Does Heroes of Might and Magic V have a Z-buffer? Auto-translated

I wanted to create a new shader for HoMM V (or rather, adapt ReShade or SweetFX) and even achieved a pretty good result, but I'm wondering if the game even has the concept of "depth" for objects. Nothing seems to directly hook into it, but since the engine is a custom-made Nival engine, it might be implemented differently.

Does anyone know which direction to explore? I really want to implement SSAO.