package org.papervision3d.core.math
  {
          import org.papervision3d.core.math.Number3D;
          
          public class @ax-student-ar-org-papervision3d-core-math-Sphere3D
          {
                  public var x:Number;
                  public var y:Number;
                  public var z:Number;
                  public var radius:Number;
                  
                  public function @ax-student-ar-org-papervision3d-core-math-Sphere3D(r:Number = 100, x:Number=0, y:Number=0, z:Number=0)
                  {
                          this.radius = r;
                          this.x = x;
                          this.y = y;
                          this.z = z;
                  }
                  
                  public function get o():Number3D{
                          return new Number3D(x, y, z);
                  }
                  
                  public function get r2():Number{
                          return radius*radius;
                  }
                  
  
                  public function intersectRay(ray:Ray3D):Number{
                          var dst:Number3D = Number3D.sub(ray.o, o);
                          var b:Number = Number3D.dot(dst, ray.d);
                          var c:Number = Number3D.dot(dst, dst)-r2;
                          var d:Number = b*b-c;
                          if(d >0)
                                  return -b-Math.sqrt(d);
                          else 
                                  return -999999;
                  }
          }
  }