code: public static final Mat4 lookAt(final Vec3 eye, final Vec3 center, final Vec3 up) {
  		final Vec3 f = center.subtract(eye).getUnitVector();
  		Vec3 u = up.getUnitVector();
  		final Vec3 s = f.cross(u).getUnitVector();
  		u = s.cross(f);
  		
  		return new Mat4(
  				s.x, u.x, -f.x, 0f,
  				s.y, u.y, -f.y, 0f,
  				s.z, u.z, -f.z, 0f,
  				-s.dot(eye), -u.dot(eye), f.dot(eye), 1f
  		);
  	}
docs: Defines a viewing transformation.  This method is analogous to the now
  deprecated {@code gluLookAt} method.
  
  @param eye position of the eye point
  @param center position of the reference point
  @param up direction of the up vector
  @return