Handle winit's WindowEvent::ModifiersChanged

crates/bevy_winit/src/lib.rs

@@ -35,6 +35,11 @@ use bevy_app::{App, AppExit, Last, Plugin, PluginsState};
 use bevy_ecs::event::ManualEventReader;
 use bevy_ecs::prelude::*;
 use bevy_ecs::system::SystemState;
+#[cfg(target_os = "macos")]
+use bevy_input::{
+    keyboard::{Key, KeyCode, KeyboardInput},
+    ButtonState,
+};
 use bevy_input::{
     mouse::{MouseButtonInput, MouseMotion, MouseScrollUnit, MouseWheel},
     touchpad::{TouchpadMagnify, TouchpadRotate},
@@ -53,6 +58,8 @@ use bevy_window::{
 };
 #[cfg(target_os = "android")]
 use bevy_window::{PrimaryWindow, RawHandleWrapper};
+#[cfg(target_os = "macos")]
+use winit::{event::Modifiers, keyboard::ModifiersKeyState};
 
 #[cfg(target_os = "android")]
 pub use winit::platform::android::activity as android_activity;
@@ -198,6 +205,9 @@ struct WinitAppRunnerState {
     wait_elapsed: bool,
     /// Number of "forced" updates to trigger on application start
     startup_forced_updates: u32,
+    #[cfg(target_os = "macos")]
+    /// State of the keyboard modifiers.
+    keyboard_modifiers: Modifiers,
 }
 
 impl WinitAppRunnerState {
@@ -218,6 +228,8 @@ impl Default for WinitAppRunnerState {
             wait_elapsed: false,
             // 3 seems to be enough, 5 is a safe margin
             startup_forced_updates: 5,
+            #[cfg(target_os = "macos")]
+            keyboard_modifiers: Modifiers::default(),
         }
     }
 }
@@ -578,7 +590,67 @@ fn handle_winit_event(
                             winit_events.send(ReceivedCharacter { window, char });
                         }
                     }
-                    winit_events.send(converters::convert_keyboard_input(event, window));
+
+                    let keyboard_event = converters::convert_keyboard_input(event, window);
+
+                    #[cfg(not(target_os = "macos"))]
+                    winit_events.send(keyboard_event);
+
+                    #[cfg(target_os = "macos")]
+                    {
+                        // Send a `KeyboardInput` event if this key is not a modifier.
+                        let mod_keys = [Key::Alt, Key::Control, Key::Shift, Key::Super];
+                        if !mod_keys.contains(&keyboard_event.logical_key) {
+                            winit_events.send(keyboard_event);
+                        }
+                    }
+                }
+                #[cfg(target_os = "macos")]
+                WindowEvent::ModifiersChanged(mods) => {
+                    // Check if the state of any modifier key has changed.
+                    let checks: [(KeyCode, Key, &mut dyn FnMut(Modifiers) -> ModifiersKeyState);
+                        8] = [
+                        (KeyCode::SuperLeft, Key::Super, &mut |mods| {
+                            mods.lsuper_state()
+                        }),
+                        (KeyCode::SuperRight, Key::Super, &mut |mods| {
+                            mods.rsuper_state()
+                        }),
+                        (KeyCode::ShiftLeft, Key::Shift, &mut |mods| {
+                            mods.lshift_state()
+                        }),
+                        (KeyCode::ShiftRight, Key::Shift, &mut |mods| {
+                            mods.rshift_state()
+                        }),
+                        (KeyCode::AltLeft, Key::Alt, &mut |mods| mods.lalt_state()),
+                        (KeyCode::AltRight, Key::Alt, &mut |mods| mods.ralt_state()),
+                        (KeyCode::ControlLeft, Key::Control, &mut |mods| {
+                            mods.lcontrol_state()
+                        }),
+                        (KeyCode::ControlRight, Key::Control, &mut |mods| {
+                            mods.rcontrol_state()
+                        }),
+                    ];
+
+                    for (key_code, key, f) in checks {
+                        let new = f(mods);
+                        let old = f(runner_state.keyboard_modifiers);
+
+                        if new != old {
+                            winit_events.send(KeyboardInput {
+                                key_code,
+                                logical_key: key,
+                                state: if new == ModifiersKeyState::Pressed {
+                                    ButtonState::Pressed
+                                } else {
+                                    ButtonState::Released
+                                },
+                                window,
+                            });
+                        }
+                    }
+
+                    runner_state.keyboard_modifiers = mods;
                 }
                 WindowEvent::CursorMoved { position, .. } => {
                     let physical_position = DVec2::new(position.x, position.y);