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// This class is a very simple implementation of AudioListener. By implementing this interface,
// you can add instances of this class to any class in Minim that implements Recordable and receive
// buffers of samples in a callback fashion. In other words, every time that a Recordable object has
// a new buffer of samples, it will send a copy to all of its AudioListeners. You can add an instance of
// an AudioListener to a Recordable by using the addListener method of the Recordable. If you want to
// remove a listener that you previously added, you call the removeListener method of Recordable, passing
// the listener you want to remove.
//
// Although possible, it is not advised that you add the same listener to more than one Recordable.
// Your listener will be called any time any of the Recordables you've added it have new samples. This
// means that the stream of samples the listener sees will likely be interleaved buffers of samples from
// all of the Recordables it is listening to, which is probably not what you want.
//
// You'll notice that the three methods of this class are synchronized. This is because the samples methods
// will be called from a different thread than the one instances of this class will be created in. That thread
// might try to send samples to an instance of this class while the instance is in the middle of drawing the
// waveform, which would result in a waveform made up of samples from two different buffers. Synchronizing
// all the methods means that while the main thread of execution is inside draw, the thread that calls
// samples will block until draw is complete. Likewise, a call to draw will block if the sample thread is inside
// one of the samples methods. Hope that's not too confusing!
class WaveformRenderer implements AudioListener
{
private float[] left;
private float[] right;
WaveformRenderer()
{
left = null;
right = null;
}
synchronized void samples(float[] samp)
{
left = samp;
}
synchronized void samples(float[] sampL, float[] sampR)
{
left = sampL;
right = sampR;
}
synchronized void draw()
{
// we've got a stereo signal if right or left are not null
if ( left != null && right != null )
{
noFill();
stroke(255);
beginShape();
for ( int i = 0; i < left.length; i++ )
{
vertex(i, height/4 + left[i]*50);
}
endShape();
beginShape();
for ( int i = 0; i < right.length; i++ )
{
vertex(i, 3*(height/4) + right[i]*50);
}
endShape();
}
else if ( left != null )
{
noFill();
stroke(255);
beginShape();
for ( int i = 0; i < left.length; i++ )
{
vertex(i, height/2 + left[i]*50);
}
endShape();
}
}
}