The FLOATBOB bug!

So, spending a bunch of time inside my house which I usually don't do but, y'know COVID19 B.S...

Anyhow, thought I'd get some editing done on my neglected deathmatch map project. I remember never figuring out how weapons and other items would float in another deathmatch WAD file I used to play the hell out of: The Last Strike Deathmatch 2004. I think I finally found it in what's called a DeHackED patch. What I was most interested in having float were the health potions as I always thought that looked cool as hell, especially on water! So, I found the line in the dehacked is:

   Thing 46 (Health Potion)
   Bits = 1 + FLOATBOB

And sure enough, the little blue bottles float in my maps now too. Except... what's going on here?! Why are my bottles sinking below the floor or flat texture?

I'm actually doing my editing in Doom Builder on an old Windows XP machine. But, in general, I live in Xubuntu 18.04LTS these days. On the XP box, I've got the testing engine set to the machine's local copy of Zandronum 2.1.2. On my Xubuntu machine, I have a newer version of Zandronum, 3.0. But the floatbob bug appears on the newer version! So I got to thinking, maybe there's a difference between the Zandronum engines between Windows and Linux versions...

I proceeded to do some testing. The results are even more peculiar! These screenshots are not from my upcoming work. Rather, I went back to MAP02 of The Last Strike Deathmatch 2004 (TLSD2004.WAD).


Here's everything hunky-dorey on Zandronum 2.1.2 for Windows

and here the bottles duck underground in Zandronum 3.0 for Linux

How about GZDoom? Not right in version 1.7.0 for Windows!

Nor is GZDoom 4.3.3 for Linux displaying correctly...

Seems this old Vavoom engine version 1.33 for Windows has issue too

Zdoom 2.50 for Windows displays correctly!

Same for version ZDoom 2.71 for Windows!!

Even version 2.8.1 of Zdoom for Linux is full of love!

Just for giggles, how about ZDaemon 1.08.08b ~ yep, great!

ZDaemon 1.10 beta 2 also awesome sauce...

Including this here because it says what version
of ZDoom, this version of GZDoom is based upon.

With this issue not being uniform across platforms nor necessarily chronologically, I really don't know where the bug was originally introduced. But I might have to forgo using this little dehacked trick in my upcoming release...

UPDATE:

All the above was submitted for bugtracking with Zandronum forums. And...
I got a response from Sosleepy:

"Play with Adjust Sprite Clipping in Display Options -> OpenGL Options -> Preferences; this only happens in OpenGL Renderer, not Software Renderer. GZDoom devs are likely aware of this issue, they probably don't think it is a bug."

My final determination to proceed despite bug:

True that! I had to turn off the OpenGL and switch to Software Renderer. In Adjust Sprite Clipping, options are Never, Smart, Smarter and Always. Well, dorky potion bottles in all four cases. Thanks! It's not a critical part of my WAD file so I think I'm going to keep the floatbob and if peeps don't like that behavior under OpenGL, they can switch to software renderer like me. So there, nyah!

Robotron INDUSTRIES