Preventing fog from moving further away at edges of the viewport

[Mugen87]

Fog was once implemented like this: distance fog by greggman · Pull Request #14633 · mrdoob/three.js · GitHub

But this change had to be reverted because of issues on certain mobile devices: Reverted distance fog. See #14736 and #14786. · mrdoob/three.js@63f6d20 · GitHub

After a year another PR tried to implement the feature: Fix fog to use view distance by supereggbert · Pull Request #17316 · mrdoob/three.js · GitHub