Brad P. TaylorI've been going through old hdd images and looking for fun stuff to post. I found a doozy today and I've put it up on github. Back in 1990 I was hired at #LucasArts and given the task of maintaining and building new tools for the #SCUMM system. Long story cut-short here is a #Win32 port of the #DOS tool named #DK. This was used to bring the #MonkeyIsland #VGA 256 color art down to 32 colors for the #Amiga. In any case I thought people should have chance to see it.
R. L. Dane 
Huh! I always thought the #Amiga had 256+ colors
chexum@RL_Dane @lardratboy Not before AGA (92+) -- at least not at the same time.
With copper tricks, different vertical stripes could also use different palette, but this wasn't used widely.
With copper tricks, different vertical stripes could also use different palette, but this wasn't used widely.
Interesting! Wasn't the first HAM mode 6-bit? Wouldn't that mean that it could display 64 colors without HAM, or am I misunderstanding?
Never had an Amiga myself, I just drooled from afar while I messed around with my monochrome classic mac ;)
@RL_Dane @lardratboy
In the old Amigas (OCS/ECS), there were only 32 palette registers. You could use 64 colours only with EHB, where the second 32 colours were a dimmed copy of the first 32 (half-brite).
But using more colors needed more memory for the bitplanes and took time from the CPU to refresh the screen, so it's all quite a hassle when the most common platform was a chip-mem-only 68k Amiga.
Ahh, ok. :-)
mnemonicoverload@RL_Dane @lardratboy @chexum It's probably worth pointing out that the choice of porting to 32 colours is a development choice. Earlier in the Amiga's life many developers instead targeted 16 colours for their ports so that they could have (rough) colour parity across their EGA, AtariST, and Amiga versions. Later in the Amiga's life developers like Sierra DID use the full 64 colour EHB mode on the Amiga when porting their 256 colour MCGA titles over but that was largely enabled by the normalization of a 1MB of RAM requirement for games on the Amiga. Using EHB mode wasn't very practical when 512KB was the target as it didn't leave enough room for game code and even most Amiga-first titles stuck to a base 32 colour max screen at that time (excluding playfield / copper tricks, etc).
(Aside: HAM mode is even more RAM intensive and due to the way artifacting worked in that mode wasn't generally practical to use for anything other than static screens like title screens.)
(Aside: HAM mode is even more RAM intensive and due to the way artifacting worked in that mode wasn't generally practical to use for anything other than static screens like title screens.)
@mnemonicoverload @lardratboy @chexum
Good to know. Yes, I had read up a bit on HAM mode. I'm impressed anyone managed to write even a paint program that targeted it.
@RL_Dane @lardratboy @chexum Hah, yes for sure. It's easy enough _now_ to write a good computationally intensive algorithm to do a good job of converting say a 16-bit colour image into HAM-6 mode, but back when it was a current, relevant thing creating a nice looking HAM image was very much a matter of careful manual pixel fiddling.
@mnemonicoverload @lardratboy @chexum
Something I forgot about that era was how hard it was to write software to fully use the capabilities of that machine ON the same machine.
The Macintosh development team, for example, were targeting 128k, but their machines all had 512k.
IIRC, the Microsoft Office programs for the Classic Macs weren't even written on Macs.
A lot of later Commodore 64 developers had REUs with 1MB or more of RAM.
@mnemonicoverload @lardratboy @chexum
A lot of the images I post on #Mastodon are covert love letters to the Amiga, because I use palette reduction as a means to make small PNGs to reduce the burden on the instance.
I usually mark them with the hashtag #LossyPNG
@mnemonicoverload @RL_Dane @lardratboy BTW, another reason for 16-colour LoRes images could have been that with 4 bitplanes, the CPU could get almost all (alternate) cycles it wanted to access the chip memory. With more colours, bitplane DMA started to eat into that, so programs needed more planning/optimisation to work just as well.
HiRes had that threshold at 4 colours, so 16 colour was useless on normal Amigas, maybe except to demonstrate how Intuition draws window borders and scrollbars :)
@RL_Dane @lardratboy @chexum On stock OCS Amigas without FastRAM expansion you certainly didn't want to use 16 colours on the Workbench for sure which is presumably why it wasn't even an option in earlier versions of the OS. For games that typically ran at 320x200-ish as was common and perfectly acceptable at the time 16 or 32 colours was perfectly fine as far as bus bandwidth availability went for a tightly coded game, especially for a booter game that ran on the bare metal and didn't even load the OS.