mathober day-26: Correspondence

let img1, img2;
let m;
let lineGroup1;
let nSymmetry;

function preload() {
  img1 = loadImage("/assets/correspondence.jpg");
  img2 = loadImage("/assets/star.png");
}

function setup() {
  createCanvas(600, 600);
  strokeWeight(0.25);
  angleMode(DEGREES);
  stroke(255);
  imageMode(CENTER);
  m1 = random(0.5, 1);
  nLines = int(random(10, 30));
  lineGroup1 = [];
  for (let i = 0; i < nLines; i++) {
    lineGroup1[i] = random(-width * 2, width * 2, 2);
  }
  nSymmetry = int(random(5, 12));
}

function draw() {
  translate(width / 2, height / 2);
  t1 = frameCount / 5;
  rotate(-t1 / 2);
  m = m1 + m1 * sin(t1 / 2);
  image(img1, 0, 0, 900, 900);
  strokeWeight(0.8);
  image(img2, 0, 0, 200, 200);
  theta = atan(m);
  stroke(225, 240, 255, 100);
  fill(225, 240, 255, 50);
  for (let j = 0; j < nSymmetry; j++) {
    push();
    rotate((360 / nSymmetry) * j);
    line(-width * 4, 0, width * 4, 0);
    for (let i = 0; i < lineGroup1.length; i++) {
      y1 = lineGroup1[i] + 200 * sin(t1);
      line(-width / 2, y1, width / 2, m * width + y1);
      circle(-y1 / m + -width / 2, 0, 2);

      if (theta <= 0) {
        arc(
          -y1 / m + -width / 2,
          0,
          50 + 150 * sin(t1),
          50 + 150 * sin(t1),
          theta,
          0
        );
      } else {
        arc(
          -y1 / m + -width / 2,
          0,
          50 + 150 * sin(t1),
          50 + 150 * sin(t1),
          0,
          theta
        );
      }
    }
    pop();
  }

  portHole();
}

function portHole() {
  push();
  noStroke();
  fill(0);
  beginShape();
  for (let i = 0; i <= 180; i++) {
    x = 280 * cos(i);
    y = 280 * sin(i);
    vertex(x, y);
  }
  vertex(-width, 0);
  vertex(-width, height);
  vertex(width, height);
  vertex(width, 0);
  endShape(CLOSE);
  beginShape();
  for (let i = 180; i <= 360; i++) {
    x = 280 * cos(i);
    y = 280 * sin(i);
    vertex(x, y);
  }
  vertex(width, 0);
  vertex(width, -height);
  vertex(-width, -height);
  vertex(-width, 0);
  endShape(CLOSE);
  stroke(4, 112, 179);
  strokeWeight(1);
  noFill();
  pop();
}

function keyPressed() {
  setup();
  draw();
}