Python/MIDI prototype for Win32! [0129.2000]

""" I just absolutely cannot believe it took me 10 hours - from around midnight to 10:00am to get this thing working... I spent most of it trying to figure out why my tuple wasn't a tuple. Sheesh.... Anyway, I'm pretty proud of this little script.. It plays the chromatic scale on a MIDI device... Nothing too useful yet, but it should be, soon! I just figured I'd post it to my site to show off..

It requires Python, and these modules:

dynwin (for windll, oracle) npstruct calldll

all of which are available from:

http://www.nightmare.com/software.html

-michal

"""
################################################################
#
# winmidi.py - python module for interfacing with MIDI for windows
# just a test script, based on a VB demo from microsoft...
# 1029.2000 by sabren@manifestation.com
#
############################################################


import sys
# yeah, I know I should do this the right way:
sys.path.append("""c:\program files\python\dynwin""") 


MAXPNAMELEN = 32  #Maximum product name length


# Error values for functions used in this sample. See the function for more information
MMSYSERR_BASE = 0
MMSYSERR_BADDEVICEID = (MMSYSERR_BASE + 2)     # device ID out of range
MMSYSERR_INVALPARAM = (MMSYSERR_BASE + 11)     # invalid parameter passed
MMSYSERR_NODRIVER = (MMSYSERR_BASE + 6)        # no device driver present
MMSYSERR_NOMEM = (MMSYSERR_BASE + 7)           # memory allocation error


MMSYSERR_INVALHANDLE = (MMSYSERR_BASE + 5)     # device handle is invalid
MIDIERR_BASE = 64
MIDIERR_STILLPLAYING = (MIDIERR_BASE + 1)      # still something playing
MIDIERR_NOTREADY = (MIDIERR_BASE + 3)          # hardware is still busy
MIDIERR_BADOPENMODE = (MIDIERR_BASE + 6)       # operation unsupported w/ open mode


import windll
import gencb
import structob


MIDIINCAPS = structob.Oracle (
    'MIDI In Capabilities for a Device',
    'Nlll' + `MAXPNAMELEN` + 'c2l',
    ( 'wMid',
      'wPid',
      'vDriverVersion',
      'szPname',
      'dwSupport' ))




HANDLE = structob.Oracle (
    "just a handle.. in this case to a MIDI thingy...",
    "Ll",
    ("value",)) # need the comma to make it a tuple!!!
                # (friggin took me 4 hours to figure that out, too..


MIDIOUTCAPS = structob.Oracle (
    'MIDI Out Capabilities for a Device',
    'Llll' + `MAXPNAMELEN` + 'cllll2l',
    ( 'wMid',
      'wPid',
      'vDriverVersion',
      'szPname',
      'wTechnology',
      'wVoices',
      'wNotes',
      'wChannelMask',
      'dwSupport' ))


winmm = windll.module("winmm")


numDevices = winmm.midiOutGetNumDevs()
print `numDevices` + " MIDI output devices found (besides Mapper):"


import string


# use this to turn the tuple into a string..
def cstr( dict ):
    res = ""
    for i in dict:
        if ord(i) == 0: # 0x00-terminated string
            break
        else:
            res = res + i
    return res




for i in range(-1,numDevices): # why must I suvtract one?? : VB does it too.. -1 is the midi mapper
    buf = windll.membuf(MIDIOUTCAPS.size)
    winmm.midiOutGetDevCaps(i, buf.address(), MIDIOUTCAPS.size)
    #print buf.read()
    dict, size = MIDIOUTCAPS.unpack (buf.read())
    #print "xxxxxxx xx: " + ("x" * 32 )
    print "szPname is: " + cstr(dict["szPname"]) #@TODO: WHY IS IT STRIPPING 4 chars?
                                                 #@TODO: also, windll has a "cstring" class..
    #print `MIDIOUTCAPS.size` + "expected, " + `size` + "received.."






curDevice = -1 # midi mapper
channel = 9 # drums
channel = 0 # piano
baseNote = 60
volume = 127
volume = 40


hmidi = windll.membuf(HANDLE.size)


print "read0:", hmidi.read()
rc = winmm.midiOutOpen(hmidi, curDevice, 0, 0, 0)
print "read1:", hmidi.read()
print "result from midiOutOpen: ", rc


print "hmidi:", HANDLE.unpack (hmidi.read())
handle = HANDLE.unpack(hmidi.read())[0]["value"]
print "handle:", handle


import time


#scale = range(1,8) + range(8,0,-1) # not chromatic.. its just by half notes
scale = (0, 2, 4, 5, 7, 9, 11, 12, 11, 9, 7, 5, 4, 2, 0) # chromatic scale
print scale
for note in scale:
    # play a note
    midimsg = 0x90 + ((baseNote + note) * 0x100) + (volume * 0x10000) + channel
    rc = winmm.midiOutShortMsg (handle, midimsg)
    time.sleep(0.25)
    # turn it off
    midimsg = 0x80 + ((baseNote + note) * 0x100) + channel
    rc = winmm.midiOutShortMsg (handle, midimsg)




rc = winmm.midiOutClose(handle) #@TODO: should be value stored in the buffer..
print "result from midiOutClose:", rc
print "........"


# had to add "import calldll" INSIDE windll.module.unload(),
# even though windll imports calldll.. dunno why..
# otherwise it was saying:
#
#Exception exceptions.AttributeError: "'None' object has no attribute 'free_library'" in
#     ignored
#


#__END__#