let ease = 0.01;

function setup() {

  createCanvas(800, 800);

  colorMode(HSB, 360, 100, 100, 100);

  p = {x: width/2, y: height/2, col: "#ff00ff", size: 50};

  t = {x: random(width), y: random(height), size: 10};

  background(0);

  noStroke();

}

​

function draw() {

  // background(0);

  drawShadow(0,0,30,p.col);

  fill(p.col);

  circle(p.x,p.y, p.size);

  fill(255);

  drawShadow(0,0,30,255);

  circle(t.x, t.y, t.size);

  let dx = t.x - p.x;

  p.x += dx * ease;

  let dy = t.y - p.y;

  p.y += dy * ease;

  t.size+=0.5;

  let dist = Math.sqrt((dx * dx) + (dy * dy));

  if (dist <= (p.size>>1) + (t.size>>1)) { // avoiding division

    t.x = random(width);

    t.y = random(height);

    t.size = 10;

  } 

}

​

function drawShadow(x,y,b,c) {

  // drawingContext.shadowOffsetX = x;

  // drawingContext.shadowOffsetY = y;

  drawingContext.shadowBlur = b;

  drawingContext.shadowColor = color(c);

}