Some objects can be seen through opacity.
Using sigma engine for most of the heavy lifting. I'm not sure if anything there would be causing it.
The doors and arches only are visible after crossing them.
The mobs, after moving them? I'm not sure, honestly.
Numbered Steps to Reproduce Problem:
Code Snippet (if applicable) to Reproduce Problem:
obj
dungeon_door
icon='dungeon_door.dmi'
var
open=0
opacity=1
density=1
icon_state="h"
vertical
name="dungeon door"
icon_state="v"
proc
open()
if(!open)
open=1
opacity=0
density=0
icon_state="open"
close()
if(open)
open=0
opacity=1
density=1
icon_state=initial(icon_state)
Cross(atom/movable/a)
open()
return 1
Uncrossed(a)
close()
arch
icon='arch.dmi'
pixel_x=-16
pixel_y=16
layer=10
Crossed(a)
if(ismob(a))
alpha=200
Uncrossed(a)
if(ismob(a))
alpha=255
When does the problem NOT occur?
when doors are left untouched and when mobs remain in their initial location
The core problem is that your arches live on the wrong tile. Set them to TILE_BOUND, and offset them in such a way as their bounding box does not overlap the surrounding tiles.