Stereopsis

This mod is too difficult to update past 1.21.3. It needs a rewrite and will not happen soon.

This mod can turn minecraft into stereopsis with a hotkey.

Usage

You'll need to bind a key for it first, it's unbound by default.
If you think the result is too narrow for hands to render, you can increase the aspect ratio by decreasing minecraft window's height.
If you don't know what is or how to use stereopsis, here's a video:

Intent

This mod is meant to enable only when you want to see the world in 3D illusion, not enabled at all time because not all screens/huds are modified to render stereopsis.
I'm not going to implement it, because modifing container screens sounds like hell, and other mods that has huds or adds elements to the screen probably won't like it either.

AR Mode

According to the github comment, this mod also works on AR glasses like XREAL glasses. But keep in mind that the dev doesn't have one and doesn't have deep knowledges about human sight, so it might look weird in some cases.

To enable AR mode, you need to switch the View Mode option in the config (requires modmenu to access it).

Compatibility

As this mod messes around with rendering methods, it's very likely to be incompatible with other rendering-related mods. But surprisingly, in my case, it doesn't cause any issues with sodium.

For shader packs, it's generally not recommanded with this mod, because it renders two times in the same frame. But if you really want it, there's a fix option in mod config that you would probably need (requires modmenu to access it). Sometimes you would need extra F3+R (reload shaders) and toggling stereopsis off and on to fix it.

Known incompatibility:

• Exordium (It won't crash in 1.2.0, but still has render issues with hud. Won't fix.)