Include SCL to MTS script with releases

share/scripts/scl_to_mts.lua

@@ -0,0 +1,221 @@
+ardour {
+	["type"]    = "EditorAction",
+	name        = "Scala to MIDI Tuning",
+	license     = "MIT",
+	author      = "Ardour Team",
+	description = [[Read scala (.scl) tuning from a file, generate MIDI tuning standard (MTS) messages and send them to a MIDI port]]
+}
+
+function factory () return function ()
+
+	-- return table of all MIDI tracks, and all instrument plugins.
+	--
+	-- MidiTrack::write_immediate_event() injects MIDI events to the track's input
+	-- PluginInsert::write_immediate_event() sends events directly to a plugin
+	function midi_targets ()
+		local rv = {}
+		for r in Session:get_tracks():iter() do
+
+			if not r:to_track():isnil() then
+				local mtr = r:to_track():to_midi_track()
+				if not mtr:isnil() then
+					rv["Track: '" .. r:name() .. "'"] = mtr
+				end
+			end
+
+			local i = 0;
+			while true do
+				local proc = r:nth_plugin (i)
+				if proc:isnil () then break end
+				local pi = proc:to_plugininsert ()
+				if pi:is_instrument () then
+					rv["Track: '" .. r:name() .. "' | Plugin: '" .. pi:name() .. "'"] = pi
+				end
+				i = i + 1
+			end
+		end
+		return rv
+	end
+
+	function log2 (v)
+		return math.log (v) / math.log (2)
+	end
+
+	-- calculate MIDI note-number and cent-offset for a given frequency
+	function freq_to_mts (hz)
+		local note = math.floor (12. * log2 (hz / 440) + 69.0)
+		local freq = 440.0 * 2.0 ^ ((note - 69) / 12);
+		assert (freq > note)
+		local cent = 1200.0 * log2 (hz / freq)
+		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 () }
+	}
+
+	local rv = LuaDialog.Dialog ("Select Scala File and MIDI Taget", dialog_options):run ()
+	dialog_options = nil -- drop references (track, plugins, shared ptr)
+	collectgarbage () -- and release the references immediately
+
+	if not rv then return end -- user cancelled
+
+	-- read the scl file
+	local freqtbl = {}
+	local ln = 0
+	local expected_len = 0
+	local f = io.open (rv["file"], "r")
+
+	if not f then
+		LuaDialog.Message ("Scala to MTS", "File Not Found", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run ()
+		return
+	end
+
+	-- parse scala file and convert all intervals to cents
+	-- http://www.huygens-fokker.org/scala/scl_format.html
+	freqtbl[1] = 0.0 -- implicit
+	for line in f:lines () do
+		line = string.gsub (line, "%s", "") -- remove all whitespace
+		if line:sub(0,1) == '!' then goto nextline end -- comment
+		ln = ln + 1
+		if ln < 2 then goto nextline end -- name
+		if ln < 3 then
+			expected_len = tonumber (line) -- number of notes on scale
+			if expected_len < 1 or expected_len > 256 then break end -- invalid file
+			goto nextline
+		end
+
+		local cents
+		if string.find (line, ".", 1, true) then
+			cents = tonumber (line)
+		else
+			local n, d = string.match(line, "(%d+)/(%d+)")
+			if n then
+				cents = 1200 * log2 (n / d)
+			else
+				local n = tonumber (line)
+				cents = 1200 * log2 (n)
+			end
+		end
+		--print ("SCL", ln - 2, cents)
+		freqtbl[ln - 1] = cents
+
+		::nextline::
+	end
+	f:close ()
+
+	-- We need at least one interval.
+	-- While legal in scl, single note scales are not useful here.
+	if expected_len < 1 or expected_len + 2 ~= ln then
+		LuaDialog.Message ("Scala to MTS", "Invalid or unusable scale file.", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run ()
+		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
+	local ref_root = 60 -- middle C
+	local ref_note = 69 -- A4
+	local ref_freq = 440.0
+
+	-- calculate frequency at ref_root
+	local ref_base = ref_freq * 2.0 ^ ((ref_root - ref_note) / 12);
+
+	-- prepare sending data
+	local tx = rv["tx"] -- output port
+	local parser = ARDOUR.RawMidiParser () -- construct a MIDI parser
+
+	-- show progress dialog
+	local pdialog = LuaDialog.ProgressWindow ("Scala to MIDI Tuning", true)
+	pdialog:progress (0, "Tuning");
+
+	-- iterate over all MIDI notes
+	for nn = 0, 127 do
+		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
+
+		-- calculate the frequency of the note according to the scl
+		local fq = calc_freq (ref_base, freqtbl [ delta_note + 1 ], delta_octv)
+		-- and then convert this frequency to the MIDI note number (and cent offset)
+		local base, cent = freq_to_mts (fq)
+
+		-- MTS uses two MIDI bytes (2^14) for cents
+		local cc = math.floor (163.83 * cent + 0.5) | 0
+		local cent_lsb = (cc >> 7) & 127
+		local cent_msb = cc & 127
+
+		--print ("MIDI Note:", nn, "scale-note:", delta_note, "Octave:", delta_octv, "-> Freq:", fq, "= note:", base, "+", cent, "cents (", cc, ")")
+
+		if (base < 0 or base > 127) then
+			-- skip out of bounds MIDI notes
+			goto continue
+		end
+
+		-- MIDI Tuning message
+		-- http://www.microtonal-synthesis.com/MIDItuning.html
+		local syx = string.char (
+			0xf0, 0x7f, -- realtime sysex
+			0x7f,       -- target-id
+			0x08, 0x02, -- tuning, note change request
+			0x00,       -- tuning program number 0 to 127 in hexadecimal
+			0x01,       -- number of notes to be changed
+			nn,         -- note number to be changed
+			base,       -- semitone (MIDI note number to retune to, unit is 100 cents)
+			cent_msb,   -- MSB of fractional part (1/128 semitone = 100/128 cents = .78125 cent units)
+			cent_lsb,   -- LSB of fractional part (1/16384 semitone = 100/16384 cents = .0061 cent units)
+			0xf7
+		)
+
+		-- parse message to C/C++ uint8_t* array (Validate message correctness. This
+		-- also returns C/C++ uint8_t* array for direct use with write_immediate_event.)
+		for b = 1, 12 do
+			if parser:process_byte (syx:byte (b)) then
+				tx:write_immediate_event (parser:buffer_size (), parser:midi_buffer ())
+				-- Slow things down a bit to ensure that no messages as lost.
+				-- Physical MIDI is sent at 31.25kBaud.
+				-- Every message is sent as 10bit message on the wire,
+				-- so every MIDI byte needs 320usec.
+				ARDOUR.LuaAPI.usleep (400 * parser:buffer_size ())
+			end
+		end
+
+		-- show progress
+		pdialog:progress (nn / 127, string.format ("Note %d freq: %.2f (%d + %d)", nn, fq, base, cc))
+		if pdialog:canceled () then break end
+
+		::continue::
+	end
+
+	-- hide modal progress dialog and destroy it
+	pdialog:done ();
+
+end end
+
+-- simple icon
+function icon (params) return function (ctx, width, height, fg)
+	ctx:set_source_rgba (ARDOUR.LuaAPI.color_to_rgba (fg))
+	local txt = Cairo.PangoLayout (ctx, "ArdourMono ".. math.ceil(math.min (width, height) * .45) .. "px")
+	txt:set_text ("SCL\nMTS")
+	local tw, th = txt:get_pixel_size ()
+	ctx:move_to (.5 * (width - tw), .5 * (height - th))
+	txt:show_in_cairo_context (ctx)
+end end