This enables the specific use case of checking whether a note's release
phase has ended, but is also potentially useful to implement a sort of
"voice stealing" algorithm in Python code, which can take account of
the note's envelope state as well as other factors specific to the
program.
this has the side effect of making some notes more accurate, the new
frequency= value in the test is closer to the true midi frequency of
830.609...Hz.
This works for me (tested playing midi to raw files on host computer, as
well as a variant of the nunchuk instrument on pygamer)
it has to re-factor how/when MIDI reading occurs, because reasons.
endorse new test results
.. and allow `-1` to specify a note with no sustain (plucked)
a waveform object (array of 'h') can be passed in, replacing the
standard square wave. This waveform must be a 'single cycle waveform'
and some obvious things to pass in are sine, triangle or sawtooth waves,
but you can construct whatever you like.
