DefaultSoundEffect.java

/*
 * $Id: DefaultSoundEffect.java 536 2008-02-19 06:03:27Z weiju $
 * 
 * Created on 2006/02/06
 * Copyright 2005-2008 by Wei-ju Wu
 * This file is part of The Z-machine Preservation Project (ZMPP).
 *
 * ZMPP is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ZMPP 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ZMPP.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.zmpp.media;

import java.util.ArrayList;
import java.util.List;

import javax.sound.sampled.Clip;
import javax.sound.sampled.FloatControl;
import javax.sound.sampled.LineEvent;
import javax.sound.sampled.LineListener;

/**
 * This class implements the SoundEffect interface and encapsulates an audio
 * clip. By this means we provide more abstractness and flexibility.
 *
 * @author Wei-ju Wu
 * @version 1.0
 */
public class DefaultSoundEffect implements SoundEffect, LineListener {

    /**
     * The volume range is between 0 and 64 for AIFF sounds.
     */
    public static final int MAX_VOLUME = 64;

    /**
     * The audio clip.
     */
    private Clip clip;

    /**
     * The listeners.
     */
    private List<SoundStopListener> listeners;

    /**
     * Constructor.
     *
     * @param clip an audio clip
     */
    public DefaultSoundEffect(final Clip clip) {

        super();
        this.clip = clip;
        listeners = new ArrayList<SoundStopListener>();
        clip.addLineListener(this);
    }

    /**
     * {@inheritDoc}
     */
    public void play(final int number, final int volume) {
        setVolume(volume);
        if (number == 1) {
            clip.start();
        } else {
            clip.loop(number - 1);
        }
    // Reset to full volume
        //setVolume(255);
    }

    /**
     * Sets the volume.
     *
     * @param vol the volume
     */
    private void setVolume(final int vol) {

        int volume = vol;
        if (volume < 0) {
            volume = MAX_VOLUME;
        }
        float gainDb = 0.0f;
        final FloatControl gain = (FloatControl) clip.getControl(FloatControl.Type.MASTER_GAIN);

        if (volume == 0) {
            gainDb = gain.getMinimum();

        } else if (volume < MAX_VOLUME) {

      // The volume algorithm is subtractive: The implementation assumes that
            // the sound is already at maximum volume, so we avoid distortion by
            // making the amplitude values
            // The scaling factor for the volume would be 20 normally, but
            // it seems that 13 is better
            gainDb = (float) (Math.log10(MAX_VOLUME - volume) * 13.0);
        }
        gain.setValue(-gainDb);
    }

    /**
     * {@inheritDoc}
     */
    public void stop() {
        clip.stop();
    }

    /**
     * {@inheritDoc}
     */
    public void addSoundStopListener(final SoundStopListener l) {
        listeners.add(l);
    }

    /**
     * {@inheritDoc}
     */
    public void removeSoundStopListener(final SoundStopListener l) {
        listeners.remove(l);
    }

    /**
     * {@inheritDoc}
     */
    public void update(final LineEvent e) {
        if (e.getType() == LineEvent.Type.STOP) {
            notifySoundStopped();
        }
    }

    /**
     * Notify all listeners that the sound has stopped.
     */
    private void notifySoundStopped() {
        for (SoundStopListener l : listeners) {
            l.soundStopped(this);
        }
    }
}