SampleBasedMetronome.java

/**
 * Metronome that counts samples rendered to make the click. --pjl   (original code by PJS)
 */

package com.frinika.sequencer;

import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;

import uk.org.toot.audio.core.AudioBuffer;
import uk.org.toot.audio.core.AudioProcess;
import uk.org.toot.audio.server.AudioServer;

import com.frinika.project.ProjectContainer;
import com.frinika.synth.envelope.MidiVolume;

public class SampleBasedMetronome implements AudioProcess, SequencerListener {
	// MyTracker tracker;
	float[] sampleData;

	float level = 0f;

	boolean active = false;

	ProjectContainer project;

	int metSamplePos = 0;

	long framePtr=0;

	private int doClick=0;
		
	public SampleBasedMetronome(ProjectContainer project) throws Exception {
//		super(project.getAudioServer(), getFramePos(project.getSequencer(), project.getAudioServer(),
//				0));
		// super(project.getAudioServer().openAudioOutput(project.getAudioServer().getAvailableOutputNames().get(0),null));
		this.project = project;
		
		final FrinikaSequencer sequencer=project.getSequencer();
		final AudioServer audioServer=project.getAudioServer();
		// this.tracker = tracker;
		
		sequencer.addSequencerListener(this);
		try {
			AudioInputStream stream = AudioSystem
					.getAudioInputStream(ClassLoader
							.getSystemResource("sounds/metronome1.wav"));
			sampleData = new float[(int) stream.getFrameLength()];

			int index = 0;

			byte[] frame = new byte[2];
			int b = stream.read(frame);
			while (b != -1) {
				sampleData[index++] = (((frame[1] * 256) + (frame[0] & 0xff)) / 32768f);
				b = stream.read(frame);
			}
		} catch (Exception e) {
			e.printStackTrace();

		}

	
		// project.getMixer().getMainBus().setOutputProcess(this);

	}

	public void dispose() {
		project.getSequencer().removeSequencerListener(this);
	}
	
	
	public void setVelocity(int velocity) {
		if (velocity > 0) {

			active = true;
			level = MidiVolume.midiVolumeToAmplitudeRatio(velocity);
			doClick=4;
		} else {
			active = false;
		}
	}

	
 	long nextClick() {
	
 		// double ticksPerBeat=project.getSequence().getResolution();
 		double bpSec=project.getSequencer().getTempoInBPM()/60.0;    // uS/beat
 		double fs=project.getAudioServer().getSampleRate();   // /s 
 		
 		double samplesPerClick = fs/bpSec;           

 		
 		long nClick=((framePtr+(long)samplesPerClick-1)/(long)samplesPerClick);
 		return (long)(nClick*samplesPerClick);
  	}
	
	public int processAudio(AudioBuffer buffer) {

		if (!active) {
			return AUDIO_OK;
		}
		
		if (!(doClick > 0 || project.getSequencer().isRunning())) return AUDIO_OK;
			
		int size=buffer.getSampleCount();

		int start=0;
		long nextClick=nextClick();
//		System. out.println(framePtr + " " + nextClick);
		if (metSamplePos >= sampleData.length) {
			doClick--;
			if (framePtr+size < nextClick) {
				framePtr+=size;
				return AUDIO_OK;
			}
			start=(int) (nextClick-framePtr);
			metSamplePos=0;
		}
			
		float left[] = buffer.getChannel(0);
		float right[] = buffer.getChannel(1);

		framePtr+=start;
		for (int n = start; (n < size)
				&& (metSamplePos < sampleData.length); n++,framePtr++) {
			if (framePtr == nextClick) {
				metSamplePos=0;
			}
			left[n] += sampleData[metSamplePos] * level;
			right[n] += sampleData[metSamplePos++] * level;
		}
		
		
		
		return AUDIO_OK; // super.processAudio(buffer);
	}

	public void open() {
		// TODO Auto-generated method stub

	}

	public void close() {
		// TODO Auto-generated method stub

	}
	
	
	long getFramePos() {
		FrinikaSequencer sequencer=project.getSequencer();
		AudioServer audioServer=project.getAudioServer();
		
		return (long) (((sequencer.getMicrosecondPosition()) * audioServer
				.getSampleRate()) / 1000000);
	}


	public void beforeStart() {		
		framePtr = getFramePos();		
	}

	public void start() {
	//	active=true;
	}

	public void stop() {
	//	active=false;
	}

}