SegaXtreme

Home	Forums	What's new	Resources

Diagonal scrolling - what games have it?

ExCyber - Oct 30, 2001

		ExCyber		Oct 30, 2001
			This may seem like an odd thing to ask, but what NES games have diagonal scrolling (without vertical or horizontal wrapping)? The only one I can think of right away is Ninja Gaiden III. Any others? Technical crap begins here: The reason I ask is that the stuff I've read about the NES PPU suggests that it's not well-suited to diagonal scrolling without having extra RAM on the cartridge - the circuitry supports a big enough BG space for it and has the appropriate features, but with the RAM inside the PPU, there is only enough room to define two BG tables; four would be needed to provide straightforward, smooth diagonal scrolling. I can think of a couple possible tricks to get diagonal scrolling without the extra RAM, but I'd like to know if there are any games that manage to actually do it.

		CrowTRobo		Oct 30, 2001
			Hrm, this is an odd question. I can't think of any specific games off-hand, but there has to be other games where you walk up/down slopes, etc while the screen scrolls. Maybe they just scrolled horizontally a bit, then vertically, then repeated it? Maybe that's what Ninja Gaiden 3 did as well? I don't exactly see the point of figuring this out, but I guess you have a reason. Quit worrying about the NES though and concentrate on the Genesis. CrowTRobo

		Karny		Oct 31, 2001
			Strider?

ExCyber

Oct 31, 2001

Heh, Strider... now there was a game that needed a month or two of more tweaking... I think you're right though.

	
	
		
		
			Maybe they just scrolled horizontally a bit, then vertically, then repeated it?

That's what diagonal scrolling would be implemented as. The thing about it is that without a suitable mapper to control the PPU address lines and (optionally?) some extra RAM, there is nothing to scroll to in at least one direction except what's already on the other side of the screen. I think this can be overcome, but don't know if my ideas would actually work.

	
	
		
		
			Quit worrying about the NES though and concentrate on the Genesis.

Right, right... still need to find a suitable CPLD that can be ordered in reasonable quantity though - I found a place with the XC9572 in an 84-pin PLCC package, which would be just about perfect, but the minimum order is $50 and I haven't (yet) found any other components at that company that I can use. I guess I should be thankful they have a $50 minimum rather than making me buy a tray of 96 chips, but it's still annoying...

		Fabrizo		Oct 31, 2001
			Seeing as how we seem to be getting all technical right now, could someone tell me what this thing is exactly: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?V...item=... It says something about PCB's or something like that. I know computer hardware to an extent, software, better then anyone I know, but I know basicly nothing about NES hardware. I should probably know what it is without having to ask, but it would be nice to know anyways. (Edited by Fabrizo at 11:56 pm on Oct. 31, 2001)

		ExCyber		Nov 1, 2001
			Well, I think it's just being called a PCB because it is just the circuit board with no housing, so it would be a bit misleading to call it a cartridge. The description mentions EPROMs, but the chips on the board look like flash ROMs (well, they could just as easily be mask ROM, but those would be totally unsuitable for prototyping). This is apparently a board that Nintendo or some third party used for pre-production testing of their games; probably a late model since there is an SA-1 chip (which was used as a coprocessor on a few late SNES/SFC games, most notably Super Mario RPG) on it.

		Don Gloton		Apr 10, 2002
			Maybe Cobra Triangle? Spanish Don Glotón

		Karny		Apr 15, 2002
			Kirbys dventure also has diagonal scrolling on the stage selection screen. However it's likely that they have done what CrowTRobo suggests and scrolled horizontally, then vertically etc...