Qt: Prevent lag disabling power on buttons when starting

src/core/host_interface.cpp

@@ -93,6 +93,7 @@ bool HostInterface::BootSystem(const SystemBootParameters& parameters)
   if (!AcquireHostDisplay())
   {
     ReportFormattedError("Failed to acquire host display");
+    OnSystemDestroyed();
     return false;
   }
 

src/duckstation-qt/mainwindow.cpp

@@ -184,9 +184,17 @@ void MainWindow::focusDisplayWidget()
   m_display_widget->setFocus();
 }
 
-void MainWindow::onEmulationStarted()
+void MainWindow::onEmulationStarting()
 {
   m_emulation_running = true;
+  updateEmulationActions(true, false);
+
+  // ensure it gets updated, since the boot can take a while
+  QGuiApplication::processEvents(QEventLoop::ExcludeUserInputEvents);
+}
+
+void MainWindow::onEmulationStarted()
+{
   updateEmulationActions(false, true);
 }
 
@@ -503,7 +511,8 @@ void MainWindow::connectSignals()
 
   connect(m_ui.actionStartDisc, &QAction::triggered, this, &MainWindow::onStartDiscActionTriggered);
   connect(m_ui.actionStartBios, &QAction::triggered, this, &MainWindow::onStartBIOSActionTriggered);
-  connect(m_ui.actionResumeLastState, &QAction::triggered, m_host_interface, &QtHostInterface::resumeSystemFromMostRecentState);
+  connect(m_ui.actionResumeLastState, &QAction::triggered, m_host_interface,
+          &QtHostInterface::resumeSystemFromMostRecentState);
   connect(m_ui.actionChangeDisc, &QAction::triggered, [this] { m_ui.menuChangeDisc->exec(QCursor::pos()); });
   connect(m_ui.actionChangeDiscFromFile, &QAction::triggered, this, &MainWindow::onChangeDiscFromFileActionTriggered);
   connect(m_ui.actionChangeDiscFromGameList, &QAction::triggered, this,
@@ -555,6 +564,7 @@ void MainWindow::connectSignals()
   connect(m_host_interface, &QtHostInterface::updateDisplayRequested, this, &MainWindow::updateDisplay,
           Qt::BlockingQueuedConnection);
   connect(m_host_interface, &QtHostInterface::focusDisplayWidgetRequested, this, &MainWindow::focusDisplayWidget);
+  connect(m_host_interface, &QtHostInterface::emulationStarting, this, &MainWindow::onEmulationStarting);
   connect(m_host_interface, &QtHostInterface::emulationStarted, this, &MainWindow::onEmulationStarted);
   connect(m_host_interface, &QtHostInterface::emulationStopped, this, &MainWindow::onEmulationStopped);
   connect(m_host_interface, &QtHostInterface::emulationPaused, this, &MainWindow::onEmulationPaused);

src/duckstation-qt/mainwindow.h

@@ -33,6 +33,8 @@ private Q_SLOTS:
   void updateDisplay(QThread* worker_thread, bool fullscreen, bool render_to_main);
   void destroyDisplay();
   void focusDisplayWidget();
+
+  void onEmulationStarting();
   void onEmulationStarted();
   void onEmulationStopped();
   void onEmulationPaused(bool paused);

src/duckstation-qt/qthostinterface.cpp

@@ -209,6 +209,7 @@ void QtHostInterface::bootSystem(const SystemBootParameters& params)
     return;
   }
 
+  emit emulationStarting();
   BootSystem(params);
 }
 
@@ -221,6 +222,7 @@ void QtHostInterface::resumeSystemFromState(const QString& filename, bool boot_o
     return;
   }
 
+  emit emulationStarting();
   if (filename.isEmpty())
     HostInterface::ResumeSystemFromMostRecentState();
   else
@@ -235,6 +237,7 @@ void QtHostInterface::resumeSystemFromMostRecentState()
     return;
   }
 
+  emit emulationStarting();
   HostInterface::ResumeSystemFromMostRecentState();
 }
 

src/duckstation-qt/qthostinterface.h

@@ -93,6 +93,7 @@ Q_SIGNALS:
   void errorReported(const QString& message);
   void messageReported(const QString& message);
   bool messageConfirmed(const QString& message);
+  void emulationStarting();
   void emulationStarted();
   void emulationStopped();
   void emulationPaused(bool paused);