let alpha = 255; // background transparency

let left = 0;

let right = 0;

​

//gravity wind

let velocity;

let gravity;

let position;

let acceleration;

let wind;

let drag = 0.99;

let mass = 50;

​

function setup() {

  textSize(18);

​

  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);

​

  // alpha is the second value in the string that Arduino sends, which is the value from the potentiometer

  //the potentiometer goes from 0 to 1023 and color goes from 0 to 255, so it is good to use the map function

  fill(220);

​

  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) {

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

    position.y = height - mass / 2;

  }

​

  console.log(position.y);

   //send value to "left" LED in arduino 

   // depending on y-position of ball 

  // if y-position is greater than 330, light up the LED

  if(position.y >= 330){

    left = 1;

  }

  // if y-position is greater than 335, turn off the LED

  if(position.y <= 335){

    left = 0;

  }

​

  if (!serialActive) {

    fill(0)

    text("Press Space Bar to select Serial Port", 20, 30);

  } else {

    text("Connected", 20, 30);

​

    //control wind with potentiometer

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

  }

}

​

function applyForce(force) {

  // Newton's 2nd law: F = M * A

  // or A = F / M

  let f = p5.Vector.div(force, mass);

  acceleration.add(f);

}

​

function keyPressed() {

  // set up connection with p5:

  if (key == " ") {

    setUpSerial();

  }

​

  // if (keyCode == LEFT_ARROW) {

  //   wind.x = -1;

  // }

  // if (keyCode == RIGHT_ARROW) {

  //   wind.x = 1;

  // }

  if (key == " ") {

    mass = random(15, 80);

    position.y = -mass;

    velocity.mult(0);

  }

}

​

// This function will be called by the web-serial library

// with each new *line* of data. The serial library reads

// the data until the newline and then gives it to us through

// this callback function

function readSerial(data) {

  ////////////////////////////////////

  //READ FROM ARDUINO HERE

  ////////////////////////////////////

​

  //if there is data, proceed to read

  if (data != null) {

    // create array to store values from Arduino

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

​

    // if the right length, then proceed

    if (fromArduino.length == 2) {

      // only store values here

      // do everything with those values in the main draw loop

​

      // converting values from from Arduino array into                numbers. values from Arduino come as characters

​

      rVal = int(fromArduino[0]);

      alpha = int(fromArduino[1]);

    }

​

    //////////////////////////////////

    //SEND TO ARDUINO HERE (handshake)

    //////////////////////////////////

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

    writeSerial(sendToArduino);

  }

}