I just got finished with my initial experiments with calculated oscillators on the PSP, with a lot of help from the wavegen sample in the SDK. For now, I've simply wrapped the sine/square/triangle waves from the sample with code that assigns a major scale to the D-pad and buttons. This is my first (working) PSP proggie, so be kind. :-)
Be aware that there is no credit taken in the wavegen sample code, but will gladly be given if somebody steps up and tells me otherwise. It's full of very valuable math that creates a helpful framework for this project.
Note: I understand the image used is a waste of space, it will be replaced with a GUI for the relevant variables that that user can edit.
This will be a slow moving project as I'm going back to school on Sunday (no, I'm not a Comp Sci major). However, I am providing it simply to garner ideas from the community, and inquire into whether or not anyone has solid knowledge of the PSP audio functions. Features I'm looking to implement are noted below.
TODO (if reasonably possible):
- sharps/flats (duh.. just looking for a smooth way to implement)
- Volume (almost done)
- Panning (running out of "live performance" controls to use)
- ADSR envelope (there's a great example in the 'polyphonic' SDK sample)
- Cutoff, Resonance (these are probably the biggest pain to implement, I'll be grabbing an audio synthesis book from a friend this week.)
- Polyphony (at least 2 channels)
- Arpeggiator!! Woo!
- Anything else that music nuts such as myself would want.
WAY OUT FUTURE IDEAS:
- Saving performance into note format file, to be used along with code that can be implemented in other homebrew projects. This would be helpful for those that don't have a music program, but want to write songs for games, etc.
- Sequencer
- Perhaps interaction with PSPRhythm, when it's a clean, final program? (I'd love that, but it's not up to me)
Link: Download PSPSynth0.2.zip for 1.5 PSPs
I will try to release it for 2.0, and will also take a look at Fanjita's loader for 2.01+ to see if I'm capable of doing that. If you have any insight into this project, please contact me at chris (at) stoptheinternet (dot) org.
Cheers!
- Cakestick