let moonX, moonY, moonSize;

​

function setup() {

  createCanvas(400, 400);

  sunX = width / 2;

  sunY = height / 2;

  sunSize = 150;

}

​

function draw() {

  background(240);

  moonX = mouseX;

  moonY = mouseY;

  moonSize = dist(mouseX, mouseY, sunX, sunY) / 2;

  fill(255, 204, 0);  

  ellipse(sunX, sunY, sunSize);

  fill(0);

  ellipse(moonX, moonY, moonSize);

}

function mousePressed() {

  save("sun.jpg");

}

​

​