let alpha = 255;

let left = 0;

let right = 0;

​

let velocity;

let gravity;

let position;

let acceleration;

let wind;

let drag = 0.99;

let mass = 50;

​

function setup() {

  createCanvas(640, 360);

  noFill();

  position = createVector(width / 2, 0);

  velocity = createVector(0, 0);

  acceleration = createVector(0, 0);

  gravity = createVector(0, 0.5 * mass);

  wind = createVector(0, 0);

  textSize(18);

}

​

function draw() {

  background(255);

  applyForce(wind);

  applyForce(gravity);

  velocity.add(acceleration);

  velocity.mult(drag);

  position.add(velocity);

  acceleration.mult(0);

  ellipse(position.x, position.y, mass, mass);

​

  if (position.y > height - mass / 2) {

    console.log("hit bottom");

    left = 1;

    velocity.y *= -0.9; // A little dampening when hitting the bottom

    position.y = height - mass / 2;

  } else {

    left = 0;

  }

​

  if (!serialActive) {

    fill(0);

    text(

      "Press Space Bar to select Serial Port and 'n' to add new ball",

      20,

      30

    );

    fill(255);

  } else {

    text("Connected", 20, 30);

    text("rVal = " + str(rVal), 20, 50);

    text("alpha = " + str(alpha), 20, 70);

    wind.x = map(alpha, 0, 1023, -1, 1);

  }

}

​

function readSerial(data) {

  if (data != null) {

    let fromArduino = split(trim(data), ",");

    if (fromArduino.length == 2) {

      rVal = int(fromArduino[0]);

      alpha = int(fromArduino[1]);

    }

    let sendToArduino = left + "," + right + "\n";

    writeSerial(sendToArduino);

  }

}

​

function applyForce(force) {

  let f = p5.Vector.div(force, mass);

  acceleration.add(f);

}

​

function keyPressed() {

  if (key == " ") {

    setUpSerial();

  }

  if (key == "n") {

    mass = random(15, 80);

    position.y = -mass;

    velocity.mult(0);

  }

}

​