[Pulstar] "Extending" horizontal resolution

As with all video signals designed during CRT days, an oversan area was required and often we do not see the top-, bottom-, left- and right-most pixels of an original signal.

The Neo Geo has the ability to output a maximum horizontal resolution of 320 pixels.

Quite a number of games have a reduced visible screen width of 304 pixels (8 pixels on each side removed).

Interestingly, for some, the full graphics are still rendered there, however, they are intentionally overlaid with a black FIX layer.
(this was a practice so much so that there are default subroutines in the BIOS to do so)

On modern flatscreen displays, however, we can see these pixels clearly.

Pulstar's typical viewable gameplay screens are 304 pixels wide. I took a look and found the subroutines that perform this 'blacking', and these are the results of bypassing them.







The mod is conveniently a simple 1 byte change at $364F8 from 1E to 64 (in Pulstar's P1).

Makes quite a visual difference.



Note, however, that the movement boundaries for your ship is still within the original 304-pixel space. I'd very much like to see someone with better debugging skills than I attempt to remove this limit.

And if it's not too much to ask, resolve the slow down issue and the weird screen transitioning flicker.
-----------------------------------------------------------------------------
IPS

NeoSD neo file

Oh mate that is absolutely fantastic.
I knew for the overscan but i thought  it was wasted pixels.
Maybe Elrayzeur can help debugging the boundaries for the plane, it would be awesome to have it move beyond the fixed box.
Oh i guess it looks a bit weird having the landscape larger than the ship movable area

Great !!

Wow, another awesome patch, thanks à lot for sharing this here

Impressive ! I didn't know anything about this overscan thing !
Thanks for sharing !

Hello Clearpaper,

and thank you for that amazing work

Thats pretty cool. Do you think you can share the p1 rom you patched? I guess I could try changing that with a hex tool?
Also would the driver need to be changed as well to reflect the 320? If you notice in the driver it shows 320? I don't know if that refers to the output but its there.

Code:

FILENAME( pulstar, neogeo, 0, 0, 0, 0, 320 )
   REGION( 0x300000, CPU1, 0 )
   ROM( 0, 089-p1.p1,  0x000000, 0x100000, 0x5e5847a2 )
   ROM( 0, 089-p2.sp2, 0x100000, 0x200000, 0x028b774c )

   REGION( 0x20000, GFX2, 0 )
   ROM( 0, 089-s1.s1, 0x00000, 0x20000, 0xc79fc2c8 )

   REGION( 0x30000, CPU2, 0 )
   ROM( 0, 089-m1.m1, 0x10000, 0x20000, 0xff3df7c7 )

   REGION( 0x800000, SOUND1, 0 )
   ROM( 0, 089-v1.v1, 0x000000, 0x400000, 0x6f726ecb )
   ROM( 0, 089-v2.v2, 0x400000, 0x400000, 0x9d2db551 )

   REGION( 0x1c00000, GFX3, 0 )
   ROMX( 0, 089-c1.c1, 0x0000000, 0x400000, 0xf4e97332, 1, 1 )
   ROMX( 0, 089-c2.c2, 0x0000001, 0x400000, 0x836d14da, 1, 1 )
   ROMX( 0, 089-c3.c3, 0x0800000, 0x400000, 0x913611c4, 1, 1 )
   ROMX( 0, 089-c4.c4, 0x0800001, 0x400000, 0x44cef0e3, 1, 1 )
   ROMX( 0, 089-c5.c5, 0x1000000, 0x400000, 0x89baa1d7, 1, 1 )
   ROMX( 0, 089-c6.c6, 0x1000001, 0x400000, 0xb2594d56, 1, 1 )
   ROMX( 0, 089-c7.c7, 0x1800000, 0x200000, 0x6a5618ca, 1, 1 )
   ROMX( 0, 089-c8.c8, 0x1800001, 0x200000, 0xa223572d, 1, 1 )
END

I went to 364f9 and the value was 00, but f8 had value of 1E, so i changed that to 64. This is the resulting CRC value:

Original crc32 5e5847a2
After Patch crc32 c568421b

I edited the driver to reflect the new CRC and the game did not run. unless i was looking at the wrong location and was just a coincidence the the address before was same value I was looking for.

Just apply the IPS patch executable in the original post. There are CRCs in the notes for confirmation.

Just took at look at the 089-p1.p1 again, you're right, I should have stated address $364F8 instead, due to the default byte-flipped state the program is stored in. I've amended the original post to reflect as such.

The resultant CRC you got is the correct one. I don't recognise the driver/emulator but it should(?) run once you update it.

Code:

ROM( 0, 089-p1.p1,  0x000000, 0x100000, 0xc568421b )

So yeah, I had to make a small tweak to get it to work but it did!

Im part of HyloStick Team and we have been working with the Arcade Stick PRO and getting all neogeo games to run on it plus now CPS1,2,3, and arcade and other systems.

I think your discovery is super cool!

Please excuse the quality but I think you can still notice the difference!



I will be sure to credit you for the fix should we decide to release an update.

I would like to test out Blazing Star tweaks as well!

Clearpaper, it's amazing.

Make this after many year that the game is released it's very cool, i have see also for Pulstar.

It's a great works, very big thanks.


It's cool too see a very hard skill of programmation for make this.

Thanks for all the feedback, guys. It's much appreciated.

Wow, awesome! Thanks for sharing Does this make any difference on a 4:3 display, or is it intended for flat screens only?

It doesn't make a difference on a CRT, unless you have a PVM/BVM and adjust geometry to show the edges.