physical-clock.lua

-- physical: clock edition
-- norns study 4
--
-- grid controls arpeggio
-- midi controls root note
-- ENC1 = bpm
-- ENC2 = divisor
-- ENC3 = scale
-- KEY2 = hold
-- KEY3 = restart sequence

engine.name = 'PolyPerc'

local music = require 'musicutil'

steps = {}
position = 1
transpose = 0
active = 1

divisor = 4

local task_id = nil

mode = math.random(#music.SCALES)
scale = music.generate_scale_of_length(60,music.SCALES[mode].name,8)

function init()
  for i=1,16 do
    table.insert(steps,math.random(8))
  end
  grid_redraw()
  
  task_id = clock.run(step)

end

function step()
  while true do
    clock.sync(1/divisor)
    if active == 1 then
      position = (position % 16) + 1
      engine.hz(music.note_num_to_freq(scale[steps[position]] + transpose))
      grid_redraw()
    end
  end
end

function key(n,z)
  if n == 2 then
    active = math.abs(z-1)
  elseif n == 3 then
    if z == 1 then
      clock.cancel(task_id)
      task_id = clock.run(step)
      position = 0
    end
  end
end

function enc(n,d)
  if n == 1 then
    params:delta("clock_tempo",d)
  elseif n == 2 then
    divisor = util.clamp(divisor + d,1,8)
  elseif n == 3 then
    mode = util.clamp(mode + d, 1, #music.SCALES)
    scale = music.generate_scale_of_length(60,music.SCALES[mode].name,8)
  end
  redraw()
end

function redraw()
  screen.clear()
  screen.level(15)
  screen.move(0,30)
  screen.text("bpm: "..params:get("clock_tempo"))
  screen.move(0,40)
  screen.text("div: 1/".. divisor*4)
  screen.move(0,50)
  screen.text(music.SCALES[mode].name)
  screen.update()
end

g = grid.connect()

g.key = function(x,y,z)
  if z == 1 then
    steps[x] = y
    grid_redraw()
  end
end

function grid_redraw()
  g:all(0)
  for i=1,16 do
    g:led(i,steps[i],i==position and 15 or 4)
  end
  g:refresh()
end

m = midi.connect()
m.event = function(data)
  local d = midi.to_msg(data)
  if d.type == "note_on" then
    transpose = d.note - 60
  end
end