Hi all,
I'm having some little/annoying problems with sprites on my emu. I've zipped some screenshots so some of you may recognize the problems quicker, as well as a little txt file explaining the problem for each one (6).

http://www.geocities.com/muchaserres/NES_SHOTS.zip

Thank you all in advance.

About the color emphasis thing... I uploaded a copy of a doc about it here:
http://www.geocities.com/disch_/Chris_Covell_Colour_Doc.txt

I couldn't find this doc on nesdev anywhere... but maybe I just overlooked it or something.

About the sprite positions (like the SMB issue)... the only thing I can think of is you're not handling the sprite coords correctly. Either that or it's a CPU issue (but that would probably cause other problems in games and not just graphical glitches).

As for games which use 8x16 sprites... Zelda, Zelda2 and SMB3 are the first to come to mind.

Here's something I've put together on this topic (I never knew Chris Covell had written something on it, that's why I did it. Mine may be crappier, but at least it contains some sample C++ code...):

http://www12.brinkster.com/hydesprojects/Color Emphasis.txt

8x16 sprites? Try the "Cart" demo (found on the main page), 1942, and 1943.

hydesprojects.cjb.net

Thanks both a lot! Quite nice docs! I have now a clear idea about how this feature works ;)

I've been working on a new & cleaner approax to the PPU, but I'm still getting the same results. I've also checked my CPU carefuly, and it looks fine to me (and Nestress says there are no opcode problems). Another issues I've seen on SMB are: mario is almost never able to kill enemies, if mario jumps high over enemies they suddenly disappear, elevators on level 1-2 do not appear.. I'm really confused cause I remember earlier versions of my emu did not have those problems...

Gradius also uses 8x16 sprites, IIRC.