This mod adds blocks that simulate sky! You can now feel little better in cave homes! And it also adds several other shader-based blocks:
Currently the only two blocks are Sky Block and Void Block
It even renders weather!
(These trippy blocks are WIP / will be added in future)
This mod currently isn't as performant as it could be. If and when this Forge pull request gets merged, there shouldn't be any performance impact at all. Currently, its just about as laggy as placing many many chests, mostly because of block entity renderer. After this PR, blocks will no longer have entities.