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Clear Paper
06-05-2020, 02:45 PM
Quite a number of Neo Geo games do not display the full horizontal resolution of 320 pixels and have a reduced visible screen width of 304 pixels.

On CRTs, the left and right most 8 pixels fall within the overscan region. On modern displays, however, we can see these pixels clearly.

Interestingly, for some games, the full graphics are still rendered there, however, they are intentionally 'blacked' out.

Pulstar's gameplay screens are 304 pixels wide. I took a look and found the subroutines that perform this 'blacking', and these are the results of not running them.

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The mod is conveniently a simple 1 byte change at $364F8 from 1E to 64.
---------------------------------------------------------
IPS (http://www.mediafire.com/file/6hda2pif7de28h2/Pulstar_0.001.200605.zip/file)

NeoSD neo file (http://www.mediafire.com/file/j6j8k1m93umbixh/pulstar0001.neo/file)

ForeverSublime
06-05-2020, 06:52 PM
I dig it. Thanks for sharing!

//Subscribed to thread.

SpamYouToDeath
06-06-2020, 12:47 AM
I assumed that was to hide glitches, if sprites near the edge of the screen were hidden/shown imprecisely.

Come to think of it - are there any games where that's actually the case - where sprites don't show soon enough, if you get rid of the fix-layer blanking?

Clear Paper
06-06-2020, 04:16 AM
I assumed that was to hide glitches, if sprites near the edge of the screen were hidden/shown imprecisely.

Come to think of it - are there any games where that's actually the case - where sprites don't show soon enough, if you get rid of the fix-layer blanking?

Yes, KOF 96 is an egregious example of it. As a developer, if you knew the non-safe (https://en.wikipedia.org/wiki/Safe_area_(television)) areas would not be seen, you would not bother so much about them.

There were 'sloppy' screen transitions that permitted the rightmost 8-pixels to be displayed.
E.g. Art of Fighting stage

If you allow the character confrontation animations to complete, you'll see this screen:
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If you tap A to skip the character confrontations(bypassing the screen transition), you'll see the rightmost 8-pixels
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Which would not be a bad thing, were it not for the background not drawing properly as it scrolls.
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There are also other overscan aberrations like this as the Character Select screen is loaded.
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Want to point out that that is the default KOF 96 without any modification.

redfield0009
06-10-2020, 10:39 PM
Is this why Metal Slug has those black bars with exposed "notches" in the bottom corners when using my XRGB?

Clear Paper
06-11-2020, 04:37 AM
56887
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Yes, similarly, the side blacking subroutine here is incomplete, because there was no need to at the juncture.

I'll get to it at some point. ;)

Burning Fight!!
07-02-2020, 04:54 PM
I always wondered what was up with how inconsistently Neo Geo games handled edge blanking, this thread is fascinating.

DanAdamKOF
07-08-2020, 08:17 PM
Awesome thread! Thanks for sharing your findings!

Man, KOF 96 is all sorts of jank haha

Missile
09-09-2020, 01:07 PM
Quite a number of Neo Geo games do not display the full horizontal resolution of 320 pixels and have a reduced visible screen width of 304 pixels.

On CRTs, the left and right most 8 pixels fall within the overscan region. On modern displays, however, we can see these pixels clearly.


In the developer's manual it tells developers to do that. To use the fix layer to blank those bits off.

I always thought that was a massive shame because you lose good space from the display area.

Should have just used better CRTs!



There were 'sloppy' screen transitions that permitted the rightmost 8-pixels to be displayed.
E.g. Art of Fighting stage


There are so many bad transitions on Neo Geo games and arcade games in general. From memory Ghoul n Ghosts by Capcom - the intro seems like a real mess in that way. Not sure why. Strider has all sorts of weird transitions. Maybe it was too much effort to code proper fades/transitions.

Burning Fight!!
09-09-2020, 04:14 PM
In the developer's manual it tells developers to do that. To use the fix layer to blank those bits off.

I always thought that was a massive shame because you lose good space from the display area.

Should have just used better CRTs!



There are so many bad transitions on Neo Geo games and arcade games in general. From memory Ghoul n Ghosts by Capcom - the intro seems like a real mess in that way. Not sure why. Strider has all sorts of weird transitions. Maybe it was too much effort to code proper fades/transitions.

Strider always felt like a rushed game to me, good as it is, it has a lot of weird rough spots including those odd transitions.

Missile
09-10-2020, 04:19 PM
Strider always felt like a rushed game to me, good as it is, it has a lot of weird rough spots including those odd transitions.

Yes I forgot about that - I remember it has the wrong soundtrack and there are some extra pixels stuck onto one of Strider's animation frames. Forgotten Worlds, Ghould N Ghosts and Strider were all in development at the same time as the first games for CPS1 hardware - so maybe they just wanted to rush them out like you say!

Digmac
09-13-2020, 03:00 AM
Any chance you could fix the Pulstar links? Or perhaps someone here can reupload?

Neo Alec
09-13-2020, 02:53 PM
Or you can just use a hex editor to change $364F8 from 1E to 64

NeoCverA
09-16-2020, 10:16 PM
Or you can just use a hex editor to change $364F8 from 1E to 64

Thats what I did.