Nodes: Add DenoiseNode.

[Mugen87]

Related issue: -

Description

This PR adds DenoiseNode which is a port of PoissonDenoiseShader. It can be used to improve the result of AO by smoothing out the noisy appearance of the default occlusion.

I'll integrate it in the AO demo with a configurable GUI when #28863 is done. GTAOPass must return the raw AO so DenoiseNode can be chained after it (but before the blend).

For comparison:

With Denoise:

Without Denoise:

[Mugen87]

This is the second pass where getViewPosition() is used. Now the time seems right to add a utility function somewhere as previously discussed in #28844.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
683.5 kB (169.2 kB)	683.5 kB (169.2 kB)	+0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
460.7 kB (111.1 kB)	460.7 kB (111.1 kB)	+0 B

[Mugen87]

Sidenote: When creating an instance of DenoiseNode, it is the responsibility of the caller to provide a noise texture. Otherwise I would have to add SimplexNoise to the core which seems inappropriate. When integrating DenoiseNode in webgpu_postprocessing_ao I'll add a generateNoise() function.