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/*
* Copyright 1997 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.unitgen;
import com.jsyn.ports.UnitInputPort;
import com.jsyn.ports.UnitVariablePort;
/**
* Output approaches Input linearly.
* <P>
* When you change the value of the input port, the ramp will start changing from its current output
* value toward the value of input. An internal phase value will go from 0.0 to 1.0 at a rate
* controlled by time. When the internal phase reaches 1.0, the output will equal input.
* <P>
*
* @author (C) 1997 Phil Burk, SoftSynth.com
* @see ExponentialRamp
* @see AsymptoticRamp
* @see ContinuousRamp
*/
public class LinearRamp extends UnitFilter {
/** Time in seconds to get to the input value. */
public UnitInputPort time;
public UnitVariablePort current;
private double source;
private double phase;
private double target;
private double timeHeld = 0.0;
private double rate = 1.0;
public LinearRamp() {
addPort(time = new UnitInputPort("Time"));
addPort(current = new UnitVariablePort("Current"));
}
@Override
public void generate(int start, int limit) {
double[] outputs = output.getValues();
double currentInput = input.getValues()[0];
double currentValue = current.getValue();
// If input has changed, start new segment.
// Equality check is OK because we set them exactly equal below.
if (currentInput != target)
{
source = currentValue;
phase = 0.0;
target = currentInput;
}
if (currentValue == target) {
// at end of ramp
for (int i = start; i < limit; i++) {
outputs[i] = currentValue;
}
} else {
// in middle of ramp
double currentTime = time.getValues()[0];
// Has time changed?
if (currentTime != timeHeld) {
rate = convertTimeToRate(currentTime);
timeHeld = currentTime;
}
for (int i = start; i < limit; i++) {
if (phase < 1.0) {
/* Interpolate current. */
currentValue = source + (phase * (target - source));
phase += rate;
} else {
currentValue = target;
}
outputs[i] = currentValue;
}
}
current.setValue(currentValue);
}
}
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