When using the Qt OpenGL back-end then it is possible to render custom OpenGL code during Qml scenegraph rendering using the QQuickWindow::beforeRenderPassRecording signal, as described in the Qt documentation: https://doc.qt.io/qt-5/qtquick-scenegraph-openglunderqml-example.html
Is a similar functionality available for the Apple Metal back-end? How can I use native Metal code in the scene graph?