Use mouse capture for Win32 instead of our global mouse state hack

app/streaming/input/input.cpp

@@ -30,7 +30,6 @@ SdlInputHandler::SdlInputHandler(StreamingPreferences& prefs, NvComputer*, int s
       m_StreamHeight(streamHeight),
       m_AbsoluteMouseMode(prefs.absoluteMouseMode),
       m_AbsoluteTouchMode(prefs.absoluteTouchMode),
-      m_PendingMouseLeaveButtonUp(0),
       m_LeftButtonReleaseTimer(0),
       m_RightButtonReleaseTimer(0),
       m_DragTimer(0),
@@ -270,13 +269,14 @@ void SdlInputHandler::notifyMouseLeave()
 {
 #ifdef Q_OS_WIN32
     // SDL on Windows doesn't send the mouse button up until the mouse re-enters the window
-    // after leaving it. This breaks some of the Aero snap gestures, so we'll fake it here.
+    // after leaving it. This breaks some of the Aero snap gestures, so we'll capture it to
+    // allow us to receive the mouse button up events later.
     if (m_AbsoluteMouseMode && isCaptureActive()) {
         // NB: Not using SDL_GetGlobalMouseState() because we want our state not the system's
         Uint32 mouseState = SDL_GetMouseState(nullptr, nullptr);
         for (Uint32 button = SDL_BUTTON_LEFT; button <= SDL_BUTTON_X2; button++) {
             if (mouseState & SDL_BUTTON(button)) {
-                m_PendingMouseLeaveButtonUp = button;
+                SDL_CaptureMouse(SDL_TRUE);
                 break;
             }
         }

app/streaming/input/input.h

@@ -7,6 +7,7 @@
 
 #define SDL_CODE_HIDE_CURSOR 1
 #define SDL_CODE_SHOW_CURSOR 2
+#define SDL_CODE_UNCAPTURE_MOUSE 3
 
 struct GamepadState {
     SDL_GameController* controller;
@@ -175,7 +176,6 @@ private:
     int m_StreamHeight;
     bool m_AbsoluteMouseMode;
     bool m_AbsoluteTouchMode;
-    Uint32 m_PendingMouseLeaveButtonUp;
 
     SDL_TouchFingerEvent m_TouchDownEvent[MAX_FINGERS];
     SDL_TimerID m_LeftButtonReleaseTimer;

app/streaming/input/mouse.cpp

@@ -133,8 +133,16 @@ void SdlInputHandler::flushMousePositionUpdate()
             // c) a mouse button is still down from before the cursor left the video region (to allow smooth dragging)
             Uint32 buttonState = SDL_GetMouseState(nullptr, nullptr);
             if (buttonState == 0) {
+                if (m_PendingMouseButtonsAllUpOnVideoRegionLeave) {
+                    // Tell the main thread to stop capturing the mouse now
+                    SDL_Event event;
+                    event.type = SDL_USEREVENT;
+                    event.user.code = SDL_CODE_UNCAPTURE_MOUSE;
+                    SDL_PushEvent(&event);
+
                     m_PendingMouseButtonsAllUpOnVideoRegionLeave = false;
                 }
+            }
             if (mouseInVideoRegion || m_MouseWasInVideoRegion || m_PendingMouseButtonsAllUpOnVideoRegionLeave) {
                 LiSendMousePositionEvent(x, y, dst.w, dst.h);
             }
@@ -251,33 +259,5 @@ Uint32 SdlInputHandler::mouseMoveTimerCallback(Uint32 interval, void *param)
     // Send mouse position updates if applicable
     me->flushMousePositionUpdate();
 
-#ifdef Q_OS_WIN32
-    // See comment in SdlInputHandler::notifyMouseLeave()
-    if (me->m_AbsoluteMouseMode && me->m_PendingMouseLeaveButtonUp != 0 && me->isCaptureActive()) {
-        int mouseX, mouseY;
-        int windowX, windowY;
-        Uint32 mouseState = SDL_GetGlobalMouseState(&mouseX, &mouseY);
-        SDL_GetWindowPosition(me->m_Window, &windowX, &windowY);
-
-        // If the button is now up, send the synthetic mouse up event
-        if ((mouseState & SDL_BUTTON(me->m_PendingMouseLeaveButtonUp)) == 0) {
-            SDL_Event event;
-
-            event.button.type = SDL_MOUSEBUTTONUP;
-            event.button.timestamp = SDL_GetTicks();
-            event.button.windowID = SDL_GetWindowID(me->m_Window);
-            event.button.which = 0;
-            event.button.button = me->m_PendingMouseLeaveButtonUp;
-            event.button.state = SDL_RELEASED;
-            event.button.clicks = 1;
-            event.button.x = mouseX - windowX;
-            event.button.y = mouseY - windowY;
-            SDL_PushEvent(&event);
-
-            me->m_PendingMouseLeaveButtonUp = 0;
-        }
-    }
-#endif
-
     return interval;
 }

app/streaming/session.cpp

@@ -1321,6 +1321,9 @@ void Session::exec(int displayOriginX, int displayOriginY)
             case SDL_CODE_SHOW_CURSOR:
                 SDL_ShowCursor(SDL_ENABLE);
                 break;
+            case SDL_CODE_UNCAPTURE_MOUSE:
+                SDL_CaptureMouse(SDL_FALSE);
+                break;
             case SDL_CODE_FLUSH_WINDOW_EVENT_BARRIER:
                 m_FlushingWindowEventsRef--;
                 break;