let _density;

  if (g == null) _density = pixelDensity();

  else _density = g.pixelDensity();

​

  const idx = 4 * _density * (int(y) * _density * width + int(x));

  return idx;

}

​

let startColor, endColor;

let border, max_dist;

function setup() {

  createCanvas(1000, 1000);

  border = width * 0.05;

  pixelDensity(1);

  background(20);

​

  startColor = color(random(255), random(255), random(255));

  endColor = color(

    255 - red(startColor),

    255 - green(startColor),

    255 - blue(startColor)

  );

​

  noiseDetail(8, 0.75);

​

  y = border;

  max_dist = dist(border, border, width - border, height - border);

}

​

let y;

let step = 0;

let r = 1;

// let t = 0;

​

function draw() {

  if (step == 0) {

    loadPixels();

    for (let x = border; x < width - border; x++) {

      let d = dist(x, y, width - border, height - border);

      let m = map(d / max_dist, 1.0, 0.0, 0.0, 1.0);

      let c = lerpColor(startColor, endColor, m);

      let idx = getPixelID(x, y, null);

      pixels[idx] = red(c);

      pixels[idx + 1] = green(c);

      pixels[idx + 2] = blue(c);

    }

    updatePixels();

    y++;

​

    if (y > height - border) {

      noFill();

      stroke(220);

      rect(border, border, width - 2 * border, height - 2 * border);

      step++;

    }

  } else if (step == 1) {

    push();

    translate(width / 2, height / 2);

​

    // let c = color(map(r, 1, width/3, 255, 20));

    let c = lerpColor(endColor, startColor, map(r, 1, width/3, 0.0, 1.0));

    noStroke();

    for (let t = 0; t < TWO_PI; t += TWO_PI / random(32, 512)) {

      let x = r * cos(t);

      let y = r * sin(t);

      for (let _r = 5; _r < 50; _r+= random(0.5, 2)) {

        let a = map(_r, 5, 50, 10, 2);

        c.setAlpha(a);

        fill(c);

        ellipse(x+random(-5,5), y+random(-5,5), _r+random(-2,2),_r+random(-2,2));

      }

      // circle(x, y, 5);

    }

​

    translate(-width / 2, -height / 2);

    pop();

    r += 5;

​

    if (r > width / 3) {

      step++;

    }

  } else {

    console.log("done");

    noLoop();

  }

}

​