Add a mouse capture fallback if SDL_SetRelativeMouseMode() fails

app/streaming/input.cpp

@@ -53,6 +53,7 @@ SdlInputHandler::SdlInputHandler(StreamingPreferences& prefs, NvComputer*, int s
     : m_MultiController(prefs.multiController),
       m_GamepadMouse(prefs.gamepadMouse),
       m_MouseMoveTimer(0),
+      m_FakeCaptureActive(false),
       m_LeftButtonReleaseTimer(0),
       m_RightButtonReleaseTimer(0),
       m_DragTimer(0),
@@ -213,7 +214,7 @@ void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
                         "Detected mouse capture toggle combo (SDLK)");
 
             // Stop handling future input
-            SDL_SetRelativeMouseMode((SDL_bool)!SDL_GetRelativeMouseMode());
+            setCaptureActive(!isCaptureActive());
 
             // Force raise all keys to ensure they aren't stuck,
             // since we won't get their key up events.
@@ -261,7 +262,7 @@ void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
                         "Detected mouse capture toggle combo (scancode)");
 
             // Stop handling future input
-            SDL_SetRelativeMouseMode((SDL_bool)!SDL_GetRelativeMouseMode());
+            setCaptureActive(!isCaptureActive());
 
             // Force raise all keys to ensure they aren't stuck,
             // since we won't get their key up events.
@@ -294,7 +295,7 @@ void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
         }
     }
 
-    if (!SDL_GetRelativeMouseMode()) {
+    if (!isCaptureActive()) {
         // Not capturing
         return;
     }
@@ -540,11 +541,11 @@ void SdlInputHandler::handleMouseButtonEvent(SDL_MouseButtonEvent* event)
     // the pressed event was consumed by this code).
     if (event->button == SDL_BUTTON_LEFT &&
             event->state == SDL_RELEASED &&
-            !SDL_GetRelativeMouseMode()) {
+            !isCaptureActive()) {
-        SDL_SetRelativeMouseMode(SDL_TRUE);
+        setCaptureActive(true);
         return;
     }
-    else if (!SDL_GetRelativeMouseMode()) {
+    else if (!isCaptureActive()) {
         // Not capturing
         return;
     }
@@ -585,7 +586,7 @@ void SdlInputHandler::handleMouseButtonEvent(SDL_MouseButtonEvent* event)
 
 void SdlInputHandler::handleMouseMotionEvent(SDL_MouseMotionEvent* event)
 {
-    if (!SDL_GetRelativeMouseMode()) {
+    if (!isCaptureActive()) {
         // Not capturing
         return;
     }
@@ -602,7 +603,7 @@ void SdlInputHandler::handleMouseMotionEvent(SDL_MouseMotionEvent* event)
 
 void SdlInputHandler::handleMouseWheelEvent(SDL_MouseWheelEvent* event)
 {
-    if (!SDL_GetRelativeMouseMode()) {
+    if (!isCaptureActive()) {
         // Not capturing
         return;
     }
@@ -1299,6 +1300,35 @@ void SdlInputHandler::raiseAllKeys()
     m_KeysDown.clear();
 }
 
+bool SdlInputHandler::isCaptureActive()
+{
+    if (SDL_GetRelativeMouseMode()) {
+        return true;
+    }
+
+    // Some platforms don't support SDL_SetRelativeMouseMode
+    return m_FakeCaptureActive;
+}
+
+void SdlInputHandler::setCaptureActive(bool active)
+{
+    if (active) {
+        // Try to activate SDL's relative mouse mode
+        if (SDL_SetRelativeMouseMode(SDL_TRUE) < 0) {
+            // Relative mouse mode didn't work, so we'll use fake capture
+            SDL_ShowCursor(SDL_DISABLE);
+            m_FakeCaptureActive = true;
+        }
+    }
+    else if (m_FakeCaptureActive) {
+        SDL_ShowCursor(SDL_ENABLE);
+        m_FakeCaptureActive = false;
+    }
+    else {
+        SDL_SetRelativeMouseMode(SDL_FALSE);
+    }
+}
+
 QString SdlInputHandler::getUnmappedGamepads()
 {
     QString ret;

app/streaming/input.h

@@ -64,6 +64,10 @@ public:
 
     void raiseAllKeys();
 
+    bool isCaptureActive();
+
+    void setCaptureActive(bool active);
+
     static
     QString getUnmappedGamepads();
 
@@ -96,6 +100,7 @@ private:
     int m_GamepadMask;
     GamepadState m_GamepadState[MAX_GAMEPADS];
     QSet<short> m_KeysDown;
+    bool m_FakeCaptureActive;
 
     SDL_TouchFingerEvent m_TouchDownEvent[MAX_FINGERS];
     float m_CumulativeDelta[MAX_FINGERS];

app/streaming/session.cpp

@@ -1101,20 +1101,19 @@ void Session::exec(int displayOriginX, int displayOriginY)
                     SDL_GetWindowPosition(m_Window, &x, &y);
                     SDL_GetWindowSize(m_Window, &width, &height);
                     if (mouseX > x && mouseX < x+width && mouseY > y && mouseY < y+height) {
-                        SDL_SetRelativeMouseMode(SDL_TRUE);
+                        m_InputHandler->setCaptureActive(true);
                     }
                 }
             }
 #endif
 
-
             if (event.window.event == SDL_WINDOWEVENT_FOCUS_LOST) {
                 // Release mouse cursor when another window is activated (e.g. by using ALT+TAB).
                 // This lets user to interact with our window's title bar and with the buttons in it.
                 // Doing this while the window is full-screen breaks the transition out of FS
                 // (desktop and exclusive), so we must check for that before releasing mouse capture.
                 if (!(SDL_GetWindowFlags(m_Window) & SDL_WINDOW_FULLSCREEN)) {
-                    SDL_SetRelativeMouseMode(SDL_FALSE);
+                    m_InputHandler->setCaptureActive(false);
                 }
 
                 // Raise all keys that are currently pressed. If we don't do this, certain keys
@@ -1247,7 +1246,7 @@ void Session::exec(int displayOriginX, int displayOriginY)
 DispatchDeferredCleanup:
     // Uncapture the mouse and hide the window immediately,
     // so we can return to the Qt GUI ASAP.
-    SDL_SetRelativeMouseMode(SDL_FALSE);
+    m_InputHandler->setCaptureActive(false);
     SDL_EnableScreenSaver();
     SDL_SetHint(SDL_HINT_TIMER_RESOLUTION, "0");