프로세싱, 공 움직임

// Ball Position

int xPos;

// Ball Direction

int xDir;

void setup(){

  size(300, 200);

  xPos = 0;

  xDir = 1;

}

void draw(){

  background(128);

  

  //Ball Drawing and Movement

  ellipse(xPos, 10, 20, 20);

  xPos = xPos + xDir;

  

  // Ball Bouncing

  if ( xPos < 0) xDir = xDir * -1;

  if ( xPos > width) xDir = xDir *= -1;

}