chaotic eye

let r1, r2, m1, m2, a1, a2;
let a1_v = 0;
let a2_v = 0;
let g;

let px2 = -1,
  py2 = -1;
let cx, cy;

function setup() {
  cnv = createCanvas(windowWidth * 0.9, windowHeight * 0.9);
  rectMode(CENTER);
  strokeWeight(0.1);
  wc = min(width, height);
  g = random(0.1, 1);
  a1 = random(-PI / 2, PI / 2);
  a2 = random(-PI / 2, PI / 2);
  r1 = random(wc / 5, wc / 3);
  r2 = random(wc / 5, wc / 3);
  nRot = int(random(2, 20));
  if (nRot === 4 || nRot === 8 || nRot === 16) {
    nRot = 2;
  }
  m1 = random(2, 8);
  m2 = random(2, 8);
  cx = width / 2;
  cy = wc / 4 + random(-wc / 10, wc / 10);
  s = random(0.1, 0.4);
  background(10, 30, 40);
  noStroke();
}

function draw() {
  translate(width / 2, height / 2);
  t = frameCount;
  a1_a =
    (-g * (2 * m1 + m2) * sin(a1) +
      -m2 * g * sin(a1 - 2 * a2) +
      -2 *
        sin(a1 - a2) *
        m2 *
        (a2_v * a2_v * r2 + a1_v * a1_v * r1 * cos(a1 - a2))) /
    (r1 * (2 * m1 + m2 - m2 * cos(2 * a1 - 2 * a2)));

  a2_a =
    (2 *
      sin(a1 - a2) *
      (a1_v * a1_v * r1 * (m1 + m2) +
        g * (m1 + m2) * cos(a1) +
        a2_v * a2_v * r2 * m2 * cos(a1 - a2))) /
    (r2 * (2 * m1 + m2 - m2 * cos(2 * a1 - 2 * a2)));
  a1_v += a1_a * s;
  a2_v += a2_a * s;
  a1 += a1_v * s;
  a2 += a2_v * s;
  x1 = r1 * sin(a1) + cx;
  y1 = r1 * cos(a1) + cy;
  x2 = x1 + r2 * sin(a2);
  y2 = y1 + r2 * cos(a2);
  fill(abs(a2) * 120, abs(a2 + a1) * 205, abs(a2 + a1) * 255, 50);

  stroke(abs(a1) * 50, 20 + abs(a2) * 205, 20 + abs(a2) * 255, 50);

  for (let i = 0; i < nRot; i++) {
    push();
    rotate((TAU / nRot) * i);
    line(-width / 2 + cx, -height / 2 + cy, -width / 2 + x1, -height / 2 + y1);

    ellipse(-width / 2 + x1, -height / 2 + y1, m1 / 3, m1 / 3);

    line(-width / 2 + x1, -height / 2 + y1, -width / 2 + x2, -height / 2 + y2);

    ellipse(-width / 2 + x2, -height / 2 + y2, m2 / 3, m2 / 3);
    pop();
  }

  border();
}

function border() {
  push();
  noFill();
  stroke(20, 50, 60);
  strokeWeight(4);
  rect(0, 0, width - 20, height - 20);
  pop();
}

function mousePressed() {
  frameCount = 0;
  setup();
  draw();
}

function keyPressed() {
  save(cnv, "chaotic", "jpg");
}

function windowResized() {
  resizeCanvas(windowWidth * 0.9, windowHeight * 0.9);
}