Hey all, so I just put together a new version of my OPL2/OPL3 FM synth chiptune player for NitrOS-9. I’ve heard a few people asking why my player requires the CoCo to be locked/frozen during playback, and the reason is this. Despite the fact that it is not ACTUALLY playing sampled audio, the VGM file format still structures the soundchip data according to the same sort of timing that regular sampled audio uses. This means that every CPU cycle is still significant and I need carefully crafted timing loops to play it accurately. I did look into ways to get around this and allow for OS9 multitasking to continue, but I just can’t think of a viable way. It would be no problem if it was custom music written specifically to run on CoCo hardware, but converting a VGM into a multitasking-friendly format would be very difficult. Soooo instead, I had an idea on how to make the player able to stop playback at anytime. To do this, I squeezed a few instructions to poll the keyboard for the BREAK key into my main timing loop and adjusted my cycle counts, and voila, you can now interrupt the “frozen” CoCo whenever you want and resume your NitrOS-9 shenanigans! 😀 An unexpected feature of this, is that for playlists, you can essentially skip a song whenever you want and move on to the next one immediately without having to wait for the current song to finish playing. Anyways, below the video is a link to a zip file containing my updated player and a few disk images that include some sample music for you to play with. (Pun INTENDED) 😛 Have fun!
TEKTODD
Computers, Ham Radio, and ALL TEH TEK!