Descent 1 bosses could always teleport, but were only placed in large
areas where free teleporting was always permitted.
Descent 2 boss 1 was placed in a confined segment and not permitted to
teleport out of it until it was opened. This was implemented by a
two-part change relative to Descent 1 rules:
- Descent 1 bosses were always permitted to teleport to any teleport
destination segment. Descent 2 bosses were only permitted to teleport
if the player was visible or the boss had recently been hit.
- When computing the permitted list of teleport destination segments,
Descent 1 used directly connected accessible segments, then stopped.
Descent 2 started with this rule, but if the list had at most 1 entry,
then it would assume this is the confined boss and recompute the list
with the first wall ignored. This recomputed list allowed the boss to
teleport to any segment in the larger arena outside its starting
segment.
After D2X-Rebirth support for emulating Descent 1 bosses was enhanced in
28bd4c1650, Descent 1 bosses gained the ability to teleport out of a
confining cube early, but only in D2X-Rebirth when emulating Descent 1.
In D1X-Rebirth, when a boss is placed in a confining cube, it can always
teleport, but only to that confining cube. In D2X-Rebirth, Descent 1
bosses retain the always-teleport rule of Descent 1, but gained the
Descent 2 rule for expanding its search to the surrounding arena. It
should only use the expanded search when it also abides by the Descent 2
restriction not to teleport before the first wall is opened. It did not
abide by that rule. This commit adds that restriction for Descent 1
bosses.
Reported-by: ef314159 <https://github.com/dxx-rebirth/dxx-rebirth/issues/348>
Fixes: 28bd4c1650 ("Enable D1 boss behavior in d2x build. So we get correct boss behavior when emulating D1, and 3rd party mn2s can include D1 bosses.")
8291391b7f