Pass through focus-gain clicks to the host in absolute mouse mode

app/streaming/input/input.cpp

@@ -19,6 +19,8 @@ SdlInputHandler::SdlInputHandler(StreamingPreferences& prefs, NvComputer*, int s
       m_StreamHeight(streamHeight),
       m_AbsoluteMouseMode(prefs.absoluteMouseMode),
       m_AbsoluteTouchMode(prefs.absoluteTouchMode),
+      m_PendingFocusGain(false),
+      m_PendingFocusButtonUp(0),
       m_LeftButtonReleaseTimer(0),
       m_RightButtonReleaseTimer(0),
       m_DragTimer(0),
@@ -203,12 +205,44 @@ void SdlInputHandler::notifyFocusGained()
 #if defined(Q_OS_WIN32) || defined(Q_OS_DARWIN)
     int mouseX, mouseY;
     Uint32 mouseState = SDL_GetGlobalMouseState(&mouseX, &mouseY);
-    if (mouseState & SDL_BUTTON(SDL_BUTTON_LEFT)) {
+    if (mouseState != 0) {
         int x, y, width, height;
         SDL_GetWindowPosition(m_Window, &x, &y);
         SDL_GetWindowSize(m_Window, &width, &height);
         if (mouseX > x && mouseX < x+width && mouseY > y && mouseY < y+height) {
-            setCaptureActive(true);
+            if (m_AbsoluteMouseMode) {
+                // We won't receive mouse events until the mouse gesture ends after gaining
+                // focus. To allow users to click directly into the unfocused window, we'll
+                // emulate mouse events using SDL_GetGlobalMouseState().
+                m_PendingFocusGain = true;
+
+                if (mouseState & SDL_BUTTON_LMASK) {
+                    m_PendingFocusButtonUp = SDL_BUTTON_LEFT;
+                }
+                else if (mouseState & SDL_BUTTON_RMASK) {
+                    m_PendingFocusButtonUp = SDL_BUTTON_RIGHT;
+                }
+                else if (mouseState & SDL_BUTTON_MMASK) {
+                    m_PendingFocusButtonUp = SDL_BUTTON_MIDDLE;
+                }
+                else if (mouseState & SDL_BUTTON_X1MASK) {
+                    m_PendingFocusButtonUp = SDL_BUTTON_X1;
+                }
+                else if (mouseState & SDL_BUTTON_X2MASK) {
+                    m_PendingFocusButtonUp = SDL_BUTTON_X2;
+                }
+                else {
+                    SDL_assert(false);
+                    m_PendingFocusGain = false;
+                }
+
+                // Update the mouse position then send the button down event
+                sendSyntheticMouseState(SDL_MOUSEMOTION, 0);
+                sendSyntheticMouseState(SDL_MOUSEBUTTONDOWN, m_PendingFocusButtonUp);
+            }
+            else if (mouseState & SDL_BUTTON_LMASK) {
+                setCaptureActive(true);
+            }
         }
     }
 #endif

app/streaming/input/input.h

@@ -77,6 +77,8 @@ public:
 
     void setCaptureActive(bool active);
 
+    void sendSyntheticMouseState(Uint32 state, Uint32 button);
+
     static
     QString getUnmappedGamepads();
 
@@ -127,6 +129,9 @@ private:
     bool m_AbsoluteMouseMode;
     bool m_AbsoluteTouchMode;
 
+    bool m_PendingFocusGain;
+    Uint32 m_PendingFocusButtonUp;
+
     SDL_TouchFingerEvent m_TouchDownEvent[MAX_FINGERS];
     SDL_TimerID m_LeftButtonReleaseTimer;
     SDL_TimerID m_RightButtonReleaseTimer;

app/streaming/input/mouse.cpp

@@ -111,6 +111,46 @@ void SdlInputHandler::handleMouseWheelEvent(SDL_MouseWheelEvent* event)
     }
 }
 
+void SdlInputHandler::sendSyntheticMouseState(Uint32 type, Uint32 button) {
+    int mouseX, mouseY;
+    int windowX, windowY;
+    SDL_Event event;
+    Uint32 buttonState = SDL_GetGlobalMouseState(&mouseX, &mouseY);
+    SDL_GetWindowPosition(m_Window, &windowX, &windowY);
+
+    switch (type) {
+    case SDL_MOUSEMOTION:
+        event.motion.type = type;
+        event.motion.timestamp = SDL_GetTicks();
+        event.motion.windowID = SDL_GetWindowID(m_Window);
+        event.motion.which = 0;
+        event.motion.state = buttonState;
+        event.motion.x = mouseX - windowX;
+        event.motion.y = mouseY - windowY;
+        event.motion.xrel = 0;
+        event.motion.yrel = 0;
+        break;
+
+    case SDL_MOUSEBUTTONDOWN:
+    case SDL_MOUSEBUTTONUP:
+        event.button.type = type;
+        event.button.timestamp = SDL_GetTicks();
+        event.button.windowID = SDL_GetWindowID(m_Window);
+        event.button.which = 0;
+        event.button.button = button;
+        event.button.state = type == SDL_MOUSEBUTTONDOWN ? SDL_PRESSED : SDL_RELEASED;
+        event.button.clicks = 1;
+        event.button.x = mouseX - windowX;
+        event.button.y = mouseY - windowY;
+        break;
+
+    default:
+        SDL_assert(false);
+    }
+
+    SDL_PushEvent(&event);
+}
+
 Uint32 SdlInputHandler::mouseMoveTimerCallback(Uint32 interval, void *param)
 {
     auto me = reinterpret_cast<SdlInputHandler*>(param);
@@ -122,5 +162,20 @@ Uint32 SdlInputHandler::mouseMoveTimerCallback(Uint32 interval, void *param)
         LiSendMouseMoveEvent(deltaX, deltaY);
     }
 
+    if (me->m_PendingFocusGain && me->m_AbsoluteMouseMode) {
+        Uint32 buttonState = SDL_GetGlobalMouseState(NULL, NULL);
+
+        // Update the position first
+        me->sendSyntheticMouseState(SDL_MOUSEMOTION, 0);
+
+        // If the button has come up since last time, send that too
+        if ((buttonState & SDL_BUTTON(me->m_PendingFocusButtonUp)) == 0) {
+            me->sendSyntheticMouseState(SDL_MOUSEBUTTONUP, me->m_PendingFocusButtonUp);
+
+            // Focus gain has completed
+            me->m_PendingFocusGain = false;
+        }
+    }
+
     return interval;
 }