/* Fake a Flog.* namespace */
  if(typeof(Flog) == 'undefined') var Flog = {};
  if(typeof(Flog.RayTracer) == 'undefined') Flog.RayTracer = {};
  
  Flog.RayTracer.Vector = Class.create();
  
  Flog.RayTracer.Vector.prototype = {
      x : 0.0,
      y : 0.0,
      z : 0.0,
      
      initialize : function(x, y, z) {
          this.x = (x ? x : 0);
          this.y = (y ? y : 0);
          this.z = (z ? z : 0);
      },
      
      copy: function(vector){
          this.x = vector.x;
          this.y = vector.y;
          this.z = vector.z;
      },
      
      normalize : function() { 
          var m = this.magnitude();
          return new Flog.RayTracer.Vector(this.x / m, this.y / m, this.z / m);
      },
      
      magnitude : function() {
          return Math.sqrt((this.x * this.x) + (this.y * this.y) + (this.z * this.z));
      },
      
      cross : function(w) {
          return new Flog.RayTracer.Vector(
                                              -this.z * w.y + this.y * w.z,
                                             this.z * w.x - this.x * w.z, 
                                            -this.y * w.x + this.x * w.y);
      },
      
      dot : function(w) {
          return this.x * w.x + this.y * w.y + this.z * w.z;
      },
      
      add : function(v, w) {
          return new Flog.RayTracer.Vector(w.x + v.x, w.y + v.y, w.z + v.z);  
      },
      
      subtract : function(v, w) {
          if(!w || !v) throw 'Vectors must be defined [' + v + ',' + w + ']'; 
          return new Flog.RayTracer.Vector(v.x - w.x, v.y - w.y, v.z - w.z);
      },
      
      multiplyVector : function(v, w) {
          return new Flog.RayTracer.Vector(v.x * w.x, v.y * w.y, v.z * w.z);  
      },
          
      multiplyScalar : function(v, w) {
          return new Flog.RayTracer.Vector(v.x * w, v.y * w, v.z * w);    
      },
      
      toString : function () {
          return 'Vector [' + this.x + ',' + this.y + ',' + this.z + ']'; 
      }
  }