let y = 0;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  let d = pixelDensity();

​

  for (let i = 0; i < d; i++) {

    for (let j = 0; j < d; j++) {

      index = 4 * ((x * d + j) * width * d + (y * d + i));

      pixels[index] = 255;

      pixels[index+1] = 255;

      pixels[index+2] = 255;

      pixels[index+3] = 255;

    }

  }

  x++;

  y++;

  console.log(x + " " + y);

}