I'm not a modder, and I know how terrible the Minecraft codebase is, so I understand if there's some technical limitation against this, but would it be possible to have a block that mimicked the sky that you could put on a ceiling?
For instance, the particular use I had in mind is I'm building an adventure map, and one of my dungeons is inspired by House of Leaves, with non euclidean geometry and changing hallways and rooms, to achieve this I make use of command blocks "/tp @p" to teleport the player to an identical room when they step in, which means most of my actual dungeon is deep under ground. I thought it would be pretty cool if for a small bit they could see the sky, to reinforce the belief that they're still in the overworld.
Now the ways I was brainstorming to accomplish this would be maybe an invisible block that renders all blocks touching it/seen throughit invisible. Kind of like how this glitch used to work.
Secondarily, it could work how End Portal currently works where the starfield texture is actually the skybox of The End, and has perspective incorrect texturing (also known as Unmoving Plaid)
This is a great idea. I was thinking the exact same thing! My particular use would be that since I have a ravine city, and I want to have yards that don't go out into the road, I could put a fake sky block and make it look like it was outside.
i would actually really love this, it would be amazing for adventure map building.
It'd be good if there were also variations for this "skybox block" that had the sky at different points of day for a "permanently sunset" or "permanently night time" effect, and had versions with the end and nether dimension skies in various colors to mimic unnatural-looking skies