Atari 8-Bit Graphics Capabilities

[Gunstar]

9 minutes ago, flashjazzcat said:

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.

Great suggestion! I'm off to read it right now!

[kenjennings]

22 hours ago, PixelCrunch said:

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

 

 

The Atari hardware has several things than can be combined that can add/vary colors, so the simple answer to this is "it depends".

 

The "Per Scanline" designation is important here, because all color options, and even graphics modes can be changed on each scan line.  Few games use only a full screen of a single graphics mode.  Multiple graphics modes mixed on screen is the norm.  Also, for the sake of the question this answer covers only what can be done strictly through inherent hardware capabilities that once set up requires no further CPU support to maintain.

 

First, is the "normal" 14 graphics modes. Depending on the display mode there could be two, or four, or five colors (per scanline).

However, Player/Missile graphics are separate color registers from the playfield and can add four more colors to this, so there could be up to nine colors (per scanline).  The Atari has nine color registers, so this would be the limit of colors created purely by color indirection (using the color registers.) (per scan line).

 

BUT, different GTIA options provide other color interpretation possibilities beyond the "normal" modes.  This allows 9 colors as playfield graphics (using color registers), or 16 colors (all the same brightness), or 16 shades of one single color.  So, the answer can be sixteen colors (per scanline).

 

HOWEVER, (there's always some other trick going on the Atari) color merging options in GTIA can mix playfield and player/missile graphics colors together, and the total number of colors possible doing this is 23 colors.  Nine of those come from color registers.  The rest of the colors are done by overlapping Player/Missile objects with each other and overlapping Playfield pixels with Player/Missiles pixels.  This would be a fairly contrived situation and has limitations, but it is do-able, and it is an inherent capability of the hardware.  So, the complete answer is the hardware can produce up to 23 colors (per scan line).

 

Edited July 4, 2019 by kenjennings
typos. left out some info

[kenjennings]

22 hours ago, PixelCrunch said:

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

 

 

Most of the time the palette is  128 colors, 8 shades of each base color.

 

Using the GTIA option for 16 shades of one color, and interrupts to change the base color at different locations on the  screen this becomes a possible 256 colors.

 

[kenjennings]

22 hours ago, PixelCrunch said:

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.

 

 

I don't completely understand this question.  The multi-plexing point suggests to me this question pre-supposes the capabilities of some other non-Atari, computer graphics hardware.  ( ? )

 

Do you simply mean page flipping between two screens for each video frame?   This would be easy to do on the Atari, but it could also be done on any other computer that can monitor frame start, and switch screen registers/pointers.  The end result is simply the math of how many colors are present on each separate screen. That math would multiply out the colors the same way on any computer that supports the page flipping method.

 

 

[Gunstar]

Space Harrier uses the page-flipping technique for all it's colors. There's also an older graphic display program called ColorView, which page flips 3 screens of red, green and blue 16-shade GTIA mode to create a virtual 4096 colors.

[+Adam+]

1 hour ago, kenjennings said:

 

 So, the complete answer is the hardware can produce up to 23 colors (per scan line).

 

Well, it's not really "the complete answer"  - for example in graphics mode 9 one may use 38 colours in line (see the picture attached):

- 16 shades of one colour (playfield pixels)

- 16 shades of another colour (missiles as the 5th player over the playfield pixels)

- 6 colours of multicoloured players (additional colours P0+P1 and P2+P3)

 

[kenjennings]

2 minutes ago, +Adam+ said:

Well, it's not really "the complete answer"  - for example in graphics mode 9 one may use 38 colours in line (see the picture attached):

- 16 shades of one colour (playfield pixels)

- 16 shades of another colour (missiles as the 5th player over the playfield pixels)

- 6 colours of multicoloured players (additional colours P0+P1 and P2+P3)

 

 

Super kewl.  I was not aware of that.  There's always another trick.  

 

[+Adam+]

Similar technique in GR.11 mode:

- black + 15 hues which share the same luminance (playfield pixels)

- black + 15 hues with another luminance (missiles as the 5th player over the playfield pixels, black is still black in this mode)

- 6 colours of multicoloured players (additional colours made of P0+P1 pixels and P2+P3 pixels)

Which means up to 37 colours in one scanline (picture attached, OlivierP palette).

[kenjennings]

27 minutes ago, +Adam+ said:

Similar technique in GR.11 mode:

- black + 15 hues which share the same luminance (playfield pixels)

- black + 15 hues with another luminance (missiles as the 5th player over the playfield pixels, black is still black in this mode)

- 6 colours of multicoloured players (additional colours made of P0+P1 pixels and P2+P3 pixels)

Which means up to 37 colours in one scanline (picture attached, OlivierP palette).

 

Are you done yet?  Anything more?   

 

[+Adam+]

At the moment I just would like to add that there exist tricks which allow to use about 90 colours in one scan line - see "New Direction" intro by MaPa and PG:

 

 

[R0ger]

You can also mix 4 hues and 4 brightness levels in 4 color mode. If you add character mode and PMG, you get 6 brightness levels. And using 2 frame flickering you can get 8 hues and 11 brightness levels. That can make images like this:

 

 

Also check the Rasta convert thread ..

[Gunstar]

Being an avid RastaConverter user, I know what it can do, if not so much how it's pulled off. But I imagine pretty similar to some of the ways already mentioned here. I was told, IIRC, it can do 10-15 colors per scan-line, depending on the image. What I know it can do from experience is a full 128 colors on-screen at once, but the average is half that. It use P/M graphics for more colors. 160x240. It's impressive. No flickering and no alternating scan-lines. I don't know if the graphics techniques used to pull this off have been given a graphic mode name, like other software graphic modes. It does it the same as Graph2font app on the PC I guess, since that can be used to pre and post edit Rasta images if you wanted. I don't. I'd like to see some form of graphic art program that runs on the Atari made for it, though I guess you'd have to lose at least a P/M or two to use as a pointer.

Edited July 5, 2019 by Gunstar

[tjlazer]

I am a big ATARI 8-bit and Commodore 64 fan but I always thought the Atari 8 bits were much superior graphic wise and wished it’s superior graphic capabilities were utilized more. Part of the problem was a lot of software was designed with the Atari 800 in mind and was limited to only 48K. That’s why a lot of Commodore 64 ports were better.

[R0ger]

54 minutes ago, tjlazer said:

I am a big ATARI 8-bit and Commodore 64 fan but I always thought the Atari 8 bits were much superior graphic wise and wished it’s superior graphic capabilities were utilized more. Part of the problem was a lot of software was designed with the Atari 800 in mind and was limited to only 48K. That’s why a lot of Commodore 64 ports were better.

Not really. IMHO C64 is generally superior. Yes it has way less colors. Yes it has less flexible modes. But for most games, you need 4 color GFX mode and sprites. Both is way better in C64. And it's certainly not problem of few less kB. There are areas where Atari has theoretically an edge, especially 3d graphics, but it's typically the same game with somewhat better FPS on Atari.

[_The Doctor__]

and oh what difference a few FPS can make!!! Especially at such low frame rates!!! It can feel like an order of magnitude better experience. Game play and feel always seem better on the Atari. I want a great experience, and the same washed out colors and slight eye candy never has made up for what has always been great response and the closer to arcade feel of the Atari.

Edited July 5, 2019 by _The Doctor__

[Gunstar]

I used to be jealous when I'd see screen shots of C64 games in 16 colors, that the same games were 4-5 colors on the Atari version. I knew the Atari could do better of course, that it was lazy ports over to the Atari from the C64 version. But once I actually got a C64 and played those games I had on my Atari, I wasn't jealous anymore. The C64 versions looked prettier, but played terribly in comparison. And when you compare Atari games, made for the Atari to utilize it's graphic wonders and speed, games like the Lucasfilm games, compared to the C64 version, the C64 version is worse graphically and with FPS and gameplay. 

 

Of course with our community developers, we are getting all the top-notch ports generally  superior to the C64 versions or Spectrum, BBC, or whatever 8-bit system it's ported from.  And new games now, that make the most of the Atari's hardware. 

 

That being said, I like the C64, but prefer the Atari, and the C64 has a lot of great games on it that aren't available for the Atari, and still probably never will be, and I intend on getting a C64 again and both computers will set proudly side-by-side in my computer room as the two best 8-bit computers ever made. I may also have a BBC micro there too, as number 3. 

 

With the 16-bit systems I'm the opposite. I prefer the Amiga over the Atari ST, but I like both. I owned both. I may own both again, but definitely an Amiga a some point. I'm an engineer fan-boy, not a brand fan-boy. And I prefer Jay Miner's engineering.

 

With 32-bit systems, it flips again, and I prefer the Falcon over the Amiga 1200/4000 (or the TT). 

Edited July 6, 2019 by Gunstar

[kiwilove]

For me - it was always about the games themselves.  That they had to measure up.  Being a coin-op videogames fan first - I wanted a home version that looked the part and was playable.  Being an all time Zaxxon fan - no home version was ever good enough, until the Synapse C-64 version appeared.  All the other home ports simply didn't satisfy me, in what I wanted in a Zaxxon game.  No surprise because it was a difficult game to port/convert.

Same with Xevious - only the PC Engine conversion came close to the arcade - no surpise it needed some capable hardware to deliver it.  A review of it at the time (1986?) simply did not appreciate this landmark game at all and said it was boring and stale, etc.

I did try my hand at my own version of it graphic wise - and found a combination of foilage/forestry graphics that works, using a minimum of characters to do so, which was put into Hawkquest - which mimicked various coin-op games graphics.

Bruce Lee as a game didn't really satisfy my yen for a Bruce Lee game - being a big Bruce Lee fan (watched that extra long Chinese TV series - which wasn't too bad?) - but with the arrival of StreetFighter II, the videogame - this was what was needed.  No surprise it revived interest in playing coin-op games and spawned a whole series of copycat games.  And the only decent home version was out on the 16-bit gaming consoles - and later 32-bit consoles.

I can't recall any good home computer version/conversion of it?  Or any similar kind of game?  IK+ probably come closest - I don't know what happened to the ST/Amiga version - as it looked terrible.

It's always the games that matter.  I did have a C-64 also, back in the day - so I'm familiar with certain titles - but so far I haven't checked out the homebrews, etc.  From around the late 80s' onwards.  The last thing I checked out on emulation, was Armalyte - which was the best shooter to date, on that hardware.

I long wanted to work on something that could show off what the Atari hardware could do, in a shooter - that became AtariBlast!

I'm sure more new levels could be done for it - but I haven't got the zest/energy to start on that - so maybe 10 years after it's appearance, I may feel the need to get started?

I don't think it is fair to compare the 2 scramble conversions done for the C-64 and Atari's.  As I would guess there were different objectives in mind for them.

That the C-64 conversion (that was completed around 2? or less years ago) wanted to stick with the arcade as close as possible.  Whereas I wanted a version/conversion - that could incorporate some new minor enhancements to it, without affecting it's original gameplay.

 

When you have projects in which the same developers are responsible for them - then, I'll say you can then compare the Atari vs C-64 versions - which can then show the hardware differences.

 

Harvey

[NuY]

On 7/6/2019 at 3:23 AM, kiwilove said:

but with the arrival of StreetFighter II, the videogame - this was what was needed.  No surprise it revived interest in playing coin-op games and spawned a whole series of copycat games.  And the only decent home version was out on the 16-bit gaming consoles - and later 32-bit consoles.

I can't recall any good home computer version/conversion of it?

 

Edited July 8, 2019 by NuY

[jefffulton]

I liked the beginning of this thread when the OP asked about the hidden capabilities of the Atari machines, before it devolved into C64 v Atari 8bit platform. 
That is always a fun discussion, but ultimately splits the community and takes people angry and go to their corners (not saying that has happened here, butit might get that far). 
What are the best tricks that haven't been discovered in the last 20 years tha twere not known or used much (if at all) from 1979 to 1991? 

How does a multi-colored sprite multiplexer work? I do see awesome demos out there, but Atari Blast is a demo as a game is kicks ass over almost every other Atari 8bit (and many C64 games I would guess) games. How was that done? 

Can the 16 colors 1 luminance Antic modes really be used for a game? 

 

Is there any way to easily swap the missile colors to not be the same at the player colors? 
 

Edited July 10, 2019 by jefffulton

[+Adam+]

3 hours ago, jefffulton said:

Can the 16 colors 1 luminance Antic modes really be used for a game? 

To be precise, in GR.11 mode there are 15 colours in 1 luminance & constant black

This mode is used in Murder on the Zinderneuf game. And in one of Atari Blast levels too.

 

3 hours ago, jefffulton said:

Is there any way to easily swap the missile colors to not be the same at the player colors? 

In general there are two options:

a) 4 missiles share the colours with 4 players

b) the missiles have one common colour ("5th player" option).

[Gunstar]

On 7/5/2019 at 9:23 PM, kiwilove said:

 

When you have projects in which the same developers are responsible for them - then, I'll say you can then compare the Atari vs C-64 versions - which can then show the hardware differences.

 

Harvey

That can be true, rarely, but more often I find it to be exactly the opposite, because the developers like one system over the other themselves and therefore have less experience with the other system and so don't know how to make the best use of the hardware. I've found that if you have different developers making the same game for the system the prefer and/or have more experience with, that is when you see the true power and hardware differences.

[kiwilove]

I believe in a fair comparison between different hardware - and praise where it's due.

I would guess it may take up to 2-3 years to fully understand the hardware to get the most out of it.  Maybe even longer, because the early releases do not show what the system could really do?

That kind of time was not available when you see releases on both systems at about the same time.

 

I could not understand at first, why AtariBlast! did not make a favourable impression upon the C-64 fanbase.  Maybe it was their reluctance to acknowledge something noteworthy on a competing hardware? But maybe it is because there is no C-64 equivalent to AB!  That to do some kind of comparable C-64Blast! would take up too much time and effort to do so.  And when completed - would not compare well against it?

 

Anyway - I think the most significant thing to AB! - was the amount of animation going on, within it - and then to list all the other stuff that is included as well.  I think the programmers can list them all.

 

While there is no direct connection between the games AtariBlast! and Scramble - there is some AB! influence to it - that Scramble would not have ended up the way it did, without the work done on AB!  And so the tip is, animate, animate, animate.

 

Like with any other hobby or interest, etc.  It is the time and effort you put into it, that you get the results out.  And that if you had the long, long desire to do something special - it will eventually get done if you really want to do it.

And you do it, because it is something that 'you' want to do.

 

Harvey

[Gunstar]

Personally, I think part of the reason AtariBlast! wasn't given the nod by the C64 community was what's his name early in the thread that seemed to want to pick a fight with me with C64 vs. Atari. Before I blocked him I read another reply or two by him to others, and he discounted it as having blocky graphics, and at another point he claimed that most of the extra Atari graphic modes were useless. I think it's because they didn't have such modes, aren't used to them, and fail to see, probably by choice, just what wonders can be accomplished with the GTIA modes.

 

They are only used to 160x200 and 320x200 modes and that's it. Once upon a time I felt the same way, thinking those graphic modes were too low-res and too Atari VCS-like, and I only wanted the higher resolutions on my Atari, a carry over from being accustomed to Apple II high-res. That all ended when I first played the incredible Lucasfilm games, and saw the advanced 3D first-person graphics and fantastic use of all those colors, and I was sold, and the GTIA modes became my favorites. The same was true with my pixel-art.

 

Once I bought Rambrandt and was introduced to the GTIA modes for graphic art, and a bit later Technicolor Dream, those modes became my favorites and what I mostly worked with. I much preferred, as an artist, the perceived resolution that is possible with all those colors, and how they made up, to me, so much more than enough for the low-resolution.

 

*Some* C64 users also like to taunt us with their 8 sprites (and area of strength that means less to me), and (though they can multiplex too), will completely discount how much the Atari can also do with multiplexing of P/M's and software sprites. Old prejudices. Some of us overcome them and like both computers for what they are, others just can't, like it's admitting their favorite machine is less, if they accept and admit the strengths of the other/another machine that was the competition once upon a time. 

Edited July 11, 2019 by Gunstar

[zzip]

On 7/3/2019 at 1:21 PM, PixelCrunch said:

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.

1. The hardware itself allows 4 playfield colors + border + 5 P/M colors in bitmapped CTIA modes

     or up to 5 playfield colors + border + 5 P/M colors in that one character mode (I forget the name)

     or up to 16 playfield colors with restrictions in GTIA mode (or 9 without restriction)

     some people have timed mid-scanline palette changes to give more apparent colors,  but this consumes CPU

2 + 3. There can be 128 colors on screen in CTIA modes and 256 on screen in in GTIA modes at once,   but this will require some technique to change palettes while the screen is being drawn on TV (such as Display list interrupts).   Otherwise the hardware limits are as described as in #1

 

Now a lot of new graphics modes have popped up since the 80s such as HIP, TIP, etc.    These promise greater color freedom.   But from what I can tell they mostly use one of two techniques to trick the eye:

   1) flip the screen really fast between two slightly different pictures and palettes.  In the best cases this really does give the impression of more colors and smoother gradients.   Worse case is it looks flickery.   It consumes more memory and maybe CPU

   2) Alternate graphics modes in a display list.   One line may have gradient values while the other has color value.   Again it tricks your eye, but if you look closely it's easy to see how this was done.

[Gunstar]

With modern LCD displays. flickering in software modes is less noticeable, or can be completely eliminated on some TV's or if upscaling converters are used like I have. I can turn it on or off with my S-video-to-VGA converter/upscaler. The color is also more vibrant due to the video upgrade in my 1200XL.

Edited July 11, 2019 by Gunstar