prototype lua midi generators & filters and port event-rewrite

4 files changed, 134 insertions, 3 deletions

diff --git a/scripts/midi_rewite.lua b/scripts/midi_rewite.lua
new file mode 100644
index 0000000000..35d2e1ddfc
--- /dev/null
+++ b/scripts/midi_rewite.lua
@@ -0,0 +1,36 @@
+ardour {
+	["type"]    = "session",
+	name        = "Rewrite Midi",
+	license     = "MIT",
+	author      = "Robin Gareus",
+	email       = "robin@gareus.org",
+	site        = "http://gareus.org",
+	description = [[An example session script preprocesses midi buffers.]]
+}
+
+function factory ()
+	-- this function is called in every process cycle, before processing
+	return function (n_samples)
+		_, t = Session:engine ():get_ports (ARDOUR.DataType.midi (), ARDOUR.PortList ())
+		for p in t[2]:iter () do
+			if not p:receives_input () then goto next end
+
+			if not p:name () == "MIDI/midi_in 1" then goto next end
+
+			midiport = p:to_midiport ()
+			assert (not midiport:isnil ())
+			mb = midiport:get_midi_buffer (n_samples);
+
+			events = mb:table() -- copy event list into lua table
+			mb:silence (n_samples, 0); -- clear existing buffer
+
+			for _,e in pairs (events) do
+				-- e is an http://ardourman/lua-scripting/class_reference/#Evoral:MidiEvent
+				e:set_channel (2)
+				mb:push_event (e)
+			end
+
+			::next::
+		end
+	end
+end
diff --git a/scripts/midifilter.lua b/scripts/midifilter.lua
new file mode 100644
index 0000000000..ceb115a727
--- /dev/null
+++ b/scripts/midifilter.lua
@@ -0,0 +1,43 @@
+ardour {
+	["type"]    = "dsp",
+	name        = "Midi Filter",
+	category    = "Utility",
+	license     = "MIT",
+	author      = "Robin Gareus",
+	email       = "robin@gareus.org",
+	site        = "http://gareus.org",
+	description = [[An Example Midi Filter for prototyping.]]
+}
+
+function dsp_ioconfig ()
+	return { { audio_in = 0, audio_out = 0}, }
+end
+
+function dsp_has_midi_input () return true end
+function dsp_has_midi_output () return true end
+
+function dsp_run (_, _, n_samples)
+	assert (type(midiin) == "table")
+	assert (type(midiout) == "table")
+	local cnt = 1;
+
+	function tx_midi (time, data)
+		midiout[cnt] = {}
+		midiout[cnt]["time"] = time;
+		midiout[cnt]["data"] = data;
+		cnt = cnt + 1;
+	end
+
+	-- for each incoming midi event
+	for _,b in pairs (midiin) do
+		local t = b["time"] -- t = [ 1 .. n_samples ]
+		local d = b["data"] -- get midi-event
+
+		if (#d == 3 and bit32.band (d[1], 240) == 144) then -- note on
+			tx_midi (t, d)
+		end
+		if (#d == 3 and bit32.band (d[1], 240) == 128) then -- note off
+			tx_midi (t, d)
+		end
+	end
+end
diff --git a/scripts/midigenerator.lua b/scripts/midigenerator.lua
new file mode 100644
index 0000000000..e9aa55d280
--- /dev/null
+++ b/scripts/midigenerator.lua
@@ -0,0 +1,52 @@
+ardour {
+	["type"]    = "dsp",
+	name        = "Midi Generator",
+	category    = "Utility",
+	license     = "MIT",
+	author      = "Robin Gareus",
+	email       = "robin@gareus.org",
+	site        = "http://gareus.org",
+	description = [[An Example Midi Generator for prototyping.]]
+}
+
+function dsp_ioconfig ()
+	return { { audio_in = 0, audio_out = 0}, }
+end
+
+function dsp_has_midi_output () return true end
+
+local tme = 0 -- sample-counter
+local seq = 1 -- sequence-step
+local spb = 0 -- samples per beat
+
+local midi_sequence = {
+	{ 0x90, 64, 127 },
+	{ 0x80, 64,   0 },
+}
+
+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)
+	local m = 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
+			midiout[m] = {}
+			midiout[m]["time"] = time
+			midiout[m]["data"] = midi_sequence[seq]
+
+			tme = 0
+			m = m + 1
+			if seq == #midi_sequence then seq = 1 else seq = seq + 1 end
+		end
+	end
+end
diff --git a/scripts/synth1.lua b/scripts/synth1.lua
index 99a5e4d6c8..9d04e29ec1 100644
--- a/scripts/synth1.lua
+++ b/scripts/synth1.lua
@@ -21,7 +21,7 @@ function dsp_ioconfig ()
 	}
 end
 
-function dsp_midi_input ()
+function dsp_has_midi_input ()
 	return true
 end
 
@@ -70,8 +70,8 @@ function dsp_run (ins, outs, n_samples)
 
 	local tme = 1
 	-- parse midi messages
-	assert (type(mididata) == "table") -- global table of midi events (for now)
-	for _,b in pairs (mididata) do 
+	assert (type(midiin) == "table") -- global table of midi events (for now)
+	for _,b in pairs (midiin) do
 		local t = b["time"] -- t = [ 1 .. n_samples ]
 
 		-- synth sound until event