CCovell Stretch demo

Discuss emulation of the Nintendo Entertainment System and Famicom.

Moderator: Moderators

Post Reply
User avatar
hap
Posts: 355
Joined: Thu Mar 24, 2005 3:17 pm
Contact:

CCovell Stretch demo

Post by hap » Wed Jun 15, 2005 11:43 am

http://nesdev.com/Stretch.zip

What causes emulators to show garbage inside and to the right of the wave ?
... cause mine doesn't, it shows black lines instead, and I think that's a bad thing :p

tepples
Posts: 21755
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Post by tepples » Wed Jun 15, 2005 12:45 pm

It has something to do with how the NES prefetches the first two tiles of the next scanline.

User avatar
hap
Posts: 355
Joined: Thu Mar 24, 2005 3:17 pm
Contact:

Post by hap » Wed Jun 15, 2005 5:10 pm

Hmm, it updates the ppu address mid-scanline. I was filling the background scanline buffer using the x tile offset from the ppu address, and that's why this demo didn't look messy in my emulator. But, it's plain wrong handling it that way, so I've fixed it and it looks alright now (meaning: lots of garbage). Plus, it fixed Rad Racer, maybe some other stuff too.

Post Reply