Ambient Occlusion in Forward Shading (early z-pass)

I’ve heard that you can use “ambient occlusion against the depth pre-pass buffer” to achieve basically a light and crude version of SSAO.

The only thing on the internet that has even remotely resembled an answer on how to achieve that in practice has been this non-UE specific forum post, with which I don’t really know what to do with.

Oh mighty rendering wizards, will you hear my prayer and explain the solution to me like I’m not very sharp.

I’m guessing that would translate to something like

( with the rest of the material, of course ).

UE doesn’t differentiate between diffuse and albedo, as far as I know.


Thanks for the response.

I think however that the answer is in the realm of post process materials and scene textures, and the part about diffuse and albedo refer to the scene when unlit and with lighting.

This is meant to be a poor man’s SSAO for VR applications, and if it were to happen inside surface shaders, there wouldn’t be any interaction between objects since they can’t access the z-pass.

You’re right. Then something similar in a PP material.

Ahem. I think I should try to get the ball rolling by saying that it does seem that the Ambient occlusion SceneTexture doesn’t output anything but pure white when hooked up to post process material’s emissive color.
Any ideas how to get it to output something?

I have no idea where to go with this. The ambient occlusion is already in part of the PP. How is this going to help?

I’m going to have to ask you to stop replying to this thread. You have misunderstood the question since your first reply and none of your posts after that have been of any help.

Yes Sir!

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