Add some lua scripts

scripts/synth1.lua

@@ -0,0 +1,100 @@
+ardour {
+	["type"]    = "dsp",
+	name        = "Simple Synth",
+	license     = "MIT",
+	author      = "Robin Gareus",
+	email       = "robin@gareus.org",
+	site        = "http://gareus.org",
+	description = [[An Example Synth for prototyping.]]
+}
+
+function dsp_ioconfig ()
+	return
+	{
+		{ audio_in = 0, audio_out = 1},
+	}
+end
+
+function dsp_midi_input ()
+	return true
+end
+
+
+local note_table = {}
+local active_notes = {}
+local phases = {}
+local env = .01;
+
+function dsp_init (rate)
+	for n = 1,128 do
+		note_table [n] = (440 / 32) * 2^((n - 10.0) / 12.0) / rate
+	end
+	env = 100 / rate
+end
+
+function dsp_run (ins, outs, n_samples)
+	-- initialize output buffer
+	assert (#outs == 1)
+	local a = {}
+	for s = 1, n_samples do a[s] = 0 end
+
+
+	-- very basic synth, simple sine, basic envelope
+	local function synth (s_start, s_end)
+		for n,v in pairs (active_notes) do
+			local vel = v["vel"] or 0
+			local tgt = v["tvel"];
+			for s = s_start,s_end do
+				local phase = phases[n] or 0
+				vel = vel + env * (tgt - vel)
+				a[s] = a[s] + math.sin(6.283185307 * phase) * vel / 167
+				phase = phase + note_table[n]
+				if (phase > 1.0) then
+					phases[n] = phase - 2.0
+				else
+					phases[n] = phase
+				end
+			end
+			if vel < 1 and tgt == 0 then
+				active_notes[n] = nil
+			else
+				active_notes[n]["vel"] = vel;
+			end
+		end
+	end
+
+	local tme = 1
+	-- parse midi messages
+	assert (type(mididata) == "table") -- global table of midi events (for now)
+	for _,b in pairs (mididata) do 
+		local t = b["time"] -- t = [ 1 .. n_samples ]
+
+		-- synth sound until event
+		synth(tme, t)
+		tme = t + 1
+
+		local d = b["data"] -- get midi-event
+		-- we ignore the midi channel
+		if (#d == 3 and bit32.band (d[1], 240) == 144) then -- note on
+			local n = 1 + d[2];
+			active_notes[n] = active_notes[n] or {}
+			active_notes[n]["tvel"] = d[3]
+		end
+		if (#d == 3 and bit32.band (d[1], 240) == 128) then -- note off
+			local n = 1 + d[2];
+			active_notes[n] = active_notes[n] or {}
+			active_notes[n]["tvel"] = 0
+		end
+		if (#d == 3 and bit32.band (d[1], 240) == 176) then -- CC
+			if (d[2] == 120 or d[2] == 123) then -- panic
+				active_notes = {}
+			end
+		end
+	end
+
+	-- synth rest of cycle
+	synth(tme, n_samples)
+
+	-- copy
+	outs[1]:set_table(a, n_samples)
+end