I just figured out that this doesn't work, when I use a array with super class as base type, for example: Drawable[] textures;
Then, I'll get the following error: "Error: function draw!(void*).draw non-virtual functions cannot be abstract". I just implemented the draw-function as empty function, which doesn't create any errors, but I seems that it's not calling the draw- function of any texture instance. It seems that it is always calling Drawable.draw() - the empty function. When I create a new instance of my Texture-class, it calls the draw-function of the texture-instance.