let gravity;

let position;

let acceleration;

let wind;

let drag = 0.99;

let mass = 50;

let potValue = 0; // potentiometer value

let serialConnected = false; 

let onGround = false; // whether ball is on the ground

​

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);

}

​

function draw() {

  background(255);

  if (!serialConnected) {

    textAlign(CENTER, CENTER);

    fill(0);

    text("Press 'Space' key on the keyboard", width / 2, height / 2);

    return;

  }

​

  applyForce(wind);

  applyForce(gravity);

  velocity.add(acceleration);

  velocity.mult(drag);

  position.add(velocity);

  acceleration.mult(0);

// check for bounce on the x axis

  if (position.x > width - mass / 2) {

    if(!onGround){

    position.x = width - mass / 2; 

    velocity.x *= -0.9;

    }

  }

    else if (position.x < mass / 2) {

      position.x = mass / 2; 

    velocity.x *= -0.9;

    }

  // check for bounce on the y axis

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

  velocity.y *= -0.9; 

  position.y = height - mass / 2; 

  if (!onGround) {

    sendBounceSignal(); 

    onGround = true; 

  }

} else {

  onGround = false; 

}

​

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

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

​

  // boundaries on x axis

  if (position.x > width - mass / 2 || position.x < mass / 2) {

    velocity.x *= -0.9; 

  }

}

​

function applyForce(force) {

  let f = p5.Vector.div(force, mass);

  acceleration.add(f);

}

​

// bouncing signal to Arduino

function sendBounceSignal() {

  if (serialActive) {

    let sendToArduino = "1\n"; 

    writeSerial(sendToArduino);

  }

}

​

// receive data from Arduino

function readSerial(data) {

    potValue = int(trim(data)); 

}

​

// initialize serial connection

function keyPressed() {

  if (key == ' ') {

    mass = random(10,100);

    setUpSerial(); 

    serialConnected = true; 

  }

}

​

function serialOpened() {

  serialActive = true; 

}