const Vector3 &get_position() const { return position; }
const Vector3 &get_look_direction() const { return look_dir; }
const Vector3 &get_up_direction() const { return up_dir; }
+ const Matrix &get_matrix() const { return matrix; }
Vector3 project(const Vector4 &) const;
Vector4 unproject(const Vector4 &) const;