Clamp Volumetric Fog Length property to prevent rendering issues

[Calinou]

This creates visual artifacts similar to what's seen in #78500.

A length of 0 units doesn't make sense anyway.

[Saul2022]

cool also it would be cool to also clamp density or have a warning to avoid some issues that causes black and white square on the screen.

[Calinou]

cool also it would be cool to also clamp density or have a warning to avoid some issues that causes black and white square on the screen.

I didn't encounter similar issues with high density, even if I set Density to 200 while having Length set to 0.01. Could you link to an issue with Density specifically?

[akien-mga]

Thanks!

[Saul2022]

I didn't encounter similar issues with high density, even if I set Density to 200 while having Length set to 0.01. Could you link to an issue with Density specifically?

After testing some bit i was not able to reproduce that white and black combining low density with 0 lenght, and the black screen is fixed by this pr, so i guess it more or less fixed, sorry for my confussion.

[YuriSizov]

Cherry-picked for 4.1.2.