Question

I am using a QMainWindow for my app and want to do some openGL rendering. 2 approaches:

1) set as central widget a QGLWidget and do all the rendering there,

OR

2) set as central widget a QGraphicsView, set the viewport to my QGLWidget to create the rendering context and do the rendering in my scene.

Which one would be preferable when it comes to efficiency? (I will be adding some other objects later which in the former case are going to be QGLWidgets (as child widgets) and in the latter QGaphicsItems)

Answer 1

Using a QGLWidget and rendering with OpenGL directly will in most cases be more efficient, but it will require more work to manage a dynamic set of rendered items. Using the QGraphicsView framework will have some overhead, but it provides many features for managing rendered items. The amount of overhead for QGraphicsView will depend upon various details, but in most cases it will not be a bottleneck and it can be adjusted for various usage patterns.