Hi! My name is Thomas and I've been working on a real-time black hole shader since 2020 as a hobby project and decided to finally release it on the Unity asset store. Check out the asset HERE. Both the URP and HDRP render pipelines are supported.
The skybox around the black hole is distorted using a lookup texture, meaning performance is high since no expensive ray marching calculations need to be done.
Scene objects can be distorted accurately. Where objects behind the black hole are normally fully or partially occluded, they are now fully visible with even multiple images visible as would be expected following General Relativity.
A volumetric accretion disk looks great up close and when flying through it but a flat accretion disk looks almost just as good from a distance and is more performant.
To try it out for yourself and test the performance download the playable demo for macOS and Windows HERE
If you need support regarding the asset or if you just have questions or suggestions, contact me at eventhorizoneffects@gmail.com.