Just a few days ago, a new Blender 4.2 node for Cycles was introduced, already considered a "game-changer" by many 3D artists online. It's very simple, yet opens up plenty of possibilities, replacing the classic parallax techniques and not only great for mapping images, windows, or portals, but also for creating fancy perspective shifts like black hole effects, lens simulations, and other production rendering tricks.
Essentially, the Ray Portal BSDF node transports rays that enter another location in the scene. It acts much like a Transparent BSDF: render passes are passed through, and it is affected by light path max transparent bounces.
