VocalEasel/mma/MMA/patBass.py

# patBass.py 

"""
This module is an integeral part of the program 
MMA - Musical Midi Accompaniment.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

Bob van der Poel <bvdp@xplornet.com>
	
"""
	


import gbl
from   MMA.notelen import getNoteLen
from   MMA.common import *
from   MMA.harmony import harmonize
from   MMA.pat import PC


class Bass(PC):
	""" Pattern class for a bass track. """

	vtype = 'BASS'	
			
	def getPgroup(self, ev):
		""" Get group for bass pattern.
				
		    Fields - start, length, note, volume
		
		"""
		
		if len(ev) != 4:	
			error("There must be n groups of 4 in a pattern definition, "
				  "not <%s>." % ' '.join(ev) )

		a = struct()

		a.offset   = self.setBarOffset(ev[0])
		a.duration = getNoteLen( ev[1] )

		offset = ev[2]
		n=offset[0]
		if n in "1234567":
			a.noteoffset = int(n)-1
		else:
			error("Note offset in Bass must be '1'...'7', not '%s'" % n )
			
		n = offset[1:2]
		if n == "#":
			a.accidental = 1
			ptr = 2
		elif n == 'b' or n == 'b' or n == '&':
			a.accidental = -1
			ptr = 2
		else:
			a.accidental = 0
			ptr = 1
		
		a.addoctave  = 0

		for n in ev[2][ptr:]:
			if n == '+':
				a.addoctave += 12
			elif n == '-':
				a.addoctave -= 12
				
			else:
				error("Only '- + # b &' are permitted after a noteoffset, not '%s'" % n)
		
		a.vol = stoi(ev[3], "Note volume in Bass definition not int.")
		
		return a

	def restart(self):
		self.ssvoice = -1
	

	def trackBar(self, pattern, ctable):
		""" Do the bass bar.
		
		Called from self.bar()
		
		"""
		
		sc = self.seq
		unify = self.unify[sc]

		for p in pattern:
			ct = self.getChordInPos(p.offset, ctable)

			if ct.bassZ:
				continue
						

			note = ct.chord.scaleList[p.noteoffset] + p.addoctave + p.accidental

			
			if not self.harmonyOnly[sc]:
				self.sendNote(
					p.offset,
					self.getDur(p.duration),
					self.adjustNote(note),
					self.adjustVolume(p.vol, p.offset))
				
					
			if self.harmony[sc]:
				h = harmonize(self.harmony[sc], note, ct.chord.noteList)
				for n in h:
					self.sendNote(
						p.offset,
						self.getDur(p.duration),
						self.adjustNote(n),
						self.adjustVolume(p.vol * self.harmonyVolume[sc], -1))