Pac-Man graphic fragment

noattack · Post by **noattack** » Sun Mar 13, 2011 8:05 am

I was wondering if anyone with a familiarity with the Tengen Pac-Man port has noticed the small sprite fragment in the upper left corner of the screen. I assume this was cropped on a number of CRT monitors, but I was curious if this was a drawing glitch or intentional for some reason.

After seeing the fragment on an emulator, I threw in my cartridge and noticed it also has a palette change from yellow to white during the 'cutscenes.'

Just curious about the technical explanation, as I'm writing a paper about differences in porting practices for Pac-Man.

Dwedit · Post by **Dwedit** » Sun Mar 13, 2011 8:51 am

It's what happens when a game sets all unused sprites to be Sprite #0 at location 0,0. It's a programming mistake, the sprites should have been set to a Y position of at least 239 to be completely off the screen.

By the way, have you read "The Pac-Man Dossier" yet? It has lots of information about how the Ghost AI originally worked. Many ports of Pac-Man don't seem to use the same AI algorithms.

noattack · Post by **noattack** » Sun Mar 13, 2011 9:03 am

Yeah, I've read through the Dossier. It's great.

It seems to me that the NES version carries over the ghost behavior, though I'm not sure if the port was accurate enough to replicate the targeting errors. My guess is no, since the NES version corrects the kill screen, but I don't know for certain.

Has anyone disassembled the NES ROM? I found the 2600 source, but no luck on other versions.

EDIT: Does any Pac-Man port maintain the kill screen?

Dwedit · Post by **Dwedit** » Sun Mar 13, 2011 9:33 am

NES version just wraps from FF to 00 with no kill screen.

Kasumi · Post by **Kasumi** » Sun Mar 13, 2011 9:48 am

Google's pacman maintains the kill screen, if you would consider that a port. They put it in intentionally though for authenticity, it wasn't a bug they never found or forgot about.