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Games that use Apple II-style artifacting for colors


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#51 Bryan OFFLINE  

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Posted Fri Mar 17, 2017 8:35 AM

We'll need that sooner or later as analog input displays are bound to die out together with new consumer devices requiring them. Of all TVs listed on a popular price comparison website here, only 2/3s are listed with analog input (and analog tuners are not even mentioned any more).

 

My take on things (at the moment):

 

1. I prefer to use vintage displays with my vintage computer when I can. However, I understand that one day all of this stuff will be dead. I will be too. :)

 

2. We will probably always have the option of connecting old video sources via some kind of interface even if it isn't a feature of the TV. These devices will probably get better and cheaper as time goes on.

 

3. If I want perfect digital video, emulators do that for me for free.

 

I know many people want modern recreations of classic hardware but having grown up with these machines, I enjoy the original experience more.



#52 _The Doctor__ ONLINE  

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Posted Fri Mar 17, 2017 9:36 AM

sorry emulators don't let you play starwars games properly..  timing and centering are off



#53 Gunstar OFFLINE  

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Posted Fri Mar 17, 2017 11:50 AM

 

My point was the lack of being able to display high resolution text on the same line as multi color graphics meant AR had a lot of wasted space on either side of the tiny "action window", compared to Ultima III which was able to use a much more efficient layout.

Thats not a "wasted" space, it IS reserved space. You buy a compass that is displayed on one side, There maybe something for the other side too, in one or both AR games. 



#54 Gunstar OFFLINE  

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Posted Fri Mar 17, 2017 11:54 AM

Here's what Ultima III looks like on the Atari:

 

attachicon.gifultima iii atari.png

 

 

That depends on the Atari and the monitor. ultima looks EXACTLY like the first Apple picture on my 130XE,though it is laid out in the squater fashion of the second picture, it goes green and purple instead of red and blue on my 1200XL (with video upgrade), but it still looks more like the top picture with different colors. I don't know what machine and monitor you are using for this picture here, Maybe PAL? The color there is the worst I've ever seen from an Atari and dfinitely not what they look like on my Atari's.


Edited by Gunstar, Fri Mar 17, 2017 11:58 AM.


#55 MrFish OFFLINE  

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Posted Fri Mar 17, 2017 12:18 PM

That depends on the Atari and the monitor. ultima looks EXACTLY like the first Apple picture on my 130XE,though it is laid out in the squater fashion of the second picture, it goes green and purple instead of red and blue on my 1200XL (with video upgrade), but it still looks more like the top picture with different colors. I don't know what machine and monitor you are using for this picture here, Maybe PAL? The color there is the worst I've ever seen from an Atari and dfinitely not what they look like on my Atari's.

 

It's just a screenshot of someone's Youtube video. I guess the colors themselves are going to be different depending on what machine you use. But my point was that NO Atari screen will look like that Apple screenshot, because the Apple is displaying more artifacted colors than are possible on an Atari, and also I think the Apple II's width in pixels is limited to something like 280 rather than the 320 that the Atari has.



#56 Gunstar OFFLINE  

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Posted Fri Mar 17, 2017 2:33 PM

 

It's just a screenshot of someone's Youtube video. I guess the colors themselves are going to be different depending on what machine you use. But my point was that NO Atari screen will look like that Apple screenshot, because the Apple is displaying more artifacted colors than are possible on an Atari, and also I think the Apple II's width in pixels is limited to something like 280 rather than the 320 that the Atari has.

There was a high-res graphic art program for the Atari, I want to say Graphic's Magician, but that may not be it, That you could get in the neighborhood of 8 artifact colors and then with some fill patterns to boot it did a great job of high-res color. It could easily reproduce the colors of that Apple screen-shot, and if you squeezed it into 280 screen ratio...

 

Actually, if it was pretty much a straight port from the Apple, then why not do it in a windowed 280? Was it easier to do the full 320? That seems like pixels would have to be added. 



#57 MrFish OFFLINE  

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Posted Fri Mar 17, 2017 4:05 PM

There was a high-res graphic art program for the Atari, I want to say Graphic's Magician, but that may not be it, That you could get in the neighborhood of 8 artifact colors and then with some fill patterns to boot it did a great job of high-res color. It could easily reproduce the colors of that Apple screen-shot, and if you squeezed it into 280 screen ratio...

 

I've heard of such a program before, but I've never seen any examples. I find it rather odd, if 8 colors are achievable, why no commercial program -- AFAIK -- used more than the 3 (+background) that everyone is familiar with? I'm guessing the program you speak of is using some trickery, like dithering 2 artifacted colors or some such, and thus they wouldn't be "true" colors.

 

I'd like to see someone reproduce that Apple screen; but even if they can, there is no Ultima game on the Atari that uses that many colors and hence my reason for asking why the Apple II version was posted in comparison to AR on the Atari to begin with.


Edited by MrFish, Fri Mar 17, 2017 4:06 PM.


#58 Keatah OFFLINE  

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Posted Fri Mar 17, 2017 5:25 PM

Reproduce which apple screen?



#59 Bryan OFFLINE  

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Posted Fri Mar 17, 2017 5:50 PM

I've heard of such a program before, but I've never seen any examples. I find it rather odd, if 8 colors are achievable, why no commercial program -- AFAIK -- used more than the 3 (+background) that everyone is familiar with? I'm guessing the program you speak of is using some trickery, like dithering 2 artifacted colors or some such, and thus they wouldn't be "true" colors.

 

The Apple II color video modes are modulated at 3.58MHz with a delay circuit which generates the 8 colors. The Atari has its delay on a separate chroma generator so you can't use it on luma. So, you get 1 color for a 010101 pattern and another for 101010 (180 degrees away) with nothing available in-between.

 

So, if you want another color, you can use some staggered patterns 010010100101 (avoiding the 11 sequence) which will give you a mangy looking area of mixed color or you throw PMG overlays on the screen.

 

The combination of all the tricks could actually result in a nice looking high-rez game (in NTSC anyway).



#60 GlowingGhoul OFFLINE  

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Posted Fri Mar 17, 2017 8:59 PM

Reproduce which apple screen?

 

I inadvertently posted an Apple II screenshot instead of an A8 screenshot of Ultima III. Mystery solved. That MrFish screenshot of Ultima III is so bad it's fair to say he couldn't have picked a better one if he were intentionally trying to make Ultima look terrible.



#61 Gunstar OFFLINE  

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Posted Fri Mar 17, 2017 9:49 PM

 

I've heard of such a program before, but I've never seen any examples. I find it rather odd, if 8 colors are achievable, why no commercial program -- AFAIK -- used more than the 3 (+background) that everyone is familiar with? I'm guessing the program you speak of is using some trickery, like dithering 2 artifacted colors or some such, and thus they wouldn't be "true" colors.

 

I'd like to see someone reproduce that Apple screen; but even if they can, there is no Ultima game on the Atari that uses that many colors and hence my reason for asking why the Apple II version was posted in comparison to AR on the Atari to begin with.

Really?!? I got news for you, ALL artifact colors are FALSE colors...there aren't any true colors. And yes, I see the quotes, on true, which only makes the statement more ridiculous to me. Regardless, who cares if dithering is used if it works?!?

 

But yes the program did use dithering patterns like checkerboard, etc., to make for example a fill of red and blue checkered dither to make a "purple" color, and in fact had an entire page or more of patterns to choose from, it also created more artifact colors like a yellow and light-green and pink (as solid looking on a composite screen as the basic red/blue or green/purple artifact colors) among others through choices of paint brushes with special pixel placement. In any case, I've been meaning to track down that art program again, if I find it I'll post it and you can see for yourself.

 

But to the Ultima stuff, sure, the Atari version doesn't use as many artifact colors as the Apple version. It doesn't mean it isn't possible. Weren't the C64 versions done in a high-res mode similar to Apple and Atari too? 


Edited by Gunstar, Fri Mar 17, 2017 10:08 PM.


#62 ZylonBane OFFLINE  

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Posted Fri Mar 17, 2017 10:25 PM

I got news for you, ALL artifact colors are FALSE colors...there aren't any true colors.

 

Wrong. NTSC artifact colors are actual colors being generated directly by the screen. They have nothing in common with dithered colors.



#63 MrFish OFFLINE  

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Posted Fri Mar 17, 2017 10:30 PM

Really?!? I got news for you, ALL artifact colors are FALSE colors...there aren't any true colors. And yes, I see the quotes, on true, which only makes the statement more ridiculous to me. Regardless, who cares if dithering is used if it works?!? In any case, I've been meaning to track down that art program again, if I find it I'll post it and you can see for yourself.

 

News of what? "ALL artifact colors are FALSE colors...there aren't any true colors."... I'm not sure I even understand what the news says. So if I look at a bunch of red or green pixels all grouped together, they're not really red or green pixels? What are they? I hope we can all agree that red and green are both "colors"?

 

As to what I mean by "true", is a color that isn't created by: dithering, flickering, cycling or some other method, which would give the impression of seeing something that is actually a combination of colors. That doesn't mean I don't think that these methods aren't useful or can't look good. But I sure know the difference when I'm looking at one or the other.


Edited by MrFish, Fri Mar 17, 2017 10:36 PM.


#64 Bryan OFFLINE  

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Posted Fri Mar 17, 2017 11:09 PM

Just a quick refresher on how NTSC color works:

 

The TV/monitor will isolate content in the picture which has a frequency at and around 3.579MHz. It will also filter this frequency out of the picture so the color information doesn't corrupt the picture with dots too much. If you send a video pattern that oscillates at that frequency, you won't see the high-low pattern being sent.  Instead, you'll get a steady average value created by the filter and the extracted waveform will cause the monitor to produce color in that area. The way to preserve all frequencies in the picture is to use S-Video where color is not extracted from the same signal as brightness.

 

The actual color applied to the image is determined by the phase of the waveform relative to the reference phase (colorburst) sent off-screen at the beginning of the line. The saturation of the color (purity of the color, its distance from gray) is determined by the amplitude of the waveform.

 

Because the NTSC Atari uses the same clock for color and pixel generation, an on-off pixel pattern produces a perfect 3.579MHz signal which looks like color information to the monitor when using composite. There's no way to prevent it- a 0101 black and white pattern in high resolution sends what the monitor can only interpret as a colored region.

 

Different Atari computers display different artifact colors because Atari kept changing the video circuits and introducing different amounts of delay in the chroma section. This shifted its relationship to luma enough to affect the phase relationship between the chroma colorburst and the pixels themselves.

 

Whether or not they're true colors depends on your point of view. To a composite monitor, it looks like color. To the computer, it's just a pixel pattern.



#65 GlowingGhoul OFFLINE  

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Posted Fri Mar 17, 2017 11:11 PM

The accepted term among experts is clearly "false color".

 

-De Re Atari says:

 

"Since the luminance can change on half color clock boundaries, this implies that two false color, or artifact pixel types can be generated. This is basically true. However, these two pixels can be combined to form two types of full color clock pixels. This is illustrated below:"

 

http://www.atariarch...dere/chaptD.php

 

 

-And in the description of the Analog Devices AD725 video processing chip, in the section on composite video artifacts:

 

"Therefore, the color that results from the luma signals in the chroma band is a false color."

 

http://www.analog.co...heets/AD725.pdf

 

-And US Patent 7460180 B2

 

Method for color artifact suppression

Abstract:
"A false-color suppression method corrects a pixel value of a pixel in a target location of a target frame while de-interlacing video data"

Edited by GlowingGhoul, Fri Mar 17, 2017 11:16 PM.


#66 MrFish OFFLINE  

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Posted Fri Mar 17, 2017 11:14 PM

That MrFish screenshot of Ultima III is so bad it's fair to say he couldn't have picked a better one if he were intentionally trying to make Ultima look terrible.

 

Haha... not so. I honestly just grabbed a screenshot of the first video I found on Youtube. That was posted at 1:30am, so I just wanted to post it and go to sleep.

 

I don't think the screenshot is so bad, but whatever emulator or palette used with the emulator by the guy who posted the video must have made the colors different than what most people expect to see. I'm not familiar enough with the game to know, other than how many artifacted colors I should see.


Edited by MrFish, Fri Mar 17, 2017 11:26 PM.


#67 MrFish OFFLINE  

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Posted Fri Mar 17, 2017 11:23 PM

The accepted term among experts is clearly "false color", regardless of MrFish's ability to understand

 

-De Re Atari says:

 

"Since the luminance can change on half color clock boundaries, this implies that two false color, or artifact pixel types can be generated. This is basically true. However, these two pixels can be combined to form two types of full color clock pixels. This is illustrated below:"

 

http://www.atariarch...dere/chaptD.php

 

 

-And in the description of the Analog Devices AD725 video processing chip, in the section on composite video artifacts:

 

"Therefore, the color that results from the luma signals in the chroma band is a false color."

 

http://www.analog.co...heets/AD725.pdf

 

-And US Patent 7460180 B2

 

Method for color artifact suppression

Abstract:
"A false-color suppression method corrects a pixel value of a pixel in a target location of a target frame while de-interlacing video data"

 

That's fine if it's just a matter of a technical term. Now that you bring up some sources, I know I've heard it before.

 

It doesn't change what I'm saying though. Just use any name that tickles your fancy for a solid/single color; there's obviously a difference between that, a dither, flickering screens, and color cycling.


Edited by MrFish, Fri Mar 17, 2017 11:24 PM.


#68 Bryan OFFLINE  

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Posted Fri Mar 17, 2017 11:28 PM

Well, the Apple II has no separate color generation. It's simple luminance output is actually always made up of on-off bit patterns to get color so S-Video isn't even possible.  But, since color is the intended result, I doubt anyone would call it false color (although in my opinion it looks like ass).



#69 Keatah OFFLINE  

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Posted Sat Mar 18, 2017 12:14 AM

I get this from Applewin. Looks nice because of the green landscape and blue water.

ultima_iii_1_000000000.png

 

Then from Altirra I get these, but not able to tweak it exactly like the Apple II.

a1.png a2.png a3.png



#70 Keatah OFFLINE  

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Posted Sat Mar 18, 2017 12:36 AM

We've already had this thread anyway.

 

This thread is better because it is actually active with new people, new emulator screenshots, and new directions.



#71 Goochman OFFLINE  

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Posted Sat Mar 18, 2017 7:16 AM

You can get brown,blue, white, green, purple and yellow.  I produced some basic games that used these.

 

Having said that only blue, brown and white can be placed wherever you want.  Purple and Yellow require a staggered pattern which cant be placed wherever you want.

 

In the attached picture you cant see it well due to emulation but the 'storm' cloud lightening bolt was yellow on my Atari 800.  It was prob more a washed out yellow, but you could see it.  You can also see the trees show some green in them.  Dont ask me how I got this to work - I really screwed around with patterns back in the day.

 

seaq.jpg



#72 Bryan OFFLINE  

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Posted Sat Mar 18, 2017 8:01 AM

Then from Altirra I get these, but not able to tweak it exactly like the Apple II.

 

This is more or less what I remember from playing on the 800:

 

U3_Game_Atari8bit.png

 

http://ultima.wikia....s_of_Ultima_III



#73 Gunstar OFFLINE  

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Posted Sat Mar 18, 2017 9:05 AM

I get this from Applewin. Looks nice because of the green landscape and blue water.

attachicon.gifultima_iii_1_000000000.png

 

Then from Altirra I get these, but not able to tweak it exactly like the Apple II.

attachicon.gifa1.pngattachicon.gifa2.pngattachicon.gifa3.png

The center picture I have never seen the like on a real Atari. The other two are the difference between my XL and XE. I remember, back in the day, not liking the reddish landscape, but I liked the fact that my XE had blue water at least. It wasn't until the mid 90's that I owned my first XL and was introduced to the green/purple artifacts, and absolutely hated it. The greens and purples always remind me of IBM CGA graphic colors which I also always hated. But I also used to fiddle with the tint on my TV/monitors to get artifact colors my eyes preferred. In any case, I prefer the artifact colors on games like Ulitma rather than my PAL S-video without them. Of course that's not true across the board, as I said before, only for games made to use artifacts. Amaurote definitely looks better without artifacting.


Edited by Gunstar, Sat Mar 18, 2017 9:09 AM.


#74 Keatah OFFLINE  

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Posted Sat Mar 18, 2017 9:55 AM

It was explained to me that Altirra needs a little more work before it can do 90 degree shifted colors like the Apple II. And interestingly, only the Atari 800 can do it. All other models don't.

 

http://atariage.com/...ased/?p=3721129

http://atariage.com/...ased/?p=3721116



#75 ZylonBane OFFLINE  

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Posted Sat Mar 18, 2017 9:17 PM

 

This thread is better because it is actually active with new people, new emulator screenshots, and new directions.

 

And because it's a new thread, which is your crack.






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