Hi everyone. Apologies in advance if I'm posting this in the wrong forum. I'm new, but questions are more important than introductions in my case.
Me and a friend are hacking Super Mario Bros. 2. In the game, the whites of the characters' eyes are overlayed (underlayed?) the main sprite, as a workaround for the three color rule on NES. We've edited the graphics of the main characters and have run into a bit of a fuzzy pickle. The whites themselves seem to be 16 pixels tall, 8 pixels wide, and just large enough to work for the original characters they were intended to be used with. Now the problem at hand is that me and my friend are incapable of changing the whites to use beyond the 8x16 tiles that they normally use. Otherwise, we'd expand the eyes to a full 16x16.
I filled in the entirety of the tiles for Mario's eyes with white (a full 16x16) to experiment, leaving me with this-
Showing the 8x16 restrictions set. I've poked around with a hex editor and came up with nothing. I'm not sure how I'll be able to extend the eyes to fit the new characters, ideally by duplicating the same white tile twice to fill the eyes.
I checked the datacrystal page on the eye addresses
and the point for Mario's eyes leads me back to D5 in the ROM-
Which is the highlighted location right here, already edited to fit the new character. According to datacrystal, Luigi's eyes point to D9, which is accurately his eye graphic location right beside Mario's at D5, so I must be in the right place.
Does anyone have any idea how I could go about fixing this problem by possibly expanding this sprite size?
EDIT: Also, as a side note, it seems like the one pixel bob that characters make as they run (all characters sans Peach, at least) is done through code. Is there any way I could also apply that bob code to Peach as well?