Rendering Depth in Vert/Frag Shader

After looking through the following posts and attempting the examples.

http://forum.unity3d.com/threads/writing-depth-value-in-fragment-program.66153/
http://forum.unity3d.com/threads/render-depth-distance.272979/
http://docs.unity3d.com/Manual/SL-DepthTextures.html

All that actually seems to write to the depth texture in Unity is setting Tags { "LightMode" = "ShadowCaster" }

I'm confused. Does anyone around have some knowledge as to how this works now?

The first post seems to imply that I can pretty much write whatever I want to the depth buffer (Woohoo!) but the posts are so old it hurts, wondering if this feature is now deprecated in favour of the UNITY_OUTPUT_DEPTH. This would be ok, however it doesn't appear to output anything.

When checking through the UnityCG.cgnic, I can see where it is defined, but presumably this then gets picked up somewhere else as all I see if a define and no real output to the Depth, which judging by the first posts it must have to do at some point.

EDIT: Was totally reading the cginc incorrectly. Think my mind got a little lost with the whole SV_Depth semantic and I was expecting something similar.

So back to my question, how do I write my own depth stuff quickly and efficiently via shaders these days without some kind of Tags { "LightMode" = "ShadowCaster" } hack. This doesn't feel right. I presume if Output depth had broken / was bugged we'd have more of an uproar, so what am I missing?

Thank you in advance.

 

I also seem to not be the only person who's confused by this in Unity currently.

http://forum.unity3d.com/threads/write-to-depth-buffer-in-a-shader-ray-tracing-objects.372215/

 

See my reply to that post, he's asking about depth for post processing specifically though, which might be slightly different than what you need.

 

I see, it is a little different, especially as it's appears to be more for a deferred render pipeline. But still very useful and clears up quite a few of my questions, which means I might be able to do a little more digging and work some things out myself.

 

Actually all of that is for the forward rendering pipeline. For deferred you just don't need to update the Camera-DepthNormalTexture.shader file to add an additional pass.

 

Yup.. Helps if my brains in my head when I read things - was very helpful anyway thank you, also re-read http://forum.unity3d.com/threads/writing-depth-value-in-fragment-program.66153/

For me the key was to write my own Depth map visualiser rather than rely on the one that comes with the unity built in DoF, it has its own quirks.