[Hold] Binned Lighting Technique for the HDRP (v3)

[sebastienlagarde]

Purpose of this PR

Add binned lighting (a.k.a. Z-binning) technique to the HDRP. Binned lighting replaces both fine-pruned tiled lighting (a.k.a. FPTL) and clustered lighting techniques. Binned lighting is essentially tiled+.

Short comparison:

Technique	Resolution in X&Y	Resolution in Z	Transparent geometry
Tiled lighting	High	None	Yes
FPTL	High	Perfect	No
Binned lighting	High	Some	Yes
Clustered lighting	Low	Low	Yes

Performance-wise, FPTL ≥ Binned lighting ≥ Tiled lighting.
Note that there is some overhead associated with filtering the light list during the lighting pass as well.

The work is incomplete.

What works:

• binning;
• classification;
• build dispatch indirect;
• Lit, TerrainLit, Deferred Lighting, Volumetric shaders;
• decals.

What doesn't:

• everything else. In particular, DeferredTile.shader does not work.

Next steps (in no particular order):

• fix ray tracing & contact shadows (which made liberal use of tiled lighting buffers);
• add the render graph support;
• add a single debug mode (more details on request).

Once all the compile errors are fixed and everything works and passes automated tests (including ray tracing and XR), we should perform manual regression testing and verify culling efficiency using the added debug mode.

The next step (once everything works) is to perform some testing on the consoles and optimize. Specifically, we must scalarize access to the data structure for AMD GPUs.

The final step is to remove the unused old code.

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Testing status

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Comments to reviewers

If anyone is interested, I accept offers to help (reach out to me or Sebastien).