Add example script to convert MIDI-CC to Plugin Automation

scripts/_midi_cc_to_automation.lua

@@ -0,0 +1,47 @@
+ardour { ["type"] = "Snippet", name = "MIDI CC to Plugin Automation" }
+
+function factory () return function ()
+	-- target automation lane: a plugin parameter on a track
+	local tgt = Session:route_by_name('Audio') -- get track
+	assert (not tgt:isnil ())
+	-- get AutomationList, ControlList and ParameterDescriptor
+	-- of the first plugin's 2nd parameter
+	local al, _, pd = ARDOUR.LuaAPI.plugin_automation (tgt:nth_plugin (0), 1)
+
+	-- Source MIDI CC parameter
+	local midi_channel = 0 -- 0..15
+	local cc_param = 0x56
+
+	local add_undo = false
+	Session:begin_reversible_command ("CC to Automation")
+	local before = al:get_state()
+	al:clear_list ()
+
+	-- for all selected MIDI regions
+	local sel = Editor:get_selection ()
+	for r in sel.regions:regionlist ():iter () do
+		local mr = r:to_midiregion ()
+		if mr:isnil () then goto next end
+
+		local bfc = ARDOUR.DoubleBeatsFramesConverter (Session:tempo_map (), r:position ())
+		local ec = mr:control (Evoral.Parameter (ARDOUR.AutomationType.MidiCCAutomation, midi_channel, cc_param), false)
+		if ec:isnil () then goto next end
+		if ec:list ():events ():size() == 0 then goto next end
+
+		for av in ec:list ():events ():iter () do
+			local val = pd.lower + (pd.upper - pd.lower) * av.value / 127
+			al:add (bfc:to (av.when), val, false, true)
+			add_undo = true
+		end
+		::next::
+	end
+
+	-- save undo
+	if add_undo then
+		local after = al:get_state()
+		Session:add_command (al:memento_command(before, after))
+		Session:commit_reversible_command (nil)
+	else
+		Session:abort_reversible_command ()
+	end
+end end