Andrew Davie
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Posts posted by Andrew Davie
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I couldn't seem to access the latest PDF from that website.
Maybe some of you will find this Word document form useful. I have attached it.
Note that I corrected some spelling errors and changed spellings from UK to US because UK spelling distracts me.
I also embedded some images (but not as many as the old PDF had).
Feel free to do whatever you want with it.
Thanks for writing the tutorial.
I voted "yes" for a hardcopy, by the way. If it gets printed, I will buy it.
First thing I suggest everyone do is change the spelling back to the way it was meant to be.
Cheers
A
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(and as far as I know, the only cart form demonstration of chronocolor interlaceing)
Wasn't Atari Charles hundred dollar cart with a Tronman picture a demo of chronocolor interlacing?
Did anyone here even get one of those?
And didn't Andrew D. come up with that technique.......or was the first to utilize it to it's full potential?
The Tronman cart was a rip-off using my original free public-domain code for the dancing baby demo and the Build Your Own Greeting Cart. Only the bankswitching method had been changed, and it was able to display 7 images, I think. The images in that cart were in my opinion very poor quality because the image conversion wasn't done correctly.
ChronoColour carts such as the Christmas GreetingCart were much better visually.
The ChronoColour technique came about when Thomas Jentzcsh and I became interested in colour display techniques, and we independantly worked on different systems, but were feeding off each others' ideas and work. Probably ChronoColour produced the best quality in the end, but there were definitely different techniques, all viable.
ChronoColour multiplexes three single-bit dithered frames for the red/green/blue components of a colour image, which are interleaved with each other such that the three frames consist of alternating red scanline, green scanline, blue scanline (one from each frame). These interleaved frames are then played in sequence while at the same time changing the colour of each scanline to either red or green or blue both on a line-by-line basis and on a frame-by-frame basis. The colour on any line cycles red one frame, green the next, blue the next, and colours on successive lines within a frame are red, green, blue, red, green, blue, etc. Put all of that together and you get your ChronoColour images.
There's a document at http://www.taswegian.com/greetingcart.html with an explanation.
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Reminds me a of a mate who ordered a penis extension device over the net.
When it came he undid the box and inside was a magnifying glass
:rolling: This would be funny if you used "enlargement" instead of "extension".
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It's very difficult to get good-focus screenshots with my camera, but attached are my first effort. This shows my implementation of BoulderDash running on a '2600, as it looks when displayed on my mechanical Televisor. The televisor is mentioned in http://www.atariage.com/forums/index.php?showtopic=105068 for those who blinked.
I thought the televisor was set up for a scan rate of 384 lines/second. How did you make it display A2600 video which is at 15,750 lines/second?
Scanlines are vertical in my televisor, and although there are only 32 scanlines, displayed at 12.5fps, each scanline has a higher resolution limited by the bandwidth of the source signal. It's hard to put a value on it, but say 50 pixels. In reality, we don't have discrete pixels on a line... just shades of grey merging into each other.
The video is simply downconverted before playing on the televisor. Doesn't matter what the '2600 displays; the video is treated on a frame by frame basis and this frame is converted to the appropriate format (ie: a wav file). In other words, no, it's not live... yet.
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Are there still talks about getting this game on cart? or has the path gone cold? Haven't heard anything about it in a while. Sorry if you're sick of people asking, but I know you put a lot of work into that game and it'd be a pity to see it go unreleased.
No, there have been no discussions bewteen First Star Software and myself about this for a number of years. I am not about to release an unlicensed version, so it looks like the project is dead. The only way this could ever be released is if First Star Software gave their blessing. It might be unreleased, but at least *I* know that I managed to pull it off... and that's what counts to me. There's a version on cart that appears at the occasional show -- might be worth chasing up.
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It's very difficult to get good-focus screenshots with my camera, but attached are my first effort. This shows my implementation of BoulderDash running on a '2600, as it looks when displayed on my mechanical Televisor. The televisor is mentioned in http://www.atariage.com/forums/index.php?showtopic=105068 for those who blinked.
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Yes, that was my work -- but there's a much much better all-colour version that came a few months after that one. See attached binary. This is from about June 2003, so it's quite old.
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... because sooner or later, like me, you will find yourself on the receiving end of Paypal's wraith.
Interesting Freudian slip. Wrath of the wraith?
Cheers
A
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I have a CreatiVision and a bunch of cartridges to suit for sale. Contact me privately.
Cheers
A
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Call me a spoilsport, but you just can't appropriate others' intellectual property and release it for profit, like this. Come up with your own idea, or get permission from the copyright owners!!!!!
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Andrew, if you wish to say something else, do it soon. This crap is going to get locked and any further thread about it, deleted.
Only to point to the copyright notice on the code...
; Copyright ©2003 Andrew Davie - adavie@atari2600.org
Cheers
A
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--Well, that's why it is open source code(build your own instructions code). But what this cart does surpases your initial design. As far as I know, Snailsoft came up with this himself. It's your opinion about the images. I am happy with the way the images turned out and the work that Snailsoft and others have done to get this cart off the ground. I am glad that you explored this option of the Atari 2600.
In the same way that photocopying an artist's paintings and selling two of them together as an "expanded work", this picture cart surpasses the initial design.
I recommend that NOBODY buy this overpriced rip-off. I will be happy to produce, free of charge, a binary of any image anyone cares to send me. And the picture quality will be as good as I can get them -- and I have lots of experience so I know how to produce the best possible -- not like these seemingly amateurish efforts. The binary I deliver can be burned to a stock-standard 4K cart (Al will do that for you, on the cheap). I consider this particular effort a ripoff both in terms of money, quality, and especially in terms of ethics. At the very least I should have been consulted and/or asked or informed -- as requested in my initial "build your own" posting. The product could have been much better.
So. DO NOT BUY THIS!
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This looks like Andrews tech to me, I doubt he calls himself Snailsoft these days.
This is the first I've heard of this, and I'm definitely not "snailsoft". The sample binaries were probably done with my 'build your own' instructions/code as posted in these forums, though the quality of the images shown here is in my opinion very poor. There's a trick to getting good quality, and I was not asked/consulted as far as this cartridge goes. I very much disapprove of somebody making/selling this type of thing, if it uses my work.
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So far the kernel seems to be coming along very nicely, I was finally able to implement a smooth scrolling algorithm by unrolling everything.... but I have some other problems that have come up:
* The first digit for the score is garbled, not sure why.. it's looking like a mangled pointer somehow....
* The scroll completes, then starts at the very beginning again. I suspect this is because i am updating state during overscan.. do I need to move the bounds enforcement (basically the AND), in-kernel?
I am pasting source and a screenshot.. but I'm showing some progress!
and the current code:
Until next time!
-Thom
To avoid this sort of variable clashing, I suggest you try the following...
SEG.U variables ORG $80 ; define your variables here ; this is an uninitialised segment -- the assembler will calculate addresses, but create no actual data in the binary ; examples... GAME_STATUS ds 1 ; 1 byte for this var! PF1DATA ds 32 ; 32 for this one PF2DATA ds 32 ; and this ; this allows you to insert/remove variables at will, and resize, without having to recalculate! ; in other words, let the assembler calculate the locations of stuff, you just state how big they are! SEG code ORG $F000 ; rest of your program here
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I never thought about it as an investment, I just enjoy collecting. Obviously, I have no intentions of actually playing this one, as there can only be a couple of sealed ones in existence. BTW, how many sealed copies are known, anyway?
I predict it will be shipped to you in a bubble-wrapped envelope, and it will be one of the very few sealed, crushed, boxed video life known to exist.
Cheers
A
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I have an Aussie (PAL) official Atari 2600 JR with the 4-position switch on the back, selecting one of 4 banks of games. That is, this is the Atari with inbuilt games only released in Australia (AFAIK). Any offers? Postage to USA will be a maximum of US$15, but I'll do it at cost if less than that.
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Ressurecting this old thread because I thought it was absolutely brilliant work.
As anything been done with this technology since the thread?
Yes, there's a thriving underground market in Atari porn, you just don't know the right people to ask.
Personally, I'm still doing very low resolution video stuff these days, only not with Atari. I'm building my own 1930s mechanical television. Really! see Narrow Band Television Association Forum
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Hi,
Me & my group have completed a 4k demo for the Atari 2600 and are planning to release it at Icons'07 demoparty (Finland) in 16-18.2.2007. I'll post a follow-up on here when it's officially released (that's why I don't yet want to give any information about it).
I sent an email to the "homebrew services" a few weeks ago and I still haven't received a reply. It's just probably because some people have a life too
I'm just wondering if this sort of thing would be worth buying in a real cart form. Of course, I will also distribute the rom-file freely. What do you think?
OK, so what you're basically asking is... do I think that it's worth buying something in cart form... something that I've not seen, that you can't give any information about, and which is planned to be released "soon".
No.
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I did a few demos, but not the carrier one you mention.
Hills shows interlaced background (the sun/hills/clouds) and two large interlaced marios.
tunnelcycle shows various primary colours in a circle.
I have also mixed colour cycling with playfield interlacing, as shown in the attached spiralwords demo.
Cheers
A
PS: Also found 'car' which is my attempt to convert a photo of my old car to a full screen image.
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Very good! I, too, like 'interlacing' like this, but it doesn't appear to be popular with others, possibly because of how it looks on emulators. I believe it's only on the real hardware (and TV) that really counts. I would encourage you to further explore the creation of multicoloured playfields using interlacing. Perhaps you can come up with a generic system that can display any image.
Cheers
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Hey Al, how about releasing sales information when the Holiday Sale is over? Maybe you could let us know what the top ten games were, what hardware sold, ect.
Not going to happen, because then we could infer how much money Al really drains out of the community
Cheers
A
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Thanks for posting all of those, Andrew! I'd seen the clown and Mario demos, but not all the others. You're right, the RGB method produces more combinations than mixing just two colors can. The only drawback is that 20Hz flicker (NTSC/60) and 17Hz flicker (PAL/50) are more apparent than 30Hz and 25Hz. Personally, I don't mind flicker, because I think the advantages of using it (more colors, more sprites) make up for the disadvantages. And the interesting thing about the RGB method is that it's similar to one of the early methods used many years ago to produce color TV pictures.
http://www.earlytelevision.org/early_color.html
http://www.earlytelevision.org/cbs_color_system.html
Michael
Very interesting links, thanks. Many people have worked on colour systems, and it's interesting to read about these early efforts. As it happens, mechanical TV is one of my other interests
Cheers
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Lots of experimentation was done about 5 years ago with colour interlacing techniques starting with methods similar to that which you describe. A more generic system is to multiplex RGB colours to form an "unlimited" palette. This can effectively be achieved by dithering the 1-bit frames. Unfortunately, the posts discussing these techniques don't seem to be in the forum anymore, nor do the binaries. Such a shame. I attach some of the experiments that lie handy on my hard drive; there were some really really interesting techniques involved. Most of these demos use RGB line multiplexing with dithered single-bit layers for each colour channel, with a rolling palette change per-line.
Cheers
A
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I actually sent many e-mails, including to Namco themselves, and done searches trying to get permission to do this. No response. I also sent two PMs to a certain person who is a member of this board who used to work for Activision (and now works for Namco) who couldn't even give me the respect of a response, regardless of what that response was.
That totally, absolutely, does not surprise me one little bit.
Cheers
A
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Atari 2600 Gameboy advance emulator
in Emulation
Posted
That was a crash project I did for a particular Activision guy I knew from these forums, to prove to his bosses that it was in fact possible to do a reasonable Atari 2600 emulator on GBA. I got it working with something like 20 Activision games installed and running at reasonable speed, and delivered it to this guy to show at an Activision meeting. I worked on this for weeks, busting my gut, and not only did he NOT even thank me for the work (of course I wasn't paid), the project was approved and given to another developer without me even being told.
After that particular kick in the teeth, I dropped the project and lost all respect for the person in question.
The bottom line is that yes, it is possible to do a pretty good Atari 2600 emulator on the GBA. I did it. It wasn't perfect, and it slowed down here and there... but I only spent a month or two on it and I'm confident it could have been optimised to achieve better speed. But it was pretty good, and pretty damn neat playing Atari 2600 on my handheld.
Cheers
A