/* built with Studio Sketchpad: 
 *   https://sketchpad.cc
 * 
 * observe the evolution of this sketch: 
 *   https://studio.sketchpad.cc/sp/pad/view/ro.x7eRu2eaHCU/rev.141
 * 
 * authors: 
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 *   Ari Bader-Natal
 *   Andor Salga
 *   
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 *   

 * license (unless otherwise specified): 
 *   creative commons attribution-share alike 3.0 license.
 *   https://creativecommons.org/licenses/by-sa/3.0/ 
 */ 



/*
  FSOSS 2010
  Andor Salga
  Collision Detection!
*/
 
// !!! create two PVector references to circle positions
    
 
int circleSize = 30;
 
int increment1 = -0.5;
int increment2 = -0.5;
 
void setup(){
  size(200, 200);
 
  // !!! instantiate circle positions across from one another
  circle1 = new PVector(15, height/2);
  circle2 = new PVector(width-15, height/2);
}
 
void draw(){
  background(200);
 
 
  // !!! reset the positions if they go past the screen
   if(circle1.x > width-15){
    circle1.x = 15;
    circle2.x = width-15;
   }
 
  // change fill color if they collided
  if(collided(circle1, circle2)){
    fill(33, 66, 99, 150);
 
    
    //increment1 = 0.5;
    //increment2 = -0.5;
  
  }
  else{
    fill(99, 33, 66);
    
    //increment1 = -0.5;
    //increment2 = 0.5;
  
  }
  
  
  // !!! move the positions towards each other
  circle1.x -= increment1;
  circle2.x += increment2;
 
  // !!! draw two circles using the positions and diameter of circleSize
  ellipse(circle1.x, circle1.y, circleSize, circleSize);
  ellipse(circle2.x, circle2.y, circleSize, circleSize);
}
 
boolean collided(PVector p1, PVector p2){
 
  // !!! subtract the vectors
  PVector r = PVector.sub(p1, p2);
  
  // if the magnitude of the result is less
  // than the size of the ball, change color
  if( r.mag() < circleSize ){
    return true;
  }
  else{
    return false;
  }
}