minimun-note-length.js

/** 

 * Herrmutt Lobby • Minimun Note length js 0.1
 * (c) Herrmutt Lobby 2013 • herrmuttlobby.com
 * This code is distributed under a 
 * Creative Commons : Attribution, Share Alike, No-commercial Licence
 *
 * INPUT  : list [ note, velocity ]
 * OUTPUT : list [ note, 0 ] - in the right scheduled time
 *
 * MADE TO BE USED WITHIN the JS object of MAX4LIVE or MAX/MSP or in PureData 
 * with the jj object of the 
 * PDJ external (http://www.le-son666.com/software/pdj/) 

**/


autowatch = 1;

// array( aka table ) of notes which are in "on" state
var notes = [];

// reset array which holds notes which are in "on" state
function reset() { notes = []; }

/** inlet 0 - list

  - receives note and velocity packed in a list
 **/
function list( note, velocity )
{
	// post();
	// post( " received list " + [note,velocity] );
	// post();

	if( velocity === 0 ) on_note_off( note );
	else {
		on_note_on( note );

		// let the note on freely pass
		outlet( 0, [note, velocity] );
	}
}

// higher priority for this call
list.immediate = 1;

// handles note on event
function on_note_on( note, velocity )
{
	// if receives note on before sending scheduled note off message
	if( notes[note] !== undefined ) {

		// send a note off instantly ( which stops the scheduler for note off )
		send_note_off( note );
	}

	notes[note] = { time : Date.now() };
}

// handles note off event	
function on_note_off( note )
{
	var duration;
	

	time     = Date.now();
	duration = parseInt( time - notes[note].time, 10 );
	
	if( duration < get_min_length() ) {

		var ms;

		ms = get_min_length() - duration;

		// post( "min_length : " + get_min_length() );
		// post();
		// post( "amount : " + get_amount() );
		// post();

		delay( ms * get_amount(), note );

	} else {

		send_note_off( note );

	}
}

// schedules a note off message to happen in defined delay time
// in milliseconds.
function delay( delay, note )
{

	// post();
	// post( "--- delaying " + note + " by " + delay + " ms " );
	// post();

	var task, funk;

	funk = function( note ) { send_note_off( note ); };
	task = new Task( funk, this, [ note ] );

	task.schedule( delay );

	notes[note].task = task;
}

// get minimun length from knob via "script name"
function get_min_length() {
	return parseInt( this.patcher.getnamed( 'min_length' ).getvalueof(), 10 );
}

// get amount from knob via "script name"
function get_amount() {

	// trick to wipe all numbers after second decimal case
	var float;

	float = this.patcher.getnamed( 'amount' ).getvalueof();

	return Math.round( float * 100 ) / 100;
}

// send_note_offs a list prepared for 
function send_note_off( note )
{
	// stop the scheduler for note off - if there's one
	if( notes[note].task ) notes[note].task.cancel();

	// free note slot
	delete notes[note].task;
	delete notes[note];

	// post();
	// post( " --> sending note off " + note );
	// post();

	outlet( 0, note, 0 );
}