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trigger_look

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class hierarchy
CTriggerLook defined in triggers.cpp
CTriggerOnce
CTriggerMultiple
CBaseTrigger
CBaseToggle
CBaseEntity

trigger_look is a brush entity available in all Source Source games. It is used to trigger something when the player looks at something.

It fires OnTrigger when the player looks at a target entity for the given amount of time while within the trigger volume. If the player leaves the trigger or looks away from the target entity, the clock resets.

If the Use Velocity instead of facing spawnflag is checked, the trigger uses the player's velocity instead of the player's view, so it determines whenever the player is moving toward the target entity; this is useful for triggering when players are driving a vehicle at something.


In code, it is represented by theCTriggerLookclass, defined in thetriggers.cppfile.
Note.pngNote:Only designed for single-player games.
Note.pngNote:As long as the player is touching the entity, facing the direction of the target entity will trigger it even if the target is not directly visible to the player (i.e. if there is world geometry in the way).
Icon-Bug.pngBug:In Portal Portal, looking at the target entity through a portal will not fire the OnTrigger output.
Icon-Bug.pngBug:If multiple entities in the map have the same name as the target entity, then OnTrigger may fire inconsistently. The output may either be delayed or never fire at all. These effects seem to worsen the more identically named entities there are in the map.

Keyvalues

Look Target (target) <targetname>
The name of the entity to be looked at.
LookTime <string>
The time, in seconds, that the player must look the target before firing the output. Resets if player leaves trigger, or looks outside the Field of View threshold.
Icon-Bug.pngBug:A value of 1.0 will prevent the entity from triggering at all, even if the player is looking directly at target.
FieldOfView <string>
How close the player has to be looking at the target. 1.0 = straight ahead\n 0.0 = +/- 90 degrees\n -1.0 = all directions).
Use LOS <boolean> (only in Mapbase)
Use LOS calculations
Timeout <float>
The time, in seconds, to wait after player enters the trigger before firing the OnTimeout output, 0 = never.

BaseTrigger:

Filter Name (filtername) <filter>
A filter entity to test potential activators against.
Start Disabled (StartDisabled) <boolean>
Stay dormant until activated (with theEnableinput).


Flags

  •  [128] : Fire Once
  •  [256] : Use Velocity instead of facing

BaseTrigger:
  •  [1] : Clients (Survivors, Special Infected, Tanks Left 4 Dead series)
  •  [2] : NPCs (Common Infected, Witches Left 4 Dead series)
  •  [8] : Physics Objects
  •  [16] : Only player ally NPCs
  •  [32] : Only clients in vehicles
  •  [64] : Everything (not including physics debris)
  •  [512] : Only clients *not* in vehicles
  •  [1024] : Physics debris
  •  [2048] : Only NPCs in vehicles (respects player ally flag)
  •  [4096] : Disallow Bots

Inputs


BaseTrigger:
Toggle
Toggles this trigger between enabled and disabled states.
Enable
Enable trigger
Disable
Disable trigger
TouchTest  (in all games since Source 2007)
Triggers either the OnTouching or OnNotTouching outputs for whether anything is touching this entity.
StartTouch  (in all games since Source 2007) !FGD
Behave as if the !caller entity had just entered the trigger volume. Accepts non-physical entities.
EndTouch  (in all games since Source 2007) !FGD
Behave as if !caller had just exited the trigger volume.
DisableAndEndTouch  (only in Source 2013 Multiplayer(Team Fortress 2))
Disables this trigger and calls EndTouch on all currently-touching entities.


Outputs

OnTimeout
Fired after the timeout interval expires if the player never looked at the target.

BaseTrigger:

OnStartTouch
Fired when a valid entity starts touching this trigger. !activator is whatever touches the trigger.
OnStartTouchAll
Fired when a valid entity starts touching this trigger, and no other entities are touching it. If there are any other entities touching the trigger when a new one begins to touch, only OnStartTouch will fire.
OnEndTouch
Fired when a valid entity stops touching this trigger.
Warning.pngWarning:This includes entities which are deleted while inside the trigger. In this case !activator will be invalid.
OnEndTouchAll
Fired when all valid entities stop touching this trigger.
OnTouching  (in all games since Source 2007)
Fired if something is currently touching this trigger when TouchTest is fired.
OnNotTouching  (in all games since Source 2007)
Fired if nothing is currently touching this trigger when TouchTest is fired.

See also

About the Trigger_Look