Blocking monster vision

[Jimmy]

Is there a way of blocking monsters' line of sight in Boom format maps? I thought for the longest time that it was done with self-referencing sectors, but this turned out to be something only ZDoom did as the result of a bug which has since been addressed. :(

Apparently the way to do it is linedef action 242 - transfer heights, though I'm really not sure how to implement a monster vision blocking line in, say, a window or a doorway. How would I set it up?

[4mer]

You can modify the reject to prevent monsters seeing the player. I think this is what was done on MAP01 of Alien Vendetta.

[traversd]

Make your doorway/window and have it or a middle section of it 0 height (floor upto ceiling or vice versa). Apply a dummy sectors height via 242 that is what the doorway or window should look like in game. Then at points where you want to allow player access/the monsters to "see" the player you can lower/raise the middle section as needed. Because the height transfer is always in effect and doesnt change there should be no real visual changes apparent to the player.

[darkreaver]

I`ve been planning to have a look into this stuff myself but never got to it.

Just wondering: won`t raising/lowering a sector to the floor/ceiling, leaving the upper/lower without textures work in vanilla(or non-GL/non-ZDoom`ish ports)? Maybe it just leaves a big ugly HOM?

I mean like an invisible box which will contain ie a cyberdemon, just staning there, loitering, unaware of your precense.

Maybe this isnt what Jimmy meant at all though :P

Would have tried myself, but I`m away from my comp atm

[traversd]

In a boom compatible engine when linedef type 242 is used the transferred dummy sectors properties are what is drawn to the player and the actual sector properties are not. So unless the dummy sector also goes to the roof/floor with no lower/upper tex then HOM should not be an issue except in some specific cases from what I can see.

Here is an example wad that uses linedef 242 and then linedef type 5 to instantly lower the floor in the 'real' sector and allow the monsters to see the player.

http://t.underworldgamers.com/wp-content/uploads/xferh_test1.zip

[Jimmy]

Thanks a bunch, traversd. :D That seems to work fine for me. :)