​

function setup() {

  createCanvas(640, 360);

}

​

function mousePressed() {

  points.push(createVector(mouseX, mouseY));

}

​

function draw() {

  background(100);

  for (let i = 0; i < points.length; i++) {

    const pt = points[i];

    const next = points[(i + 1) % points.length];

    stroke(0);

    strokeWeight(2);

    lineDash(pt.x, pt.y, next.x, next.y, [5]);

    stroke(255);

    strokeWeight(10);

    point(pt.x, pt.y);

  }

  if (points.length > 0) {

    stroke(255);

    strokeWeight(10);

    point(points[0].x, points[0].y);

  }

}

​

function lineDash(x1, y1, x2, y2, list) {

   drawingContext.setLineDash(list);

   line(x1, y1, x2, y2);

   drawingContext.setLineDash([]);

}