Async mouse input on windows

osu.Framework/Platform/SDL3/SDL3Window.cs

@@ -287,12 +287,13 @@ protected void RunFrame()
         /// As per SDL's recommendation, application events should always be handled via the event filter.
         /// See: https://wiki.libsdl.org/SDL3/SDL_EventType#android_ios_and_winrt_events
         /// </remarks>
-        protected virtual void HandleEventFromFilter(SDL_Event evt)
+        /// <returns>A <c>bool</c> denoting whether to keep the event. <c>false</c> will drop the event.</returns>
+        protected virtual bool HandleEventFromFilter(SDL_Event e)
         {
-            switch (evt.Type)
+            switch (e.Type)
             {
                 case SDL_EventType.SDL_EVENT_TERMINATING:
-                    handleQuitEvent(evt.quit);
+                    handleQuitEvent(e.quit);
                     break;
 
                 case SDL_EventType.SDL_EVENT_DID_ENTER_BACKGROUND:
@@ -306,7 +307,22 @@ protected virtual void HandleEventFromFilter(SDL_Event evt)
                 case SDL_EventType.SDL_EVENT_LOW_MEMORY:
                     LowOnMemory?.Invoke();
                     break;
+
+                case SDL_EventType.SDL_EVENT_MOUSE_MOTION:
+                    handleMouseMotionEvent(e.motion);
+                    return false;
+
+                case SDL_EventType.SDL_EVENT_MOUSE_BUTTON_DOWN:
+                case SDL_EventType.SDL_EVENT_MOUSE_BUTTON_UP:
+                    handleMouseButtonEvent(e.button);
+                    return false;
+
+                case SDL_EventType.SDL_EVENT_MOUSE_WHEEL:
+                    handleMouseWheelEvent(e.wheel);
+                    return false;
             }
+
+            return true;
         }
 
         protected void HandleEventFromWatch(SDL_Event evt)
@@ -327,7 +343,7 @@ private static SDLBool eventFilter(IntPtr userdata, SDL_Event* eventPtr)
         {
             var handle = new ObjectHandle<SDL3Window>(userdata);
             if (handle.GetTarget(out SDL3Window window))
-                window.HandleEventFromFilter(*eventPtr);
+                return window.HandleEventFromFilter(*eventPtr);
 
             return true;
         }
@@ -514,19 +530,6 @@ protected virtual void HandleEvent(SDL_Event e)
                     handleKeymapChangedEvent();
                     break;
 
-                case SDL_EventType.SDL_EVENT_MOUSE_MOTION:
-                    handleMouseMotionEvent(e.motion);
-                    break;
-
-                case SDL_EventType.SDL_EVENT_MOUSE_BUTTON_DOWN:
-                case SDL_EventType.SDL_EVENT_MOUSE_BUTTON_UP:
-                    handleMouseButtonEvent(e.button);
-                    break;
-
-                case SDL_EventType.SDL_EVENT_MOUSE_WHEEL:
-                    handleMouseWheelEvent(e.wheel);
-                    break;
-
                 case SDL_EventType.SDL_EVENT_JOYSTICK_AXIS_MOTION:
                     handleJoyAxisEvent(e.jaxis);
                     break;

osu.Framework/Platform/SDL3/SDL3Window_Input.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Drawing;
+using System.Threading;
 using osu.Framework.Bindables;
 using osu.Framework.Configuration;
 using osu.Framework.Extensions.EnumExtensions;
@@ -151,11 +152,12 @@ private void enqueueJoystickButtonInput(JoystickButton button, bool isPressed)
 
         private PointF previousPolledPoint = PointF.Empty;
 
-        private SDL_MouseButtonFlags pressedButtons;
+        private volatile uint pressedButtons;
 
         private void pollMouse()
         {
             float x, y;
+            var pressed = (SDL_MouseButtonFlags)pressedButtons;
             SDL_MouseButtonFlags globalButtons = SDL_GetGlobalMouseState(&x, &y);
 
             if (previousPolledPoint.X != x || previousPolledPoint.Y != y)
@@ -170,18 +172,18 @@ private void pollMouse()
             }
 
             // a button should be released if it was pressed and its current global state differs (its bit in globalButtons is set to 0)
-            SDL_MouseButtonFlags buttonsToRelease = pressedButtons & (globalButtons ^ pressedButtons);
+            SDL_MouseButtonFlags buttonsToRelease = pressed & (globalButtons ^ pressed);
 
             // the outer if just optimises for the common case that there are no buttons to release.
             if (buttonsToRelease != 0)
             {
+                Interlocked.And(ref pressedButtons, (uint)~buttonsToRelease);
+
                 if (buttonsToRelease.HasFlagFast(SDL_MouseButtonFlags.SDL_BUTTON_LMASK)) MouseUp?.Invoke(MouseButton.Left);
                 if (buttonsToRelease.HasFlagFast(SDL_MouseButtonFlags.SDL_BUTTON_MMASK)) MouseUp?.Invoke(MouseButton.Middle);
                 if (buttonsToRelease.HasFlagFast(SDL_MouseButtonFlags.SDL_BUTTON_RMASK)) MouseUp?.Invoke(MouseButton.Right);
                 if (buttonsToRelease.HasFlagFast(SDL_MouseButtonFlags.SDL_BUTTON_X1MASK)) MouseUp?.Invoke(MouseButton.Button1);
                 if (buttonsToRelease.HasFlagFast(SDL_MouseButtonFlags.SDL_BUTTON_X2MASK)) MouseUp?.Invoke(MouseButton.Button2);
-
-                pressedButtons &= ~buttonsToRelease;
             }
         }
 
@@ -440,10 +442,17 @@ private void handleMouseWheelEvent(SDL_MouseWheelEvent evtWheel)
         {
             bool isPrecise(float f) => f % 1 != 0;
 
+            bool precise;
+
             if (isPrecise(evtWheel.x) || isPrecise(evtWheel.y))
+            {
+                precise = true;
                 lastPreciseScroll = evtWheel.timestamp;
-
-            bool precise = evtWheel.timestamp < lastPreciseScroll + precise_scroll_debounce;
+            }
+            else
+            {
+                precise = evtWheel.timestamp < lastPreciseScroll + precise_scroll_debounce;
+            }
 
             // SDL reports horizontal scroll opposite of what framework expects (in non-"natural" mode, scrolling to the right gives positive deltas while we want negative).
             TriggerMouseWheel(new Vector2(-evtWheel.x, evtWheel.y), precise);
@@ -458,12 +467,12 @@ private void handleMouseButtonEvent(SDL_MouseButtonEvent evtButton)
             switch (evtButton.type)
             {
                 case SDL_EventType.SDL_EVENT_MOUSE_BUTTON_DOWN:
-                    pressedButtons |= mask;
                     MouseDown?.Invoke(button);
+                    Interlocked.Or(ref pressedButtons, (uint)mask);
                     break;
 
                 case SDL_EventType.SDL_EVENT_MOUSE_BUTTON_UP:
-                    pressedButtons &= ~mask;
+                    Interlocked.And(ref pressedButtons, (uint)~mask);
                     MouseUp?.Invoke(button);
                     break;
             }

osu.Framework/Platform/Windows/SDL3WindowsWindow.cs

@@ -60,16 +60,16 @@ public override void Create()
                 Native.Input.SetWindowFeedbackSetting(WindowHandle, feedbackType, false);
         }
 
-        protected override void HandleEventFromFilter(SDL_Event evt)
+        protected override bool HandleEventFromFilter(SDL_Event e)
         {
-            switch (evt.Type)
+            switch (e.Type)
             {
                 case SDL_EventType.SDL_EVENT_WINDOW_FOCUS_LOST:
                     warpCursorFromFocusLoss();
                     break;
             }
 
-            base.HandleEventFromFilter(evt);
+            return base.HandleEventFromFilter(e);
         }
 
         public Vector2? LastMousePosition { get; set; }