hololens shader and shadows

Hi

I am working on a project to simulate the hololens in VR, and I use custom shaders, which allow me to have holograms that I can only see through the Hololense.
This works well but I have a little problem : I can't see the shadows of the objects of my scene through the Hololense, and I don't understand why.

Can someoune help ?

Thanks a lot


I join the hololens shader and a hologram shader for example