let shadow;

​

let points = [];

​

function setup() {

  createCanvas(400, 400);

  shape = createGraphics(width, height);

  shadow = createGraphics(width, height);

  generatePoints();

  noLoop();

}

​

function generatePoints() {

  points = [];

  const x = width/2;

  const y = height/2;

  for(let i = 0; i < TAU; i += TAU/10) {

    const r = random(100, 200);

    points.push(createVector(cos(i) * r + x, sin(i) * r + y));

  }

}

​

function draw() {

  shape.clear();

  shadow.clear();

  shape.fill(255, 0, 0);

  shape.noStroke();

  shadow.noFill();

  shadow.stroke(100, 0, 0);

  shadow.strokeWeight(10);

  shape.beginShape();

  shadow.beginShape();

  for(let p of points) {

    shape.vertex(p.x, p.y);

    shadow.vertex(p.x, p.y);

  }

  shape.endShape(CLOSE);

  shadow.endShape(CLOSE);

  shadow.filter(BLUR, 15);

  let shadowImage = shadow.get();

  shadowImage.mask(shape);

  image(shape, 0, 0);

  image(shadowImage, 0, 0, width, height);

}