Java example source code file (SoftLowFrequencyOscillator.java)

This example Java source code file (SoftLowFrequencyOscillator.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

pi2, softlowfrequencyoscillator, softprocess, string

The SoftLowFrequencyOscillator.java Java example source code

/*
 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.sun.media.sound;

/**
 * LFO control signal generator.
 *
 * @author Karl Helgason
 */
public final class SoftLowFrequencyOscillator implements SoftProcess {

    private final int max_count = 10;
    private int used_count = 0;
    private final double[][] out = new double[max_count][1];
    private final double[][] delay = new double[max_count][1];
    private final double[][] delay2 = new double[max_count][1];
    private final double[][] freq = new double[max_count][1];
    private final int[] delay_counter = new int[max_count];
    private final double[] sin_phase = new double[max_count];
    private final double[] sin_stepfreq = new double[max_count];
    private final double[] sin_step = new double[max_count];
    private double control_time = 0;
    private double sin_factor = 0;
    private static final double PI2 = 2.0 * Math.PI;

    public SoftLowFrequencyOscillator() {
        // If sin_step is 0 then sin_stepfreq must be -INF
        for (int i = 0; i < sin_stepfreq.length; i++) {
            sin_stepfreq[i] = Double.NEGATIVE_INFINITY;
        }
    }

    public void reset() {
        for (int i = 0; i < used_count; i++) {
            out[i][0] = 0;
            delay[i][0] = 0;
            delay2[i][0] = 0;
            freq[i][0] = 0;
            delay_counter[i] = 0;
            sin_phase[i] = 0;
            // If sin_step is 0 then sin_stepfreq must be -INF
            sin_stepfreq[i] = Double.NEGATIVE_INFINITY;
            sin_step[i] = 0;
        }
        used_count = 0;
    }

    public void init(SoftSynthesizer synth) {
        control_time = 1.0 / synth.getControlRate();
        sin_factor = control_time * 2 * Math.PI;
        for (int i = 0; i < used_count; i++) {
            delay_counter[i] = (int)(Math.pow(2,
                    this.delay[i][0] / 1200.0) / control_time);
            delay_counter[i] += (int)(delay2[i][0] / (control_time * 1000));
        }
        processControlLogic();
    }

    public void processControlLogic() {
        for (int i = 0; i < used_count; i++) {
            if (delay_counter[i] > 0) {
                delay_counter[i]--;
                out[i][0] = 0.5;
            } else {
                double f = freq[i][0];

                if (sin_stepfreq[i] != f) {
                    sin_stepfreq[i] = f;
                    double fr = 440.0 * Math.exp(
                            (f - 6900.0) * (Math.log(2) / 1200.0));
                    sin_step[i] = fr * sin_factor;
                }
                /*
                double fr = 440.0 * Math.pow(2.0,
                (freq[i][0] - 6900.0) / 1200.0);
                sin_phase[i] += fr * sin_factor;
                 */
                /*
                sin_phase[i] += sin_step[i];
                while (sin_phase[i] > PI2)
                sin_phase[i] -= PI2;
                out[i][0] = 0.5 + Math.sin(sin_phase[i]) * 0.5;
                 */
                double p = sin_phase[i];
                p += sin_step[i];
                while (p > PI2)
                    p -= PI2;
                out[i][0] = 0.5 + Math.sin(p) * 0.5;
                sin_phase[i] = p;

            }
        }
    }

    public double[] get(int instance, String name) {
        if (instance >= used_count)
            used_count = instance + 1;
        if (name == null)
            return out[instance];
        if (name.equals("delay"))
            return delay[instance];
        if (name.equals("delay2"))
            return delay2[instance];
        if (name.equals("freq"))
            return freq[instance];
        return null;
    }
}