Modify z-buffer in perpixel shader

Hi all. I watch this video, and very impressed. This is awesome idea for parallax shaders, but i don't understand, how this works (how send custom depth info into depth buffer). Any ideas?

 

Maybe the Using Depth Textures and Camera’s Depth Texture documentation is what you're looking for? Hope it helps!

 

It's just a shader that writes depth at it's simplest. Pretty much what resident evil used to do. If you have static backgrounds that need to be interacted with, it can be useful.

You however need to save the depth information somehow from your 3D modelling package or from a high resolution scene.

 

Yes. I understand this. What i want to do:
1) Calc all visual data in shader.
2) Calc the depth offset based on textures.
3) Send new depth into z-buffer.
But I don't know how to implement the last point... and how it works on different pc operation systems.