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/*
Copyright (C) 2019 Leo Tenenbaum
This file is part of AutoArt.
AutoArt is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
AutoArt is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with AutoArt. If not, see <https://www.gnu.org/licenses/>.
*/
package autoart
import (
"github.com/pommicket/autoart/autoutils"
"io"
)
func GenerateAudio(output io.Writer, duration float64, sampleRate int32,
functionLength int, rectifier int) error {
samples := int64(duration * float64(sampleRate))
err := autoutils.WriteAudioHeader(output, samples, 1, sampleRate)
if err != nil {
return err
}
vars := make([]float64, 1)
const sampleBufferSize = 4096
sampleBuffer := make([]uint8, sampleBufferSize)
sampleBufferIndex := 0
var function autoutils.Function
function.Generate(1, functionLength)
for s := int64(0); s < samples; s++ {
t := float64(s) / float64(sampleRate)
vars[0] = t
value := rectify(function.Evaluate(vars), rectifier)
sampleBuffer[sampleBufferIndex] = uint8(255 * value)
sampleBufferIndex++
if sampleBufferIndex == sampleBufferSize {
err = autoutils.WriteAudioSamples(output, sampleBuffer)
if err != nil {
return err
}
sampleBufferIndex = 0
}
}
return autoutils.WriteAudioSamples(output, sampleBuffer[:sampleBufferIndex])
}
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