Glitchy 3D MidTex Collision on Spawn

[NeuralStunner]

The demonstration map is built with two tall sectors and platforms built from walkable MidTextures.

- The real floor is at 0. The "fake floor" is at the 128 mark.
- Players are teleported over the walkways by a wide margin (to Z height 160) when they spawn. However, I fall to the real floor instantly, as if I were teleported just below the walkway.
- The Imp and Candelabra on this red side also fall through.
- The blue side has invisible bridge things at Z 112, and 16 units thick. This would supposedly have its top at the 128 mark. However they spawn just below the walkway as well.
- Players added on the blue side (add a few bots to see), and the Imp, won't fall through, because they're spawned over the bridge thing.
- The Cadelabra on that side will fall through. (Possibly related to the flag?)

[Project Shadowcat]

And how WIDE are these bridge things?

[NeuralStunner]

Radius 128, so 2 was enough to span that entire half of the room.

I also discovered that the tiniest bit of horizontal velocity on the actor's part will cause the walkways to be detected. However, bots tend to slide helpless and get "stuck" when this happens. So I have to shove them up as well, and then use Thing_Stop.

[Graf Zahl]

That problem can all be attributed to one thing: When Doom spawns stuff it doesn't do a proper z check - and that has to be preserved at all costs because so many maps depend on it to hide stuff in holes. As a result much stuff related to z-heights can't be done properly because it would interfere with this.

It also doesn't help that vertical and horizontal movement are completely separated in the code.

[NeuralStunner]

Okay, I'll stick with the push functions in the script. (I don't seem to be having as much trouble with monsters now, for some reason...)

[Graf Zahl]

I never said I won't fix it. It's just not that simple, unfortunately. And your test map with its automatic teleporter doesn't help much. A general advice for demo maps: Never *EVER* use automatic actions to demonstrate the problem. If I want to debug I need to

a) be able to manually trigger the problem action
a) be able to run the problem action more than once
c) not have too many actors in the map. In your case the candelabras don't make it easier to debug.

For such case it's best to provide separate maps for each problem.

[Gez]

That problem can all be attributed to one thing: When Doom spawns stuff it doesn't do a proper z check - and that has to be preserved at all costs because so many maps depend on it to hide stuff in holes.

Can't it be optioned with a MAPINFO setting?

[Graf Zahl]

Sure.

Anyway, fixed the teleporter. The teleport code was missing one small but crucial bit of coordinate adjustment and checked the teleport destination with the telporting actor's source z-position - which obviously did not work.

I'll see if I can do something about the candelabras.

[Graf Zahl]

Fixed the candelabra, too. Seems the original check for being above a 3D midtexture was incomplete for newly spawned things.

[NeuralStunner]

Ah, neat! Also I'll try remember to divide things up next time.

And hopefully this is the last of the 3D MidTex bugs.