Thread by @bgolus

I implemented a couple of different approaches to reconstruct normals from a depth texture. No separate script dependencies, and works for Unity's built in and URP as a post process or on world objects.

gist.github.com/bgolus/a07ed65…

No script dependencies comes from @_kzr 's latest version of his inverse projection setup, which oddly still uses a script to setup an inverse view matrix Unity already provides by default.
github.com/keijiro/DepthI…

"Improved" method based on János Turánszki's Improved Normal Reconstruction with some minor optimizations. Works surprisingly well for getting rid of depth disparity artifacts, but adds others on interior edges.
wickedengine.net/2019/09/22/imp…

"Accurate" method based on Yuwen Wu's Accurate Normal Reconstruction, altered (based on comments in that article) to work with Unity's existing non-linear depth texture. Only minorly more expensive than János's "improved" method.
atyuwen.github.io/posts/normal-r…

It should be noted that all 4 options have different benefits and different problem cases.

Thanks to @_kzr @turanszkij and @atyuwen for posting their stuff.

If anyone is wondering why I didn't include a ddx/ddy based approach, that's because they're terrible and you should feel bad for suggesting it.

I should also note I don't exactly match @atyuwen 's example. I calculate the each derivative from the diff of the center position and one offset position rather than using the diff of two offset position. I'm not sure if the original approach is better?

Compared my "centered" modification to the original "offset" approach.

The original is definitely worse, so I have to assume it was a typo in the article? In the below there's a phantom ghost edge that pops up here.

I realized I was being dumb here. For a post process you do still need an external script since the inverse view matrix I’m using isn’t the same as when rendering the shader on a mesh.

However it might still work if replaced with unity_CameraToWorld instead. I’ll have to try.