Hi,
QML / Javascript as the main programming language is a real time-saver when creating UI-centric applications. That’s why we built Felgo on top of Qt to utilize the power of QML for creating mobile games and apps.
While we only offer access to our components via QML, e.g. the Gaming Components for physics, collision detection, etc are implemented in pure C++ and only exposed as QML types for simple and easy use in your QML UI. And as QML runs quite fast as well, many use-cases don’t necessarily require to implement app or game logic in C++.
However, just as Marcin said it is possible to freely mix-in any C++ logic or components to e.g. perform data-intense calculations, threaded operations or use Qt C++ features like e.g. Qt Networking. Please see here to learn more about C++ and QML: http://doc.qt.io/qt-5/qtqml-cppintegration-topic.html
Best,
Günther from Felgo