ID:2834073
 
Resolved
The black tiles for SEE_PIXELS and SEE_BLACKNESS were on the wrong plane and at the wrong position.
BYOND Version:515.1595
Operating System:Linux
Web Browser:Chrome 107.0.0.0
Applies to:Dream Seeker
Status: Resolved (515.1596)

This issue has been resolved.
Don't remember whether or not I've had someone test this on Windows, but it would be a really weird thing to be the first Linux-exclusive bug I've ever encountered outside browser controls.

Descriptive Problem Summary:
The black overlays rendered by SEE_BLACKNESS do not render in the correct locations or on the correct plane. First, they render on plane -1 instead of 0. Second, they render offset one tile southeast, or sometimes not at all except all the way south of where they should, or something. I haven't made a minimal test project and I'm not sure exactly which observations are caused directly by the bug and which are caused by its interactions with the rest of the game.
I hope the whole bug isn't caused by some weird interaction. It's definitely new to 515, but since I haven't made a minimal test case, I'm not 100% sure if it's this simple.

Numbered Steps to Reproduce Problem:
1. Have SEE_BLACKNESS in a world with all turfs on a negative plane (< -2 just to be safe)
2. Stand directly to the east or west of a single opaque object/turf

Expected Results:
A single line of obscured turfs extending from the side of the opaque blockage opposite you.

Actual Results:
That, but also a line of black turfs one tile south of the obscured turfs.
Using plane -1 PLANE_MASTERs will tell you that the black turfs to the south are still rendered, but just covered by the SEE_BLACKNESS overlay.

Did the problem NOT occur in any earlier versions? If so, what was the last version that worked? (Visit http://www.byond.com/download/build to download old versions for testing.)
New to 515. I believe all versions of 515, but I'm not 100% sure about the earliest couple.

Workarounds:
Probably some nonsense with PLANE_MASTERs and render_target, but who cares
Can you post a small test project for this so I can be sure we're on the same page?
Luckily, it was as simple to reproduce as I had hoped.
https://gofile.io/d/xTyX8C
The black turfs do look incorrect, but I'm not seeing other stuff you talked about. You mentioned plane masters but there are none in use in your test case, so it seems the test case is incomplete.
The PLANE_MASTERs aren't necessary to the case. I was just suggesting, for example, using one to make the SEE_BLACKNESS overlays partially transparent to show that the turfs under them are still rendered. Turns out the overlays are mouse transparent by default, though, so you can just hover over the black squares to get similar information.
The one detail that's not explicitly shown in the test case is that the overlays are on plane -1 instead of 0. I guess I can add something to show that if necessary, but I would expect the cause of that one to be pretty clear internally?
I'm just looking to be sure we're on the same page with the issue and I'm able to verify via the test case what you're seeing. The test case really isn't enough to do that.
I should have just not mentioned PLANE_MASTER, but here you go. https://gofile.io/d/7zzobJ
The plane master actually helps a lot because it really clarifies the problem. Looks like I'm seeing black squares where turfs didn't get drawn, while also seeing the SEE_BLACKNESS tiles drawn over them in the wrong position. So effectively two separate issues are happening here between the plane problem and the offset. (I don't think a new report is needed though.) I'll get in a fix for this.
Lummox JR resolved issue with message:
The black tiles for SEE_PIXELS and SEE_BLACKNESS were on the wrong plane and at the wrong position.