[not a bug] monster aiming >1 portal layers

[Mordeth]

Monsters don't aim correctly at the player when there's >1 portal layer between them. If you have a stack of, say, 4 portals on top of each other and the player is in the bottom plane and a monster in the upper one, the monster's projectile will consistently miss and instead go overhead the player. This behaviour continues, until the portal layer difference is just 1.

[printz]

Trying with this map (three portals) it works. Play with Doom 2 on nightmare. The imp will easily hit you.

https://dl.dropboxusercontent.com/u/5103936/forum-posts/eternity/stacktest.wad

Did you also try on a similar setup with the same height difference but no portals? Do the projectile throwers hit you? It's a known Doom issue for monsters to miss you when the height difference and distance are too big.

[Mordeth]

I did some more testing, and with a 3 portal difference an unmodified imp most of the times hits me but sometimes overshoots. I guess it's the distance / height difference that's too much.

The map I first (really) noticed has another quirk: linedefs >4k in length. Apart from causing other issues reported earlier (such as hitscan collision being off), I guess it might also influence monster targeting.