Post via forum by datahead <cjj_009@xxxxxxxxxx>: I hadn't realized most of the derived classes were calling the base class implementations of the (currently empty) Scene methods. However, according to this reference, we can still have base class default implementations for pure virtual functions if we want to: http://www.programmerinterview.com/index.php/c-cplusplus/pure-virtual-fun... If we make them pure virtual, though, I would probably say we should not have a default implementation for now if it is going to be empty. -- Sent by Chessboard.

Post via forum by datahead <cjj_009@xxxxxxxxxx>: This was done with commit id 3551037c8647d45bc877bbedf337710b17173e31. [quote]It may happen later that we want to implement behaviour that is common to all scenes, but in that case we can just remove the purely virtual definition again.[/quote] We could also try the trick outlined in the website to which I linked, which suggests it is possible to have implementations for pure virtual functions. This way it is still an abstract class from C++'s perspective. -- Sent by Chessboard.