MAMEWorld Forums - News - Re: MAME 0.210

>I read somewhere that there is 2 different working ideas for the star field in Galaga & Gaplus is this right?

Two different items regarding star field emulation and the various links self-explain the details.

This link provides the details: https://github.com/mamedev/mame/pull/3532

Item #1 -

galaga.cpp: Replaced star field lookup table with Galois LFSR implementation. [Jindřich Makovička, Wolfgang Scherr, Couriersud]

2019-05-12
https://github.com/mamedev/mame/commit/4be4bb12e983c6e4effba4e8c5e462fae2c59581

galaga: Manually apply pull request #3532: star field lfsr
implementation

Manually applied the lfsr part of #3532 and verifying against static
star field. Also added documentation and my findings about the known
star field decoding algorithms.

==

Item #2 -

tutankham.cpp: Implemented star field, and improved colors. [Couriersud, Guru]
* Konami 084 and bootleg star fields are implemented, selectable in machine configuration.
* Colors are now based on galaxian, giving a better approximation.

bug report: https://mametesters.org/view.php?id=2932

2019-05-07

https://github.com/mamedev/mame/commit/1c0ed14c006d68b1b45616ddaed7472f52fddc41

tutankham: Implement starfield, better colors. [Guru, Couriersud]

Used color code from galaxian for better color approximation.
The starfield code was added to better document the 084 custom chip.
There are two star fields implemented now. The active one can be
selected in Machine Configuration.

a) Scramble Starfield

1/3 star width like scramble/galaxian, starfield code same as scramble.
This one is similar to the Konami starfield video below. The 084 uses
the same signals as scramble.

b) Bootleg Starfield

Guru provided schematics of a daughter-board which on a Konami bootleg
replaced the custom chip 084. This starfield matches the starfield
(picture) of this bootleg.
At least there is now a starfield which matches a real-life(tm) bootleg.

None of the two alterntives reproduces the star field which can be
observed in the Stern videos on youtube.

The Konami video mentioned in video/tutankhm.cpp is different from
tutankhm. Looks like we are missing an early board dump