Demos ‘R’ Us

Posted Wed, Jul. 24th 2013 in

Sheppy unveils his latest top secret Apple IIgs project.

Apple II demo software celebrates KansasFest

Posted Fri, Dec. 21st 2012 in News

KansasFest alumnus Dagen Brock just released an 8-bit KansasFest-themed demo for us to enjoy over the holidays.  Dagen also agreed to an interview (see below) about his work.

What were your goals for this project?

I had wanted to port and release this fire code to an 8-bit platform for some time.  I had a GS prototype years ago and realized it would probably run fast enough on a IIe, but I had to rewrite some of the 16-bit instructions.  I finally got around to it sometime in early November, and once it was done I decided it would be neater to release it as a little demo with some extra effects.

What about KansasFest inspired you to pursue this project?

The people involved with KansasFest are inspiring for their commitment to the platform.  So many people are still creating new content and hardware for a platform that is 100% commercially unviable.  Those people do it for the thrill and the love, not for money.  So this is about love. ;)

Did you work on this alone?  If not, who contributed?

This was all me.  I should collaborate more.  We all should.  It makes everything better.  However, I was only able to do this “alone” due to all of the people who have helped me learn along the way.  There’s a great community on the CSA2 newsgroups that is always incredibly helpful when I get stuck.

What languages or tools did you use for this demo?

I started this in Merlin 8/16+ on the Apple IIgs emulator “kegs”.  Then I decided to move to a more modern editor so I built some custom tools that allow me to write code in “vi” on a modern computer, and then rapidly bundle that to a disk image and build it back in Merlin under kegs.  I also wrote some image/sprite conversion tools in PHP and my bundler uses a custom version of to_pro to make ProDOS images, which is written in C.  Finally, I test on a real IIe with the help of the awesome CFFA3000 card that lets me copy my bundle to a USB thumbdrive and boot it up.

What obstacles did you encounter?  

I didn’t learn assembly until I got an Apple IIgs as an early teen.  So I’ve never really done strictly 8-bit assembly programming before.  There’s a lot effort involved because you end up using a lot more zero-page pointers since you can’t use 16-bit index registers.

Where may I find the demo, including a video and disk image?

Demo is online in a “.dsk” file that you should be able to boot up in any Apple II emulator.  I have all of the assembly source code there too, but not all of the image tools I used to generate it.  I may clean those up and post them as well if I get time or there’s interest.

Disk Image/Source Code:

Festro by Digarok

Happy Holidays!  See you at KFest!