AO/SSGI: Noise reduction.

[marcofugaro]

Description

The updated implementation of GTAONode introduced in #33895 introduced some noisiness in the half-resolution version, we should look into some smoothing approaches to reduce the noise as we're currently doing for other stochastic effects like SSR.

The original activision paper authors also mention it needing some kind of smoothing/denoising at halfres, from page 85 onwards of the slides: https://blog.selfshadow.com/publications/s2016-shading-course/activision/s2016_pbs_activision_occlusion.pdf

Reproduction steps

1. Open https://rawcdn.githack.com/mrdoob/three.js/dev/examples/webgpu_postprocessing_ao.html
2. See detail

Code

/

Live example

https://rawcdn.githack.com/mrdoob/three.js/dev/examples/webgpu_postprocessing_ao.html

Screenshots

Version

dev

Device

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Browser

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OS

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[Mugen87]

A potential solution for this approach is outlined in #33663 (comment) and #33895 (comment).

tl;dr Adapting the existing denoise and temporal accumulation nodes of SSR for SSGI and AO as well.

[Mugen87]

I've renamed the issue so it's a more general one we can use for SSGI and AO.

[marcofugaro]

Ok I've implemented my solution in #33918.
I don't think a single denoise/temporal accumulation solution that works for all effects would be realistic. The codepaths are different.

[jensensfamilyjensen-oss]

it dose have CEO for me but it's fine doing SSGI brings down more