Handle individual windows closing properly

crates/bevy_window/Cargo.toml

@@ -10,6 +10,7 @@ keywords = ["bevy"]
 
 [dependencies]
 # bevy
+bevy_ecs = { path = "../bevy_ecs", version = "0.5.0" }
 bevy_app = { path = "../bevy_app", version = "0.5.0" }
 bevy_math = { path = "../bevy_math", version = "0.5.0" }
 bevy_utils = { path = "../bevy_utils", version = "0.5.0" }

crates/bevy_window/src/event.rs

@@ -28,6 +28,9 @@ pub struct WindowCreated {
 
 /// An event that is sent whenever a close was requested for a window. For example: when the "close"
 /// button is pressed on a window.
+///
+/// By default, these events are handled by closing the corresponding [`crate::Window`].
+/// To disable this behaviour, set `close_when_requested` on the [`crate::WindowPlugin`] to `false`
 #[derive(Debug, Clone)]
 pub struct WindowCloseRequested {
     pub id: WindowId,
@@ -36,7 +39,10 @@ pub struct WindowCloseRequested {
 /// An event that is sent whenever a window is closed.
 /// This will only be sent in response to the [`Window::close`] method.
 ///
-/// [`Window::close`]: `crate::window::Window::close`
+/// By default, when no windows are open, the app will close.
+/// To disable this behaviour, set `exit_on_all_closed` on the [`crate::WindowPlugin`] to `false`
+///
+/// [`Window::close`]: `crate::Window::close`
 #[derive(Debug, Clone)]
 pub struct WindowClosed {
     pub id: WindowId,

crates/bevy_window/src/lib.rs

@@ -19,15 +19,20 @@ pub mod prelude {
 use bevy_app::{prelude::*, Events};
 
 pub struct WindowPlugin {
+    /// Whether to add a default window based on the [`WindowDescriptor`] resource
     pub add_primary_window: bool,
-    pub exit_on_close: bool,
+    /// Whether to close the app when there are no open windows
+    pub exit_on_all_closed: bool,
+    /// Whether to close windows when they are requested to be closed (i.e. when the close button is pressed)
+    pub close_when_requested: bool,
 }
 
 impl Default for WindowPlugin {
     fn default() -> Self {
         WindowPlugin {
             add_primary_window: true,
-            exit_on_close: true,
+            close_when_requested: true,
+            exit_on_all_closed: true,
         }
     }
 }
@@ -66,8 +71,11 @@ impl Plugin for WindowPlugin {
             });
         }
 
-        if self.exit_on_close {
-            app.add_system(exit_on_window_close_system);
+        if self.exit_on_all_closed {
+            app.add_system(exit_on_all_closed);
+        }
+        if self.close_when_requested {
+            app.add_system(close_when_requested);
         }
     }
 }

crates/bevy_window/src/system.rs

@@ -1,11 +1,18 @@
-use crate::WindowCloseRequested;
+use crate::{Window, WindowCloseRequested, Windows};
 use bevy_app::{AppExit, EventReader, EventWriter};
+use bevy_ecs::prelude::{Res, ResMut};
 
-pub fn exit_on_window_close_system(
-    mut app_exit_events: EventWriter<AppExit>,
-    mut window_close_requested_events: EventReader<WindowCloseRequested>,
-) {
-    if window_close_requested_events.iter().next().is_some() {
+pub fn exit_on_all_closed(mut app_exit_events: EventWriter<AppExit>, windows: Res<Windows>) {
+    if windows.iter().count() == 0 {
         app_exit_events.send(AppExit);
     }
 }
+
+pub fn close_when_requested(
+    mut windows: ResMut<Windows>,
+    mut closed: EventReader<WindowCloseRequested>,
+) {
+    for event in closed.iter() {
+        windows.get_mut(event.id).map(Window::close);
+    }
+}