/*
 * Copyright 2007 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.media.sound;

/**
 * 
 * LFO control signal generator.
 * 
 * @version %I%, %E%
 * @author Karl Helgason
 */
public class SoftLowFrequencyOscillator implements SoftProcess {

	private int max_count = 10;

	private int used_count = 0;

	private double[][] out = new double[max_count][1];

	private double[][] delay = new double[max_count][1];

	private double[][] delay2 = new double[max_count][1];

	private double[][] freq = new double[max_count][1];

	private int[] delay_counter = new int[max_count];

	private double[] sin_phase = new double[max_count];
	
	private double[] sin_stepfreq = new double[max_count];
	private double[] sin_step = new double[max_count];

	private double control_time = 0;

	private double sin_factor = 0;
	
	private static double PI2 = 2.0 * Math.PI;

	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;
			sin_stepfreq[i] = 0;
			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;
	}

}