Teleport Destinations

[magicsofa]

So,

I made a part in a map where there is a lift that you can teleport to. Originally it was just going to be a "secret" lift, in which I placed a very small hole so that it would lower past the surrounding floors. I thought it was too obscure, however, and wanted the player to teleport right there - and then realized that I could use the little hole to have the teleporter's tag. Now, I'm aware in retrospect that I could have just had two actions point to the same tag, so it's really not necessary, but here is the curiosity:

I originally worried you might get stuck in the hole if the lift was not all the way down, which of course did not happen (at least in Zdoom). Instead the player just ports onto wherever the lift is, since the hole is too small to fit. So my question is; Is it built into the vanilla engine that teleporting actors will avoid being stuck in walls, at least when its possible to fix via vertical adjustment? Or, does the teleport destination thing ride the elevator up and down because it too is too big for the hole?

Just curious :P

[Gez]

Doom, at the core, is a 2D game. Things (including teleport destinations) are spawned without information about their Z-height. The engine just puts them where they have enough room to be.

[Graf Zahl]

To be precise, the z-coordinate of the teleport destination is never used. A teleport always teleports to the floor - unless you use the Final Doom EXE where you land at the same z-height as when the teleport started. (I hope I got the last part right. If not, please someone correct me who has better knowledge of the DOS executables.)

[printz]

Can the teleportation specials point to Map Spots not Teleport Destinations?

[Gez]

printz said:

Can the teleportation specials point to Map Spots not Teleport Destinations?

They can, but it's a bad idea in many cases. The teleport destionations have special coding to handle teleportation that generic map spots do not. I know there are a few ZDoom maps that were broken after the way map spots were handled had been changed (to correct another problem) because they didn't use teleport destinations as the destinations of teleporters.

I can't say I really understand why people don't want to use the right tool for the right job -- is there really a reason not to use teleport destinations for teleport destinations? To me, replacing them with map spots seems useless and futile.

[DaniJ]

What is this "Map Spot" of which you speak?

[Gez]

Something that is used for scripts, an invisible and nonsolid actor that is given a tag. It's just a way to have stuff happen at a given place. Hexen has two of them (ednums 9001 and 9013, see INFO.C line 3116 and following), and therefore ZDoom does too; but Legacy had a map spot as well, for FraggleScript (ednum 5004).

[magicsofa]

Graf Zahl said:

To be precise, the z-coordinate of the teleport destination is never used. A teleport always teleports to the floor - unless you use the Final Doom EXE where you land at the same z-height as when the teleport started. (I hope I got the last part right. If not, please someone correct me who has better knowledge of the DOS executables.)

That makes sense - once in Zdoom I tried to make a teleport pop you out mid-air just by giving the destination thing a z-height, which did not work. I believe it was, however, NOT a map spot - either way, it seems the only way to accomplish this is via scripting.

[Graf Zahl]

ZDoom has teleport destination types that are z-sensitive. But they are not available in other ports.

[Gez]

Graf Zahl said:

ZDoom has teleport destination types that are z-sensitive.

For reference, ednums 9043 and 9044.