Difference between revisions of "Noclip bug"

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(W1 actions are *not* used up if the line activation is entirely skipped. W1 activations are used up when a W1 action affects a busy sector and fails to activate, which is an entirely separate bug.)
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The '''noclip bug''' can occur whenever the player crosses a [[Tags|tagged]] [[linedef]] (e.g. a teleporter, a trap which opens or closes a door, or a trigger for a lift). Every so often, the action of a tag simply fails. [[Wallrunning]] is one way in which this bug can be triggered, as the player may move fast enough to completely skip clipping checks against the linedefs in question.
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The '''noclip bug''' can occur whenever the player crosses a [[Tags|tagged]] [[linedef]] (e.g. a teleporter, a trap which opens or closes a door, or a trigger for a lift) while moving at a very high speed (such as [[straferunning]], [[rocket jumping]], or through [[wallrunning]]). The player moves fast enough that the game engine never detects the line trigger as having been crossed.
  
This anomaly has occasionally been exploited in [[speedrun]]s as a time-saving tactic (i.e. by recording many abortive [[demo]]s of the same level until the bug occurs in the desired location).
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This anomaly has occasionally been exploited in [[speedrun]]s as a time-saving tactic (i.e. by recording many abortive [[demo]]s of the same level until the bug occurs in the desired location). The bug is more likely to affect orthogonal linedefs; mappers can reduce the chances of the bug happening by using non-orthogonal trigger lines, and doubling important triggers as a precaution.
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This should not be confused with a separate bug which causes W1 linedefs to fail activation due to their target sector being busy when crossed. See [[Single-use line actions can fail]] for information on that phenomenon.
  
 
==External links==
 
==External links==
*[http://www.doom2.net/~compet-n/index.cgi?action=nostalg&page=e3m1 Compet-N page about the "E3M1 shotgun trick"]
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* [http://www.doom2.net/compet-n/index.cgi?action=nostalg&page=e3m1 Compet-N page about the "E3M1 shotgun trick"]
*[ftp://competn.doom2.net:8002/pub/compet-n/tnt/speed/ev31-030.zip A demo from the Compet-N database illustrating a more typical encounter with the noclip bug] (see the file BLOOPER1.LMP)
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* {{competnftp|tnt/speed/ev31-030.zip|A demo from the Compet-N database illustrating a more typical encounter with the noclip bug}} (See the file BLOOPER1.LMP)
  
 
[[Category:Errors and bugs]]
 
[[Category:Errors and bugs]]
 
[[Category:Doom engine]]
 
[[Category:Doom engine]]

Revision as of 11:26, 27 March 2020

The noclip bug can occur whenever the player crosses a tagged linedef (e.g. a teleporter, a trap which opens or closes a door, or a trigger for a lift) while moving at a very high speed (such as straferunning, rocket jumping, or through wallrunning). The player moves fast enough that the game engine never detects the line trigger as having been crossed.

This anomaly has occasionally been exploited in speedruns as a time-saving tactic (i.e. by recording many abortive demos of the same level until the bug occurs in the desired location). The bug is more likely to affect orthogonal linedefs; mappers can reduce the chances of the bug happening by using non-orthogonal trigger lines, and doubling important triggers as a precaution.

This should not be confused with a separate bug which causes W1 linedefs to fail activation due to their target sector being busy when crossed. See Single-use line actions can fail for information on that phenomenon.

External links