101 lines
2.6 KiB
Lua
101 lines
2.6 KiB
Lua
ardour {
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["type"] = "dsp",
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name = "Simple Synth",
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category = "Instrument",
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license = "MIT",
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author = "Ardour Team",
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description = [[An Example synth for prototyping: Sine-wave with a basic attack/sustain/release envelope, variable number of output channels.]]
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}
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function dsp_ioconfig ()
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return
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{
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-- { midi_in = 1, audio_in = 0, audio_out = -1}, -- any number of channels
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-- { midi_in = 1, audio_in = 0, audio_out = 1}, -- values > 0, precisely N channels
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{ midi_in = 1, audio_in = 0, audio_out = 2}, -- values > 0, precisely N channels
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{ midi_in = 1, audio_in = 0, audio_out = 4}, -- values > 0, precisely N channels
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{ midi_in = 1, audio_in = 0, audio_out = 8}, -- values > 0, precisely N channels
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-- { midi_in = 1, audio_in = 0, audio_out = -6}, -- values < -2, up to -N channels, here 1,..,6
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}
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end
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local note_table = {}
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local active_notes = {}
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local phases = {}
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local env = .01;
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function dsp_init (rate)
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for n = 1,128 do
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note_table [n] = (440 / 32) * 2^((n - 10.0) / 12.0) / rate
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end
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env = 100 / rate
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end
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function dsp_run (ins, outs, n_samples)
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-- initialize output buffer
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local a = {}
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for s = 1, n_samples do a[s] = 0 end
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-- very basic synth, simple sine, basic envelope
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local function synth (s_start, s_end)
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for n,v in pairs (active_notes) do
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local vel = v["vel"] or 0
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local tgt = v["tvel"];
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for s = s_start,s_end do
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local phase = phases[n] or 0
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vel = vel + env * (tgt - vel)
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a[s] = a[s] + math.sin(6.283185307 * phase) * vel / 167
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phase = phase + note_table[n]
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if (phase > 1.0) then
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phases[n] = phase - 2.0
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else
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phases[n] = phase
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end
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end
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if vel < 1 and tgt == 0 then
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active_notes[n] = nil
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else
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active_notes[n]["vel"] = vel;
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end
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end
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end
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local tme = 1
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-- parse midi messages
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assert (type(midiin) == "table") -- global table of midi events (for now)
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for _,b in pairs (midiin) do
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local t = b["time"] -- t = [ 1 .. n_samples ]
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-- synth sound until event
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synth(tme, t)
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tme = t + 1
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local d = b["data"] -- get midi-event
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-- we ignore the midi channel
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if (#d == 3 and (d[1] & 240) == 144) then -- note on
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local n = 1 + d[2];
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active_notes[n] = active_notes[n] or {}
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active_notes[n]["tvel"] = d[3]
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end
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if (#d == 3 and (d[1] & 240) == 128) then -- note off
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local n = 1 + d[2];
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active_notes[n] = active_notes[n] or {}
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active_notes[n]["tvel"] = 0
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end
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if (#d == 3 and (d[1] & 240) == 176) then -- CC
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if (d[2] == 120 or d[2] == 123) then -- panic
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active_notes = {}
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end
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end
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end
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-- synth rest of cycle
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synth(tme, n_samples)
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-- copy
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for c = 1,#outs do
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outs[c]:set_table(a, n_samples)
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end
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end
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