Talk:SmileBASIC (Petit Computer 3)/@comment-5334617-20140924000118

It just occurred to me that it appears there is only one 'graphics' layer on the upper display. This means that shapes drawn with,  ,  , and the like, will always be at the same 'depth' from the viewer, at any instant. This is a VERY big restriction. It means, for instance,  cannot be used to generate a 3-D wireframe drawing: only a 2-D line drawing at some fixed distance. Everything drawn to any layer other than the graphics layer must be a bitmap (BG or sprite or text). To draw two vector shapes at different depths, you'd have to 'draw' one of them onto a sprite.

It makes a certain aspect of implementation much much easier for the designers of SmileBasic: they don't need a z-buffer. There is a fixed finite set of drawing objects, and every one is at a single depth, so they are just ordered from furthest to nearest and pasted on top of one another. It also means semi-transparency is quite easy. So I understand their reasons for implementing it that way, but, it is limiting.