/* 
 title: bouncing ball 
 description: ball deflects off sketch window edges 
 based on: sketch created August 9, 2005 by Ira Greenberg 
 modified: With 3 balls, and initial random ball
           placement, Sept. 13, 2006 by Fred Green
 further modified: Done with Vector2D objects,
           10/22/2007
 further modified: Encapsulate velocities in a Particle class,
           10/29/2007
 */ 
 
// declare global variables 
int wdth, ht;
Particle p1, p2, p3;
Vector2D velocity1, velocity2, velocity3; 
Vector2D position1, position2, position3;
Vector2D acceleration;
 
//initialize sketch 
void setup(){ 
  
  //set sketch window size and background color 
  size(500, 400); 
  background(0); 
  
   
  //first ball velocity 
  velocity1 = new Vector2D(0.3, 0.4);
 
  //2nd ball velocity
  velocity2 = new Vector2D(0.5, 0.6); 
  
  // ... and 3rd
  velocity3 = new Vector2D(.7, 0.8);
   
  //ball size 
  wdth = 20; 
  ht = 20; 
   
  // turn off shape stroke rendering 
  noStroke(); 
  
  //initial ball placement 
  position1 = new Vector2D(random(10, width-10), random(10, height-10));
  position2 = new Vector2D(random(10, width-10), random(10, height-10));
  position3 = new Vector2D(random(10, width-10), random(10, height-10));
  
  //initialize acceleration
  acceleration = new Vector2D(0, 0.0);
  
  //Create particles
  p1 = new Particle(position1, velocity1, acceleration, wdth, ht);
  p2 = new Particle(position2, velocity2, acceleration, wdth, ht);
  p3 = new Particle(position3, velocity3, acceleration, wdth, ht);
  
 //set the animation loop speed 
  frameRate(200); 
  smooth();
} 
 
// begin animation loop 
void draw(){ 
 
  //update background 
  background(0); 
   
  //draw balls
  p1.render();
  p2.render();
  p3.render();
  
  //move them
  p1.move();
  p2.move();
  p3.move();
      
}