一次只能播放一个声音片段

Question

I wrote a custom sound system for my game, but if two sounds are requested to play within a few ms of eachother only one sound clip will play.

I tried running the playback on a new thread like this but it did not work. No exceptions are being thrown, it just wont play both sounds.

Thread one = new Thread() {
    public void run() {
        try {
            CustomSound.playSound(id, loop, dist);
        } catch (Exception e) {
        e.printStackTrace();
        }
    }  
};

Here is the sound player class

public class CustomSound {

    /*
     * Directory of your sound files
     * format is WAV
     */
    private static final String DIRECTORY = sign.signlink.findcachedir()+"audio/effects/";

    /*
     * Current volume state
     * 36 chosen for default 50% volume state
     */
    public static float settingModifier = 70f;

    /*
     * Current volume state
     */
    public static boolean isMuted;

    /*
     * Clips
     */
    private static Clip[] clipIndex = null;

    /*
     * Get number of files in directory
     */
    private static final int getDirectoryLength() {
        return new File(DIRECTORY).list().length;
    }

    /**
     * Loads the sound clips into memory
     * during startup to prevent lag if loading
     * them during runtime.
     **/
    public static void preloadSounds() {
        clipIndex = new Clip[getDirectoryLength()];
        int counter = 0;
        for (int i = 0; i < clipIndex.length; i++) {
            try {
                File f = new File(DIRECTORY+"sound "+i+".wav");
                AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(f);
                clipIndex[i] = AudioSystem.getClip();
                clipIndex[i].open(audioInputStream);    
                counter++;
            } catch (MalformedURLException e) {
                System.out.println("Sound effect not found: "+i);
                e.printStackTrace();
                return;
            } catch (UnsupportedAudioFileException e) {
                System.out.println("Unsupported format for sound: "+i);
                return;
            } catch (LineUnavailableException e) {
                e.printStackTrace();
                return;
            } catch (Exception e) {
                e.printStackTrace();
                return;
            }   
        }
        System.out.println("Succesfully loaded: "+counter+" custom sound clips.");
    }

    /**
     * Plays a sound
     * @param soundID - The ID of the sound
     * @param loop - How many times to loop this sound
     * @param distanceFromSource - The distance from the source in tiles
     */
    public static void playSound(final int soundID, int loop, int distanceFromSource) { 

        try {
            if (!isMuted) {
                clipIndex[soundID].setFramePosition(0);
                applyVolumeSetting(clipIndex[soundID], getDistanceModifier(distanceFromSource)*settingModifier);
                if (loop == 1 || loop == 0) {
                    clipIndex[soundID].start(); 
                } else {
                    clipIndex[soundID].loop(loop);
                }
                /* shows how to close line when clip is finished playing
            clipIndex[soundID].addLineListener(new LineListener() {
                public void update(LineEvent myLineEvent) {
                    if (myLineEvent.getType() == LineEvent.Type.STOP)
                        clipIndex[soundID].close();
                }
            });
                 */
            }
        } catch (Exception e) {
            System.out.println("Error please report: ");
            e.printStackTrace();
        }
    }

    /**
     * Applies volume setting to the clip
     * @param line - the Clip to adjust volume setting for
     * @param volume - the volume percentage (0-100)
     * @return - the volume with applied setting
     */
    public static float applyVolumeSetting(Clip line, double volume) {
        //System.out.println("Modifying volume to "+volume);
        if (volume > 100.0) volume = 100.0;
        if (volume >= 0.0) {
            FloatControl ctrl = null;
            try {
                ctrl = (FloatControl)(line.getControl(FloatControl.Type.MASTER_GAIN));
            } catch (IllegalArgumentException iax1) {
                try {
                    ctrl = (FloatControl)(line.getControl(FloatControl.Type.VOLUME));
                } catch (IllegalArgumentException iax2) {
                    System.out.println("Controls.setVolume() not supported.");
                    return -1;
                }
            }
            float minimum = ctrl.getMinimum();
            float maximum = ctrl.getMaximum();
            float newValue = (float)(minimum + volume * (maximum - minimum) / 100.0F);
            //System.out.println("System min: " + minimum);
            //System.out.println("System max: " + maximum);         
            if (newValue <= ctrl.getMinimum())
                newValue = ctrl.getMinimum();
            if (newValue >= ctrl.getMaximum())
                newValue = ctrl.getMaximum();           

            ctrl.setValue(newValue);
            //System.out.println("Setting modifier = " + volume);
            //System.out.println("New value = " + newValue);
            return newValue;
        }
        return -1;
    }

    /**
     * Calculates tile distance modifier
     * @param tileDistance - distance in tiles from source
     * @return - the distance modifier
     */
    public static float getDistanceModifier(int tileDistance) {
        if (tileDistance <= 0) {
            tileDistance = 0;
        }
        if (tileDistance >= 10) {
            tileDistance = 10;
        }
        float distanceModifier = 0;
        if (tileDistance == 10)
            distanceModifier = 0.40f;
        if (tileDistance == 9)
            distanceModifier = 0.55f;
        if (tileDistance == 8)
            distanceModifier = 0.60f;
        if (tileDistance == 7)
            distanceModifier = 0.65f;
        if (tileDistance == 6)
            distanceModifier = 0.70f;
        if (tileDistance == 5)
            distanceModifier = 0.75f;
        if (tileDistance == 4)
            distanceModifier = 0.80f;
        if (tileDistance == 3)
            distanceModifier = 0.85f;
        if (tileDistance == 2)
            distanceModifier = 0.90f;
        if (tileDistance == 1)
            distanceModifier = 0.95f;
        if (tileDistance == 0)
            distanceModifier = 1.00f;

        return distanceModifier;
    }

}

Answer 1

When I tested your code on my Windows machine, I had no problems playing two different sounds in short succession:

public static void main(String[] args) throws Exception {

    CustomSound.preloadSounds();

    CustomSound.playSound(0, 0, 0);
    CustomSound.playSound(1, 0, 0);

    Thread.sleep(5000);
}

Note however, that DataLine#start() is an asynchronous call. That could be related to your problem.

Also, according to the documentation of DataLine#start() ,

If invoked on a line that is already running, this method does nothing.

If that is your problem, and you want to play the same sound twice simultaneously, one possible solution would be to get another Clip instance that plays the same sound and start that.

However I'm no expert at Java's sound API so there might a more efficient way.