C64 Cruising on Broadway Development – Part 16

Last week I got to work transposing the music from the Gameboy game Choplifter II (Level 1) to 3 voices suitable for coding to the SID chip. That done I had 7 days at work in a row with very little time spare for coding.

Today I got to work on the music routine itself. I did steal a frequency table, but I call this fare game as it’s out in the public domain and my ears just won’t allow me to create this without help.

An hour or so later I had the base tracking routine in place. Converted the notes to numbers the tracker would recognise in a series of patterns (I based it on the formula used by the 16 bit era trackers) and tested. A few bugs ironed out and I completed the pattern entry. This was a self contained project and runs via interrupt while the computer is free for other things, and controlled with a simple POKE command to turn the music on and off.

The code and data was then moved to the main project, and a few changes made to sync the intro screen text scroller to the music. The result is in the video below.

Video re-uploaded due to changing the main tune octave.

As always, it’s available for download here 🙂

About Ponder

I'm a train driver from Cardiff, have been married a long time and have 4 wonderful kids. Warning: I tend to feel pretty low lately in Winter and especially poor weather!
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