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View Full Version : How often do Homebrews implement "standard" Neo-Geo logic?



Burning Fight!!
11-09-2019, 08:11 PM
I'm talking about letting the bios do the logo animation, have a predictable gameplay flow and UI elements like in the official Neo manual, actually being Arcade ready, etc.

Are those a dealbreaker to you? Having a Neo-Geo cartridge that behaves differently from official software seems kinda common, from small homebrew projects that don't bother with anything but the game itself to NGDev games that have their own menus and shenanigans.

I'm just asking because it doesn't seem THAT difficult to implement that stuff, especially in areas the BIOS can help (I was very surprised to learn the How to Play screen on Nam-1975 was BIOS provided for instance), but also I don't know if those things are consistent or available throughout the range of MVS/AES hardware (excluding Neo CD naturallY which is another beast of its own).

Aside from technical difficulties the only "problematic" thing about it might be the Neo logo/eye catcher because of Trademark infringement but that doesn't seem like something nu-SNK will actively fight you over unless you also include their logos on packaging and promotional material.

Burning Fight!!
11-09-2019, 10:08 PM
https://www.youtube.com/watch?v=1WVyJHV4BaQ

Found this video by Razoola. Was this ever released? Having no luck using the forum's search function.

max 330 mega
11-10-2019, 12:20 AM
I've never seen or heard of that program before. Razoola is away from the scene currently, so I guess you'll need to wait until and if he returns to programming neo stuff to ask him about it.

Hine62
11-11-2019, 08:36 AM
I've done some research on this... here is a link to the routines that can handle program flow such as that in the neogeo manual. NeoGeo User Sub Routines (https://www.yaronet.com/topics/171604-user-subroutine-with-neobitz-c-dev-kit-datlib)

Just by changing the line in the crt0_cart.s file you can get the NEO-GEO logo to animate. The sound will probably play also...

_EYE_CATCHER = 0x00 /*;eye catcher (0-common 1-custom 2-off)*/

I did a quick try with my current project and it animated just like the real logo, but the graphic was wrong and sound was missing. This means that graphics and sound need to be in the correct place, which is most likely why it is turned off.

Here is a link on the Eyecatcher (https://wiki.neogeodev.org/index.php?title=Eyecatcher)

mikew
11-11-2019, 11:34 PM
Found this video by Razoola. Was this ever released? Having no luck using the forum's search function.

If I remember correctly, this was a framework Raz was going to release for homebrew development when we were working on the pc2neo USB code.

Burning Fight!!
11-12-2019, 09:23 PM
I've done some research on this... here is a link to the routines that can handle program flow such as that in the neogeo manual. NeoGeo User Sub Routines (https://www.yaronet.com/topics/171604-user-subroutine-with-neobitz-c-dev-kit-datlib)

Just by changing the line in the crt0_cart.s file you can get the NEO-GEO logo to animate. The sound will probably play also...

_EYE_CATCHER = 0x00 /*;eye catcher (0-common 1-custom 2-off)*/

I did a quick try with my current project and it animated just like the real logo, but the graphic was wrong and sound was missing. This means that graphics and sound need to be in the correct place, which is most likely why it is turned off.

Here is a link on the Eyecatcher (https://wiki.neogeodev.org/index.php?title=Eyecatcher)

Thanks, I suppose you could supply a non-neo logo (eg. your own ficticious software label) but I don't know if that would be too tacky for long time neo owners. Nice to know that the sound (MML?) is supplied by the cart, too.


If I remember correctly, this was a framework Raz was going to release for homebrew development when we were working on the pc2neo USB code.

Too bad but I suppose that's cool for actually looking at stuff myself and not using his code as a crutch. Would be nice to take a peek at, still.