hull,

    firstPoint,

    currentVertex,

    nextVertex,

    currentPoint;

​

function setup() {

  createCanvas(400, 400);

  const buffer = 20;

  points = [];

  for (let i = 0; i < 100; i++) {

    points.push(createVector(random(buffer, width - buffer), random(buffer, height - buffer)));

  }

  points.sort((a, b) => a.x - b.x);

  hull = [];

  firstPoint = points[0];

  currentVertex = firstPoint;

  hull.push(currentVertex);

  nextVertex = points[1];

  currentPoint = 2;

}

​

function draw() {

  const checking = points[currentPoint],

        a = p5.Vector.sub(nextVertex, currentVertex),

        b = p5.Vector.sub(checking, currentVertex);

  background(22);

  strokeWeight(2);

  stroke(233, 122, 0);

  beginShape();

  for (const p of hull) {

    vertex(p);

  }

  endShape();

  stroke(0, 122, 233);

  line(currentVertex.x, currentVertex.y, nextVertex.x, nextVertex.y);

  stroke(255);

  line(currentVertex.x, currentVertex.y, points[currentPoint].x, points[currentPoint].y);

  if (a.cross(b).z < 0) {

    nextVertex = checking;

  }

  currentPoint += 1;

  if (currentPoint === points.length) {

    hull.push(nextVertex);

    currentVertex = nextVertex;

    currentPoint = 0;

  }

  strokeWeight(8);

  stroke(233);

  for (const p of points) {

    point(p);

  }

  stroke(0, 233, 122);

  point(firstPoint);

  stroke(0, 122, 233)

  point(currentVertex);

}