MIDI FX Trill Script

trill.js

//-----------------------------------------------------------------------------
// Trill script adapted from Simple Arpeggiator
//-----------------------------------------------------------------------------

var NeedsTimingInfo = true;
var activeNotes = [];

function HandleMIDI(event) {
	if (event instanceof NoteOn) {
		// add note to array
		activeNotes.push(event);
	} 	
	else if (event instanceof NoteOff) {
		// remove note from array
		for (i=0; i < activeNotes.length; i++) {
			if (activeNotes[i].pitch == event.pitch) {
				activeNotes.splice(i, 1);
				break;
			}
		}
	}
	// pass non-note events through
	else event.send();
}

//-----------------------------------------------------------------------------

function ProcessMIDI() {
	// Get timing information from the host application
	var musicInfo = GetTimingInfo();

	if (activeNotes.length != 0) {	
		
		// get parameters
		var division = GetParameter("Beat Division");
		var noteLength = (GetParameter("Note Length") / 100) * (1 / division);
		var interval = GetParameter("Interval");
		
		// calculate beat to schedule
		var lookAheadEnd = musicInfo.blockEndBeat;
		var nextBeat = Math.ceil(musicInfo.blockStartBeat * division) / division;
			
		// loop through the beats that fall within this buffer
		while (nextBeat >= musicInfo.blockStartBeat && nextBeat < lookAheadEnd) {			
			// calculate step
			var lastNotePitch = activeNotes[activeNotes.length - 1].pitch;
				
			// send events
			var noteLowOn = new NoteOn();
			noteLowOn.pitch = lastNotePitch;
			noteLowOn.sendAtBeat(nextBeat);
			var noteLowOff = new NoteOff(noteLowOn);
			noteLowOff.sendAtBeat(nextBeat + noteLength/2)
			
			var noteHighOn = new NoteOn();
			noteHighOn.pitch = lastNotePitch + interval;
			noteHighOn.sendAtBeat(nextBeat + 0.5 / division);
			var noteHighOff = new NoteOff(noteHighOn);
			noteHighOff.sendAtBeat(nextBeat + 0.5 / division + noteLength/2)

			// advance to next beat
			nextBeat += 0.001;
			nextBeat = Math.ceil(nextBeat * division) / division;
		}
	}
}

//-----------------------------------------------------------------------------
var PluginParameters = 
[
		{name:"Beat Division", type:"linear",
		minValue:1, maxValue:8, numberOfSteps:70, defaultValue:4},	
		{name:"Note Length", unit:"%", type:"linear",
		minValue:1, maxValue:200, defaultValue:50.0, numberOfSteps:199},
		{name:"Interval", unit:" semi", type:"linear",
		minValue:1, maxValue:12, defaultValue:3, numberOfSteps:11},
];