SwarmOfOscillators.java

package com.jsyn.examples;

import com.jsyn.JSyn;
import com.jsyn.Synthesizer;
import com.jsyn.ports.UnitOutputPort;
import com.jsyn.unitgen.Add;
import com.jsyn.unitgen.AsymptoticRamp;
import com.jsyn.unitgen.Circuit;
import com.jsyn.unitgen.LineOut;
import com.jsyn.unitgen.Pan;
import com.jsyn.unitgen.SawtoothOscillatorDPW;
import com.jsyn.unitgen.SineOscillator;
import com.jsyn.unitgen.UnitOscillator;
import com.jsyn.unitgen.UnitSource;

/**
 * Make a bunch of oscillators that swarm around a moving frequency.
 * 
 * @author Phil Burk (C) 2009 Mobileer Inc
 * 
 */
public class SwarmOfOscillators
{
	private Synthesizer synth;
	Follower[] followers;
	SineOscillator lfo;
	LineOut lineOut;
	private Add tiePoint;
	private static final int NUM_FOLLOWERS = 30;

	class Follower extends Circuit implements UnitSource
	{
		UnitOscillator osc;
		AsymptoticRamp lag;
		Pan panner;

		Follower()
		{
			// Add a tone generator.
			add( osc = new SawtoothOscillatorDPW() );
			osc.amplitude.set( 0.03 );

			// Use a lag to smoothly change frequency.
			add( lag = new AsymptoticRamp() );
			double hlife = 0.01 + (Math.random() * 0.9);
			lag.halfLife.set( hlife );

			// Set left/right pan randomly between -1.0 and +1.0.
			add( panner = new Pan() );
			panner.pan.set((Math.random() * 2.0) - 1.0);
			
			// Track the frequency coming through the tiePoint.
			tiePoint.output.connect( lag.input );
			// Add the LFO offset.
			lfo.output.connect( lag.input );
			
			lag.output.connect( osc.frequency );

			// Connect the oscillator to the left and right audio output.
			osc.output.connect( panner.input );
		}

		public UnitOutputPort getOutput()
		{
			return panner.output;
		}
	}

	private void test()
	{
		synth = JSyn.createSynthesizer();

		// Add an output mixer.
		synth.add( lineOut = new LineOut() );

		// Add a unit just to distribute the control frequency.
		synth.add( tiePoint = new Add() );
		synth.add( lfo = new SineOscillator() );
		lfo.amplitude.set( 40.0 );
		lfo.frequency.set( 2.3 );

		followers = new Follower[NUM_FOLLOWERS];
		for( int i = 0; i < followers.length; i++ )
		{
			Follower follower = new Follower();
			synth.add( follower );

			// Every follower can connect directly to the lineOut because all input ports are mixers.
			follower.getOutput().connect( 0, lineOut.input, 0 );
			follower.getOutput().connect( 1, lineOut.input, 1 );
			
			followers[i] = follower;
		}

		// Start synthesizer using default stereo output at 44100 Hz.
		synth.start();
		// We only need to start the LineOut. It will pull data from the
		// oscillator.
		lineOut.start();

		// Get synthesizer time in seconds.
		double timeNow = synth.getCurrentTime();

		// Advance to a near future time so we have a clean start.
		double duration = 0.9;
		double time = timeNow + duration;
		double freq = 400.0; // hertz
		tiePoint.inputA.set( freq, time );

		// Randomly change the target frequency for the followers.
		try
		{
			for( int i = 0; i < 20; i++ )
			{
				// Schedule this to happen a bit later.
				time += duration;
				freq = 200.0 + (Math.random() * 500.0);
				tiePoint.inputA.set( freq, time );

				// Sleep while the sound is being generated in the background
				// thread.
				synth.sleepUntil( time - 0.2 );
			}
		} catch( InterruptedException e )
		{
			e.printStackTrace();
		}

		System.out.format( "CPU usage = %4.2f%c\n", synth.getUsage()*100,'%' );

		// Stop everything.
		synth.stop();
	}

	public static void main( String[] args )
	{
		new SwarmOfOscillators().test();
	}
}