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91 lines
3.3 KiB
Python
91 lines
3.3 KiB
Python
#!/usr/bin/python2.5
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#
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# Copyright 2014 Emilie Gillet.
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#
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# Author: Emilie Gillet (emilie.o.gillet@gmail.com)
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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#
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# See http://creativecommons.org/licenses/MIT/ for more information.
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#
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# -----------------------------------------------------------------------------
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#
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# Lookup table definitions.
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import numpy
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SAMPLE_RATE = 20000000.0 / 510 / 16#/ 4 # hz
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WAVETABLE_SIZE = 1024
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"""----------------------------------------------------------------------------
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LFO and envelope increments.
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----------------------------------------------------------------------------"""
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lookup_tables = []
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lookup_tables_32 = []
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excursion = 1 << 32
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sample_rate = SAMPLE_RATE
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num_values = 257
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min_frequency = 1.0 / 32.0 # Hertz
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max_frequency = 160.0 # Hertz
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min_increment = excursion * min_frequency / sample_rate
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max_increment = excursion * max_frequency / sample_rate
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# Create lookup table for envelope times (x^0.25).
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max_time = 8.0 # seconds
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min_time = 0.0005
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gamma = 0.175
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min_increment = excursion / (max_time * sample_rate)
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max_increment = excursion / (min_time * sample_rate)
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rates = numpy.linspace(numpy.power(max_increment, -gamma),
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numpy.power(min_increment, -gamma), num_values)
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values = numpy.power(rates, -1/gamma).astype(int)
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lookup_tables_32.append(
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('env_increments', values)
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)
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# Tides envelopes
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max_time = 60.0 * 2 # seconds
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min_time = .5
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gamma = 0.175
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min_increment = excursion / (max_time * sample_rate)
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max_increment = excursion / (min_time * sample_rate)
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rates = numpy.linspace(numpy.power(max_increment, -gamma),
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numpy.power(min_increment, -gamma), num_values)
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values = numpy.power(rates, -1/gamma).astype(int)
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lookup_tables_32.append(
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('env_increments_slow', values)
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)
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"""----------------------------------------------------------------------------
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Envelope curves
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-----------------------------------------------------------------------------"""
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env_linear = numpy.arange(0, 257.0) / 256.0
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env_linear[-1] = env_linear[-2]
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env_quartic = env_linear ** 3.32
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env_expo = 1.0 - numpy.exp(-4 * env_linear)
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lookup_tables.append(('env_linear', env_linear / env_linear.max() * 65535.0))
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lookup_tables.append(('env_expo', env_expo / env_expo.max() * 65535.0))
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lookup_tables.append(
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('env_quartic', env_quartic / env_quartic.max() * 65535.0))
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