public class CircleMath
{	
  PVector inter0 = new PVector();
  PVector inter1 = new PVector();	
  public CircleMath()
  {

  }

  public boolean intersection( Circle c0, Circle c1 )
  {
    float h;	//height from common center line to intersection
    float a;	//length from circle0 center to 
    float d;	//distance between centers
    float dx;
    float dy;
    float rx;
    float ry;
    float rDiff;
    PVector p0 = c0.getCenter();
    PVector p1 = c1.getCenter();
    float r0 = c0.getRadius();
    float r1 = c1.getRadius();
    PVector p2 = new PVector();


    dx = p1.x - p0.x;
    dy = p1.y - p0.y;

    d = sqrt(pow(( dx ), 2) + pow(( dy ), 2));
 
     rDiff = r0 - r1;
//    println(sqrt(pow(r0 - r1, 2)) + " " + (r1 + r0) + " " + d);

    if( d > ( r1 + r0) || d < sqrt(pow(r0 - r1, 2)) || (d == 0 && r0 == r1 ) )
    {
      return false;
    }
 
    a = (( r0 * r0 ) - ( r1 * r1) + ( d * d)) / ( d * 2 );

    p2.x = p0.x + (a * dx) / d;
    p2.y = p0.y + (a * dy) / d;

    h = sqrt( (r0 * r0) - ( a * a) );

    rx = -dy * ( h / d); 
    ry = dx * ( h / d); 			

    inter0.x = p2.x + rx; 
    inter0.y = p2.y + ry;
    inter1.x = p2.x - rx; 
    inter1.y = p2.y - ry;

    return true;

  }
  public PVector getFirstIntersection()
  {
    return inter0;
  }

  public PVector getSecondIntersection()
  {
    return inter1;    
  }
}