While looking at something else, I noticed that newsym() was checking for pool and lava by examining the terrain type directly rather than using the pool and lava checks, so it would never show a gas cloud at a closed drawbridge (the spot in front of the portcullis). Level's terrain at a closed drawbridge spot is DRAWBRIDGE_UP; need to look at drawbridgemask field to figure out whether the accessible terrain at that spot is moat or lava.
78 KiB
78 KiB