ghmidi.py

#!/usr/bin/env python
# -* coding: utf-8 *-
'''
Guitar Hero® World Tour wireless PS3 drums to MIDI adapter for Linux in python.

usage: PROG [hidraw device, default: /dev/hidraw4] [MIDI device number, default: last output]
'''

# FIXME: I dunno... refactor maybe? ;)
# FIXME: Sadly, latency is quite noticable
# TODO: Make buttons fire MIDI events too!

import pypm
import sys
import os

# MIDI Notes fired on drum hits, in the following order:
# Yellow, Red, Green, Blue, Kick, Orange (look at the bottom for further
# information, following bindings are reasonable in default Hydrogen drumset)
NOTES = [49, 38, 41, 43, 36, 46]

DEFAULT_DEV = '/dev/hidraw4'

REPORT_SIZE = 27
MAX_VELOCITY = 122
DEBUG = False

def main(argv):

    hidraw_dev = argv[0] if len(argv) >= 1 else DEFAULT_DEV

    # Wroom wroom wroom!
    devices = [dict(zip(['interface', 'name', 'input', 'output', 'open'], pypm.GetDeviceInfo(i)), id=i) for i in xrange(pypm.CountDevices())]
    output_devices = filter(lambda x: x['output'], devices)

    chosen_device = devices[int(argv[1])] if len(argv) >= 2 and devices[int(argv[1])] in output_devices else output_devices[-1]

    for d in output_devices:
        print '%(id)2d: %(star)s%(name)s' % dict(star='*' if chosen_device == d else ' ', **d)

    MidiOut = pypm.Output(chosen_device['id'], 0)
    
    if not os.access(hidraw_dev, os.R_OK):
        import getpass
        print >>sys.stderr, '\n*** You have no access to %s device, try:\n***\tsudo chown %s %s\n' % (hidraw_dev, getpass.getuser(), hidraw_dev)
    hidraw = open(hidraw_dev)

    state = [0, 0, 0, 0, 0, 0]

    lastbuf = None

    while True:
        buf = hidraw.read(REPORT_SIZE)
        for i, prev in enumerate(state):
            if ord(buf[11 + i]) != prev:
                state[i] = ord(buf[11 + i])
                if state[i] == 127:
                    # Action Buttons
                    pass
                elif state[i] > 0:
                    # Drum hit
                    print 'Hit',i
                    MidiOut.WriteShort(0x90, NOTES[i], state[i])
                else:
                    # Drum/key release
                    pass
                    #MidiOut.WriteShort(0x80, NOTES[i], prev)

        if DEBUG:
            if lastbuf != None:
                diff = [(i, lastbuf[i], n) for i, n in enumerate(buf) if n != lastbuf[i]]
                for i, p, c in diff:
                    print 'byte %d changed from %d to %d' % (i, ord(p), ord(c))

            lastbuf = buf

if __name__ == '__main__':
    try:
        main(sys.argv[1:])
    except KeyboardInterrupt: pass

'''
Some notes
==========

Drum state/velocity bytes in report:
    buf[11]     yellow / square
    buf[12]     red    / circle
    buf[13]     green  / cross
    buf[14]     blue   / triangle
    buf[15]     kick
    buf[16]     orange / L1

Buttons:
    buf[0] & 1  Square
    buf[0] & 2  Cross
    buf[0] & 4  Circle
    buf[0] & 8  Triangle

    buf[11:15] == 127 Square/Cross/Circle/Triangle (look above)

    buf[1] & 1  SELECT
    buf[1] & 2  START
    buf[1] & 16 PS/HOME

    buf[7]      D-Pad Right
    buf[8]      D-Pad Left
    buf[9]      D-Pad Up
    buf[10]     D-Pad Down

Drums disconnected:
    byte 5 changed from 0 to 128
    byte 6 changed from 0 to 128
    byte 20 changed from 0 to 2
    byte 22 changed from 0 to 2
    byte 24 changed from 0 to 2

Drums reconnected:
    byte 5 changed from 128 to 0
    byte 6 changed from 128 to 0
    byte 20 changed from 2 to 0
    byte 22 changed from 2 to 0
    byte 24 changed from 2 to 0

Drum/state byte behaviour when button is kept pressed:
    byte 13 changed from 0 to 127       [button pressed]
    byte 13 changed from 127 to 122     [drum hit]
    byte 13 changed from 122 to 127     [drum released, button still pressed]

'''