Bug #2012

[Doom] Boom bug in Memento Mori II

Added by vermil about 9 years ago. Updated about 7 years ago.

Vanilla emulation
Target version:
Start date:
% Done:




Memento Mori II Map 25 suffers a well known game breaking bug in Boom, due to changed behaviour in Boom versus Vanilla.

Dday's Boom support has progressed far enough that it has now implemented the changed Boom behaviour in question and hence suffers this bug (when previously, it obviously didn't, due to lack of Boom support).

Other Boom supporting port's have dealt with the issue through optional and/or forced compatibility options when running the map. Dday doesn't yet feature a compatibility option for dealing with it however.

Related issues

Related to Feature #1552: Tag 667 Compatibility OptionNew2012-02-11

Related to Feature #1768: Boom compatibilityProgressed2004-02-08


#1 Updated by sonicdoommario about 9 years ago

Hm, Tag 667 in Doomsday has this same issue too, right?

Map07 of Alien Vendetta cannot be completed without cheating in Doomsday, as the bridge to the exit raises too high after all Arachnotrons are killed. Doomsday uses Boom's method of raising a floor by its shortest texture.

If a compatibility option is implemented it needs to also affect Tag 667, as opposed to just the linedef action for raising by the shortest texture.

I do have a feature request in called "Tag 667 Compatibility Option" (#1552)

#2 Updated by skyjake about 9 years ago

  • Tags changed from Boom, Vanilla, emulation to Boom, Doom, Mod
  • Category set to Vanilla emulation

#3 Updated by skyjake about 9 years ago

  • Description updated (diff)

#4 Updated by vermil about 9 years ago

Indeed, tag667 is another trigger type that uses the shortest texture; all line and sector triggers that use the shortest texture (I believe the line types are 30 and 96 and the sector types are 667) are affected by this change Boom made to Vanilla Doom's behaviour.

One compatibility option could probably handle them all.

#5 Updated by skyjake about 9 years ago

#6 Updated by sonicdoommario about 9 years ago

That reminds me of this bug:

In Map17 of Doom II, there is a switch that rises from the ground after walking over a line (with action 30). In the bug report, it mentions that it rises too high. It was fixed and now it raises to the correct height.

Looking at that MM2 teleporter in Map25, they basically function the same. They are both affected by line action 30 and they should both rise by 64 due to not having a back lower texture (and not having any lower texture smaller than 64), but only the switch in Doom II Map17 does so.

What makes them different? If Doomsday is applying the correct behavior to Doom II Map17, why does it not do it in MM2 Map25?

#7 Updated by vermil about 9 years ago

My completely untested theory is that the Dday is possibly completely ignoring part's of a linedef that have no texture (which are internally converted to AASHITTY (Doom2 and 64 units high) or AASTINKY (Doom1 and 72 units high) by Doom) on either side, when selecting a texture to base off.

Vanilla Doom however doesn't appear to ignore part's of a linedef that have no texture on either side when selecting a texture to base off.

#8 Updated by skyjake about 7 years ago

  • Target version set to Modding

#9 Updated by skyjake over 4 years ago

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