Fix jumpy first mouse movement in capture mouse mode

src/3d/qgscameracontroller.cpp

@@ -436,9 +436,15 @@ void QgsCameraController::onKeyPressed( Qt3DInput::QKeyEvent *event )
     {
       mCaptureFpsMouseMovements = !mCaptureFpsMouseMovements;
       if ( mCaptureFpsMouseMovements )
+      {
+        mIgnoreNextMouseMove = true;
         qApp->setOverrideCursor( QCursor( Qt::BlankCursor ) );
+      }
       else
+      {
+        mIgnoreNextMouseMove = false;
         qApp->restoreOverrideCursor();
+      }
       return;
     }
   }
@@ -566,6 +572,13 @@ void QgsCameraController::onPositionChangedFlyNavigation( Qt3DInput::QMouseEvent
   if ( !mMousePressed && !mCaptureFpsMouseMovements )
     return;
 
+  if ( mIgnoreNextMouseMove )
+  {
+    mMousePos = QPoint( mouse->x(), mouse->y() );
+    mIgnoreNextMouseMove = false;
+    return;
+  }
+
   double dx = mouse->x() - mMousePos.x();
   double dy = mouse->y() - mMousePos.y();
   if ( mPressedButton ==  Qt3DInput::QMouseEvent::LeftButton || mPressedButton ==  Qt3DInput::QMouseEvent::MiddleButton || ( mCaptureFpsMouseMovements && mPressedButton != Qt3DInput::QMouseEvent::RightButton ) )

src/3d/qgscameracontroller.h

@@ -235,6 +235,7 @@ class _3D_EXPORT QgsCameraController : public Qt3DCore::QEntity
 
     QSet< int > mDepressedKeys;
     bool mCaptureFpsMouseMovements = false;
+    bool mIgnoreNextMouseMove = false;
     QTimer *mFpsNavTimer = nullptr;
 };