Qt: Add a way for the emulation thread to request fullscreen state

src/duckstation-qt/mainwindow.cpp

@@ -81,7 +81,11 @@ void MainWindow::destroyDisplayWindow()
 
 void MainWindow::toggleFullscreen()
 {
-  const bool fullscreen = !m_display_widget->isFullScreen();
+  setFullscreen(!m_display_widget->isFullScreen());
+}
+
+void MainWindow::setFullscreen(bool fullscreen)
+{
   if (fullscreen)
   {
     m_ui.mainContainer->setCurrentIndex(0);
@@ -335,6 +339,7 @@ void MainWindow::connectSignals()
   connect(m_host_interface, &QtHostInterface::createDisplayWindowRequested, this, &MainWindow::createDisplayWindow,
           Qt::BlockingQueuedConnection);
   connect(m_host_interface, &QtHostInterface::destroyDisplayWindowRequested, this, &MainWindow::destroyDisplayWindow);
+  connect(m_host_interface, &QtHostInterface::setFullscreenRequested, this, &MainWindow::setFullscreen);
   connect(m_host_interface, &QtHostInterface::toggleFullscreenRequested, this, &MainWindow::toggleFullscreen);
   connect(m_host_interface, &QtHostInterface::messageReported, this, &MainWindow::reportMessage);
   connect(m_host_interface, &QtHostInterface::emulationStarted, this, &MainWindow::onEmulationStarted);

src/duckstation-qt/mainwindow.h

@@ -26,6 +26,7 @@ private Q_SLOTS:
   void reportMessage(const QString& message);
   void createDisplayWindow(QThread* worker_thread, bool use_debug_device);
   void destroyDisplayWindow();
+  void setFullscreen(bool fullscreen);
   void toggleFullscreen();
   void onEmulationStarted();
   void onEmulationStopped();

src/duckstation-qt/qthostinterface.h

@@ -71,6 +71,7 @@ Q_SIGNALS:
   void gameListRefreshed();
   void createDisplayWindowRequested(QThread* worker_thread, bool use_debug_device);
   void destroyDisplayWindowRequested();
+  void setFullscreenRequested(bool fullscreen);
   void toggleFullscreenRequested();
   void systemPerformanceCountersUpdated(float speed, float fps, float vps, float avg_frame_time,
                                         float worst_frame_time);