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Coke Zero - Revision 2015 Demo

Posted by Thomas Jentzsch, in Atari 06 April 2015 · 2,194 views

Demo Atari 2600 Coke Zero Revision 2015

A while ago I had some discussion with SvOlli about improving a part of his winning Bang! demo called "Snake Sprite". Initially he wanted to add more colors, but I thought more about removing the repositioning gaps. This seemed like something never done before inside a 48 pixel kernel, so I took the challenge.
After making it possible, SvOlli suggested to integrate my little demo into a bigger mega demo. So I spiced up the demo a bit, scripted it into 4 parts and added some pompous demo text scroller. Unfortunately the mega demo didn't make it, so we decided that it should stand by itself, now called Coke Zero (you will understand the name when watching it).
Since I have no talent for this, SvOlli contacted Skyrunner, a musician who would provide the necessary demo track. Space was very limited at that time, so it was quite a challenge for both of us to squeeze in the music. My part was optimizing for space and for that I improved Paul Slocum's old music player once again. Now it is fully customizable and even more space efficient than it was before. Skyrunner had the harder part, since he had to please me AND the space limitations. Posted Image
This Easter weekend the world's biggest pure Demoscene event Revison 2015 happened and Svolli and Skyrunner who both admitted the party (look out for SvOlli's seminars on YouTube and Skyrunner's other prod) submitted my little demo to the 4K Oldschool Intro competition. I have been watching much of the event via live streaming and saw some great demos. Today the Prizegiving event happened and to my big surprise, our little demo became 2ndPosted Image
You can find the binary and full source code in the attachment. Enjoy!

Attached Files

Slick demo. Congrats on 2nd!
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Cool :)

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Congratulations for demo and second place!

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Video link added.

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Thomas Jentzsch - saving bits and impressing other Stella programmers since August 1999!



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I love seeing new demo prods for the VCS! Very slick. :)


I tried making an NTSC build today so I could run it on my own Atari (all I did was set the PAL50 switch to 0 and NTSC to 1), but DASM aborted when I tried the assembly and reported ">CharTbl must be even!" in font.inc.

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Yea, the NTSC support is not finished yet. I will look into this.

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Thank you.

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Is NTSC support any closer to being finished?

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It took a while, but now I found the time and converted to demo into NTSC.


It was more work than it may look like, because I found a bug which had to be fixed for proper NTSC.

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Amazing! Thank you very much!


This isn't a very big deal, but when I run Coke Zero (from the Harmony Cart menu) while my AtariVox is plugged in, the program sends it some spurious sound data that subsides after a few seconds.

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No clue while this happens.


So I suppose you have to live with it (or unplug the AtariVox). :)

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(or unplug the AtariVox). :)

Yeah, that's what I did.

I'll take a look at the code sometime later and see if anything hinky is happening to SWACNT.

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I do not set SWACNT to input, so maybe that's the problem. Though I never do that in my other games etc. too.

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