Is there a known projection shader for a panini projection?

http://tksharpless.net/vedutismo/Pannini/

Basically a panini projection is projecting vertices onto a cylinder (if I get it right), which is then unrolled on screen.

Here is how blinky, a quake mode, is doing is, using some LUA script:

https://github.com/shaunlebron/blinky/blob/master/game/lua-scripts/lenses/panini.lua

Not sure it’s a real projection since it’s using globes and lenses.

The thing about non-linear projections is that the projection of a straight line isn’t a straight line. So you can’t project a triangle simply by projecting the vertices. Typically, you’d either use tessellation to get a sufficient approximation, or project onto the faces of a cube map and then project the cube map as a post-processing step using a fragment shader.