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/*
* Copyright 2010 Phil Burk, Mobileer Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.jsyn.data;
import com.jsyn.unitgen.EnvelopeDAHDSR;
import com.jsyn.unitgen.VariableRateMonoReader;
/**
* Store an envelope as a series of line segments. Each line is described as a duration and a target
* value. The envelope can be played using a {@link VariableRateMonoReader}. Here is an example that
* generates an envelope that looks like a traditional ADSR envelope.
*
* <pre>
* <code>
* // Create an amplitude envelope and fill it with data.
* double[] ampData = {
* 0.02, 0.9, // duration,value pair 0, "attack"
* 0.10, 0.5, // pair 1, "decay"
* 0.50, 0.0 // pair 2, "release"
* };
* SegmentedEnvelope ampEnvelope = new SegmentedEnvelope( ampData );
*
* // Hang at end of decay segment to provide a "sustain" segment.
* ampEnvelope.setSustainBegin( 1 );
* ampEnvelope.setSustainEnd( 1 );
*
* // Play the envelope using queueOn so that it uses the sustain and release information.
* synth.add( ampEnv = new VariableRateMonoReader() );
* ampEnv.dataQueue.queueOn( ampEnvelope );
* </code>
* </pre>
*
* As an alternative you could use an {@link EnvelopeDAHDSR}.
*
* @author Phil Burk (C) 2010 Mobileer Inc
* @see VariableRateMonoReader
* @see EnvelopeDAHDSR
*/
public class SegmentedEnvelope extends SequentialDataCommon {
private double[] buffer;
public SegmentedEnvelope(int maxFrames) {
allocate(maxFrames);
}
public SegmentedEnvelope(double[] pairs) {
this(pairs.length / 2);
write(pairs);
}
public void allocate(int maxFrames) {
buffer = new double[maxFrames * 2];
this.maxFrames = maxFrames;
this.numFrames = 0;
}
/**
* Write frames of envelope data. A frame consists of a duration and a value.
*
* @param startFrame Index of frame in envelope to write to.
* @param data Pairs of duration and value.
* @param startIndex Index of frame in data[] to read from.
* @param numToWrite Number of frames (pairs) to write.
*/
public void write(int startFrame, double[] data, int startIndex, int numToWrite) {
System.arraycopy(data, startIndex * 2, buffer, startFrame * 2, numToWrite * 2);
if ((startFrame + numToWrite) > numFrames) {
numFrames = startFrame + numToWrite;
}
}
public void read(int startFrame, double[] data, int startIndex, int numToRead) {
System.arraycopy(buffer, startFrame * 2, data, startIndex * 2, numToRead * 2);
}
public void write(double[] data) {
write(0, data, 0, data.length / 2);
}
public void read(double[] data) {
read(0, data, 0, data.length / 2);
}
/** Read the value of an envelope, not the duration. */
@Override
public double readDouble(int index) {
return buffer[(index * 2) + 1];
}
@Override
public void writeDouble(int index, double value) {
buffer[(index * 2) + 1] = value;
if ((index + 1) > numFrames) {
numFrames = index + 1;
}
}
@Override
public double getRateScaler(int index, double synthesisPeriod) {
double duration = buffer[index * 2];
if (duration < synthesisPeriod) {
duration = synthesisPeriod;
}
return 1.0 / duration;
}
@Override
public int getChannelsPerFrame() {
return 1;
}
}
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