[Runtime Feature]: Hybrid Shift Mapping in Remix

What is the context of the feature/improvement?

This feature already exists in one of the ReSTIR (ReSTIR PT). HSM helps with
*Reducing Noises

*Better handling glossy reflection/refraction

*Handling caustics without ghosting

Paper: https://graphics.cs.utah.edu/research/projects/gris/sig22_GRIS.pdf
Video link: https://youtu.be/fvgIku4uZKU?si=2j3D5GklZNivZjmz

Please describe the feature/improvement?

This is most important when it comes to ReSTIR FG. The problem is that if any of the surfaces has low roughness, there is simply no caustics, as the developer himself answered:

As a solution to the problem, he pointed out this feature, which is present in ReSTIR PT. However, upon learning later, it turned out that this feature cannot be used, since it is used mainly in “interactive renderers”. Having asked again how to implement this, he said that this feature could be made “temporal”:

What would be your solution? (optional)

Implement this in Remix when ReSTIR GI replaces ReSTIR FG. Make this feature to be turned on and off for players at their , since, as was said by SirKero (developer of ReSTIR FG), this feature involves tracing more rays.

Version

0.5.4

Media

No response

Start by reading the linked HSM paper and the existing ReSTIR PT implementation, then determine how the feature could fit the planned ReSTIR GI replacement for ReSTIR FG. Done would mean a temporal hybrid shift mapping implementation in Remix with a player-facing toggle, while preserving the stated benefits for low-roughness surfaces and caustics.