Enhancement: Dynamic blending between cubemaps when moving physics props

[lenship2]

What would this enhancement be for?

Rendering

Describe your enhancement suggestion in more detail

Currently, physics props using an envmap will use the closest cubemap available and overlay it based on whatever parameters the material has. While this is relatively fine by itself, the behavior becomes noticeably apparent when a physics prop is moved from one cubemap to another. I think an appropriate solution to this behavior would be to dynamically blend between cubemaps as a prop is moved, removing the jarring switch from one cubemap to the other.

https://github.com/user-attachments/assets/390df097-6c91-45ed-be5e-d3527b96888a

This video shows the current behavior of cubemaps on a hl2 barrel prop. This enhancement proposes that the immediate switch between cubemaps is replaced with a fading effect between them based on radius instead.