In QtCreator IDE (C++) any kind of image buffer - result of CPU raytracing or (what I did) frames captured from the camera can be easily rendered or painted on Widget - which is simplest part of the UI available in QtDesigner - UI designer.

You could send your ray tracing engine class to another thread and use timer which would emit signal to send your image through signal/slot mechanism to GUI main thread and paint it on the widget. It's quite simple actually. No need of OpenGL or DirectX API.

In QtCreator IDE (C++) any kind of image buffer - result of CPU raytracing or (what I did) frames captured from the camera can be easily rendered or painted on Widget - which is simplest part of the UI available in QtDesigner - UI designer.

You could send your ray tracing engine class to another thread and use timer which every once in a while would emit signal to send your image through signal/slot mechanism to GUI main thread and paint it on the widget. It's quite simple actually. No need of OpenGL or DirectX API.