Unexpected behavior with portals and swimmable 3D floors

[boris]

GZDoom doesn't seem to recognize swimmable 3D floors if the player sticks their head through a portal that has a swimmable 3D floors. Since it's a bit hard to describe in words here's an image:



This has two effects:

Player does not drown if the head is in the upper part of the portal
Physics are wonky. When passing from the upper part into the lower part the player suddenly drops. The player can't just use the jump button to swim up through the portal, but just wobbles up and down, just like when pressing the jump button at a normal water surface.

Here's a video of the behavior:



In the first part you can see the sudden drop. In the second part the wobbling when jumping. And for fun you can lastly see that the player if perfectly fine (i.e. not drowning) when standing on the platform, with the head sticking through the portal.

Example WAD attached.

[Graf Zahl]

Welcome to the wonderful world of Doom physics. As you noticed, proper behavior for portals inside swimmable water has never been implemented. That's mainly because this stuff is no natural part of the engine but rather tacked on.