1D Perlin Noise Modulator for Cubase ModScripter

PerlinNoise.vstpreset.js

//
// 1D Perlin Noise Modulator for Cubase ModScripter
// by aike
// MIT License
//

getDescription = function () {
  return "Perlin Noise";
}

var x = 0;

// params
var speed = 0.01;
var octaves = 1;
var persistence = 0.5;

processModulation = function (inputValue, numSamples) {
  x += speed * 0.003 + 0.0003;
  return inputValue + OctavePerlin(x, octaves + 1, persistence) - 0.5;
}

onParamChange = function(paramIndex, paramValue) {
  if (paramIndex == 1) {
    speed = paramValue;
  }
  if (paramIndex == 2) {
    octaves = Math.round(paramValue * 10);
  }
  if (paramIndex == 3) {
    persistence = paramValue;
  }
}

paramValueToString = function(paramIndex, paramValue) {
  if (paramIndex == 2) {
    return (paramValue * 5).toFixed(0);
  }
  if (paramIndex == 1 || paramIndex == 3) {
    return aramValue.toFixed(2)
  }
}

stringToParamValue = function(paramIndex, string) {
  if (paramIndex == 2) {
    value = parseInt(string);
    if (!isNaN(value)) {
      return value / 5;
    }
  }
  if (paramIndex == 1 || paramIndex == 3) {
    value = parseFloat(string);
    if (!isNaN (value)) {
      return value;
    }
  }
}

getParamStepCount = function (paramIndex) {
  if (paramIndex == 2) {
    return 5;
  }
  return 0;
}

getParamTitle = function (paramIndex) {
  if (paramIndex == 1)
    return "Speed";
  if (paramIndex == 2)
    return "Octaves";
  if (paramIndex == 3)
    return "Persistence";
}


////////////////////////////////////////////////////////
var repeat = 256;

function OctavePerlin(x, octaves, persistence) {
  var total = 0;
  var frequency = 1;
  var amplitude = 1;
  var maxValue = 0;
  for (var i = 0; i < octaves; i++) {
    total += perlin(x * frequency) * amplitude;
    maxValue += amplitude;
    amplitude *= persistence;
    frequency *= 2;
  }
  return total / maxValue;
}
  
var permutation = [ 151,160,137,91,90,15,
  131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
  190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
  88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
  77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
  102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
  135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
  5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
  223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
  129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
  251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
  49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
  138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
];
  
var p = Array(512);
for (var x = 0; x < 512; x++) {
  p[x] = permutation[x % 256];
}
  
function perlin(x) {
  if(repeat > 0) {
    x = x % repeat;
  }
  var xi = Math.floor(x) & 255;
  var xf = x - Math.floor(x);
  var u = fade(xf);

  var aaa, baa;
  aaa = p[p[p[xi]]];
  baa = p[p[p[(xi + 1) % repeat]]];
  
  var x1 = lerp(grad(aaa, xf), grad(baa, xf - 1), u);
  return (x1 + 1) / 2;
}
    
function grad(hash, x) {
  switch (hash & 0xF) {
    case 0x0: return  x;
    case 0x1: return -x;
    case 0x2: return  x;
    case 0x3: return -x;
    case 0x4: return  x;
    case 0x5: return -x;
    case 0x6: return  x;
    case 0x7: return -x;
    case 0x8:
    case 0x9:
    case 0xA:
    case 0xB: return  0;
    case 0xC: return  x;
    case 0xD: return  0;
    case 0xE: return -x;
    case 0xF: return  0;
  }
  return 0;
}
  
function fade(t) {
  return t * t * t * (t * (t * 6 - 15) + 10);
}
  
function lerp(a, b, x) {
  return a + x * (b - a);
}