CAn anyone tell me what I am doing wrong? I am suer new to all of this. I keep getting this error. Thanks a million.



import beads.*;

AudioContext ac;

float varRate = 1;

GranularSamplePlayer player;
Envelope rateEnvelope;
Envelope newRateEnvelope;


void setup() {
size(300,300);

//set up AudioContext, make an instance of the class -- kind of like an audio object
ac = new AudioContext();

// path to file must be absolute path on your machine, something like this
String audioFile = "/Users/aileen/Documents/Processing/beads_audio/oriental_gong.wav";

//init granular sample player
player = new GranularSamplePlayer(ac, SampleManager.sample(audioFile));

//loop the sample at its end points
player.setLoopType(SamplePlayer.LoopType.LOOP_ALTERNATING);

//set begin of defined envelope to start
player.getLoopStartEnvelope().setValue(0);

//set end of defined envelope to end
player.getLoopEndEnvelope().setValue(SampleManager.sample(audioFile).getLength());

//set initial playback rate object (UGen)
Envelope rateEnvelope = new Envelope(ac,varRate);

// tell player to set the rate envelope to the envelope we created
player.setRateEnvelope(rateEnvelope);
//a bit of noise can be nice

//set gain to another UGen and add to our audioContext
Gain g = new Gain(ac, 2, 0.3);
g.addInput(player);
ac.out.addInput(g);
ac.start();
}


void draw() {

/////// YOU COULD ENTER SOME CODE HERE TO CHECK FOR A VALUE //////

//varRate = <getExternalValue>;
//Envelope newRateEnvelope = new Envelope(ac, varRate);
//player.setRateEnvelope(newRateEnvelope);
}


// Example uses keypresses of [ and ] to change rate envelope

void keyPressed() {
if (key == ']') {
varRate += .2;
}
else if (key == '[') {
varRate += -.2;
}
Envelope newRateEnvelope = new Envelope(ac, varRate);
player.setRateEnvelope(newRateEnvelope);
}




ERROR:


processing.app.debug.RunnerException: NullPointerException
    at processing.app.Sketch.placeException(Sketch.java:1543)
    at processing.app.debug.Runner.findException(Runner.java:583)
    at processing.app.debug.Runner.reportException(Runner.java:558)
    at processing.app.debug.Runner.exception(Runner.java:498)
    at processing.app.debug.EventThread.exceptionEvent(EventThread.java:367)
    at processing.app.debug.EventThread.handleEvent(EventThread.java:255)
    at processing.app.debug.EventThread.run(EventThread.java:89)
Exception in thread "Animation Thread" java.lang.NullPointerException
    at beads.GranularSamplePlayer.<init>(Unknown Source)
    at sketch_feb16b.setup(sketch_feb16b.java:44)
    at processing.core.PApplet.handleDraw(PApplet.java:1583)
    at processing.core.PApplet.run(PApplet.java:1503)
    at java.lang.Thread.run(Thread.java:613)