terrible fm synthesis, it's just awful

randomorganelle.py

#!/usr/bin/python3

import wave
import sys
import struct
import math

outpath=sys.argv[0].rsplit('.',1)[0]+".wav"
print("Writing to {}".format(outpath))

samp_rate = 44100.
w = wave.open(outpath,'wb')
w.setframerate(samp_rate)
w.setsampwidth(2)
w.setnchannels(2)

SCALE=2**14
TIMESTEP=1./samp_rate

def wf_saw(phi):
    mphi = phi % (2*math.pi)
    return -1. + (mphi / math.pi)

def wf_tri(phi):
    mphi = phi % (2*math.pi)
    if mphi < math.pi:
        return -1. + 2*(mphi / math.pi)
    else:
        return -1. + 2*((2*math.pi-mphi) / math.pi) 

def ramp(v1,v2,t1,t2):
    delta = (v2-v1) / ((t2-t1)/TIMESTEP)
    while t1 > 0.:
        yield v1
        t1 -= TIMESTEP
        t2 -= TIMESTEP
    while t2 > 0.:
        v1 += delta
        yield v1
        t2 -= TIMESTEP
    while True:
        yield v2

def osc(freq,phi=0.,wf=math.sin):
    delta = TIMESTEP*2*math.pi*freq
    while True:
        yield wf(phi)
        phi += delta

def vosc(vfreq,phi=0.,wf=math.sin):
    while True:
        yield wf(phi)
        phi += TIMESTEP*2*math.pi*next(vfreq)

def switch(f1,f2,time):
    while time > 0.:
        yield next(f1)
        time -= TIMESTEP
    while True:
        yield next(f2)

def alternate(f1,f2,t1,t2):
    while True:
        time = t1
        while time > 0.:
            yield next(f1)
            time -= TIMESTEP
        time = t2
        while time > 0.:
            yield next(f2)
            time -= TIMESTEP

def generate(l,r,duration):
    time = 0.
    while time < duration:
        yield (next(l),next(r))
        time += TIMESTEP

dat = bytearray()
l = alternate(osc(500),osc(500,wf=wf_tri),.5,.5)
r = vosc(ramp(60,200,1,3))

for (left,right) in generate(l,r,5):
    dat.extend(struct.pack('hh',int(left*SCALE),int(right*SCALE)))
w.writeframes(dat)
w.close()