pong

int
    // ball
    ballX = 0, // pradedu nuo viršutinio kairiojo kampo
    ballY = 0,
    wayX = 1, // ballX direction (positive of negative)
    wayY = 1, // ballY direction (positive or negative)
    ballStep, // ball speed
    ballSize,

    // paddle
    paddleX,
    paddleY,
    paddleW, // paddle width
    paddleH, // paddle height
    paddleStep; // paddle speed


void setup () {
    //frameRate (300);
    size (1280, 740);
    rectMode (CENTER);

    ballStep = width / 100;
    ballSize = height / 10;

    paddleX = width / 2;
    paddleY = int(height * 0.95);
    paddleW = width / 8;
    paddleH = height / 30;
    paddleStep = width / 100;

    textSize(128);
}

void ball () {
    ballX += ballStep * wayX;
    ballY += ballStep * wayY;

    if ((ballX < 0) || (ballX > width)) // tikrinu šonus
        wayX *= -1;

    if (
        (ballY < 0) || // tikrinu viršų
            ((ballY + ballSize / 2 > paddleY - paddleH / 2) // apačia, atsimušti tik tada, jei liečia paddle
            &&
            (ballX > paddleX - paddleW/2 && ballX < paddleX + paddleW/2))
    )
        wayY *= -1;

    if (ballY > height)
        stop ();

    fill (255);
    circle (ballX, ballY, ballSize);
}

void paddle () {
    if (keyPressed) {
        if (keyCode == RIGHT)
            paddleX += paddleStep;
        if (keyCode == LEFT)
            paddleX -= paddleStep;
    }

    fill (255, 0, 0);
    rect (paddleX, paddleY, paddleW, paddleH);
}

void draw () {
    background (0);
    ball ();
    paddle ();
    //text (frameCount, 1000, 200);
}