A quick question regarding CPS2 resolution.

[justjustin]

Not sure why it popped into my head just now, but here's my question: How does a CPS2 game's resolution work? What's the reasoning behind a 384 x 224 resolution when it's displayed on a 4:3 monitor? To fit a game on the entire display the graphics would have to be distorted to some degree.

Anyone know? I'm curious...

[Smithee]

I think it has to do with the scanlines, and they are slightly distorted like that on the arcade I can go to... Otherwise I'm not sure.

[Discoalucard]

I read something once about oblong pixels?

[butanebob]

I read that somewhere also, can't remember where though but as Disco said the pixels aren't actually square...

[YourAverageJoe]

Yeah, the oblong pixels are one of the reasons for why Megaman's sprite looks so stretched in Megaman: Power Fighters.

[roushimsx]

Oct 11, 2008 22:20:54 GMT -5 Discoalucard said:

I read something once about oblong pixels?

This. A ton of games have non square pixels, so when you're using MAME (or whatever emulator) just make sure you're checking the "Stretch to Fit" or similar option. You know, except for the multimonitor games that go like 8:3 and 12:3 or the random game that's actually 16:9.

Speaking of which, I want a shmup that's multiple screens tall.

[justjustin]

Ah ok. Thanks for the responses. Non-square pixels, eh? I can barely wrap my head around that. It also does have something to do with scanlines, or they were at least factored in when making the graphics. I guess I'll look into this.

[YourAverageJoe]

I think the Commodore 64 also had non-square pixels, considering all the screenshots of the system look stretched to hell.

[roushimsx]

Oct 12, 2008 12:00:02 GMT -5 YourAverageJoe said:

I think the Commodore 64 also had non-square pixels, considering all the screenshots of the system look stretched to hell.

Yea, a lot of DOS games were in the same boat with their at-the-time-nice 320x200 action. There's a pretty straightforward writeup on how it affects Doom here.

[PooshhMao]

CPS2 graphics were actually designed to take this into account.
That's why sprite rips look squashed vertically.

[Yuan]

Well, it does have to do with scanlines.

The resolution of the monitor is limited vertically by its refresh rate. At 60 fps, a game can have 240 lines, but typically 224 are used for graphics because not all monitors can display all 240 for sure.

Mortal Kombat runs at less frames per second to provide a "taller vertical resolution, because each frame takes longer to draw since it has more lines.

If you wanted more than 240 lines of resolution, you would have to interlace the video, thus halving the frames in 480i (interlaced) at 30 fps. Most arcade games of the past output at 240p (true progressive 60fps with scanlines).

The horizontal resolution, however, is virtually limited only by the monitor's pixels (here as the "picture elements" which compose the PHYSICAL screen). A monitor with "many" pixels (the little RGB things you see when you put a magnifying glass on your TV or CRT monitor, specially visible when displaying white) can have a much clearer image than one with fewer density. Thus, even if your 27 inch CRT TV is bigger, your CRT monitor is much clearer and more detailed because it has a higher pixel density (again, pixel not as in computer pixel).

The higher the horizontal resolution, the more pixels, and more details can be displayed. Since most consoles of the past are tile based, all the numbers are divisible by 16.

A Famicom or Super Famicom game displays less horizontal resolution, thus having less detail and "squashed" pixels. A Mega Drive or Neo Geo typically displays 320 horizontal resolution, which is higher and the pixels look closer to squares. A CPS I/II/III arcade board displays even more horizontal pixels, having "long" pixels that can fit more detail on the screen.

They ALL output 240 vertical lines, typically using only 224 for important graphics.

In other words, it's the only way to make the resolution "higher" without sacrificing the 60 frames per second.

It is of much higher quality, but you need to work with special monitors when designing the game, to keep the aspect ratio correct.

Hope this helps.

[justjustin]

Thanks for the explanation, Yuan, much appreciated. It makes sense that pixels are defined by the technology that interprets them. I never realized how pixels could work so differently depending on the display being used. Cool stuff, and that explains why Alien vs. Predator looked correct on an arcade monitor back when I played it about a year ago, and wrong on my computer in the game's native resolution (which I thought was the correct way to see it).

[vnisanian2001]

This may be a bit off-topic, but anyone know why Capcom gave up on CPS games? They haven't made one since the CPS2 release in December 2003 that was Hyper Street Fighter: The Anniversary Edition.

[justjustin]

My guess: It's because technology became more standardized, so they moved to more standard formats. Also, the reason they used CPS2 for Hyper Street Fighter in '03 was so they didn't have to redraw everything.

Not sure, though!

[Yuan]

The CPS II encryption method was fully reverse-engineered recently, thus making quick pirating of the boards possible.

I don't have anything against emulation, in fact, I'm in favor of many of its advantages and preservation of game software and hardware; however, this was what ultimately killed the NeoGeo, as they left the board in favor of the Atomiswave because of rampant piracy, not because they really wanted to leave the system.

It is a shame that so many people are irresponsible about it, and dump boards that are commercially available. People forget it is theft.