added jitter parameter to lights, currently uses random vectors, which i'm not happy with; added Vector::getPerpendicularVector() which will be used to replace random jitter for lights

git-svn-id: svn://anubis/fart/trunk@256 7f9b0f55-74a9-4bce-be96-3c2cd072584d

util/Vector.cc

@@ -83,6 +83,18 @@ Vector Vector::reflect(const Vector & target) const
     return (*this) + me_to_proj * 2.0;
 }
 
+Vector Vector::getPerpendicularVector() const
+{
+    Vector t = *this;
+    t.normalize();
+    Vector p = t * Vector(0, 0, 1);
+    if (p.mag() <= 0.1)
+    {
+        p = t * Vector(1, 0, 0);
+    }
+    return p;
+}
+
 std::ostream & operator<<(std::ostream & out, const Vector & v)
 {
     out << "[" << v[0] << ", " << v[1] << ", " << v[2] << "]";

util/Vector.h

@@ -19,7 +19,8 @@ class Vector
         double dist_to(const Vector & other) const;
         Vector proj(const Vector & target) const;
         Vector reflect(const Vector & target) const;
-        operator double() { return mag(); }
+        operator double() const { return mag(); }
+        Vector getPerpendicularVector() const;
 
     protected:
         double  m_array[3];