Evaluate Activision's new ZH3 Approximation for Diffuse Lighting

[RobertBeckebans]

I chose to use store the irradiance data per lightgrid point as 32x32 RGB16F pixels. That resulted in 6 GB download data and if the player plays through the maps they even get decompressed and saved again in the .bimage files which may result in a total extra size of 12 GB.

This new technique promises to store the spherical harmonics using a quality between SH1 and SH2 with just 4 floats.

https://arisilvennoinen.github.io/

There is a also a new SIGGRAPH presentation about the latest Call of Duty lighting:

https://advances.realtimerendering.com/s2024/content/Roughton/SIGGRAPH%20Advances%202024%20-%20Hemispheres%20Presentation%20Notes.pdf

https://www.activision.com/cdn/research/HemiLighting-1.pdf