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    1   /*
    2    * Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   package com.sun.media.sound;
   26   
   27   /**
   28    * LFO control signal generator.
   29    *
   30    * @author Karl Helgason
   31    */
   32   public class SoftLowFrequencyOscillator implements SoftProcess {
   33   
   34       private int max_count = 10;
   35       private int used_count = 0;
   36       private double[][] out = new double[max_count][1];
   37       private double[][] delay = new double[max_count][1];
   38       private double[][] delay2 = new double[max_count][1];
   39       private double[][] freq = new double[max_count][1];
   40       private int[] delay_counter = new int[max_count];
   41       private double[] sin_phase = new double[max_count];
   42       private double[] sin_stepfreq = new double[max_count];
   43       private double[] sin_step = new double[max_count];
   44       private double control_time = 0;
   45       private double sin_factor = 0;
   46       private static double PI2 = 2.0 * Math.PI;
   47   
   48       public SoftLowFrequencyOscillator() {
   49           // If sin_step is 0 then sin_stepfreq must be -INF
   50           for (int i = 0; i < sin_stepfreq.length; i++) {
   51               sin_stepfreq[i] = Double.NEGATIVE_INFINITY;
   52           }
   53       }
   54   
   55       public void reset() {
   56           for (int i = 0; i < used_count; i++) {
   57               out[i][0] = 0;
   58               delay[i][0] = 0;
   59               delay2[i][0] = 0;
   60               freq[i][0] = 0;
   61               delay_counter[i] = 0;
   62               sin_phase[i] = 0;
   63               // If sin_step is 0 then sin_stepfreq must be -INF
   64               sin_stepfreq[i] = Double.NEGATIVE_INFINITY;
   65               sin_step[i] = 0;
   66           }
   67           used_count = 0;
   68       }
   69   
   70       public void init(SoftSynthesizer synth) {
   71           control_time = 1.0 / synth.getControlRate();
   72           sin_factor = control_time * 2 * Math.PI;
   73           for (int i = 0; i < used_count; i++) {
   74               delay_counter[i] = (int)(Math.pow(2,
   75                       this.delay[i][0] / 1200.0) / control_time);
   76               delay_counter[i] += (int)(delay2[i][0] / (control_time * 1000));
   77           }
   78           processControlLogic();
   79       }
   80   
   81       public void processControlLogic() {
   82           for (int i = 0; i < used_count; i++) {
   83               if (delay_counter[i] > 0) {
   84                   delay_counter[i]--;
   85                   out[i][0] = 0.5;
   86               } else {
   87                   double f = freq[i][0];
   88   
   89                   if (sin_stepfreq[i] != f) {
   90                       sin_stepfreq[i] = f;
   91                       double fr = 440.0 * Math.exp(
   92                               (f - 6900.0) * (Math.log(2) / 1200.0));
   93                       sin_step[i] = fr * sin_factor;
   94                   }
   95                   /*
   96                   double fr = 440.0 * Math.pow(2.0,
   97                   (freq[i][0] - 6900.0) / 1200.0);
   98                   sin_phase[i] += fr * sin_factor;
   99                    */
  100                   /*
  101                   sin_phase[i] += sin_step[i];
  102                   while (sin_phase[i] > PI2)
  103                   sin_phase[i] -= PI2;
  104                   out[i][0] = 0.5 + Math.sin(sin_phase[i]) * 0.5;
  105                    */
  106                   double p = sin_phase[i];
  107                   p += sin_step[i];
  108                   while (p > PI2)
  109                       p -= PI2;
  110                   out[i][0] = 0.5 + Math.sin(p) * 0.5;
  111                   sin_phase[i] = p;
  112   
  113               }
  114           }
  115       }
  116   
  117       public double[] get(int instance, String name) {
  118           if (instance >= used_count)
  119               used_count = instance + 1;
  120           if (name == null)
  121               return out[instance];
  122           if (name.equals("delay"))
  123               return delay[instance];
  124           if (name.equals("delay2"))
  125               return delay2[instance];
  126           if (name.equals("freq"))
  127               return freq[instance];
  128           return null;
  129       }
  130   }

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