Add API for raw mouse motion

crates/eframe/src/native/glow_integration.rs

@@ -446,6 +446,33 @@ impl WinitApp for GlowWinitApp {
                 }
             }
 
+            winit::event::Event::DeviceEvent {
+                device_id: _,
+                event: winit::event::DeviceEvent::MouseMotion { delta },
+            } => {
+                if let Some(running) = &mut self.running {
+                    let mut glutin = running.glutin.borrow_mut();
+                    if let Some(viewport) = glutin
+                        .focused_viewport
+                        .and_then(|viewport| glutin.viewports.get_mut(&viewport))
+                    {
+                        if let Some(egui_winit) = viewport.egui_winit.as_mut() {
+                            egui_winit.on_mouse_motion(*delta);
+                        }
+
+                        if let Some(window) = viewport.window.as_ref() {
+                            EventResult::RepaintNext(window.id())
+                        } else {
+                            EventResult::Wait
+                        }
+                    } else {
+                        EventResult::Wait
+                    }
+                } else {
+                    EventResult::Wait
+                }
+            }
+
             #[cfg(feature = "accesskit")]
             winit::event::Event::UserEvent(UserEvent::AccessKitActionRequest(
                 accesskit_winit::ActionRequestEvent { request, window_id },

crates/eframe/src/native/wgpu_integration.rs

@@ -456,6 +456,33 @@ impl WinitApp for WgpuWinitApp {
                 }
             }
 
+            winit::event::Event::DeviceEvent {
+                device_id: _,
+                event: winit::event::DeviceEvent::MouseMotion { delta },
+            } => {
+                if let Some(running) = &mut self.running {
+                    let mut shared = running.shared.borrow_mut();
+                    if let Some(viewport) = shared
+                        .focused_viewport
+                        .and_then(|viewport| shared.viewports.get_mut(&viewport))
+                    {
+                        if let Some(egui_winit) = viewport.egui_winit.as_mut() {
+                            egui_winit.on_mouse_motion(*delta);
+                        }
+
+                        if let Some(window) = viewport.window.as_ref() {
+                            EventResult::RepaintNext(window.id())
+                        } else {
+                            EventResult::Wait
+                        }
+                    } else {
+                        EventResult::Wait
+                    }
+                } else {
+                    EventResult::Wait
+                }
+            }
+
             #[cfg(feature = "accesskit")]
             winit::event::Event::UserEvent(UserEvent::AccessKitActionRequest(
                 accesskit_winit::ActionRequestEvent { request, window_id },

crates/egui-winit/src/lib.rs

@@ -475,6 +475,13 @@ impl State {
         }
     }
 
+    pub fn on_mouse_motion(&mut self, delta: (f64, f64)) {
+        self.egui_input.events.push(egui::Event::MouseMoved(Vec2 {
+            x: delta.0 as f32,
+            y: delta.1 as f32,
+        }));
+    }
+
     /// Call this when there is a new [`accesskit::ActionRequest`].
     ///
     /// The result can be found in [`Self::egui_input`] and be extracted with [`Self::take_egui_input`].

crates/egui/src/data/input.rs

@@ -396,6 +396,12 @@ pub enum Event {
     /// The mouse or touch moved to a new place.
     PointerMoved(Pos2),
 
+    /// The mouse moved, the units are unspecified.
+    /// Represents the actual movement of the mouse, without acceleration or clamped by screen edges.
+    /// `PointerMoved` and `MouseMoved` can be sent at the same time.
+    /// This event is optional. If the integration can not determine unfiltered motion it should not send this event.
+    MouseMoved(Vec2),
+
     /// A mouse button was pressed or released (or a touch started or stopped).
     PointerButton {
         /// Where is the pointer?

crates/egui/src/input_state.rs

@@ -617,6 +617,11 @@ pub struct PointerState {
     /// How much the pointer moved compared to last frame, in points.
     delta: Vec2,
 
+    /// How much the mouse moved since the last frame, in unspecified units.
+    /// Represents the actual movement of the mouse, without acceleration or clamped by screen edges.
+    /// May be unavailable on some integrations.
+    motion: Option<Vec2>,
+
     /// Current velocity of pointer.
     velocity: Vec2,
 
@@ -664,6 +669,7 @@ impl Default for PointerState {
             latest_pos: None,
             interact_pos: None,
             delta: Vec2::ZERO,
+            motion: None,
             velocity: Vec2::ZERO,
             pos_history: History::new(0..1000, 0.1),
             down: Default::default(),
@@ -690,6 +696,9 @@ impl PointerState {
 
         let old_pos = self.latest_pos;
         self.interact_pos = self.latest_pos;
+        if self.motion.is_some() {
+            self.motion = Some(Vec2::ZERO);
+        }
 
         for event in &new.events {
             match event {
@@ -775,6 +784,7 @@ impl PointerState {
                     self.latest_pos = None;
                     // NOTE: we do NOT clear `self.interact_pos` here. It will be cleared next frame.
                 }
+                Event::MouseMoved(delta) => *self.motion.get_or_insert(Vec2::ZERO) += *delta,
                 _ => {}
             }
         }
@@ -819,6 +829,14 @@ impl PointerState {
         self.delta
     }
 
+    /// How much the mouse moved since the last frame, in unspecified units.
+    /// Represents the actual movement of the mouse, without acceleration or clamped by screen edges.
+    /// May be unavailable on some integrations.
+    #[inline(always)]
+    pub fn motion(&self) -> Option<Vec2> {
+        self.motion
+    }
+
     /// Current velocity of pointer.
     #[inline(always)]
     pub fn velocity(&self) -> Vec2 {
@@ -1139,6 +1157,7 @@ impl PointerState {
             latest_pos,
             interact_pos,
             delta,
+            motion,
             velocity,
             pos_history: _,
             down,
@@ -1155,6 +1174,7 @@ impl PointerState {
         ui.label(format!("latest_pos: {latest_pos:?}"));
         ui.label(format!("interact_pos: {interact_pos:?}"));
         ui.label(format!("delta: {delta:?}"));
+        ui.label(format!("motion: {motion:?}"));
         ui.label(format!(
             "velocity: [{:3.0} {:3.0}] points/sec",
             velocity.x, velocity.y

crates/egui/src/response.rs

@@ -336,6 +336,20 @@ impl Response {
         }
     }
 
+    /// If dragged, how far did the mouse move?
+    /// This will use raw mouse movement if provided by the integration, otherwise will fall back to [`Response::drag_delta`]
+    /// Raw mouse movement is unaccelerated and unclamped by screen boundaries, and does not relate to any position on the screen.
+    /// This may be useful in certain situations such as draggable values and 3D cameras, where screen position does not matter.
+    #[inline]
+    pub fn drag_motion(&self) -> Vec2 {
+        if self.dragged() {
+            self.ctx
+                .input(|i| i.pointer.motion().unwrap_or(i.pointer.delta()))
+        } else {
+            Vec2::ZERO
+        }
+    }
+
     /// If the user started dragging this widget this frame, store the payload for drag-and-drop.
     #[doc(alias = "drag and drop")]
     pub fn dnd_set_drag_payload<Payload: Any + Send + Sync>(&self, payload: Payload) {

crates/egui_demo_app/src/apps/custom3d_glow.rs

@@ -55,7 +55,7 @@ impl Custom3d {
         let (rect, response) =
             ui.allocate_exact_size(egui::Vec2::splat(300.0), egui::Sense::drag());
 
-        self.angle += response.drag_delta().x * 0.01;
+        self.angle += response.drag_motion().x * 0.01;
 
         // Clone locals so we can move them into the paint callback:
         let angle = self.angle;

crates/egui_demo_app/src/apps/custom3d_wgpu.rs

@@ -173,7 +173,7 @@ impl Custom3d {
         let (rect, response) =
             ui.allocate_exact_size(egui::Vec2::splat(300.0), egui::Sense::drag());
 
-        self.angle += response.drag_delta().x * 0.01;
+        self.angle += response.drag_motion().x * 0.01;
         ui.painter().add(egui_wgpu::Callback::new_paint_callback(
             rect,
             CustomTriangleCallback { angle: self.angle },

examples/custom_3d_glow/src/main.rs

@@ -69,7 +69,7 @@ impl MyApp {
         let (rect, response) =
             ui.allocate_exact_size(egui::Vec2::splat(300.0), egui::Sense::drag());
 
-        self.angle += response.drag_delta().x * 0.01;
+        self.angle += response.drag_motion().x * 0.01;
 
         // Clone locals so we can move them into the paint callback:
         let angle = self.angle;