Crushing ceiling



Crushing ceilings appear in Doom, Heretic, Hexen, and Strife.

A crushing ceiling cycles between its starting height and eight units above its sector's floor. It damages any player or monster that happens to be in between. In Doom, barrels explode when crushed, corpses become pools of blood, and weapons and ammunition dropped by monsters disappear. (Ghost monsters and their corpses are unaffected.) Crushing ceilings also destroy projectiles, whether fired by the player or by monsters.

Crushing ceilings are set in motion by specific linedef types. Once started, they remain running for the remainder of the level, even if temporarily suspended with a "stop" linedef type. Some or all other actions in the sector may be locked out thereafter (depending on the source port used for play). A stopped crusher can be restarted, but not changed, with any crusher "start" linedef.

A crusher can be either slow or fast. A slow crusher does more damage, simply by being applied longer. When a slow crusher is moving down and hits a player or monster, it slows down even more, by a factor of eight. This persists until it reaches the bottom of its stroke and starts upward again. Fast crushers do not slow down.

A crusher does 10 hit points of damage every 4 tics, equivalent to 87.5 points per second. The total amount of damage per cycle will vary depending on the height of the object being crushed. In vanilla Doom, given the height of the player (56), a fast crusher will deal 60 hit points of damage before returning to a height at which the player can escape. A slow crusher will inflict 940 points of damage.

Crushing ceilings are listed as part of the "dangerous Doom environment" in the printed game booklets.

Certain types of rising floors can also inflict crush damage: see Varieties of floors.

The Boom source port defines additional varieties of crushers: see Crusher ceilings.

In Hexen, a crusher ceiling can inflict any amount of damage based on a parameter to the linedef action or script, still at a fixed rate of once every 4 tics. Unlike Doom, the crusher stops if there's something in the way, allowing those trapped to escape or to even allow a player to slip under the ceiling while it crushes.

Source

 * Boom source code:
 * Hexen source code: