When there's no sustain, the release step needs to be calculated from
the attack level, not the sustain level. Otherwise, contrary to intent,
this leads to the actual release taking a loooonnngg time.
A note can be placed in the center (panning=0) or moved to just the left
(panning=1) or right (panning=-1) channels. Fractional panning values
place it partially in both channels.
Now the vibrato 'units' are 1.0 = one octave, 1/12 = one semitone,
1/1200 = one cent. Before, the units were somewhat arbitrary and were not
perceptually "symmetrical" around the base frequency.
For vibrato_depth = 1/12 and base frequency of 440,
before: pitch from 403.33 to 476.67Hz, not corresponding to any notes
after: pitch from 415.30 to 466.16Hz, corresponding to G# and A#
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.
and re-vamp overall envelope calculation again.
Now, if you set a low overall attack level like 0.2 this avoids the
"diminishing volume" effect when many notes sound at once. You need
simply choose a maximum attack level that is appropriate for the max
number of voices that will actually be played.
This class allows much more expressive sound synthesis:
* tremolo & vibrato
* arbitrary frequency
* different evelope & waveform per note
* all properties dynamically settable from Python code
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)
Add address_little_endian for epaper displays with little endian
(low byte first) addresses.
Also clears allocated display and display bus memory so it has a
known state. The acep member wasn't always set so it varied
accidentally.
Fixes#7560. May fix#7778. Fixes#5119.
