Portamento / Glide MIDI Scripter Plugin for Logic Pro X

PortamentoGlideLogicProX

/*

Portamento / Glide MIDI Scripter Plugin for Logic Pro X

https://www.reddit.com/r/Logic_Studio/comments/8901vy/request_midi_script_for_faking_glideportamento/

Bolasol, Inc. 2018

*/

var PluginParameters = [
{
	name:"Glide time (ms)", 
	type:"lin", 
	defaultValue:50, 
	minValue:0, 
	maxValue:500,
	numberOfSteps:500
}, 
{
	name:"Glide resolution (ms)", 
	type:"lin", 
	defaultValue:1, 
	minValue:1, 
	maxValue:50,
	numberOfSteps:49
}, 
{
	name:"Inst. Bend Range", 
	type:"lin", 
	defaultValue:12, 
	minValue:1, 
	maxValue:24, 
	numberOfSteps:23
}];

//Stores the last note played so we know where we are gliding from.
var lastPitch = 0;

function HandleMIDI(event) {

  var glideTime = GetParameter("Glide time (ms)");
  var glideResolution = GetParameter("Glide resolution (ms)");
  var pitchBendRange = GetParameter("Inst. Bend Range");
  
  if (event instanceof NoteOn) {
  
    if(lastPitch > 0 && pitchBendRange > 0) {
  		
      //Determine distance incoming note and last note played
      var interval = event.pitch - lastPitch;
  			  			
      //Translate that interval to the pitch bend value (-8192 - 8191)
      var startingPitchBendValue = -8192 * (interval / pitchBendRange);
  			
      //clamp to real pitch bend values
      startingPitchBendValue  = clamp(startingPitchBendValue, -8192, 8191);

      var numberOfSteps = (glideTime / glideResolution);
	  		
      //Scheduling pitch bend messages for 'glide'
      for(var i = 0; i <= numberOfSteps; i++) {
        var pb = new PitchBend();
        pb.value = (startingPitchBendValue / numberOfSteps) * (numberOfSteps - i);
        pb.sendAfterMilliseconds(i * glideResolution);	
      }
    }
    
    //store the pitch of this message so we can compare
    //the next message to it.
    lastPitch = event.pitch;
  }
  event.send();
}

function clamp(num, min, max) {
  return num <= min ? min : num >= max ? max : num;
}