Store mouse cursor position in Window (#940)

crates/bevy_window/src/event.rs

@@ -41,6 +41,16 @@ pub struct CursorMoved {
     pub position: Vec2,
 }
 
+#[derive(Debug, Clone)]
+pub struct CursorEntered {
+    pub id: WindowId,
+}
+
+#[derive(Debug, Clone)]
+pub struct CursorLeft {
+    pub id: WindowId,
+}
+
 /// An event that is sent whenever a window receives a character from the OS or underlying system.
 #[derive(Debug, Clone)]
 pub struct ReceivedCharacter {

crates/bevy_window/src/lib.rs

@@ -9,7 +9,10 @@ pub use window::*;
 pub use windows::*;
 
 pub mod prelude {
-    pub use crate::{CursorMoved, ReceivedCharacter, Window, WindowDescriptor, Windows};
+    pub use crate::{
+        CursorEntered, CursorLeft, CursorMoved, ReceivedCharacter, Window, WindowDescriptor,
+        Windows,
+    };
 }
 
 use bevy_app::prelude::*;
@@ -36,6 +39,8 @@ impl Plugin for WindowPlugin {
             .add_event::<WindowCloseRequested>()
             .add_event::<CloseWindow>()
             .add_event::<CursorMoved>()
+            .add_event::<CursorEntered>()
+            .add_event::<CursorLeft>()
             .add_event::<ReceivedCharacter>()
             .init_resource::<Windows>();
 

crates/bevy_window/src/window.rs

@@ -1,3 +1,4 @@
+use bevy_math::Vec2;
 use bevy_utils::Uuid;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
@@ -42,6 +43,7 @@ pub struct Window {
     decorations: bool,
     cursor_visible: bool,
     cursor_locked: bool,
+    cursor_position: Option<Vec2>,
     mode: WindowMode,
     #[cfg(target_arch = "wasm32")]
     pub canvas: Option<String>,
@@ -107,6 +109,7 @@ impl Window {
             decorations: window_descriptor.decorations,
             cursor_visible: window_descriptor.cursor_visible,
             cursor_locked: window_descriptor.cursor_locked,
+            cursor_position: None,
             mode: window_descriptor.mode,
             #[cfg(target_arch = "wasm32")]
             canvas: window_descriptor.canvas.clone(),
@@ -145,13 +148,15 @@ impl Window {
             .push(WindowCommand::SetResolution { width, height });
     }
 
-    #[doc(hidden)]
+    #[allow(missing_docs)]
+    #[inline]
     pub fn update_resolution_from_backend(&mut self, width: u32, height: u32) {
         self.width = width;
         self.height = height;
     }
 
-    #[doc(hidden)]
+    #[allow(missing_docs)]
+    #[inline]
     pub fn update_scale_factor_from_backend(&mut self, scale_factor: f64) {
         self.scale_factor = scale_factor;
     }
@@ -227,11 +232,22 @@ impl Window {
         });
     }
 
+    #[inline]
+    pub fn cursor_position(&self) -> Option<Vec2> {
+        self.cursor_position
+    }
+
     pub fn set_cursor_position(&mut self, x: i32, y: i32) {
         self.command_queue
             .push(WindowCommand::SetCursorPosition { x, y });
     }
 
+    #[allow(missing_docs)]
+    #[inline]
+    pub fn update_cursor_position_from_backend(&mut self, cursor_position: Option<Vec2>) {
+        self.cursor_position = cursor_position;
+    }
+
     #[inline]
     pub fn mode(&self) -> WindowMode {
         self.mode

crates/bevy_winit/src/lib.rs

@@ -14,8 +14,8 @@ use bevy_ecs::{Resources, World};
 use bevy_math::Vec2;
 use bevy_utils::tracing::{error, trace};
 use bevy_window::{
-    CreateWindow, CursorMoved, ReceivedCharacter, Window, WindowCloseRequested, WindowCreated,
-    WindowResized, Windows,
+    CreateWindow, CursorEntered, CursorLeft, CursorMoved, ReceivedCharacter, Window,
+    WindowCloseRequested, WindowCreated, WindowResized, Windows,
 };
 use winit::{
     event::{self, DeviceEvent, Event, WindowEvent},
@@ -224,17 +224,43 @@ pub fn winit_runner(mut app: App) {
                     let mut cursor_moved_events =
                         app.resources.get_mut::<Events<CursorMoved>>().unwrap();
                     let winit_windows = app.resources.get_mut::<WinitWindows>().unwrap();
+                    let mut windows = app.resources.get_mut::<Windows>().unwrap();
                     let window_id = winit_windows.get_window_id(winit_window_id).unwrap();
-                    let window = winit_windows.get_window(window_id).unwrap();
-                    let position = position.to_logical(window.scale_factor());
-                    let inner_size = window.inner_size().to_logical::<f32>(window.scale_factor());
+                    let winit_window = winit_windows.get_window(window_id).unwrap();
+                    let window = windows.get_mut(window_id).unwrap();
+                    let position = position.to_logical(winit_window.scale_factor());
+                    let inner_size = winit_window
+                        .inner_size()
+                        .to_logical::<f32>(winit_window.scale_factor());
+
                     // move origin to bottom left
                     let y_position = inner_size.height - position.y;
+
+                    let position = Vec2::new(position.x, y_position);
+                    window.update_cursor_position_from_backend(Some(position));
+
                     cursor_moved_events.send(CursorMoved {
                         id: window_id,
-                        position: Vec2::new(position.x, y_position),
+                        position,
                     });
                 }
+                WindowEvent::CursorEntered { .. } => {
+                    let mut cursor_entered_events =
+                        app.resources.get_mut::<Events<CursorEntered>>().unwrap();
+                    let winit_windows = app.resources.get_mut::<WinitWindows>().unwrap();
+                    let window_id = winit_windows.get_window_id(winit_window_id).unwrap();
+                    cursor_entered_events.send(CursorEntered { id: window_id });
+                }
+                WindowEvent::CursorLeft { .. } => {
+                    let mut cursor_left_events =
+                        app.resources.get_mut::<Events<CursorLeft>>().unwrap();
+                    let winit_windows = app.resources.get_mut::<WinitWindows>().unwrap();
+                    let mut windows = app.resources.get_mut::<Windows>().unwrap();
+                    let window_id = winit_windows.get_window_id(winit_window_id).unwrap();
+                    let window = windows.get_mut(window_id).unwrap();
+                    window.update_cursor_position_from_backend(None);
+                    cursor_left_events.send(CursorLeft { id: window_id });
+                }
                 WindowEvent::MouseInput { state, button, .. } => {
                     let mut mouse_button_input_events =
                         app.resources.get_mut::<Events<MouseButtonInput>>().unwrap();