#![warn(missing_docs)] //! `bevy_winit` provides utilities to handle window creation and the eventloop through [`winit`] //! //! Most commonly, the [`WinitPlugin`] is used as part of //! [`DefaultPlugins`](https://docs.rs/bevy/latest/bevy/struct.DefaultPlugins.html). //! The app's [runner](bevy_app::App::runner) is set by `WinitPlugin` and handles the `winit` [`EventLoop`]. //! See `winit_runner` for details. pub mod accessibility; mod converters; mod system; mod winit_config; mod winit_windows; use bevy_a11y::AccessibilityRequested; use bevy_utils::{Duration, Instant}; use system::{changed_windows, create_windows, despawn_windows, CachedWindow}; pub use winit_config::*; pub use winit_windows::*; use bevy_app::{App, AppExit, Last, Plugin, PluginsState}; use bevy_ecs::event::{Events, ManualEventReader}; use bevy_ecs::prelude::*; use bevy_ecs::system::{SystemParam, SystemState}; use bevy_input::{ keyboard::KeyboardInput, mouse::{MouseButtonInput, MouseMotion, MouseScrollUnit, MouseWheel}, touch::TouchInput, touchpad::{TouchpadMagnify, TouchpadRotate}, }; use bevy_math::{ivec2, DVec2, Vec2}; #[cfg(not(target_arch = "wasm32"))] use bevy_tasks::tick_global_task_pools_on_main_thread; use bevy_utils::tracing::{error, trace, warn}; use bevy_window::{ exit_on_all_closed, ApplicationLifetime, CursorEntered, CursorLeft, CursorMoved, FileDragAndDrop, Ime, ReceivedCharacter, RequestRedraw, Window, WindowBackendScaleFactorChanged, WindowCloseRequested, WindowCreated, WindowDestroyed, WindowFocused, WindowMoved, WindowOccluded, WindowResized, WindowScaleFactorChanged, WindowThemeChanged, }; #[cfg(target_os = "android")] use bevy_window::{PrimaryWindow, RawHandleWrapper}; #[cfg(target_os = "android")] pub use winit::platform::android::activity as android_activity; use winit::{ event::{self, DeviceEvent, Event, StartCause, WindowEvent}, event_loop::{ControlFlow, EventLoop, EventLoopBuilder, EventLoopWindowTarget}, }; use crate::accessibility::{AccessKitAdapters, AccessKitPlugin, WinitActionHandlers}; use crate::converters::convert_winit_theme; /// [`AndroidApp`] provides an interface to query the application state as well as monitor events /// (for example lifecycle and input events). #[cfg(target_os = "android")] pub static ANDROID_APP: std::sync::OnceLock = std::sync::OnceLock::new(); /// A [`Plugin`] that uses `winit` to create and manage windows, and receive window and input /// events. /// /// This plugin will add systems and resources that sync with the `winit` backend and also /// replace the existing [`App`] runner with one that constructs an [event loop](EventLoop) to /// receive window and input events from the OS. #[derive(Default)] pub struct WinitPlugin { /// Allows the window (and the event loop) to be created on any thread /// instead of only the main thread. /// /// See [`EventLoopBuilder::build`] for more information on this. /// /// # Supported platforms /// /// Only works on Linux (X11/Wayland) and Windows. /// This field is ignored on other platforms. pub run_on_any_thread: bool, } impl Plugin for WinitPlugin { fn build(&self, app: &mut App) { let mut event_loop_builder = EventLoopBuilder::<()>::with_user_event(); // This is needed because the features checked in the inner // block might be enabled on other platforms than linux. #[cfg(target_os = "linux")] { #[cfg(feature = "x11")] { use winit::platform::x11::EventLoopBuilderExtX11; // This allows a Bevy app to be started and ran outside of the main thread. // A use case for this is to allow external applications to spawn a thread // which runs a Bevy app without requiring the Bevy app to need to reside on // the main thread, which can be problematic. event_loop_builder.with_any_thread(self.run_on_any_thread); } #[cfg(feature = "wayland")] { use winit::platform::wayland::EventLoopBuilderExtWayland; event_loop_builder.with_any_thread(self.run_on_any_thread); } } #[cfg(target_os = "windows")] { use winit::platform::windows::EventLoopBuilderExtWindows; event_loop_builder.with_any_thread(self.run_on_any_thread); } #[cfg(target_os = "android")] { use winit::platform::android::EventLoopBuilderExtAndroid; event_loop_builder.with_android_app( ANDROID_APP .get() .expect("Bevy must be setup with the #[bevy_main] macro on Android") .clone(), ); } app.init_non_send_resource::() .init_resource::() .set_runner(winit_runner) .add_systems( Last, ( // `exit_on_all_closed` only checks if windows exist but doesn't access data, // so we don't need to care about its ordering relative to `changed_windows` changed_windows.ambiguous_with(exit_on_all_closed), despawn_windows, ) .chain(), ); app.add_plugins(AccessKitPlugin); let event_loop = event_loop_builder .build() .expect("Failed to build event loop"); // iOS, macOS, and Android don't like it if you create windows before the event loop is // initialized. // // See: // - https://github.com/rust-windowing/winit/blob/master/README.md#macos // - https://github.com/rust-windowing/winit/blob/master/README.md#ios #[cfg(not(any(target_os = "android", target_os = "ios", target_os = "macos")))] { // Otherwise, we want to create a window before `bevy_render` initializes the renderer // so that we have a surface to use as a hint. This improves compatibility with `wgpu` // backends, especially WASM/WebGL2. #[cfg(not(target_arch = "wasm32"))] let mut create_window_system_state: SystemState<( Commands, Query<(Entity, &mut Window)>, EventWriter, NonSendMut, NonSendMut, ResMut, ResMut, )> = SystemState::from_world(&mut app.world); #[cfg(target_arch = "wasm32")] let mut create_window_system_state: SystemState<( Commands, Query<(Entity, &mut Window)>, EventWriter, NonSendMut, NonSendMut, ResMut, ResMut, )> = SystemState::from_world(&mut app.world); #[cfg(not(target_arch = "wasm32"))] let ( commands, mut windows, event_writer, winit_windows, adapters, handlers, accessibility_requested, ) = create_window_system_state.get_mut(&mut app.world); #[cfg(target_arch = "wasm32")] let ( commands, mut windows, event_writer, winit_windows, adapters, handlers, accessibility_requested, ) = create_window_system_state.get_mut(&mut app.world); create_windows( &event_loop, commands, windows.iter_mut(), event_writer, winit_windows, adapters, handlers, accessibility_requested, ); create_window_system_state.apply(&mut app.world); } // `winit`'s windows are bound to the event loop that created them, so the event loop must // be inserted as a resource here to pass it onto the runner. app.insert_non_send_resource(event_loop); } } #[derive(SystemParam)] struct WindowAndInputEventWriters<'w> { // `winit` `WindowEvent`s window_resized: EventWriter<'w, WindowResized>, window_close_requested: EventWriter<'w, WindowCloseRequested>, window_scale_factor_changed: EventWriter<'w, WindowScaleFactorChanged>, window_backend_scale_factor_changed: EventWriter<'w, WindowBackendScaleFactorChanged>, window_focused: EventWriter<'w, WindowFocused>, window_occluded: EventWriter<'w, WindowOccluded>, window_moved: EventWriter<'w, WindowMoved>, window_theme_changed: EventWriter<'w, WindowThemeChanged>, window_destroyed: EventWriter<'w, WindowDestroyed>, lifetime: EventWriter<'w, ApplicationLifetime>, keyboard_input: EventWriter<'w, KeyboardInput>, character_input: EventWriter<'w, ReceivedCharacter>, mouse_button_input: EventWriter<'w, MouseButtonInput>, touchpad_magnify_input: EventWriter<'w, TouchpadMagnify>, touchpad_rotate_input: EventWriter<'w, TouchpadRotate>, mouse_wheel_input: EventWriter<'w, MouseWheel>, touch_input: EventWriter<'w, TouchInput>, ime_input: EventWriter<'w, Ime>, file_drag_and_drop: EventWriter<'w, FileDragAndDrop>, cursor_moved: EventWriter<'w, CursorMoved>, cursor_entered: EventWriter<'w, CursorEntered>, cursor_left: EventWriter<'w, CursorLeft>, // `winit` `DeviceEvent`s mouse_motion: EventWriter<'w, MouseMotion>, } /// Persistent state that is used to run the [`App`] according to the current /// [`UpdateMode`]. struct WinitAppRunnerState { /// Current active state of the app. active: ActiveState, /// Is `true` if a new [`WindowEvent`] has been received since the last update. window_event_received: bool, /// Is `true` if the app has requested a redraw since the last update. redraw_requested: bool, /// Is `true` if enough time has elapsed since `last_update` to run another update. wait_elapsed: bool, /// The time the last update started. last_update: Instant, /// The time the next update is scheduled to start. scheduled_update: Option, } #[derive(PartialEq, Eq)] enum ActiveState { NotYetStarted, Active, Suspended, WillSuspend, } impl ActiveState { #[inline] fn should_run(&self) -> bool { match self { ActiveState::NotYetStarted | ActiveState::Suspended => false, ActiveState::Active | ActiveState::WillSuspend => true, } } } impl Default for WinitAppRunnerState { fn default() -> Self { Self { active: ActiveState::NotYetStarted, window_event_received: false, redraw_requested: false, wait_elapsed: false, last_update: Instant::now(), scheduled_update: None, } } } /// The default [`App::runner`] for the [`WinitPlugin`] plugin. /// /// Overriding the app's [runner](bevy_app::App::runner) while using `WinitPlugin` will bypass the /// `EventLoop`. pub fn winit_runner(mut app: App) { if app.plugins_state() == PluginsState::Ready { app.finish(); app.cleanup(); } let event_loop = app .world .remove_non_send_resource::>() .unwrap(); app.world .insert_non_send_resource(event_loop.create_proxy()); let mut runner_state = WinitAppRunnerState::default(); // prepare structures to access data in the world let mut app_exit_event_reader = ManualEventReader::::default(); let mut redraw_event_reader = ManualEventReader::::default(); let mut focused_windows_state: SystemState<(Res, Query<&Window>)> = SystemState::new(&mut app.world); let mut event_writer_system_state: SystemState<( WindowAndInputEventWriters, NonSend, Query<(&mut Window, &mut CachedWindow)>, NonSend, )> = SystemState::new(&mut app.world); let mut create_window_system_state: SystemState<( Commands, Query<(Entity, &mut Window), Added>, EventWriter, NonSendMut, NonSendMut, ResMut, ResMut, )> = SystemState::from_world(&mut app.world); // setup up the event loop let event_handler = move |event: Event<()>, event_loop: &EventLoopWindowTarget<()>| { #[cfg(feature = "trace")] let _span = bevy_utils::tracing::info_span!("winit event_handler").entered(); if app.plugins_state() != PluginsState::Cleaned { if app.plugins_state() != PluginsState::Ready { #[cfg(not(target_arch = "wasm32"))] tick_global_task_pools_on_main_thread(); } else { app.finish(); app.cleanup(); } if let Some(app_exit_events) = app.world.get_resource::>() { if app_exit_event_reader.read(app_exit_events).last().is_some() { event_loop.exit(); return; } } } match event { Event::NewEvents(start_cause) => match start_cause { StartCause::Init => { #[cfg(any(target_os = "ios", target_os = "macos"))] { let ( commands, mut windows, event_writer, winit_windows, adapters, handlers, accessibility_requested, ) = create_window_system_state.get_mut(&mut app.world); create_windows( event_loop, commands, windows.iter_mut(), event_writer, winit_windows, adapters, handlers, accessibility_requested, ); create_window_system_state.apply(&mut app.world); } } _ => { if let Some(t) = runner_state.scheduled_update { let now = Instant::now(); let remaining = t.checked_duration_since(now).unwrap_or(Duration::ZERO); runner_state.wait_elapsed = remaining.is_zero(); } } }, Event::WindowEvent { event, window_id, .. } => { let (mut event_writers, winit_windows, mut windows, access_kit_adapters) = event_writer_system_state.get_mut(&mut app.world); let Some(window_entity) = winit_windows.get_window_entity(window_id) else { warn!( "Skipped event {:?} for unknown winit Window Id {:?}", event, window_id ); return; }; let Ok((mut window, mut cache)) = windows.get_mut(window_entity) else { warn!( "Window {:?} is missing `Window` component, skipping event {:?}", window_entity, event ); return; }; // Allow AccessKit to respond to `WindowEvent`s before they reach // the engine. if let Some(adapter) = access_kit_adapters.get(&window_entity) { if let Some(window) = winit_windows.get_window(window_entity) { adapter.process_event(window, &event); } } runner_state.window_event_received = true; match event { WindowEvent::Resized(size) => { react_to_resize(&mut window, size, &mut event_writers, window_entity); } WindowEvent::CloseRequested => { event_writers .window_close_requested .send(WindowCloseRequested { window: window_entity, }); } WindowEvent::KeyboardInput { ref event, .. } => { if event.state.is_pressed() { if let Some(char) = &event.text { event_writers.character_input.send(ReceivedCharacter { window: window_entity, char: char.clone(), }); } } let keyboard_event = converters::convert_keyboard_input(event, window_entity); event_writers.keyboard_input.send(keyboard_event); } WindowEvent::CursorMoved { position, .. } => { let physical_position = DVec2::new(position.x, position.y); window.set_physical_cursor_position(Some(physical_position)); event_writers.cursor_moved.send(CursorMoved { window: window_entity, position: (physical_position / window.resolution.scale_factor() as f64) .as_vec2(), }); } WindowEvent::CursorEntered { .. } => { event_writers.cursor_entered.send(CursorEntered { window: window_entity, }); } WindowEvent::CursorLeft { .. } => { window.set_physical_cursor_position(None); event_writers.cursor_left.send(CursorLeft { window: window_entity, }); } WindowEvent::MouseInput { state, button, .. } => { event_writers.mouse_button_input.send(MouseButtonInput { button: converters::convert_mouse_button(button), state: converters::convert_element_state(state), window: window_entity, }); } WindowEvent::TouchpadMagnify { delta, .. } => { event_writers .touchpad_magnify_input .send(TouchpadMagnify(delta as f32)); } WindowEvent::TouchpadRotate { delta, .. } => { event_writers .touchpad_rotate_input .send(TouchpadRotate(delta)); } WindowEvent::MouseWheel { delta, .. } => match delta { event::MouseScrollDelta::LineDelta(x, y) => { event_writers.mouse_wheel_input.send(MouseWheel { unit: MouseScrollUnit::Line, x, y, window: window_entity, }); } event::MouseScrollDelta::PixelDelta(p) => { event_writers.mouse_wheel_input.send(MouseWheel { unit: MouseScrollUnit::Pixel, x: p.x as f32, y: p.y as f32, window: window_entity, }); } }, WindowEvent::Touch(touch) => { let location = touch .location .to_logical(window.resolution.scale_factor() as f64); event_writers .touch_input .send(converters::convert_touch_input(touch, location)); } WindowEvent::ScaleFactorChanged { scale_factor, mut inner_size_writer, } => { event_writers.window_backend_scale_factor_changed.send( WindowBackendScaleFactorChanged { window: window_entity, scale_factor, }, ); let prior_factor = window.resolution.scale_factor(); window.resolution.set_scale_factor(scale_factor as f32); let new_factor = window.resolution.scale_factor(); let mut new_inner_size = winit::dpi::PhysicalSize::new( window.physical_width(), window.physical_height(), ); if let Some(forced_factor) = window.resolution.scale_factor_override() { // This window is overriding the OS-suggested DPI, so its physical size // should be set based on the overriding value. Its logical size already // incorporates any resize constraints. let maybe_new_inner_size = winit::dpi::LogicalSize::new(window.width(), window.height()) .to_physical::(forced_factor as f64); if let Err(err) = inner_size_writer.request_inner_size(new_inner_size) { warn!("Winit Failed to resize the window: {err}"); } else { new_inner_size = maybe_new_inner_size; } } else if approx::relative_ne!(new_factor, prior_factor) { event_writers.window_scale_factor_changed.send( WindowScaleFactorChanged { window: window_entity, scale_factor, }, ); } let new_logical_width = new_inner_size.width as f32 / new_factor; let new_logical_height = new_inner_size.height as f32 / new_factor; if approx::relative_ne!(window.width(), new_logical_width) || approx::relative_ne!(window.height(), new_logical_height) { event_writers.window_resized.send(WindowResized { window: window_entity, width: new_logical_width, height: new_logical_height, }); } window .resolution .set_physical_resolution(new_inner_size.width, new_inner_size.height); } WindowEvent::Focused(focused) => { window.focused = focused; event_writers.window_focused.send(WindowFocused { window: window_entity, focused, }); } WindowEvent::Occluded(occluded) => { event_writers.window_occluded.send(WindowOccluded { window: window_entity, occluded, }); } WindowEvent::DroppedFile(path_buf) => { event_writers .file_drag_and_drop .send(FileDragAndDrop::DroppedFile { window: window_entity, path_buf, }); } WindowEvent::HoveredFile(path_buf) => { event_writers .file_drag_and_drop .send(FileDragAndDrop::HoveredFile { window: window_entity, path_buf, }); } WindowEvent::HoveredFileCancelled => { event_writers.file_drag_and_drop.send( FileDragAndDrop::HoveredFileCanceled { window: window_entity, }, ); } WindowEvent::Moved(position) => { let position = ivec2(position.x, position.y); window.position.set(position); event_writers.window_moved.send(WindowMoved { entity: window_entity, position, }); } WindowEvent::Ime(event) => match event { event::Ime::Preedit(value, cursor) => { event_writers.ime_input.send(Ime::Preedit { window: window_entity, value, cursor, }); } event::Ime::Commit(value) => { event_writers.ime_input.send(Ime::Commit { window: window_entity, value, }); } event::Ime::Enabled => { event_writers.ime_input.send(Ime::Enabled { window: window_entity, }); } event::Ime::Disabled => { event_writers.ime_input.send(Ime::Disabled { window: window_entity, }); } }, WindowEvent::ThemeChanged(theme) => { event_writers.window_theme_changed.send(WindowThemeChanged { window: window_entity, theme: convert_winit_theme(theme), }); } WindowEvent::Destroyed => { event_writers.window_destroyed.send(WindowDestroyed { window: window_entity, }); } _ => {} } if window.is_changed() { cache.window = window.clone(); } } Event::DeviceEvent { event: DeviceEvent::MouseMotion { delta: (x, y) }, .. } => { let (mut event_writers, ..) = event_writer_system_state.get_mut(&mut app.world); event_writers.mouse_motion.send(MouseMotion { delta: Vec2::new(x as f32, y as f32), }); } Event::Suspended => { let (mut event_writers, ..) = event_writer_system_state.get_mut(&mut app.world); event_writers.lifetime.send(ApplicationLifetime::Suspended); // Mark the state as `WillSuspend`. This will let the schedule run one last time // before actually suspending to let the application react runner_state.active = ActiveState::WillSuspend; } Event::Resumed => { let (mut event_writers, ..) = event_writer_system_state.get_mut(&mut app.world); match runner_state.active { ActiveState::NotYetStarted => { event_writers.lifetime.send(ApplicationLifetime::Started); } _ => { event_writers.lifetime.send(ApplicationLifetime::Resumed); } } runner_state.active = ActiveState::Active; #[cfg(target_os = "android")] { // Get windows that are cached but without raw handles. Those window were already created, but got their // handle wrapper removed when the app was suspended. let mut query = app .world .query_filtered::<(Entity, &Window), (With, Without)>(); if let Ok((entity, window)) = query.get_single(&app.world) { use raw_window_handle::{HasRawDisplayHandle, HasRawWindowHandle}; let window = window.clone(); let ( _, _, _, mut winit_windows, mut adapters, mut handlers, accessibility_requested, ) = create_window_system_state.get_mut(&mut app.world); let winit_window = winit_windows.create_window( event_loop, entity, &window, &mut adapters, &mut handlers, &accessibility_requested, ); let wrapper = RawHandleWrapper { window_handle: winit_window.raw_window_handle(), display_handle: winit_window.raw_display_handle(), }; app.world.entity_mut(entity).insert(wrapper); } event_loop.set_control_flow(ControlFlow::Poll); } } Event::AboutToWait => { if runner_state.active.should_run() { if runner_state.active == ActiveState::WillSuspend { runner_state.active = ActiveState::Suspended; #[cfg(target_os = "android")] { // Remove the `RawHandleWrapper` from the primary window. // This will trigger the surface destruction. let mut query = app.world.query_filtered::>(); let entity = query.single(&app.world); app.world.entity_mut(entity).remove::(); event_loop.set_control_flow(ControlFlow::Wait); } } let (config, windows) = focused_windows_state.get(&app.world); let focused = windows.iter().any(|window| window.focused); let should_update = match config.update_mode(focused) { UpdateMode::Continuous | UpdateMode::Reactive { .. } => { // `Reactive`: In order for `event_handler` to have been called, either // we received a window or raw input event, the `wait` elapsed, or a // redraw was requested (by the app or the OS). There are no other // conditions, so we can just return `true` here. true } UpdateMode::ReactiveLowPower { .. } => { runner_state.wait_elapsed || runner_state.redraw_requested || runner_state.window_event_received } }; if app.plugins_state() == PluginsState::Cleaned && should_update { // reset these on each update runner_state.wait_elapsed = false; runner_state.window_event_received = false; runner_state.redraw_requested = false; runner_state.last_update = Instant::now(); app.update(); // decide when to run the next update let (config, windows) = focused_windows_state.get(&app.world); let focused = windows.iter().any(|window| window.focused); match config.update_mode(focused) { UpdateMode::Continuous => { event_loop.set_control_flow(ControlFlow::Poll); } UpdateMode::Reactive { wait } | UpdateMode::ReactiveLowPower { wait } => { if let Some(next) = runner_state.last_update.checked_add(*wait) { runner_state.scheduled_update = Some(next); event_loop.set_control_flow(ControlFlow::WaitUntil(next)); } else { runner_state.scheduled_update = None; event_loop.set_control_flow(ControlFlow::Wait); } } } if let Some(app_redraw_events) = app.world.get_resource::>() { if redraw_event_reader.read(app_redraw_events).last().is_some() { runner_state.redraw_requested = true; event_loop.set_control_flow(ControlFlow::Poll); } } if let Some(app_exit_events) = app.world.get_resource::>() { if app_exit_event_reader.read(app_exit_events).last().is_some() { event_loop.exit(); } } } // create any new windows // (even if app did not update, some may have been created by plugin setup) let ( commands, mut windows, event_writer, winit_windows, adapters, handlers, accessibility_requested, ) = create_window_system_state.get_mut(&mut app.world); create_windows( event_loop, commands, windows.iter_mut(), event_writer, winit_windows, adapters, handlers, accessibility_requested, ); create_window_system_state.apply(&mut app.world); } } _ => (), } }; trace!("starting winit event loop"); if let Err(err) = event_loop.run(event_handler) { error!("winit event loop returned an error: {err}"); } } fn react_to_resize( window: &mut Mut<'_, Window>, size: winit::dpi::PhysicalSize, event_writers: &mut WindowAndInputEventWriters<'_>, window_entity: Entity, ) { window .resolution .set_physical_resolution(size.width, size.height); event_writers.window_resized.send(WindowResized { window: window_entity, width: window.width(), height: window.height(), }); }