Doubled Dancing Demon

Leo Christopherson's Dancing Demon is a masterful display of TRS-80 graphics and sound. Recently I looked at it and wondered if it were possible to increase the demon's vertical resolution. Certainly being a relatively tall and skinny graphic worked to its advantage. It didn't take me too long to put together a 28 x 60 graphics kernel as a basis. I also discovered that it had been released into the public domain and I could make a derived work of the original.

A bunch of reverse engineering followed. I extract the graphics, decoded the animation format and figured out how it did sound. The graphics were then semi-automatically doubled in resolution by a little utility program. The sound had to be raised in pitch so that it would fit within part of a frame. Putting it all together to stay in sync was a considerable challenge. The end result is my most technically sophisticated graphics demo yet.

Here's (someone elses') video of the original which highlights the difference in graphics.

Double Dancing Demon only works on a TRS-80 Model III, but I think it has a chance on the Model I.


Watch the demon dance then press space bar to watch him again.

George Phillips, July 13, 2009. george -at-