novabox.py

   1 # A primitive drum machine interface for Novation Nocturn.
   2 #
   3 # Usage:
   4 #   - make sure that Novation Nocturn is connected *and* that the USB device
   5 #     that corresponds to it can be opened by the current user
   6 #   - create an ini file containing a scene with a single instrument using
   7 #     a sampler or fluidsynth engine + some drum mappings in SFZ or SF2
   8 #   - ensure that the ini file contains 7 drum patterns, pat1..pat7, these
   9 #     can be copied from cboxrc-example
  10 #   - user buttons 1..7 start drum patterns
  11 #   - user button 8 stops the playback
  12 #   - encoder knob 1 adjusts the volume
  13 #   - mixer button exits the application
  14
  15 import math
  16 import sys
  17
  18 sys.path = ["./py"] + sys.path
  19
  20 import nocturn
  21 import cbox
  22
  23 quit = False
  24
  25 instr_name = cbox.Document.get_scene().status().instruments.keys()[0]
  26
  27 def clamp(val, min, max):
  28     if val < min:
  29         val = min
  30     elif val > max:
  31         val = max
  32     return val
  33
  34 class NovaBox:
  35     def __init__(self):
  36         self.nocturn = nocturn.Nocturn()
  37         self.cur_pattern = None
  38         self.handlers = {}
  39         self.handlers[83] = self.on_xfade_touch
  40         for i in range(7):
  41             self.handlers[112 + i] = lambda cmd, val: self.on_buttonN_press(cmd - 112) if val > 0 else None
  42         self.handlers[112 + 7] = lambda cmd, val: self.on_button8_press() if val > 0 else None
  43         self.handlers[64] = self.on_knob1_change
  44         self.handlers[65] = self.on_knob2_change
  45         self.handlers[127] = lambda cmd, val: self.on_mixer_press() if val > 0 else None
  46
  47     def on_knob1_change(self, cmd, val):
  48         scene = cbox.Document.get_scene()
  49         instr = scene.status().instruments[instr_name][1]
  50         gain = instr.get_things('/output/1/status', ['gain']).gain
  51         if val > 63:
  52             val = -128 + val
  53         instr.cmd('/output/1/gain', None, gain + val * 0.5)
  54
  55     def on_knob2_change(self, cmd, val):
  56         tempo = cbox.GetThings("/master/status", ['tempo'], []).tempo
  57         if val > 63:
  58             val = -128 + val
  59         tempo = clamp(tempo + val * 0.5, 30, 300)
  60         cbox.do_cmd('/master/set_tempo', None, [tempo])
  61
  62     def on_buttonN_press(self, button):
  63         cbox.do_cmd("/master/stop", None, [])
  64         song = cbox.Document.get_song()
  65         song.loop_single_pattern(lambda: song.load_drum_pattern('pat%d' % (button + 1)))
  66         cbox.do_cmd("/master/seek_ppqn", None, [0])
  67         cbox.do_cmd("/master/play", None, [])
  68         self.cur_pattern = button
  69
  70     def on_button8_press(self):
  71         self.cur_pattern = None
  72         cbox.do_cmd("/master/stop", None, [])
  73
  74     def on_mixer_press(self):
  75         global quit
  76         quit = True
  77
  78     def on_xfade_touch(self, cmd, val):
  79         if val > 0:
  80             print "Do not touch"
  81
  82     def handler(self, cmd, val):
  83         if cmd in self.handlers:
  84             self.handlers[cmd](cmd, val)
  85             return
  86
  87     def poll(self):
  88         self.nocturn.poll(self.handler)
  89
  90     def update(self):
  91         scene = cbox.Document.get_scene()
  92         cmds = nocturn.NocturnCommands()
  93         master = cbox.GetThings("/master/status", ['playing'], [])
  94         for i in range(7):
  95             cmds.setModeButtonLight(i, self.cur_pattern == i)
  96         gain = scene.status().instruments[instr_name][1].get_things('/output/1/status', ['gain']).gain
  97         cmds.setEncoderMode(0, 0)
  98         cmds.setEncoderValue(0, clamp(int(gain * 2 + 64), 0, 127))
  99
 100         cmds.setModeButtonLight(7, self.cur_pattern is None)
 101         self.nocturn.execute(cmds)
 102
 103 nb = NovaBox()
 104 while not quit:
 105     nb.poll()
 106     nb.update()
 107 nb.nocturn.reset()