bounce with class

Transformations:

• class
  • member field declarations: int x; -> x;
    • multiple variable declarators: int x, y; -> x; y;
  • ClassName() -> constructor()
  • int methodName() -> methodName()
  • x -> this.x (add this. prefix to unprefixed member references and method calls that are not local variables)
  • ignore field, method, and class modifiers (e.g. public, final, …)
  • comment out constructor declarations after the first
• for-each loop -> for-of loop
• simple ArrayList implementation in Javascript (wrapper over Array), prepended to converted code

Converted p5.js:

class ArrayList extends Array {
    constructor() {
        super(...[]);
    }
    size() {
        return this.length;
    }
    add(x) {
        this.push(x);
    }
    get(i) {
        return this[i];
    }
    remove(i) {
        this.splice(i, 1);
    }
}

//
// bounce_with_class
//
class Ball {
    x;
    y;
    vx = 0;
    vy = 0;
    c;
    static radius = 50; //static int getRadius() {return radius;} // not valid Processing
    constructor(x, y) {
        this.x = x;
        this.y = y;
        this.vx = random(-3, 3);
        this.vy = random(-2, 2);
        this.c = color(random(255), random(255), random(255));
    }
    display() {
        fill(this.c);
        ellipse(this.x, this.y, Ball.radius * 2, Ball.radius * 2);
        this.update();
    }
    update() {
        this.x += this.vx;
        this.y += this.vy;
        if (this.x < Ball.radius || this.x > width - Ball.radius) this.vx *= -1;
        if (this.y < Ball.radius || this.y > height - Ball.radius)
            this.vy *= -1;
    }
    test(x) {
        x = 1;
        this.x = 2;
        this.y = 3;
        this.y = 4;
        let position = new p5.Vector();
        position.x = 5;
        position.y = 6;
        return 0;
    }
}
let ball;
let balls;
function setup() {
    createCanvas(400, 400);
    console.log("Ball.radius: " + Ball.radius); //println("Ball.getRadius(): " + Ball.getRadius());
    ball = new Ball(width / 2, height / 2);
    balls = new ArrayList();
    for (let i = 0; i < 5; i++) createBall();
}
function createBall() {
    balls.add(new Ball(random(50, width - 50), random(50, height - 50)));
}
function draw() {
    background(0);
    ball.display();
    for (let b of balls) b.display();
    let temp = balls.get(0);
    temp.x += 50;
    temp.display();
    temp.x -= 50;
}
function keyPressed() {
    if (key == "a") createBall();
    else if (key == "r" && balls.size() > 1) balls.remove(0);
    else {
        console.log("We're here!");
    }
}
class Dummy {
    w;
    x;
    y;
    z;
    c = color(255, 0, 0);
    constructor() {} // public is optional/unnecessary in Processing
    /*constructor( x ) { } */ // multiple constructors not ok in Javascript
    hello() {
        console.log("Hello, world!");
        let c = color(255, 0, 0);
    }
}

Original Processing:

//
// bounce_with_class
//


class Ball
{
    float x, y;
    float vx = 0, vy = 0;
    int c;
    static final int radius = 50;
    //static int getRadius() {return radius;} // not valid Processing

    Ball(float x, float y)
    {
        this.x = x;
        this.y = y;
        vx = random(-3, 3);
        vy = random(-2, 2);
        c = color(random(255), random(255), random(255));
    }

    void display()
    {
        fill(c); 
        ellipse(x, y, radius*2, radius*2);
        update();
    }

    void update()
    {
        x += vx;
        y += vy;

        if (x < radius || x > width-radius)
            vx *= -1;

        if (y < radius || y > height-radius)
            vy *= -1; }

    int test(int x)
    {
        x = 1;
        this.x = 2;
        y = 3;
        this.y = 4;
        PVector position = new PVector();
        position.x = 5;
        position.y = 6;
        return 0;
    }
}


Ball ball;
ArrayList<Ball> balls;

void setup()
{
    size(400, 400);
    println("Ball.radius: " + Ball.radius);
    //println("Ball.getRadius(): " + Ball.getRadius());

    ball = new Ball(width/2, height/2);
    balls = new ArrayList<Ball>();

    for (int i=0; i<5; i++)
        createBall();      
}


void createBall()
{
    balls.add(new Ball(random(50,width-50), random(50,height-50)));
}


void draw()
{
    background(0);
    ball.display();

    for (Ball b : balls)
      b.display();

    Ball temp = balls.get(0);
    temp.x += 50;
    temp.display();
    temp.x -= 50;
}


void keyPressed()
{
    if (key == 'a')
        createBall();

    else if (key == 'r' && balls.size() > 1)
        balls.remove(0);

    else
    {
      println("We're here!");
    }
}


public class Dummy
{
    int w, x, y, z;

    int c = color(255, 0, 0);

    public Dummy() {} // public is optional/unnecessary in Processing

    public Dummy(int x) {} // multiple constructors not ok in Javascript

    public void hello() 
    {
        println("Hello, world!");
        int c = color(255, 0, 0);
    }
}