​

function preload() {

  bgImage = loadImage(

    'https://mbkassets.s3-eu-west-1.amazonaws.com/dev/andy/TexturesCom_Camouflage0018_seamless_S.jpg'

  );

  topImage = loadImage(

    'https://mbkassets.s3-eu-west-1.amazonaws.com/dev/andy/TexturesCom_ConcretePlates0207_1_seamless_S.jpg'

  );

}

​

function setup() {

  createCanvas(400, 600);

  mask = createGraphics(width, height);

}

​

function draw() {

  // draw background image

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

  // Draw mask shape

  mask.background(0);

  mask.ellipseMode(CENTER);

  mask.fill(255);

  mask.noStroke();

  mask.ellipse(mouseX, mouseY, 200, 200);

​

  maskClone = mask.get();

  // apply mask to top image & draw top image

  topImage.mask(maskClone);

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

}