let MAXVEL = 3;

​

let nScale;

​

function setup() {

  createCanvas(400, 400);

  stroke(0, 130);

​

  for (let i = 0; i < 1000; i++) {

    pos.push({

      x: random(width),

      y: random(height),

    });

  }

​

  createP("noise scale factor").style("height", "6px");

  nScale = createSlider(10, 200, 100, 1);

  background(255);

}

​

function draw() {

  //   background(220, 20, 120);

  background(255, 10);

  let mScale = nScale.value();

  for (let i = 0; i < pos.length; i++) {

    let xparam = pos[i].x / mScale;

    let yparam = pos[i].y / mScale;

    let tparam = frameCount / mScale;

​

    let nx = noise(xparam, yparam, tparam);

    let ny = noise(tparam, xparam, yparam);

​

    // turn [0,1] -> [-3,3]

    let vx = map(nx, 0, 1, -MAXVEL, MAXVEL);

    let vy = map(ny, 0, 1, -MAXVEL, MAXVEL);

​

    // update

    pos[i].x += vx;

    pos[i].y += vy;

​

    // reset x

    if (pos[i].x > width || pos[i].x < 0) {

      pos[i].x = random(width);

    }

​

    // reset y

    if (pos[i].y > height || pos[i].y < 0) {

      pos[i].y = random(height);

    }

​

    // ellipse(pos.x, pos.y, 16, 24);

    point(pos[i].x, pos[i].y);

  }

}

​

function mouseClicked() {

  background(255);

}

​