message: Transform ray.dir like a vector
diff: @@ -170,8 +170,7 @@ inline auto intersect(
  basic_ray<T> transformed_ray = ray;
  transformed_ray.ori = (matrix<4, 4, T>(b.transform_inv()) * vector<4, T>(ray.ori, T(1.0))).xyz();
  - auto p2 = (matrix<4, 4, T>(b.transform_inv()) * vector<4, T>(ray.ori + ray.dir, T(1.0))).xyz();
  - transformed_ray.dir = (p2 - transformed_ray.ori);
  + transformed_ray.dir = (matrix<4, 4, T>(b.transform_inv()) * vector<4, T>(ray.dir, T(0.0))).xyz();
  // NOTE: dir is in general *not* normalized!
  auto hr = intersect<Traversal, MultiHitMax>(
  