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Update Scala to MTS script: 

* relax octave requirement, allow the scale
  to repeat at intervals other than 1200 cents
* fix frequency alignment of root note
  to use the given scale (not equal temperament)
This commit is contained in:
Robin Gareus 2020-06-17 16:18:07 +02:00
parent 0f95bf001d
commit 0d5e01eda6
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
1 changed files with 10 additions and 17 deletions
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27
share/scripts/scl_to_mts.lua
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@ -50,11 +50,6 @@ function factory () return function ()
return note, cent
end
-- apply octave and cent offset to the given frequency
function calc_freq (hz, cent, octave)
return hz * 2 ^ ((cent + 1200 * octave) / 1200)
end
local dialog_options = {
{ type = "file", key = "file", title = "Select .scl file" },
{ type = "dropdown", key = "tx", title = "MIDI SysEx Target", values = midi_targets () }
@ -117,15 +112,8 @@ function factory () return function ()
return
end
-- The last entry must be an octave to map it
if freqtbl[expected_len + 1] ~= 1200 then
LuaDialog.Message ("Scala to MTS", "The scale does not repeat after an octave.", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run ()
return
end
assert (expected_len + 2 == ln)
assert (expected_len > 0)
assert (freqtbl[expected_len + 1] == 1200)
-- TODO consider reading a .kbm file or make these configurable in the dialog
-- http://www.huygens-fokker.org/scala/help.htm#mappings
@ -134,7 +122,11 @@ function factory () return function ()
local ref_freq = 440.0
-- calculate frequency at ref_root
local ref_base = ref_freq * 2.0 ^ ((ref_root - ref_note) / 12);
local delta = ref_note - ref_root
local delta_octv = math.floor (delta / expected_len)
local delta_note = delta % expected_len
local ref_base = ref_freq * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / -1200)
-- prepare sending data
local tx = rv["tx"] -- output port
@ -149,12 +141,13 @@ function factory () return function ()
if pdialog:canceled () then break end
-- calculate the note relative to kbm's ref_root
local delta = nn - ref_root
local delta_octv = math.floor (delta / expected_len)
local delta_note = delta % expected_len
delta = nn - ref_root
delta_octv = math.floor (delta / expected_len)
delta_note = delta % expected_len
-- calculate the frequency of the note according to the scl
local fq = calc_freq (ref_base, freqtbl [ delta_note + 1 ], delta_octv)
local fq = ref_base * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / 1200)
-- and then convert this frequency to the MIDI note number (and cent offset)
local base, cent = freq_to_mts (fq)