Implement AMD FidelityFX Brixelizer GI in the Vulkan renderer

[mahdisml]

Describe the project you are working on

3D horror game

Describe the problem or limitation you are having in your project

Dynamic GI

Describe the feature / enhancement and how it helps to overcome the problem or limitation

AMD FidelityFX Brixelizer + Brixelizer GI features the following:

Denoised indirect diffuse and indirect specular outputs
Implemented in compute without hardware-accelerated ray-tracing
Optional modes to output at lower than native resolutions
Native DirectX® 12 and Vulkan® SDK backend implementation libraries
Fully dynamic global illumination with multiple bounces

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

https://gpuopen.com/learn/getting-the-most-out-of-fidelityfx-brixelizer/
https://gpuopen.com/fidelityfx-brixelizer/

If this enhancement will not be used often, can it be worked around with a few lines of script?

idk

Is there a reason why this should be core and not an add-on in the asset library?

HDDAGI vs SDFGI vs Brixelizer GI
It's a complicated issue :) I have no expertise in this field

[Calinou]

Moving to discussion, as there is no concrete technical implementation provided.

Note that I don't expect Brixelizer to be useful in Godot, since HDDAGI is nearing completion and will be finished for a future 4.x release. There isn't much that is missing in HDDAGI, so I would be surprised if it was scrapped and replaced with a different solution entirely.

I expect future GI efforts to be more focused on raytracing (such as GI-1.1) once HDDAGI is working well. These techniques can provide higher visual quality without the limitations of SDF-based approaches, such as slow (re)generation times which can be the source of traversal stutter. I'd say this is 2025+ territory either way, at which point support for raytracing will start to become more widespread.