Qt: Hook up mouse wheel to ImGui

src/duckstation-qt/qtdisplaywidget.cpp

@@ -177,6 +177,13 @@ bool QtDisplayWidget::event(QEvent* event)
       return true;
     }
 
+    case QEvent::Wheel:
+    {
+      const QWheelEvent* wheel_event = static_cast<QWheelEvent*>(event);
+      emit windowMouseWheelEvent(wheel_event->angleDelta());
+      return true;
+    }
+
     case QEvent::Resize:
     {
       QWidget::event(event);

src/duckstation-qt/qtdisplaywidget.h

@@ -30,6 +30,7 @@ Q_SIGNALS:
   void windowKeyEvent(int key_code, bool pressed);
   void windowMouseMoveEvent(int x, int y);
   void windowMouseButtonEvent(int button, bool pressed);
+  void windowMouseWheelEvent(const QPoint& angle_delta);
 
 protected:
   bool event(QEvent* event) override;

src/duckstation-qt/qthostinterface.cpp

@@ -413,7 +413,35 @@ void QtHostInterface::onDisplayWindowMouseButtonEvent(int button, bool pressed)
   HandleHostMouseEvent(button, pressed);
 }
 
-void QtHostInterface::onHostDisplayWindowResized(int width, int height)
+void QtHostInterface::onDisplayWindowMouseWheelEvent(const QPoint& delta_angle)
+{
+  DebugAssert(isOnWorkerThread());
+
+  if (ImGui::GetCurrentContext())
+  {
+    ImGuiIO& io = ImGui::GetIO();
+
+    if (delta_angle.x() > 0)
+      io.MouseWheelH += 1.0f;
+    else if (delta_angle.x() < 0)
+      io.MouseWheelH -= 1.0f;
+
+    if (delta_angle.y() > 0)
+      io.MouseWheel += 1.0f;
+    else if (delta_angle.y() < 0)
+      io.MouseWheel -= 1.0f;
+
+    if (io.WantCaptureMouse)
+    {
+      // don't consume input events if it's hitting the UI instead
+      return;
+    }
+  }
+
+  // HandleHostMouseWheelEvent(delta_angle.x(), delta_angle.y());
+}
+
+void QtHostInterface::onDisplayWindowResized(int width, int height)
 {
   Log_WarningPrintf("resize %dx%d", width, height);
   // this can be null if it was destroyed and the main thread is late catching up
@@ -441,7 +469,7 @@ void QtHostInterface::onHostDisplayWindowResized(int width, int height)
   }
 }
 
-void QtHostInterface::onHostDisplayWindowFocused()
+void QtHostInterface::onDisplayWindowFocused()
 {
   if (!m_display || !m_lost_exclusive_fullscreen)
     return;
@@ -539,14 +567,15 @@ void QtHostInterface::connectDisplaySignals(QtDisplayWidget* widget)
 {
   widget->disconnect(this);
 
-  connect(widget, &QtDisplayWidget::windowFocusEvent, this, &QtHostInterface::onHostDisplayWindowFocused);
-  connect(widget, &QtDisplayWidget::windowResizedEvent, this, &QtHostInterface::onHostDisplayWindowResized);
+  connect(widget, &QtDisplayWidget::windowFocusEvent, this, &QtHostInterface::onDisplayWindowFocused);
+  connect(widget, &QtDisplayWidget::windowResizedEvent, this, &QtHostInterface::onDisplayWindowResized);
   connect(widget, &QtDisplayWidget::windowRestoredEvent, this, &QtHostInterface::redrawDisplayWindow);
   connect(widget, &QtDisplayWidget::windowClosedEvent, this, &QtHostInterface::powerOffSystem,
           Qt::BlockingQueuedConnection);
   connect(widget, &QtDisplayWidget::windowKeyEvent, this, &QtHostInterface::onDisplayWindowKeyEvent);
   connect(widget, &QtDisplayWidget::windowMouseMoveEvent, this, &QtHostInterface::onDisplayWindowMouseMoveEvent);
   connect(widget, &QtDisplayWidget::windowMouseButtonEvent, this, &QtHostInterface::onDisplayWindowMouseButtonEvent);
+  connect(widget, &QtDisplayWidget::windowMouseWheelEvent, this, &QtHostInterface::onDisplayWindowMouseWheelEvent);
 }
 
 void QtHostInterface::updateDisplayState()

src/duckstation-qt/qthostinterface.h

@@ -143,9 +143,6 @@ public Q_SLOTS:
   void applySettings(bool display_osd_messages = false);
   void updateInputMap();
   void applyInputProfile(const QString& profile_path);
-  void onDisplayWindowKeyEvent(int key, bool pressed);
-  void onDisplayWindowMouseMoveEvent(int x, int y);
-  void onDisplayWindowMouseButtonEvent(int button, bool pressed);
   void bootSystem(std::shared_ptr<const SystemBootParameters> params);
   void resumeSystemFromState(const QString& filename, bool boot_on_failure);
   void resumeSystemFromMostRecentState();
@@ -179,8 +176,12 @@ public Q_SLOTS:
 
 private Q_SLOTS:
   void doStopThread();
-  void onHostDisplayWindowResized(int width, int height);
-  void onHostDisplayWindowFocused();
+  void onDisplayWindowMouseMoveEvent(int x, int y);
+  void onDisplayWindowMouseButtonEvent(int button, bool pressed);
+  void onDisplayWindowMouseWheelEvent(const QPoint& delta_angle);
+  void onDisplayWindowResized(int width, int height);
+  void onDisplayWindowFocused();
+  void onDisplayWindowKeyEvent(int key, bool pressed);
   void doBackgroundControllerPoll();
   void doSaveSettings();