samer@0: /*
samer@0:  *	Copyright (c) 2000, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
samer@0:  *	without even the implied warranty of MERCHANTABILITY or 
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package samer.units;
samer@0: import samer.tools.*;
samer@0: import samer.maths.*;
samer@0: import samer.core.types.*;
samer@0: 
samer@0: /**
samer@0: 	Generates a 1 for each element that rises above threshold,
samer@0: 	and a -1 for when it drops back below. Can be used to
samer@0: 	drive MidiSynth, which interprets +1 as note-on and -1
samer@0: 	as note-off.
samer@0:  */
samer@0: 
samer@0: public class Trigger extends AnonymousTask
samer@0: {
samer@0: 	boolean	[] states;
samer@0: 	VDouble	thresh;
samer@0: 	VVector	output;
samer@0: 	double[]	in,out;
samer@0: 	int		n;
samer@0: 
samer@0: 	public Trigger(VVector input, double th)
samer@0: 	{
samer@0: 		n = input.size();
samer@0: 		states = new boolean[n];
samer@0: 		in=input.array();
samer@0: 		thresh=new VDouble("thresh",th);
samer@0: 		output=new VVector("trigger",n);
samer@0: 		out=output.array();
samer@0: 	}
samer@0: 
samer@0: 	public VVector output() { return output; }
samer@0: 
samer@0: 	public void run()
samer@0: 	{
samer@0: 		double th=thresh.value;
samer@0: 
samer@0: 		for (int i=0; i<n; i++) {
samer@0: 			if (in[i]>th) {
samer@0: 				if (!states[i]) { out[i]=in[i]; states[i]=true; }
samer@0: 				else out[i]=0;
samer@0: 			} else {
samer@0: 				if (states[i]) { out[i]=-1; states[i]=false; }
samer@0: 				else out[i]=0;
samer@0: 			}
samer@0: 		}
samer@0: 		output.changed();
samer@0: 	}
samer@0: }