Space shows up as white/green outside of the station z-level

[MonkestationIssueBot]

Reporting client info: Client Information:
BYOND:515.1647
Key:michirecroom

Round ID:

8988

Testmerges:

• Tgui Player & Options panel - Please Review Me
• Lead Poisoning Station: A bizarro station for use on monke
• Spess.tv
• Update Medical cyborgs.
• Pipebombs to replace IEDs
• Even more various fixes
• Paramedic Gps
• Heliostation from fulp
• The Derelict / KS13 Engineering Update
• [BOUNTY] Port Skyrat's feature to be able to play the character we want in a ghost role (using character loadouts
• Can no longer pee into containers forever
• Renaming viro subtypes and fixing disease severities and maintence panels (AKA a bunch of fixes for viro at this point.)
• The shot gun
• Brings back NIF hiveminds, this time they are fully functional and not broken
• [DNM] inline some replay marking procs
• Fix some stuff related to antag token config loading
• Adding more tramstation areas/bar touchups
• Moves boxstation's engineering mail destination to the foyer

Reproduction:

See title. Not sure what's going on here.

Basically, the outer edges of the z-level show up as a long rectangle of white. This white starts at the point where you would exit the z-level, and ends only at the black edges (which are presumably rendered by BYOND itself).

Exiting the z-level by going through the white causes you to be surrounded by green - as if the entire space background has just been replaced with a green texture. Turning on my helmet light reveals it to be the same white texture - just colored green, due to how space is rendered.

It's similar to what happens if you Observe a player - space is just completely white and doesn't render properly.

I have NO idea what's going on here, nor what caused it.

I'm running the game in widescreen mode; the game is not in fullscreen; changing the Multi-Z Detail or Parallax options doesn't appear to help; and in case it matters, my screen resolution is 1920x1080. (The map, round ID, and BYOND version are attached above, thanks to the bug reporter.)

I hope any of this information is useful in tracking down whatever's happening.

[LikeLakers2]

Here's a bunch of screenshots of the issue occurring:

Screenshots