One problem with TFC's teleporters is that you don't know where they lead to. There's a Metamod plugin running on Drippy's 2fort which works great, however it's private AFAIK. I decided to write my own. It sorta works, however it has some flaws.
To get hold of the necessary info, I'm tracking players as they teleport, and make a correlation between teleporters this way. Disadvantage with this method is that when the teleporters are originally built, there is no arrow yet as no one has used the teleporter yet.
I made two versions. The first one draws arrows from the entrance all the way to the exit, across the whole map if necessary. These teleporter routes are only visible by the corresponding team and by spectators.
The 2nd version is the standard approach, that is drawing a single arrow above the tele entrance.
Difficulty with AMXX is that it doesn't give access to certain private entity data of buildings, such as owner of a teleporter and whether it's entrance or exit.
EDIT: What I meant was that reading
this thread I was under the impression that dealing with entity pointers inside the private entity data (e.g. owner of a building) wasn't possible without using a modified TFCX module which is available in the linked thread, but probably outdated. Perhaps this was actually the case at the time of writing (2007). However with the info from Arkshine I now managed to access such data, but haven't integrated this into the plugin yet.
v1
v2
There was a bug in the original release, the entity numbers can on some maps be higher than the entity limit (512), e.g. coolfort2. I ran an entity test plugin and it said the maximum allowed entities were 1565. I raised the maximum number to 2048, hopefully this will do!