# this is a script for generating a wavetable file
# a wavetable file consists of a one-dimensional array of samples representing one period of a waveform
# metadata includes:
#   - file version (for program compatibilty)
#   - binary format (float, double, int32, etc.)
#   - domain (eg phase is represented from [0, 2pi) )
#   - range (determined by datatype, e.g. float=[-1,1], int32=[-2^15, 2^15-1])
#   - waveform RMS (for loudness normalization)
#   - sample count
# the synth program uses the filename, not any metadata

# this script uses the input function to calculate samples
# if you want a custom wavetable, copt/edit/modify the example function (i used desmos for brainstorming)
# import this script and call generateWavetable(processFunction) to generate a custom wavetable

from array import array
import math

wavetableLength = 2048

def createFile(name):
    filename = name
    print("Creating file " + filename)
    file = open(filename, "wb")
    return file

def writeMetadata(file):
    print(">> im writing metadata")
    
def writeData(file, processFunction):
    print(">> im generating the wavetable")

    # init variables
    data_list = [None] * wavetableLength
    phaseInc = 2*math.pi / wavetableLength
    x = 0
    accumulator = 0

    # generate each discrete sample
    for i in range(wavetableLength):
        sample = processFunction(x)
        accumulator += sample * sample
        x += phaseInc
        data_list[i] = sample

    # normalize by rms
    rms = math.sqrt(accumulator/wavetableLength)
    print(">> wavetable RMS: ", rms)
    for i in range(wavetableLength):
        data_list[i] /= rms

    # write to file
    binary_data = array("f", data_list)
    file.write(binary_data)

def closeFile(file):
    print(">> finishing up")
    file.close()

def generateWavetable(name, processFunction):
    print("Hello main")
    file = createFile(name)
    writeMetadata(file)
    writeData(file, processFunction)
    closeFile(file)
    print("Done")