71 lines
2.1 KiB
Python
71 lines
2.1 KiB
Python
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## This file generates headers with lookup tables for various waveforms
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## Add your own.
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import math
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## phase is in degrees: 360 is a full cycle, and this is probably what you want
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def phaseSteps(maxPhase, length=256):
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steps = range(0, length)
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steps = [1.0*x/length * 2.0*math.pi * (maxPhase/360.0) for x in steps]
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return steps
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def sine(maxPhase=360, length=256):
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wave = [math.sin(x) for x in phaseSteps(maxPhase, length)]
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return scaleAndRound(wave)
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def sawtooth(maxPhase=360, length=256):
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wave = [x for x in range(length)]
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return scaleAndRound(wave)
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def square(maxPhase=360, length=256):
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wave = [0]*(length//2)
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wave.extend([1]*(length//2))
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return scaleAndRound(wave)
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def triangle(maxPhase=360, length=256):
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wave = [x for x in range(length//2)]
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wave.extend([length//2 - x for x in range(length//2)])
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return scaleAndRound(wave)
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def bandlimitedSawtooth(numberPartials, maxPhase=360, length=256):
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wave = [0]*length
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sign = 1.0
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for k in range(1, numberPartials+1):
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phases = phaseSteps(maxPhase*k, length)
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for i in range(length):
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wave[i] += sign * math.sin(phases[i]) / k
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sign = sign * -1
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return scaleAndRound(wave)
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def bandlimitedSquare(numberPartials, maxPhase=360, length=256):
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wave = [0]*length
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for k in range(1, numberPartials*2, 2):
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phases = phaseSteps(maxPhase*k, length)
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for i in range(length):
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wave[i] += math.sin(phases[i]) / k
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return scaleAndRound(wave)
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def bandlimitedTriangle(numberPartials, maxPhase=360, length=256):
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wave = [0]*length
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sign = 1.0
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for k in range(1, numberPartials*2, 2):
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phases = phaseSteps(maxPhase*k, length)
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for i in range(length):
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wave[i] += sign * math.sin(phases[i]) / k**2
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sign = sign * -1
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return scaleAndRound(wave)
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def scaleAndRound(data, scale=2**16-1, signedInt=True):
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data = [0.0+x-min(data) for x in data]
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data = [1.0*x/max(data)*scale for x in data]
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data = [int(round(x)) for x in data]
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if signedInt:
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data = [int(x-(scale+1)//2) for x in data]
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return(data)
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if __name__ == "__main__":
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sawtooth_sample = sawtooth(7)
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