Revert failed experiment, scripted multiple MIDI outputs via dsp_run()

This reverts commit 8702ff2189,
and b10d9cf09b.

There was a misconception on the iterator (port vs message
in sequence), besides Ardour's mixer-strip is preferably used
with a single MIDI port. Most plugin-standards also only support
one port.

If need be LuaDSP run_map() can be used to handle multiple
MIDI I/O ports already.

libs/ardour/luaproc.cc

@@ -725,15 +725,12 @@ LuaProc::connect_and_run (BufferSet& bufs,
 
 			// copy back midi events
 			if (_has_midi_output && lua_midi_sink_tbl.isTable ()) {
-				uint32_t count = 0;
-				uint32_t idx;
-				for (luabridge::Iterator i (lua_midi_sink_tbl); !i.isNil (); ++i) {
-					bool iter_is_valid;
-					idx = out.get(DataType::MIDI, count, &iter_is_valid);
-					count++;
-					if (iter_is_valid && bufs.count().n_midi() > idx) {
-						MidiBuffer& mbuf = bufs.get_midi(idx);
-						mbuf.silence(0, 0);
+				bool valid;
+				const uint32_t idx = out.get(DataType::MIDI, 0, &valid);
+				if (valid && bufs.count().n_midi() > idx) {
+					MidiBuffer& mbuf = bufs.get_midi(idx);
+					mbuf.silence(0, 0);
+					for (luabridge::Iterator i (lua_midi_sink_tbl); !i.isNil (); ++i) {
 						if (!i.key ().isNumber ()) { continue; }
 						if (!i.value ()["time"].isNumber ()) { continue; }
 						if (!i.value ()["data"].isTable ()) { continue; }

share/scripts/_midigenerator_multi_ports.lua

@@ -1,48 +0,0 @@
-ardour {
-	["type"]    = "dsp",
-	name        = "MIDI generator with multiple ports",
-	category    = "Example",
-	license     = "MIT",
-	author      = "R8000",
-	description = [[An Example Midi Generator for prototyping.]]
-}
-
-function dsp_ioconfig () return { { midi_out = 5} } end
-
-local tme = 0 -- sample-counter
-local seq = 0 -- sequence-step
-local spb = 0 -- samples per beat
-
-local midi_sequence_one = {
-	{ 0x90, 64, 127 },
-	{ 0x80, 64,   0 },
-}
-local midi_sequence_two = {
-	{ 0x90, 60,  70 },
-	{ 0x80, 60,   0 },
-}
-
-local midi_sequences = { midi_sequence_one, midi_sequence_two }
-
-function dsp_init (rate)
-	local bpm = 120
-	spb = rate * 60 / bpm
-	if spb < 2 then spb = 2 end
-end
-
-function dsp_run (_, _, n_samples)
-	assert (type(midiout) == "table")
-	assert (spb > 1)
-
-	for time = 1,n_samples do -- not very efficient
-		-- TODO, timestamp the sequence in beats, calc/skip to next event
-		tme = tme + 1
-		if tme >= spb then
-			for m = 1, 5 do
-				midiout[m] = {time = time, data = midi_sequences[m % 2 + 1][seq + 1]}
-			end
-			tme = 0
-			seq = (seq + 1) % 2
-		end
-	end
-end