> Yes i think that was the main thing i was thinking as well, I just didn't
> realise it had a name "front-to-back" ;-)
Front-to-back rendering is _not_ an optimization. It's actually quite a bit slower because for each pixel, you need to check to make sure there's nothing in the frame buffer with a higher priority. It's almost like Z-buffering except that you don't necessarily need a separate occlusion buffer (though I think Stef mentioned Gens uses one.)
Genecyst encoded priority information into the upper 2 bits of each pixel and it used that to determine whether something was already there (because obviously the color data alone tells you nothing.)
Front-to-back rendering is required for complete accuracy, though. If you're comfortable with sacrificing that, I'd stick to a back-to-front method because even though there's going to be overdraw, you don't have to worry about reading the frame buffer contents at each pixel.