Atari 8-Bit Graphics Capabilities

[PixelCrunch]

Hi, Pixel Here, i’m new here, so forgive me if my writing and grammar is crap.

 

I was wondering about the Atari 8-Bit Series of Computers graphical and color capabilities.

 

Some of the existing documentation on the graphical capabilities seem wrong to me. If you’ve seen some of the more well known Atari 8-Bit demos out there (Numen, Garfield, Ect, Ect.) The graphical capabilities seem WAY more advanced than what the documented lists say. Smooth gradients were done in said demos, at relatively high resolution. So, could someone tell me that:

 

1: The Atari 8-Bit Series could have X Colors per Scanline (A-La The Atari 2600 and Atari Lynx)

2: There really can be only X Colors on screen at once, Perioid.

3: There can be X amount of colors on screen, but there can be multiple play fields to increase the amount of colors via Multiplexing.

 

Thanks for reading, and please respond!

 

-PixelCrunch

Edited July 3, 2019 by PixelCrunch
Grammar and Formating

[+DrVenkman]

I’m not a graphics coding guy but the gist of it is that modern demos and even some games use undocumented modes and programming tricks that were never even known to the original system designers. There is a body of knowledge built up in the last 40 years about this kind of stuff. The hardware as built has some behaviors that are just sort of accidental or not necessarily intended. Coders and hardware hackers have spent a lot of time digging into the guts of OS code, hardware behavior and machine timing in the real world and learning how to take advantage of these “happy accidents” and developed coding tricks and tools to use these characteristics in making their demos and games.  

[Gunstar]

One of the biggest advantages of the Atari 8-bits is they have two graphic chips with a combined 16 graphic and text (character graphics) modes (11 and 5 respectively*) and their ability to use DLI's (Display List Interrupts) and VBI's (Vertical Blank Interrupts) and through these allow to mix graphic modes on-screen, and allow far more colors per scan-line than any one graphic mode alone. Which is also possible because of the Antic chips 128 color palette and the GTIA chip's 256 color palette, far more than any other (6502 based at least) 8-bit computer of the day.

 

Then you have it's clock speed of 1.79Mhz, which is nearly double most other 6502 machines of the day, except the BBC Micro (2Mhz). It was engineered in spectacular fashion by Jay Miner and company, who were also the brains behind the Amiga.

 

Then you have the more modern coders who found the "happy accidents" and tricks @DrVenkman referred too, which has allowed coders to do even more things with mixed software graphic modes than the engineers conceived.

 

The Atari 8-bit was way ahead of it's time in it's design, in every area, and even the Commodore 64 and later 8-bit computers really only improved upon it with more sprites capable, but still fell short in most everything else, graphic-wise.

 

*even more with DLI mixed modes and software graphic modes invented by coders.

Edited July 3, 2019 by Gunstar

[Forrest]

The Atari 8-bit computers were not well documented when they were released in 1979, but by 1982 they were. For reference, see Atari's Operating System User's Manual, Source Listing and Hardware Manual, DeReAtari and books from independent publishers (Compute!'s Mapping the Atari book and Compute! magazine) and Lon Poole's Your Atari Computer. Many of the best Atari 8-bit games were released by 1982/1983.

[kiwilove]

What is done in a 'demo' does not necessarily apply to within a game situation - unless the demo was to demonstrate a game situation/application.  ie. a graphics demo is just that.  A game demo is something different.

If you look at 16K games - which was the standard cart size for 1982/83 - you can see that the graphics are not that sophisticated - as it was the 32K and 48K games that looked far better.  Just compare Defender with Dropzone.

By the time the XE/XEGS came out - bankswitched carts appeared, so even more can be fitted into a cart.  Maybe someone can list these titles - commercial and homebrews?

 

It is up to the programmer as to how much you want to push the graphics within a game, and probably show someone relatively new to the Atari hardware versus someone who's done various game projects already for it.  I would say more tricks/techniques need to be employed to add a Wow to the graphics.

 

It is always subjective as to what are the best titles - whether it be for the graphics or gameplay, or both. You should be able to have access to most of them, and can decide for yourself - what are the best?

 

Harvey

I like designing graphics, and am no programmer.

[polbit]

4 hours ago, Gunstar said:

One of the biggest advantages of the Atari 8-bits is they have two graphic chips with a combined 16 graphic and text (character graphics) modes (11 and 5 respectively*) and their ability to use DLI's (Display List Interrupts) and VBI's (Vertical Blank Interrupts) and through these allow to mix graphic modes on-screen, and allow far more colors per scan-line than any one graphic mode alone. Which is also possible because of the Antic chips 128 color palette and the GTIA chip's 256 color palette, far more than any other (6502 based at least) 8-bit computer of the day.

 

Then you have it's clock speed of 1.79Mhz, which is nearly double most other 6502 machines of the day, except the BBC Micro (2Mhz). It was engineered in spectacular fashion by Jay Miner and company, who were also the brains behind the Amiga.

 

Then you have the more modern coders who found the "happy accidents" and tricks @DrVenkman referred too, which has allowed coders to do even more things with mixed software graphic modes than the engineers conceived.

 

The Atari 8-bit was way ahead of it's time in it's design, in every area, and even the Commodore 64 and later 8-bit computers really only improved upon it with more sprites capable, but still fell short in most everything else, graphic-wise.

 

*even more with DLI mixed modes and software graphic modes invented by coders.

Why is it that people always feel the need to put down other machines when describing the one they enjoy the most? And usually spreading FUD along with it?

 

Enjoy the Atari for what it was, a brilliant machine released 3 years ahead of the C64. That's an eternity in technology. C64 had color RAM to define each 8x8 separately, even at 320x200, 8 big sprites hardware scrollable in each direction, etc, etc. Atari had two advantages - more overall colors and effectively 20% or so faster clock, depending on the mode.

Edited July 3, 2019 by polbit

[Gunstar]

46 minutes ago, polbit said:

Why is it that people always feel the need to put down other machines when describing the one they enjoy the most? And usually spreading FUD along with it?

 

Enjoy the Atari for what it was, a brilliant machine released 3 years ahead of the C64. That's an eternity in technology. C64 had color RAM to define each 8x8 separately, even at 320x200, 8 big sprites hardware scrollable in each direction, etc, etc. Atari had two advantages - more overall colors and effectively 20% or so faster clock, depending on the mode.

I'm not putting down anything, I like the C64 too, I'm just telling the truth. If I wanted to put it down, I would have left out that it's better a sprites, for instance.  But other than that, I prefer Atari's bit-mapped graphic modes over 8x8, basically character graphics, in as much as color placement. And I DO hate the C64's color palette, not just how small it is, but how washed out and muddy the colors are-now that's a "put-down" AND the truth.

 

And if we were talking about more than graphics I'd have mentioned other areas where the C64 and Atari have their strengths. And YOU are the one now down-playing the Atari's 16 modes and DLI's, etc.! So get off your high-horse arse-hole!

 

Oh, and the two things you did say were Atari advantages, are HUGE advantages. And technically, the Atari has 8 Player/missile (sprites) too, 4 that are 8 pixels wide and 4 that are 2 pixels wide, and can be as tall as the screen vertically. But, yes, the C64 sprites are better over-all because, for one, they can have more colors per sprite.

Edited July 3, 2019 by Gunstar

[kenjennings]

6 hours ago, Gunstar said:

 a combined 16 graphic and text (character graphics) modes (11 and 5 respectively*)

 

Six text modes (ANTIC 2 through 7)

Eight Map modes (ANTIC 8 through F)

 

So, 14 graphics modes.

 

Then there are four possible color interpretations by GTIA.   14 * 4 == 56 graphics modes.

 

Though many of these combinations may not have a  practical use.   So, so somewhere in the ballpark of 17 "easy to use modes"  (the base 14 modes plus 3 GTIA color interpretations on mode F ) up to around 20 to 26 usable configurations depending on your creativity.

 

Not including DLI gymnastics that game vertical scrolling to cut down text mode heights or to stretch map modes. 

 

Edited July 4, 2019 by kenjennings
gramar. then there, not there there

[Gunstar]

Thanks for the refinement @kenjennings , but as far as the graphic & text modes, Atari themselves included the GTIA modes as graphic modes. And I don't know about the 6th text mode, why there was no mention of it in the ad posted below.

[kenjennings]

6 hours ago, PixelCrunch said:

Hi, Pixel Here, i’m new here, so forgive me if my writing and grammar is crap.

 

I was wondering about the Atari 8-Bit Series of Computers graphical and color capabilities.

 

There's tons of information about the hardware here on the Altirra site:

http://www.virtualdub.org/altirra.html

And the Altirra hardware reference manual:

www.virtualdub.org/downloads/Altirra%20Hardware%20Reference%20Manual.pdf

 

And wikipedia has pretty much the same info...

https://en.wikipedia.org/wiki/CTIA_and_GTIA

https://en.wikipedia.org/wiki/ANTIC

 

[kenjennings]

Just now, Gunstar said:

Thanks for the refinement @kenjennings , but as far as the graphic & text modes, Atari themselves included the GTIA modes as graphic modes. And I don't know about the 6th text mode, why there was no mention of it in the ad posted below.

 

Right, the marketing stuff was never very accurate about what the machine could actually do.   In the marketing war with Commodore they let Commodore get away with saying the Atari could only display 192 scan lines.   Atari never weaponized the fact of the built-in horizontal/vertical overscan capability :-).

 

[Sugarland]

6 hours ago, PixelCrunch said:

Hi, Pixel Here, i’m new here, so forgive me if my writing and grammar is crap.

 

I was wondering about the Atari 8-Bit Series of Computers graphical and color capabilities.

 

Some of the existing documentation on the graphical capabilities seem wrong to me. If you’ve seen some of the more well known Atari 8-Bit demos out there (Numen, Garfield, Ect, Ect.) The graphical capabilities seem WAY more advanced than what the documented lists say. Smooth gradients were done in said demos, at relatively high resolution. So, could someone tell me that:

 

1: The Atari 8-Bit Series could have X Colors per Scanline (A-La The Atari 2600 and Atari Lynx)

2: There really can be only X Colors on screen at once, Perioid.

3: There can be X amount of colors on screen, but there can be multiple play fields to increase the amount of colors via Multiplexing.

 

Thanks for reading, and please respond!

 

-PixelCrunch

 

That's not an easy question to answer because of the many graphics modes, sprites colors and mixing of modes at the same time and more. 

 

AFAIK, A8's can display all 256 colors at once in a vertical rainbow.  I believe Alternate Reality: The City in a practical gameplay sense, having about 128 colors on screen at once was the most colorful across the whole game. See here.    And as far as the C64 having 'better' sprites, I'm not so sure they are as fast or as flexible as A8. I'd love to see a technical breakdown and in-depth performance comparison. My guess is that A8's sprites are much faster, if that even matters to gameplay.  Also all A8 sprites can be re-used on the next row while I really doubt C64's can dream of that. Also A8 sprites combine colors when on top of each other and in this way can be multicolored, at the cost of losing a sprite or missile.

 

 

Edited July 4, 2019 by Sugarland

[polbit]

31 minutes ago, Gunstar said:

I'm not putting down anything, I like the C64 too, I'm just telling the truth. If I wanted to put it down, I would have left out that it's better a sprites, for instance.  But other than that, I prefer Atari's bit-mapped graphic modes over 8x8, basically character graphics, in as much as color placement. And I DO hate the C64's color palette, not just how small it is, but how washed out and muddy the colors are-now that's a "put-down" AND the truth.

 

And if we were talking about more than graphics I'd have mentioned other areas where the C64 and Atari have their strengths. And YOU are the one now down-playing the Atari's 16 modes and DLI's, etc.! So get off your high-horse arse-hole!

 

Oh, and the two things you did say were Atari advantages, are HUGE advantages. And technically, the Atari has 8 Player/missile (sprites) too, 4 that are 8 pixels wide and 4 that are 2 pixels wide, and can be as tall as the screen vertically. But, yes, the C64 sprites are better over-all.

 

You said Atari's 1.79MHz CPU is nearly double the speed. Nope, since the ANTIC overhead kills most of the advantage as compared to C64 for example. You said Atari has has 16 graphic/text modes, but most of them are utterly useless, and not used much. Atari is hamstrung by color resolution, and no amount of modes is going to stop that. You said DLI is an advantage, but it's just a different approach. I happen to enjoy it as it's fun to program, but there is nothing better or worse about it. You said C64 fell short in most other aspects besides sprites, graphics-wise. Nope, C64 has better color resolution, better hardware scrolling, better character modes, Atari only has more colors (see below.)

 

C64 sprites are a HUGE (just to make it bigger than yours) advantage for certain games, as there is 8 of them, are much larger (24x21), and are hardware-scrolled at 320x200 in both directions no matter what mode. They can also be multicolor at half the resolution (12x21). You have to manually scroll Atari sprites vertically, and their horizontal hardware scroll is only at line resolution. There is also only 4 8-bit players + 4 2-bit missiles, or 5 8-bit wide players. No comparison really. 

 

Atari has a huge advantage of 256 colors for certain games. I happen to like C64 palette, but I grew up with it, so I'm used to it. Not going to pass judgment as to quality of it, let's call it subjective, but obviously 256 colors is better, especially when you fix the horrid stock output on most 8-bits. It also has some speed advantage for 3D games, but somewhat mitigated by color resolution again.

[polbit]

25 minutes ago, Sugarland said:

And as far as the C64 having 'better' sprites, I'm not so sure they are as fast or as flexible as A8. I'd love to see a technical breakdown and in-depth performance comparison. My guess is that A8's sprites are much faster, if that even matters to gameplay.  Also all A8 sprites can be re-used on the next row while I really doubt C64's can dream of that. Also A8 sprites combine colors when on top of each other and in this way can be multicolored, at the cost of losing a sprite or missile.

 

It's not that hard to Google you know. How are A8 sprites faster?? What does that even mean? They are scrolled at certain resolution. C64 has finer scrolling for sprites in all but hi-res bitmap mode, where they are equal. Vertically you have to scroll sprites manually on A8, whereas C64 has hardware scroll just like horizontally. 8 sprites vs 5. single or multicolor sprites (turned on individually) vs multicolor overlap only.

 

C64 sprites can be multiplexed, for a total of 112 non-clipped per frame. 

[kiwilove]

In this kind of discussion - it's always helpful to cite examples to illustrate - instead of simply quoting specs.

 

When you compare say Pole Position vs Pole Position on Atari vs C64 - you could say the C-64 version was hardly trying to outdo the other.  Being both from Atari?  You can say they're trying to keep both versions more or less the same.

 

However comparing Dropzone to Dropzone - done by the same author, it is said the Atari version (done first) is faster and more maniac than the other.  I haven't played both to compare.

 

When you look at Blue Max - I think you're comparing the programmers more - that there is a change in scale on the C-64 to it's disadvantage.  The original was done on Atari first and is brilliantly done.

 

Xevious on C-64 was a big disappointment.  The programmer wasn't up to the task.  It seems to be more like the 7800 version than of the coin-op.  But Xevious wasn't successfully done for the 8-bit Atari also.

 

Spelunker is a good comparison, whereby the Atari version shows overscan in use.

 

Encounter?  I haven't checked out the C-64 version - but will imagine the Atari version comes out better?  Being the first version out.

 

Some comparisons will come out virtually identical?  Say for Choplifter, Lode Runner, Bristles and others.

 

Some will have the Atari version being the better version - say for Miner 2049'er, Boulderdash and others.

 

Others will have the C-64 being better done such as Zaxxon, (2 out for C-64, the better one being from Synapse) and others? 

 

At least the hardware comparisons between the C-64 and Atari 8-bit is not so clear cut, as with the likes of the Apple II, and Spectrum.

 

But then, you can bring up the Atari killer app Star Raiders - here is an 8K game, that uses low res (well, med res) graphics - that is fast moving in real time - that was ready in 1979.  Try citing a C-64 equivalent - and how many years later on, was that?

 

Harvey

[polbit]

20 minutes ago, kiwilove said:

In this kind of discussion - it's always helpful to cite examples to illustrate - instead of simply quoting specs.

 

Specs never translate well into actual products, because it takes a good programmer to use them. Just look at some of the Speccy games, that have no right to look as good as they do. I honestly don't have much exposure to the Atari games, as I grew up around C64. Nowadays I don't play many games, but enjoy 6502 assembly. Looking at equivalents to what I played as a kid, like Pitstop II, or Zaxxon, or Ghostbusters, C64 looks much better to me but I also do love Star Raiders, and some of the newer stuff is pretty amazing on both systems. Both Atari and C64 have their strengths and weaknesses, and tend to favor one type of game vs another. 

 

At the end of the day, most of us identify what we grew up with. I'm really enjoying playing with the 800XL because it's new to me, and the new hardware like U1MB and SIDE2, and clean video output really makes it interesting. Learning SDX, OS layout, etc. is pure fun, but I can use a C64 with my eyes closed. The half-shifted cursor keys are second nature, JiffyDOS is ingrained into my brain, Turbo Assembler is what I use to judge other 6502 assemblers, and so on. Just what it is.

[Kyle22]

How does AtariBlast look on your Commie? Oh, wait, yeah that's right your machine is a retard running at 1 Mhz vs 1.79. Even with the ANTIC DMA, the Atari is always faster than the Commie.

 

You have NO possibility EVER of running a game like that.

 

You guys can't even run Rescue on Fractulus properly.

Do you like a slideshow?   Please!

 

 

 

[polbit]

4 hours ago, Kyle22 said:

How does AtariBlast look on your Commie? Oh, wait, yeah that's right your machine is a retard running at 1 Mhz vs 1.79. Even with the ANTIC DMA, the Atari is always faster than the Commie.

 

You have NO possibility EVER of running a game like that.

 

You guys can't even run Rescue on Fractulus properly.

Do you like a slideshow?   Please!

 

 

 

 

Rather than try to argue, I'll just leave this right here: https://www.youtube.com/watch?v=pXfq5PDt2aE

 

Apologies accepted.

[_The Doctor__]

To be completely honest... I prefer AtariBlast! over that any day!

I also enjoy Space Harrier and the subsequent updated releases.

 

I was all hyped up to click the link, then was let down as it was the tired and slow old Armalyte clip...

I think most of the coders here said... why bother we've already got this sort of thing covered with better game-play. I suspect a person such as yourself wouldn't be satisfied until someone ports it though...

 

Off I go to play Scramble. But have fun as you sight two or three games that look decent and have acceptable game play. While you do your research, I'll choose from a multitude of wonderful titles with great game play coded by people who do unique, well crafted games that really stand out. When they do a port it normally supersedes whatever else is out there just because they can.

 

I'll top my fun filled gleeful celebration with stunt car racer. As was discovered- it's one of the best ports going. I played it on my Commie and it suxxored. I played it on the Atari because I wanted to see how bad it would be based on commodore users saying the Atari wouldn't be able to compete blah blah blah, what made me start laughing was how much faster and more responsive the Atari port was right out of the gate and I couldn't believe how much better it was all the way around. For once the game was fun and playable on an older 8 bit retro system, without help from silly add on devices either!

[polbit]

4 minutes ago, _The Doctor__ said:

To be completely honest... I prefer AtariBlast! over that any day!

 

Well, it is of course your right to enjoy blocky graphics, poor-res explosions, jerky movement, and tiny sprites, on a limited size screen. AtariBlast is pretty awful, don't really understand why it's used as an example so many times, unless there's simply nothing better. 

 

Anyway, this discussion which I tried to keep technical has of course descended into another stupid pissing match. I guess some people just can't let go of the mine-is-better mentality, even 30 years later. Have fun, I'm out.

[carlsson]

 

Even as a C64 guy originally, I've learned to appreciate the Atari 8-bit as well for its strengths, and have enough drawers to keep both in my collection.

 

PixelCrunch seemingly innocently asked about Atari graphics, and within five posts it turned into another Atari vs Commodore thread...

[Gury]

22 minutes ago, polbit said:

 

Well, it is of course your right to enjoy blocky graphics, poor-res explosions, jerky movement, and tiny sprites, on a limited size screen. AtariBlast is pretty awful, don't really understand why it's used as an example so many times, unless there's simply nothing better. 

 

Anyway, this discussion which I tried to keep technical has of course descended into another stupid pissing match. I guess some people just can't let go of the mine-is-better mentality, even 30 years later. Have fun, I'm out.

Man, you have personal issues...

[PixelCrunch]

I’ve started another Atari v. Commodore war did i? Please stop.

[Gunstar]

1 hour ago, carlsson said:

 

Even as a C64 guy originally, I've learned to appreciate the Atari 8-bit as well for its strengths, and have enough drawers to keep both in my collection.

 

PixelCrunch seemingly innocently asked about Atari graphics, and within five posts it turned into another Atari vs Commodore thread...

I guess it's my fault for just mentioning the C64 in passing, barely used as an example: "C64 and other 8-bits." But I didn't know there was a Knob like Polbit that would come and suggest I was putting it down, and as the hypocrite I quickly learned he is, in two posts, he starts off putting down the A8 on every point he can and his points being completely absurd too. That's why after my first reply to him I stopped replying immediately and put him on ignore. What a tool!

 

It's not your fault @PixelCrunch , if it weren't for this troll, we would still just be discussing Atari graphics.

Edited July 4, 2019 by Gunstar
Trying to get the flakey tag thing to work, and couldn't

[flashjazzcat]

As previously suggested and in light of 'ANTIC color palette', etc: Read the ANTIC and CTIA/GTIA sections of the Altirra Hardware Reference Manual carefully before comparing the Atari's graphics capabilities with those of other machines. This is a great FUD avoidance technique.