view src/samer/units/Trigger.java @ 0:bf79fb79ee13

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/*
 *	Copyright (c) 2000, Samer Abdallah, King's College London.
 *	All rights reserved.
 *
 *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
 *	without even the implied warranty of MERCHANTABILITY or 
 *	FITNESS FOR A PARTICULAR PURPOSE.
 */

package samer.units;
import samer.tools.*;
import samer.maths.*;
import samer.core.types.*;

/**
	Generates a 1 for each element that rises above threshold,
	and a -1 for when it drops back below. Can be used to
	drive MidiSynth, which interprets +1 as note-on and -1
	as note-off.
 */

public class Trigger extends AnonymousTask
{
	boolean	[] states;
	VDouble	thresh;
	VVector	output;
	double[]	in,out;
	int		n;

	public Trigger(VVector input, double th)
	{
		n = input.size();
		states = new boolean[n];
		in=input.array();
		thresh=new VDouble("thresh",th);
		output=new VVector("trigger",n);
		out=output.array();
	}

	public VVector output() { return output; }

	public void run()
	{
		double th=thresh.value;

		for (int i=0; i<n; i++) {
			if (in[i]>th) {
				if (!states[i]) { out[i]=in[i]; states[i]=true; }
				else out[i]=0;
			} else {
				if (states[i]) { out[i]=-1; states[i]=false; }
				else out[i]=0;
			}
		}
		output.changed();
	}
}