First.lua

--- unique melody box
-- each crow sings it's own song

length = {}
rhythm = {}
notes  = {}
step   = {}
bits   = {}
scale  = { {0,2,4,7,9}, {0,2,4,5,7,9,11} }
decay  = 0.4
attack = 0.04

function set_d(t) decay = (t-1)/8 + 0.05 end
function set_a(t) attack = (t-1)/64 + 0.003 end

function play(out,ix)
  -- play rhythm
  if rhythm[ix][ step[ix] ] & 8 == 8 then
    if ix == 1 then set_d(t[ix]) else set_a(t[ix]) end
    t[ix] = 0
    output[out+1]()
  end
  -- set note
  if rhythm[ix+2][ step[ix+2] ] & 8 == 8 then
    n1 = notes[ix][ step[ix+2] ]
    n2 = notes[ix][ step[ix] ]
    abs = math.abs(input[2].volts)/5
    note = n1 + abs*(n2-n1)
    note = math.floor(note * (abs*3 + 0.1))
    s = scale[input[2].volts > -0.04 and 1 or 2]
    nn = s[ note%(#s) + 1 ]
    oct = math.floor(note/12)
    output[out].volts = nn/12 + oct
  end
  step[ix] = (step[ix] % length[ix]) + 1
  step[ix+2] = (step[ix+2] % length[ix+2]) + 1
end

input[1].change = function(s)
  play(1,1)
  play(3,2)
end

sd = 0
function lcg(seed)
  local s = seed or sd
  sd = (1103515245*s + 12345) % (1<<31)
  return sd
end

function get_d() return decay end
function get_a() return attack end

t = {0,0}
function env(count)
  for i=1,2 do t[i] = t[i] + 1 end
end

function init()
  -- generate unique tables
  lcg(unique_id())
  lcg()
  lcg()
  lcg()

  for i=1,4 do
    length[i] = lcg()%19 + 6
    rhythm[i] = {}
    for n=1,32 do
      rhythm[i][n] = lcg()
    end
    step[i] = 1
  end

  -- notes
  for i=1,4 do
    notes[i] = {0}
    for n=1,31 do
      notes[i][n+1] = notes[i][n] + (lcg() % 7) -3
    end
  end

  -- out params
  output[1].slew   = 0
  output[1].volts  = 0
  output[2].action = ar(get_a,get_d)
  output[3].slew   = 0.01
  output[3].volts  = 0
  output[4].action = ar(get_a,get_d)

  -- start sequence!
  input[1]{ mode = 'change', direction = 'rising' }
  dec = metro.init{ event = env, time = 0.1 }
  dec:start()
end