Tech question.

mog123 · Post by **mog123** » Sat Jul 25, 2009 6:22 pm

Some emulators I tried with FF6 have one problem, they can't display the backgrounds in FF6 battles - so what is responsible for displaying/loading the backgrounds? Here's a screen of what it looks like: It looks almost the same on every early stage snes emu:

http://img150.imageshack.us/i/ff6.png/

Deathlike2 · Post by **Deathlike2** » Sat Jul 25, 2009 6:41 pm

This is a guess (since I don't work on the rendering), but it's something between RTO and HDMA. If you've ever turned off layers when you see a proper picture, there's a lot of behind-the-scenes junk that goes on into rendering it. I'm sure there's a lot more to what I've said.

Edit: Oh yes, there's certainly a lot of windowing that goes on there too.

Post by **grinvader** » Sat Jul 25, 2009 8:18 pm

holy shit that's some nice bg fuckup right there.

@Deathlike: RTO affects oam, not bgs.
HDMA issues wouldn't cause THAT sort of stuff (since hdma means "affect some registers every hblank", you usually end up with per-line issues).
Windowing issues might be the cause, but that would affect all games, not just ff6 battles...

Nah, that just looks like completely wrong tilemap/charmap addressing.
Maybe mode 1 without BG3 high priority support ?

mog123 · Post by **mog123** » Sat Jul 25, 2009 8:45 pm

forced mode 1 and disabled bg3, still looks the same.

Post by **grinvader** » Sat Jul 25, 2009 9:00 pm

mog123 wrote:forced mode 1 and disabled bg3, still looks the same.

... because that would be the issue. BG3 priority 1 goes in front of everything with $2105.3 ('BG3 high priority') set. Disabling BG3 wouldn't fix that at all (and would break the picture if it got rendered properly).
However, note that was just a wild guess. It could be many, many things. That's why you don't want to use early stage emus.

How did you 'force' mode 1 btw ?
Anyway; forcing a different mode than intended can only break display. Palette entries will likely get fumbled.

From what pf can remember, ff6 battles use mode 4. So, it's not high priority issues. Maybe OPT ?

mog123 · Post by **mog123** » Sat Jul 25, 2009 9:13 pm

grinvader wrote:Maybe OPT ?

And that's?

creaothceann · Post by **creaothceann** » Sat Jul 25, 2009 11:41 pm

Offset-Per-Tile mode. Can be used in BG modes 2, 4 and 6 to scroll tiles individually. (see Black Omen fade-in)

From what I can see FF6 uses BG mode 1, but that might be incorrect because of the status bars at the bottom.

Jonas Quinn · Post by **Jonas Quinn** » Sat Jul 25, 2009 11:52 pm

It's HDMA. If you disable it in ZSNES you will see a similar screen.

Post by **grinvader** » Sun Jul 26, 2009 7:38 am

Jonas once again saves the day.