So if in the vertex shader you write "oDepth = oPos.z/oPos.w", then in the pixel shader, oDepth will equal oPos.z/oPos.w/oPos.w.
Now you got me confused. I thought that just output position is affected "behind scene"?
If we saved in vertex shader z/w in oDepth, oDepth should not be affected later on? Or i am wrong?
I am interested in DX9 pipeline, don't know about DX11.