subs2.lua

--- subharmonic pitch source

magic = 1/math.log(2)

function init()
  output[1].volts = 0
  metro[1].time = 1.0
  metro[1].event = next_step
  metro[1]:start()
  --input[1].mode( 'stream', 0.002)

  metro[2].time = 0.002
  metro[2].event = bang_outputs
  metro[2]:start()

  metro[3].time = 0.666
  metro[3].event = nextnext_step
  metro[3]:start()
end

-- 0, -12, -19, -24, -28, -31, -33.5, -36

function just_volts( f )
    return math.log(f) * magic
end

-- sequence of pairs of ratios
otone = { 1,5,7,3 }
utone = { 1,4,2,6,3 }
otoneIX = 1
utoneIX = 1

-- TODO independent sequences for otone & utone

overtone  = 1
undertone = 1
function next_step()
  overtone  = otone[otoneIX]
  print( overtone.."/".. undertone )
  otoneIX = (otoneIX % #otone) + 1 -- increment our index, and wrap to #seq
end

function nextnext_step()
  undertone = utone[utoneIX]
  print( overtone.."/".. undertone )
  utoneIX = (utoneIX % #utone) + 1 -- increment our index, and wrap to #seq
end


slew = {0.01,0.01}
function process_v(v,index)
  --slew
  local _input = v
  local old = slew[index]
  --local rate = 0.005 -- sets the slew rate (0..1)
  local rate = 0.02 -- sets the slew rate (0..1)
  local _output = old + rate * (_input - old) -- linear interpolation
  slew[index] = _output

  --quantize to integers
  _output = math.floor(_output)

  return _output
end

function bang_outputs()
  output[1].volts = just_volts( process_v( overtone,1)/ process_v( undertone,2 ))
end

--- using the inputs to control numerator & denomenator directly

--slew = {0,0}
--function process_v(v,index)
--  v = 1 + (v+5)*1.3 -- convert (-5..5) into (1..14)
--  --v = math.floor(v)
--
--  local _input = v
--  local old = slew[index]
--  local rate = 0.02 -- sets the slew rate (0..1)
--  local _output = old + rate * (_input - old) -- linear interpolation
--  slew[index] = _output
--
--  _output = math.floor(_output)
--
--  return _output
--end
--
--input[1].stream = function(v)
--  local overtone = process_v( input[2].volts,1 )
--  output[1].volts = just_volts( overtone/process_v(v,2) )
--
--end