Re: Games: Apple IIgs vs. Atari ST vs. Amiga

[heuser.marcus@freenet.de]

> Halfbrite allowed for 64 colors, however artists and programmers had no
> control over the secondary palette. From what I recall, it would mirror the
> main palette (32 colors) with a duplicate palette, only each color was half
> the lumance of each original color. Nice for shadowing effects but not
> really practical. I think there were pixel placement restrictions as well?

No placement restrictions as you had 6 totally linear bit planes.
As you described the highest order bit of the 6 controls the luminance
of the palette color indexed by the other 5 bits.
IMHO having 32 additional colors is practical when it costs so little
extra memory / CPU cycles.

> The Apple IIGS's multi-palette mode at least allowed 256 colors
> (arbitrarily selectable) on screen at once. You were restricted to no
> more than 16 colors per scanline, however it worked well for games
> where you could easily split sections of the screen.

For this the Amiga had the "Copper" - a part of the two graphics ASICs
(I think in the Denise-chip) which could semi-autonomously do raster
line interrupts. This didn't cost CPU cycles (at least not many) and
was very widely used - Shadow of the Beast by Psygnosis was probably
the best known game to feature this.
The Copper could do much more than that - changing graphics modes was
easy, too. The demo scene made heavy use of its features (so called
"Copper-effects").

> HAM was somewhat similar to the GS's 3200 color mode; also in the
> sense of not being practical for game software. Incidentally, did the ST
> have any trickery to purpose more than 16 colors per screen?

Only raster interrupts, which cost some CPU cycles, AFAIK.

> Overall, the Apple IIGS and Amiga were fairly similar for graphics when
> it came to gaming software.

If you reduce gaming software to 320x200 with approximately the same
amount of colors then you come close. But you didn't account for
hardware sprites and the Blitter co-processor ;-)

As for the sound hardware of the IIgs: I think too, that it is way more
advanced than the one in the Amiga. But its a fact that there are not
masses of games that really take advantage of that. And lots of IIgs
games don't sound better than the Amiga.

My explanation would be that the hardware was too advanced (know-how
must be aquired to use this to its full potential = expensive) and the
IIgs market was too small (resulting in low projected sales) that most
software houses did decide to not grace the IIgs with the software it
should have had.

Just my 2 ct.

bye
Marcus