//let theta; //field angle [rad]

const layeralt = [100, 200, 300, 400];

const freq = [0.02, 0.02, 0.02, 0.02];

const strength = [80, 80, 80, 80];

let alpha1;

let alpha2;

​

function setup() {

  theta = 20 * PI / 180;

  alpha1 = createSlider(-30, 30, -10);

  alpha2 = createSlider(-30, 30, 10);

  createCanvas(600, 1000);

}

​

function draw() {

  let mean1 = [];

  let mean2 = [];

  background(235);

  push();

  translate(width * 0.5 , height * 0.5);

  noFill();

  strokeWeight(2);

  stroke(100);

  line(-r, 0, r, 0);

  stroke(100);

  //line(-r, 0, -r - height * tan(theta), -height);

  //line(r, 0, r + height * tan(theta), -height);

  /*for (let ni = 0; ni < layeralt.length; ni++) {

    let alt = -layeralt[ni];

    strokeWeight(0.5);

    line(-width / 2, -layeralt[ni], width / 2, -layeralt[ni]);

    strokeWeight(1);

    for (let mi = 0; mi < width; mi++) {

      line(-width / 2 + mi,

        alt + strength[ni] * (noise(mi * freq[ni], 10 * ni) - 0.5),

        -width / 2 + mi + 1,

        alt + strength[ni] * (noise((mi + 1) * freq[ni], 10 * ni) - 0.5));

    }

  }*/

  // dir 1 

    strokeWeight(1);

  let alpha = alpha1.value() * PI / 180;

  stroke(200, 0, 0);

  line(-r, 0, -r + height * tan(alpha), -height);

  line(r, 0, r + height * tan(alpha), -height);

  for (let mi = 0; mi < width; mi++) {

    mean1.push(0);

    mean2.push(0);

    if (-width / 2 + mi < -r || -width / 2 + mi + 1 > r)

      continue;

    let sum1 = 0;

    let sum2 = 0;

    for (let ni = 0; ni < layeralt.length; ni++) {

      sum1 += strength[ni] * (noise((mi + layeralt[ni] * tan(alpha)) * freq[ni], 10 * ni) - 0.5);

      sum2 += strength[ni] * (noise((mi + 1 + layeralt[ni] * tan(alpha)) * freq[ni], 10 * ni) - 0.5);

    }

    mean1[mi] = sum1;

    mean2[mi] = sum2;

    line(-width / 2 + mi, sum1, -width / 2 + mi + 1, sum2);

  }

​

  /*

  // dir 2

  alpha = alpha2.value() * PI / 180;

  stroke(0, 0, 200);

  line(-r, 0, -r + height * tan(alpha), -height);

  line(r, 0, r + height * tan(alpha), -height);

  for (let mi = 0; mi < width; mi++) {

    if (-width / 2 + mi < -r || -width / 2 + mi + 1 > r)

      continue;

    stroke(0, 0, 200);

    let sum1 = 0;

    let sum2 = 0;

    for (let ni = 0; ni < layeralt.length; ni++) {

      sum1 += strength[ni] * (noise((mi + layeralt[ni] * tan(alpha)) * freq[ni], 10 * ni) - 0.5);

      sum2 += strength[ni] * (noise((mi + 1 + layeralt[ni] * tan(alpha)) * freq[ni], 10 * ni) - 0.5);

    }

    line(-width / 2 + mi, sum1, -width / 2 + mi + 1, sum2);

    mean1[mi] += sum1;

    mean2[mi] += sum2;

    mean1[mi] /= 2;

    mean2[mi] /= 2;

    stroke(0, 200, 0);

    line(-width / 2 + mi, mean1[mi], -width / 2 + mi + 1, mean2[mi]);

  }

  */

  pop();

}