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package com.sun.media.sound;

LFO control signal generator.
Author:Karl Helgason
/** * 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; } } @Override 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; } @Override 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(); } @Override 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; } } } @Override 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; } }