#!/usr/bin/env python3
#
# sinegen3.py
# Released under the GPLv3 license.
#
# Initial release: August 4, 2009, G. Forrest Cook
# revision: Feb 24, 2022, cleaned up and verified for Python 3
# revision: Feb 21, 2024, removed obsolete pylab import, now use plt. and np.
#
# Generate and display exponentially weighted sine wave patterns for
# a Vibrato/Tremolo LFO circuit.
# The waveform is scaled to a range of 0-255 to support an
# 8 bit digital to analog converter (DAC).
#
# This requires the Ubuntu Matplotlib package (python3-matplotlib)
# Note that the commented lines were used to produce differently weighted
# sine waves using a slightly different method, the final values chosen worked
# best with the Lil' Tiger amp's pitch-shifting vibrato circuit, see:
# http://www.solorb.com/elect/musiccirc/ArduinoLFO2/
#

import matplotlib.pyplot as plt
import numpy as np

val = 0.0
count = 0

# minval and maxval start with out of range values.
minval = 255
maxval = 0

wavetable = []

# Bottom Heavy "Big Bottom" wave
for ind in range(0, 256):
    val = (75 * pow(2.1, (1.0 - np.cos(2*np.pi*ind/256.0)))) - 75

# Calculate maxval and minval values.
    if val > maxval:
        maxval = val
    if val < minval:
        minval = val

    wavetable.append(val)

# print either right-side-up or inverted wave data:
    print("%d, " % val, end=""),
#    print("%d, " % (255.9-val), end=""),
    count = count+1

print("\nMin:%d, Max:%d, count:%d" % (minval, maxval, count))
#print(wavetable)	# array of floats

plt.grid(True)
plt.plot(wavetable)
plt.show()
quit()

#
# v2 = 0.0
# v3 = 0.0
#
# for ind in range (steps):
#    v1 = (370 * pow (1.3, (1.0 - cos(2*pi*ind/256.0)))) - 370
#    v1 = (204 * pow (1.5, (1.0 - cos(2*pi*ind/256.0)))) - 204
#    v1 = (135 * pow (1.7, (1.0 - cos(2*pi*ind/256.0)))) - 135
#    v1 = (40 * exp ((1.0 - cos(2*pi*ind/256.0)))) -40
#
#    v1 = 127.9 * (1.0 - cos(2*pi*ind/256.0))
#    v1 = 84 * (1.0 - cos(2*pi*ind/256.0))
#    v2 = 43 * (1.0 - cos(2*pi*ind/768.0))
#
#    v1 = 71.5 * (1.0 - cos(2*pi*ind/256.0))
#    v2 = 39 * (1.0 - cos(2*pi*ind/768.0))
#    v3 = 17 * (1.0 - cos(2*pi*ind/1280.0))
#
# Top Heavy inverted wave
#    val = 255 - v1