Atari ST graphics hardware compared to PC EGA

[LeChuck]

I dont have much experience of the Atari ST line of computers beyond playing around in emulation. Curious to learn more about it.

EGA was introduced in late 1984 and was able to display 16 colours on screen but from a fixed 16 colour palette, Atari ST displayed 16 colours on screen too but from a vastly larger palette of 512 colours.
Neither feature hardware sprites nor hardware scrolling which is very evident in a lot of software developed for both.
However, Atari ST devs were able to achieve smooth scrolling, even fairly impressive parallax at times like Enchanted Lands for example, the Turrican 2 port was impressive too though not as good as the Amiga version.
took ages for PC clones to have any kind of decent scrolling.

Is this just clever programming from ST devs or is there something in the hardware that makes it more suitable for action games than an EGA PC?
Was there just more of a culture of really pushing the hardware from Atari coder side compared to "IMB-combatible" dev scene?

A lot of games on ST seems pretty straight up ports from EGA such as Monkey Island for example, but you do also have exceptions such as Prince of Persia which looks very different on the 2 platforms. I was wondering what were the best examples of games that were on both that clearly took advantage of higher palette of ST?

[nobody]

I believe EGA and VGA had hardware scrolling but wasn't used because it wasn't compatible with all cards and plus to be able to run in CGA that didn't have any hardware scrolling.

[britelite]

Originally Posted by nobody

I believe EGA and VGA had hardware scrolling but wasn't used because it wasn't compatible with all cards and plus to be able to run in CGA that didn't have any hardware scrolling.

Indeed, vertical scrolling works on all EGA/VGA cards (at least in the 4 bitplane mode) but horizontal pixel scrolling isn't implemented by all clone-cards.

[AmigaHope]

Originally Posted by LeChuck

EGA was introduced in late 1984 and was able to display 16 colours on screen but from a fixed 16 colour palette

EGA actually allowed 16 colors from a 6-bit (64 color) palette. The PCjr/Tandy enhanced CGA graphics mode was 16 colors from the fixed 16-color 4-bit RGBI palette, and EGA had similar modes available, but the best EGA modes had 6-bit (2 bits per channel) RGB palette.

[Seiya]

Atari Graphics are very similar to Tandy than EGA.

[LeChuck]

Thank you for setting me straight on hardware scrolling AND the palette of EGA, obviously my knowledge of the EGA specs is lacking.

Commander Keen I believe was the first PC platformer with nice and smooth scrolling and it was an EGA game, AFAIK John Carmack didnt use any sort of harware scrolling and that adaptive tile refresh engine he was doing was all software based.

Enchanted Land on Atari ST came out 1990 like Commander Keen but also featured several layers of parallax. Surely a decently high clocking 286 with an EGA card should have been able to achieve parallax scrolling in the right hands too?

[idrougge]

Originally Posted by LeChuck

Commander Keen I believe was the first PC platformer with nice and smooth scrolling and it was an EGA game, AFAIK John Carmack didnt use any sort of harware scrolling and that adaptive tile refresh engine he was doing was all software based.

AFAIK his routine was basically the same as used on both the Amiga and consoles, using hardware scrolling to scroll part of the screen while building upcoming scenery on a background buffer or unexposed part of the screen. So, in short, hardware scrolling.

Originally Posted by LeChuck

Enchanted Land on Atari ST came out 1990 like Commander Keen but also featured several layers of parallax. Surely a decently high clocking 286 with an EGA card should have been able to achieve parallax scrolling in the right hands too?

My impression is that PC game makers were very unimaginative, hence why Carmack has gone down in history and they even have a special name for everyday techniques we don't even care to given any names on other platforms.

[dreadnought]

Originally Posted by idrougge

My impression is that PC game makers were very unimaginative, hence why Carmack has gone down in history and they even have a special name for everyday techniques we don't even care to given any names on other platforms.

Way to ignore the fact that pre 90s PC was a completely different beast than home computers. It was an expensive business machine with limited fx capabilities, and there was no big market for arcade games (though these certainly existed even since PC booter days).

Games from PC-specific genres, such as Flight Simulator or King's Quest seem pretty imaginative though.

[roondar]

I've always felt the PC arcade/action gaming market of the 1980's/1990's was kind of split into three "eras": the early years with CGA composite out, which had some nice arcade style games (Burger King is quite good for instance). Then came the digital CGA/EGA years where the arcade style games tended to be a lot worse than what the competition offered and bad scrolling was the norm. Lastly came the VGA/SVGA era in which the PC showed us all it could do those games just fine given the proper hardware.

[Foebane]

I remember reading that the Atari ST used "off the shelf" parts, so I got the impression that Atari, having lost the Amiga to Commodore, hastily threw together a simple design to be deliberately cheap.

And since then, decades later, I heard that there was an attempt at custom hardware for the video, namely something called the "Shifter" which does yield somewhat impressive effects in the Demoscene, namely the ST's abilities to display hundreds of colours at once, with no HAM mode, that can be faded in and out (something which very few Amiga demos have tried with HAM, AFAIK).

[roondar]

Yup, the ST does not actually use of the shelf parts for graphics. It just didn't include any Dual Layer/Sprite/Blitter hardware (and also lacks the Copper).

As I understand the ST's method for display many hundreds of colours (i.e. PhotoChrome), it actually uses the CPU to rapidly set colour registers to new values as the scanline progresses. It relies on very tight timing to do so. My guess is that an Amiga equivalent should be doable, but since the Amiga already has stuff like HAM and Copper based colour reloading it's generally not done that way.

[BSzili]

Originally Posted by idrougge

AFAIK his routine was basically the same as used on both the Amiga and consoles, using hardware scrolling to scroll part of the screen while building upcoming scenery on a background buffer or unexposed part of the screen. So, in short, hardware scrolling.



My impression is that PC game makers were very unimaginative, hence why Carmack has gone down in history and they even have a special name for everyday techniques we don't even care to given any names on other platforms.

That's correct. The big "discovery" that lead to the formation of id Software were the EGA hardware scrolling registers, to achieve console-like smooth scrolling on PC. Keen Dreams is open source, so there's no need to speculate, they only used software scrolling in CGA.

[nobody]

The ST and Amiga were (way) better than EGA, the ST in particular easily beats any EGA, just try to draw graphics with this palette lol.




Or better say, try draw this with an EGA

[roondar]

I thought EGA had a 64 colours to choose from, not 16?

[nobody]

Standard EGA monitors do not support use of the extended color palette in 200-line modes, because the monitor couldn't tell if CGA or EGA so they had to use CGA palette.
64 color palette was available in 640x350

example given, Sim City used the extra colors at 640x350

[roondar]

Ah, that does explain it. Most games didn't run in the hires modes so it makes sense they then used the fixed palette.

[frank_b]

EGA was pretty horrible. Better than CGA but that's not saying much. VGA was pretty horrible pre VLB for performance but the colours and palette were decent. I don't think you can compare the Amiga or ST to a PC in 1985. It's a different class of machine. The ST and Amiga smoke the 85 PC on performance and cost effectiveness.

[fxgogo]

So my Dad used to work for Unisys back in the day and bought a 286 EGA monster when most of my friends still had XT’s with monochrome or CGA. We still had our Atari ST at the time and initially I thought the ST was way better. Over time the PC won me over with the HD and Sierra games, but for arcade action, it was still the ST for me.

Looking back now I appreciate the EGA gfx for what they were and the inventiveness of the artists to make more of what was there. I really need to look back at ST again to appreciate it’s unique qualities

[dreadnought]

Originally Posted by frank_b

The ST and Amiga smoke the 85 PC on performance and cost effectiveness.

Yeah, totally, which is why they were widely adopted by businesses and eventually, because of their world wide market penetration, set a standard which we're using to this day.

Smh.

[idrougge]

I'm sure that standard was based totally on technical superiority, just like the EGA colour palette was based on artistic superiority.