Continuity is a Fabric mod that allows resource packs that use the OptiFine connected textures format, OptiFine emissive textures format (only for blocks and item models), or OptiFine custom block layers format to work without OptiFine.
Continuity depends on Fabric API and is client-side only. It includes two built-in resource packs. The Default Connected Textures pack provides connected textures for glass, sandstone, and bookshelves, similar to the built-in connected textures provided by OptiFine. The Glass Pane Culling Fix pack culls faces between vertically stacked glass panes to make them look seamless with connected textures.
Formally, Continuity implements the Continuity connected textures specification, Continuity emissive textures specification, and Continuity custom block layers specification. All of these are extensions of the corresponding OptiFine specification and were created to provide more features to resource pack authors. The documentation for the Continuity specifications can be found at the Continuity wiki.
An official Forge version of Continuity is not planned at this time due to major technical differences between the Fabric and Forge APIs. An official Forge version of Continuity may be considered if these differences are minimized, possibly via the use of libraries.