let input;

let bg;

function setup() {
  createCanvas(800, 600);

  input = new p5.AudioIn();
  input.start();

  bg = color(0, 255, 0);
  background(bg);
}

function draw() {
  let volume = input.getLevel();

  let threshold = 0.02;

  if (volume > threshold) {
    drawCircleCluster(volume);
}
}

function drawCircleCluster(volume) {
  noStroke();

  let largerCircleColor = color(255, 165, 0);
  fill(largerCircleColor);

  let cx = random(width);
  let cy = random(height);

  let numCircles = int(random(5, 10));
  for (let i = 0; i < numCircles; i++) {
    let angle = random(TWO_PI);
    let radius = random(10, 80);
    let x = cx + cos(angle) * radius;
    let y = cy + sin(angle) * radius;

    let size = map(volume, 0, 1, 5, 150);
    size = constrain(size, 5, 150);

    circle(x, y, size);
}
}

function keyPressed() {
  if (key === 'C' || key === 'c') {
    background(bg);
  }
}