// See `bevy::winit::WinitPlugin` and [`ScheduleRunnerPlugin`](crate::schedule_runner::ScheduleRunnerPlugin).
pub runner: Box<dyn Fn(App)>,
/// A container of [`Stage`]s set to be run in a linear order.
pub schedule: Schedule,
sub_apps: HashMap<Box<dyn AppLabel>, SubApp>,
}
/// Each [`SubApp`] has its own [`Schedule`] and [`World`], enabling a separation of concerns.
struct SubApp {
app: App,
runner: Box<dyn Fn(&mut World, &mut App)>,
}
impl Default for App {
fn default() -> Self {
let mut app = App::empty();
#[cfg(feature = "bevy_reflect")]
app.init_resource::<bevy_reflect::TypeRegistryArc>();
app.add_default_stages()
.add_event::<AppExit>()
.add_system_to_stage(CoreStage::Last, World::clear_trackers.exclusive_system());
#[cfg(feature = "bevy_ci_testing")]
{
crate::ci_testing::setup_app(&mut app);
}
app
}
}
impl App {
/// Creates a new [`App`] with some default structure to enable core engine features.
/// This is the preferred constructor for most use cases.
pub fn new() -> App {
App::default()
}
/// Creates a new empty [`App`] with minimal default configuration.
///
/// This constructor should be used if you wish to provide a custom schedule, exit handling, cleanup, etc.
pub fn empty() -> App {
Self {
world: Default::default(),
schedule: Default::default(),
runner: Box::new(run_once),
sub_apps: HashMap::default(),
}
}
/// Advances the execution of the [`Schedule`] by one cycle.
///
/// See [`Schedule::run_once`] for more details.
pub fn update(&mut self) {
#[cfg(feature = "trace")]
let bevy_frame_update_span = info_span!("frame");
#[cfg(feature = "trace")]
let _bevy_frame_update_guard = bevy_frame_update_span.enter();
self.schedule.run(&mut self.world);
for sub_app in self.sub_apps.values_mut() {
(sub_app.runner)(&mut self.world, &mut sub_app.app);
}
}
/// Starts the application by calling the app's [runner function](Self::set_runner).
///
/// Finalizes the [`App`] configuration. For general usage, see the example on the item
/// level documentation.
pub fn run(&mut self) {
#[cfg(feature = "trace")]
let bevy_app_run_span = info_span!("bevy_app");
#[cfg(feature = "trace")]
let _bevy_app_run_guard = bevy_app_run_span.enter();
let mut app = std::mem::replace(self, App::empty());
let runner = std::mem::replace(&mut app.runner, Box::new(run_once));
(runner)(app);
}
/// Adds a [`Stage`] with the given `label` to the last position of the app's
/// [`Schedule`].
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// # let mut app = App::new();
/// #
/// app.add_stage("my_stage", SystemStage::parallel());
/// ```
pub fn add_stage<S: Stage>(&mut self, label: impl StageLabel, stage: S) -> &mut Self {
self.schedule.add_stage(label, stage);
self
}
/// Adds a [`Stage`] with the given `label` to the app's [`Schedule`], located
/// immediately after the stage labeled by `target`.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// # let mut app = App::new();
/// #
/// app.add_stage_after(CoreStage::Update, "my_stage", SystemStage::parallel());
/// ```
pub fn add_stage_after<S: Stage>(
&mut self,
target: impl StageLabel,
label: impl StageLabel,
stage: S,
) -> &mut Self {
self.schedule.add_stage_after(target, label, stage);
self
}
/// Adds a [`Stage`] with the given `label` to the app's [`Schedule`], located
/// immediately before the stage labeled by `target`.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// # let mut app = App::new();
/// #
/// app.add_stage_before(CoreStage::Update, "my_stage", SystemStage::parallel());
/// ```
pub fn add_stage_before<S: Stage>(
&mut self,
target: impl StageLabel,
label: impl StageLabel,
stage: S,
) -> &mut Self {
self.schedule.add_stage_before(target, label, stage);
self
}
/// Adds a [`Stage`] with the given `label` to the last position of the
/// [startup schedule](Self::add_default_stages).
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// # let mut app = App::new();
/// #
/// app.add_startup_stage("my_startup_stage", SystemStage::parallel());
/// ```
pub fn add_startup_stage<S: Stage>(&mut self, label: impl StageLabel, stage: S) -> &mut Self {
self.schedule
.stage(CoreStage::Startup, |schedule: &mut Schedule| {
schedule.add_stage(label, stage)
});
self
}
/// Adds a [startup stage](Self::add_default_stages) with the given `label`, immediately
/// after the stage labeled by `target`.
///
/// The `target` label must refer to a stage inside the startup schedule.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// # let mut app = App::new();
/// #
/// app.add_startup_stage_after(
/// StartupStage::Startup,
/// "my_startup_stage",
/// SystemStage::parallel()
/// );
/// ```
pub fn add_startup_stage_after<S: Stage>(
&mut self,
target: impl StageLabel,
label: impl StageLabel,
stage: S,
) -> &mut Self {
self.schedule
.stage(CoreStage::Startup, |schedule: &mut Schedule| {
schedule.add_stage_after(target, label, stage)
});
self
}
/// Adds a [startup stage](Self::add_default_stages) with the given `label`, immediately
/// before the stage labeled by `target`.
///
/// The `target` label must refer to a stage inside the startup schedule.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// # let mut app = App::new();
/// #
/// app.add_startup_stage_before(
/// StartupStage::Startup,
/// "my_startup_stage",
/// SystemStage::parallel()
/// );
/// ```
pub fn add_startup_stage_before<S: Stage>(
&mut self,
target: impl StageLabel,
label: impl StageLabel,
stage: S,
) -> &mut Self {
self.schedule
.stage(CoreStage::Startup, |schedule: &mut Schedule| {
schedule.add_stage_before(target, label, stage)
});
self
}
/// Fetches the [`Stage`] of type `T` marked with `label` from the [`Schedule`], then
/// executes the provided `func` passing the fetched stage to it as an argument.
///
/// The `func` argument should be a function or a closure that accepts a mutable reference
/// to a struct implementing `Stage` and returns the same type. That means that it should
/// also assume that the stage has already been fetched successfully.
///
/// See [`Schedule::stage`] for more details.
///
/// # Example
///
/// Here the closure is used to add a system to the update stage:
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn my_system() {}
/// #
/// app.stage(CoreStage::Update, |stage: &mut SystemStage| {
/// stage.add_system(my_system)
/// });
/// ```
pub fn stage<T: Stage, F: FnOnce(&mut T) -> &mut T>(
&mut self,
label: impl StageLabel,
func: F,
) -> &mut Self {
self.schedule.stage(label, func);
self
}
/// Adds a system to the [update stage](Self::add_default_stages) of the app's [`Schedule`].
///
/// Refer to the [system module documentation](bevy_ecs::system) to see how a system
/// can be defined.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # fn my_system() {}
/// # let mut app = App::new();
/// #
/// app.add_system(my_system);
/// ```
pub fn add_system<Params>(&mut self, system: impl IntoSystemDescriptor<Params>) -> &mut Self {
self.add_system_to_stage(CoreStage::Update, system)
}
/// Adds a [`SystemSet`] to the [update stage](Self::add_default_stages).
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn system_a() {}
/// # fn system_b() {}
/// # fn system_c() {}
/// #
/// app.add_system_set(
/// SystemSet::new()
/// .with_system(system_a)
/// .with_system(system_b)
/// .with_system(system_c),
/// );
/// ```
pub fn add_system_set(&mut self, system_set: SystemSet) -> &mut Self {
self.add_system_set_to_stage(CoreStage::Update, system_set)
}
/// Adds a system to the [`Stage`] identified by `stage_label`.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn my_system() {}
/// #
/// app.add_system_to_stage(CoreStage::PostUpdate, my_system);
/// ```
pub fn add_system_to_stage<Params>(
&mut self,
stage_label: impl StageLabel,
system: impl IntoSystemDescriptor<Params>,
) -> &mut Self {
self.schedule.add_system_to_stage(stage_label, system);
self
}
/// Adds a [`SystemSet`] to the [`Stage`] identified by `stage_label`.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn system_a() {}
/// # fn system_b() {}
/// # fn system_c() {}
/// #
/// app.add_system_set_to_stage(
/// CoreStage::PostUpdate,
/// SystemSet::new()
/// .with_system(system_a)
/// .with_system(system_b)
/// .with_system(system_c),
/// );
/// ```
pub fn add_system_set_to_stage(
&mut self,
stage_label: impl StageLabel,
system_set: SystemSet,
) -> &mut Self {
self.schedule
.add_system_set_to_stage(stage_label, system_set);
self
}
/// Adds a system to the [startup stage](Self::add_default_stages) of the app's [`Schedule`].
///
/// * For adding a system that runs for every frame, see [`add_system`](Self::add_system).
/// * For adding a system to specific stage, see [`add_system_to_stage`](Self::add_system_to_stage).
///
/// ## Example
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// fn my_startup_system(_commands: Commands) {
/// println!("My startup system");
/// }
///
/// App::new()
/// .add_startup_system(my_startup_system.system());
/// ```
pub fn add_startup_system<Params>(
&mut self,
system: impl IntoSystemDescriptor<Params>,
) -> &mut Self {
self.add_startup_system_to_stage(StartupStage::Startup, system)
}
/// Adds a [`SystemSet`] to the [startup stage](Self::add_default_stages)
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn startup_system_a() {}
/// # fn startup_system_b() {}
/// # fn startup_system_c() {}
/// #
/// app.add_startup_system_set(
/// SystemSet::new()
/// .with_system(startup_system_a)
/// .with_system(startup_system_b)
/// .with_system(startup_system_c),
/// );
/// ```
pub fn add_startup_system_set(&mut self, system_set: SystemSet) -> &mut Self {
self.add_startup_system_set_to_stage(StartupStage::Startup, system_set)
}
/// Adds a system to the [startup schedule](Self::add_default_stages), in the stage
/// identified by `stage_label`.
///
/// `stage_label` must refer to a stage inside the startup schedule.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn my_startup_system() {}
/// #
/// app.add_startup_system_to_stage(StartupStage::PreStartup, my_startup_system);
/// ```
pub fn add_startup_system_to_stage<Params>(
&mut self,
stage_label: impl StageLabel,
system: impl IntoSystemDescriptor<Params>,
) -> &mut Self {
self.schedule
.stage(CoreStage::Startup, |schedule: &mut Schedule| {
schedule.add_system_to_stage(stage_label, system)
});
self
}
/// Adds a [`SystemSet`] to the [startup schedule](Self::add_default_stages), in the stage
/// identified by `stage_label`.
///
/// `stage_label` must refer to a stage inside the startup schedule.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # let mut app = App::new();
/// # fn startup_system_a() {}
/// # fn startup_system_b() {}
/// # fn startup_system_c() {}
/// #
/// app.add_startup_system_set_to_stage(
/// StartupStage::PreStartup,
/// SystemSet::new()
/// .with_system(startup_system_a)
/// .with_system(startup_system_b)
/// .with_system(startup_system_c),
/// );
/// ```
pub fn add_startup_system_set_to_stage(
&mut self,
stage_label: impl StageLabel,
system_set: SystemSet,
) -> &mut Self {
self.schedule
.stage(CoreStage::Startup, |schedule: &mut Schedule| {
schedule.add_system_set_to_stage(stage_label, system_set)
});
self
}
/// Adds a new [`State`] with the given `initial` value.
/// This inserts a new `State<T>` resource and adds a new "driver" to [`CoreStage::Update`].
/// Each stage that uses `State<T>` for system run criteria needs a driver. If you need to use
/// your state in a different stage, consider using [`Self::add_state_to_stage`] or manually
/// adding [`State::get_driver`] to additional stages you need it in.
pub fn add_state<T>(&mut self, initial: T) -> &mut Self
where
T: StateData,
{
self.add_state_to_stage(CoreStage::Update, initial)
}
/// Adds a new [`State`] with the given `initial` value.
/// This inserts a new `State<T>` resource and adds a new "driver" to the given stage.
/// Each stage that uses `State<T>` for system run criteria needs a driver. If you need to use
/// your state in more than one stage, consider manually adding [`State::get_driver`] to the
/// stages you need it in.
pub fn add_state_to_stage<T>(&mut self, stage: impl StageLabel, initial: T) -> &mut Self
where
T: StateData,
{
self.insert_resource(State::new(initial))
.add_system_set_to_stage(stage, State::<T>::get_driver())
}
/// Adds utility stages to the [`Schedule`], giving it a standardized structure.
///
/// Adding those stages is necessary to make some core engine features work, like
/// adding systems without specifying a stage, or registering events. This is however
/// done by default by calling `App::default`, which is in turn called by
/// [`App::new`].
///
/// # The stages
///
/// All the added stages, with the exception of the startup stage, run every time the
/// schedule is invoked. The stages are the following, in order of execution:
/// - **First:** Runs at the very start of the schedule execution cycle, even before the
/// startup stage.
/// - **Startup:** This is actually a schedule containing sub-stages. Runs only once
/// when the app starts.
/// - **Pre-startup:** Intended for systems that need to run before other startup systems.
/// - **Startup:** The main startup stage. Startup systems are added here by default.
/// - **Post-startup:** Intended for systems that need to run after other startup systems.
/// - **Pre-update:** Often used by plugins to prepare their internal state before the
/// update stage begins.
/// - **Update:** Intended for user defined logic. Systems are added here by default.
/// - **Post-update:** Often used by plugins to finalize their internal state after the
/// world changes that happened during the update stage.
/// - **Last:** Runs right before the end of the schedule execution cycle.
///
/// The labels for those stages are defined in the [`CoreStage`] and [`StartupStage`]
/// `enum`s.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// #
/// let app = App::empty().add_default_stages();
/// ```
pub fn add_default_stages(&mut self) -> &mut Self {
self.add_stage(CoreStage::First, SystemStage::parallel())
.add_stage(
CoreStage::Startup,
Schedule::default()
.with_run_criteria(RunOnce::default())
.with_stage(StartupStage::PreStartup, SystemStage::parallel())
.with_stage(StartupStage::Startup, SystemStage::parallel())
.with_stage(StartupStage::PostStartup, SystemStage::parallel()),
)
.add_stage(CoreStage::PreUpdate, SystemStage::parallel())
.add_stage(CoreStage::Update, SystemStage::parallel())
.add_stage(CoreStage::PostUpdate, SystemStage::parallel())
.add_stage(CoreStage::Last, SystemStage::parallel())
}
/// Setup the application to manage events of type `T`.
///
/// This is done by adding a `Resource` of type `Events::<T>`,
/// and inserting a `Events::<T>::update_system` system into `CoreStage::First`.
///
/// See [`Events`](bevy_ecs::event::Events) for defining events.
///
/// # Example
///
/// ```
/// # use bevy_app::prelude::*;
/// # use bevy_ecs::prelude::*;
/// #
/// # struct MyEvent;
/// # let mut app = App::new();
/// #
/// app.add_event::<MyEvent>();
/// ```
pub fn add_event<T>(&mut self) -> &mut Self
where
T: Resource,
{
self.init_resource::<Events<T>>()
.add_system_to_stage(CoreStage::First, Events::<T>::update_system)
}
/// Inserts a resource to the current [App] and overwrites any resource previously added of the same type.
///
/// A resource in Bevy represents globally unique data. Resources must be added to Bevy Apps
/// before using them. This happens with [`insert_resource`](Self::insert_resource).
///
/// See also `init_resource` for resources that implement `Default` or [`FromWorld`].
///
/// ## Example
/// ```
/// # use bevy_app::prelude::*;
/// #
/// struct MyCounter {
/// counter: usize,
/// }
///
/// App::new()
/// .insert_resource(MyCounter { counter: 0 });
/// ```
pub fn insert_resource<T>(&mut self, resource: T) -> &mut Self
where
T: Resource,
{
self.world.insert_resource(resource);
self
}
/// Inserts a non-send resource to the app
///
/// You usually want to use `insert_resource`, but there are some special cases when a resource must
/// be non-send.
///
/// ## Example
/// ```
/// # use bevy_app::prelude::*;
/// #
/// struct MyCounter {
/// counter: usize,
/// }
///
/// App::new()
/// .insert_non_send_resource(MyCounter { counter: 0 });
/// ```
pub fn insert_non_send_resource<T>(&mut self, resource: T) -> &mut Self
where
T: 'static,
{
self.world.insert_non_send(resource);
self
}
/// Initialize a resource in the current [`App`], if it does not exist yet
///
/// If the resource already exists, nothing happens.
///
/// Adds a resource that implements `Default` or [`FromWorld`] trait.
///
/// ## Example
/// ```
/// # use bevy_app::prelude::*;
/// #
/// struct MyCounter {
/// counter: usize,
/// }
///
/// impl Default for MyCounter {
/// fn default() -> MyCounter {
/// MyCounter {
/// counter: 100
/// }
/// }
/// }
///
/// App::new()
/// .init_resource::<MyCounter>();
/// ```
pub fn init_resource<R>(&mut self) -> &mut Self
where
R: FromWorld + Send + Sync + 'static,
{
// PERF: We could avoid double hashing here, since the `from_resources` call is guaranteed
// not to modify the map. However, we would need to be borrowing resources both
// mutably and immutably, so we would need to be extremely certain this is correct
if !self.world.contains_resource::<R>() {
let resource = R::from_world(&mut self.world);
self.insert_resource(resource);
}
self
}
/// Initialize a non-send resource in the current [`App`], if it does not exist yet.
///
/// Adds a resource that implements `Default` or [`FromWorld`] trait.
pub fn init_non_send_resource<R>(&mut self) -> &mut Self
where
R: FromWorld + 'static,
{
// See perf comment in init_resource
if self.world.get_non_send_resource::<R>().is_none() {
let resource = R::from_world(&mut self.world);
self.world.insert_non_send(resource);
}
self
}
/// Sets the function that will be called when the app is run.
///
/// The runner function (`run_fn`) is called only once by [`App::run`]. If the
/// presence of a main loop in the app is desired, it is responsibility of the runner
/// function to provide it.
///
/// The runner function is usually not set manually, but by Bevy integrated plugins
/// (e.g. winit plugin).
///
/// ## Example
/// ```
/// # use bevy_app::prelude::*;
/// #
/// fn my_runner(mut app: App) {
/// loop {
/// println!("In main loop");
/// app.update();
/// }
/// }
///
/// App::new()
/// .set_runner(my_runner);
/// ```
pub fn set_runner(&mut self, run_fn: impl Fn(App) + 'static) -> &mut Self {
self.runner = Box::new(run_fn);
self
}
/// Adds a single plugin
///
/// One of Bevy's core principles is modularity. All Bevy engine features are implemented
/// as plugins. This includes internal features like the renderer.
///
/// Bevy also provides a few sets of default plugins. See [`add_plugins`](Self::add_plugins).
///
/// ## Example
/// ```
/// # use bevy_app::prelude::*;
/// #
/// App::new().add_plugin(bevy_log::LogPlugin::default());
/// ```
pub fn add_plugin<T>(&mut self, plugin: T) -> &mut Self
where
T: Plugin,
{
debug!("added plugin: {}", plugin.name());
plugin.build(self);
self
}
/// Adds a group of plugins
///
/// Bevy plugins can be grouped into a set of plugins. Bevy provides
/// built-in `PluginGroups` that provide core engine functionality.
///
/// The plugin groups available by default are `DefaultPlugins` and `MinimalPlugins`.
///
/// ## Example
/// ```
/// # use bevy_app::{prelude::*, PluginGroupBuilder};
/// #
/// # // Dummy created to avoid using bevy_internal, which pulls in to many dependencies.
/// # struct MinimalPlugins;
/// # impl PluginGroup for MinimalPlugins {
/// # fn build(&mut self, group: &mut PluginGroupBuilder){;}
/// # }
/// #
/// App::new()
/// .add_plugins(MinimalPlugins);
/// ```
pub fn add_plugins<T: PluginGroup>(&mut self, mut group: T) -> &mut Self {
let mut plugin_group_builder = PluginGroupBuilder::default();
group.build(&mut plugin_group_builder);
plugin_group_builder.finish(self);
self
}
/// Adds a group of plugins with an initializer method
///
/// Can be used to add a group of plugins, where the group is modified
/// before insertion into Bevy application. For example, you can add
/// extra plugins at a specific place in the plugin group, or deactivate
/// specific plugins while keeping the rest.
///
/// ## Example
/// ```
/// # use bevy_app::{prelude::*, PluginGroupBuilder};
/// #
/// # // Dummies created to avoid using bevy_internal which pulls in to many dependencies.
/// # struct DefaultPlugins;
/// # impl PluginGroup for DefaultPlugins {
/// # fn build(&mut self, group: &mut PluginGroupBuilder){
/// # group.add(bevy_log::LogPlugin::default());
/// # }
/// # }
/// #
/// # struct MyOwnPlugin;
/// # impl Plugin for MyOwnPlugin {
/// # fn build(&self, app: &mut App){;}
/// # }
/// #
/// App::new()
/// .add_plugins_with(DefaultPlugins, |group| {
/// group.add_before::<bevy_log::LogPlugin, _>(MyOwnPlugin)
/// });
/// ```
pub fn add_plugins_with<T, F>(&mut self, mut group: T, func: F) -> &mut Self
where
T: PluginGroup,
F: FnOnce(&mut PluginGroupBuilder) -> &mut PluginGroupBuilder,
{
let mut plugin_group_builder = PluginGroupBuilder::default();
group.build(&mut plugin_group_builder);
func(&mut plugin_group_builder);
plugin_group_builder.finish(self);
self
}
/// Adds the type `T` to the type registry resource.
#[cfg(feature = "bevy_reflect")]
pub fn register_type<T: bevy_reflect::GetTypeRegistration>(&mut self) -> &mut Self {
{
let registry = self
.world
.get_resource_mut::<bevy_reflect::TypeRegistryArc>()
.unwrap();
registry.write().register::<T>();
}
self
}
/// Adds a "sub app" to this [`App`].
///
/// Sub apps are a largely experimental feature: each `SubApp` has its own [`Schedule`] and [`World`].
pub fn add_sub_app(
&mut self,
label: impl AppLabel,
app: App,
f: impl Fn(&mut World, &mut App) + 'static,
) -> &mut Self {
self.sub_apps.insert(
Box::new(label),
SubApp {
app,
runner: Box::new(f),
},
);
self
}
/// Retrieves a "sub app" stored inside this [App]. This will panic if the sub app does not exist.
pub fn sub_app_mut(&mut self, label: impl AppLabel) -> &mut App {
match self.get_sub_app_mut(label) {
Ok(app) => app,
Err(label) => panic!("Sub-App with label '{:?}' does not exist", label),
}
}
/// Retrieves a "sub app" inside this [App] with the given label, if it exists. Otherwise returns
/// an [Err] containing the given label.
pub fn get_sub_app_mut(&mut self, label: impl AppLabel) -> Result<&mut App, impl AppLabel> {
self.sub_apps
.get_mut((&label) as &dyn AppLabel)
.map(|sub_app| &mut sub_app.app)
.ok_or(label)
}
/// Retrieves a "sub app" stored inside this [App]. This will panic if the sub app does not exist.
pub fn sub_app(&self, label: impl AppLabel) -> &App {
match self.get_sub_app(label) {
Ok(app) => app,
Err(label) => panic!("Sub-App with label '{:?}' does not exist", label),
}
}
/// Retrieves a "sub app" inside this [App] with the given label, if it exists. Otherwise returns
/// an [Err] containing the given label.
pub fn get_sub_app(&self, label: impl AppLabel) -> Result<&App, impl AppLabel> {
self.sub_apps
.get((&label) as &dyn AppLabel)
.map(|sub_app| &sub_app.app)
.ok_or(label)
}
}
fn run_once(mut app: App) {
app.update();
}
/// An event that indicates the app should exit. This will fully exit the app process.
#[derive(Debug, Clone)]
pub struct AppExit;