trigger_look

Class hierarchy
CTriggerLook ↳CTriggerOnce ↳CTriggerMultiple ↳CBaseTrigger ↳CBaseToggle ↳CBaseEntity
triggers.cpp

trigger_look is a brush entity available in all 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.

Note:Only designed for single-player games.

Note: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).

Bug:In Portal, looking at the target entity through a portal will not fire the OnTrigger output.  [todo tested in ?]

Bug: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.  [todo tested in ?]

Keyvalues

Name (targetname) <string>

The name that other entities refer to this entity by, via Inputs/Outputs or other keyvalues (e.g. parentname or target).
Also displayed in Hammer's 2D views and Entity Report.

See also:  Generic Keyvalues, Inputs and Outputs available to all entities

Look Target (target) <targetname>

The name of the entity to be looked at.

LookTime (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.

Bug:A value of 1.0 will prevent the entity from triggering at all, even if the player is looking directly at target.  [todo tested in ?]

FieldOfView (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).

Timeout (Timeout) <float>

The time, in seconds, to wait after player enters the trigger before firing the OnTimeout output, 0 = never.

Use LOS (UseLOS) <boolean> (only in )

Use LOS calculations

BaseTrigger

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

Flags

Fire Once : [128]

Use Velocity instead of facing : [256]

BaseTrigger

Everything (not including physics debris) : [64] Clients (Survivors, Special Infected, Tanks ) : [1] Only clients in vehicles : [32] Only clients *not* in vehicles : [512] Disallow Bots (removed since ) : [4096] NPCs (Common Infected, Witches ) : [2] Only player ally NPCs : [16] Only NPCs in vehicles (respects player ally flag) : [2048] Physics Objects (not including physics debris) : [8] Physics debris (include also physics debris) : [1024] Pushables (Passes entities with classname func_pushable) : [4]  Deprecated. Equivalent to using Everything + filter_activator_class that filters func_pushable.

Inputs

BaseTrigger

Toggle Toggles this trigger between enabled and disabled states. Enable Enable trigger Disable Disable trigger TouchTest  (in all games since ) Triggers either the OnTouching or OnNotTouching outputs for whether anything is touching this entity. Bug:Sleeping prop_physics will never fire "OnTouching". Also applies to entities using prop_physics as base.  (tested in: ) StartTouch  (in all games since ) !FGD Behave as if the !caller entity had just entered the trigger volume. Accepts non-physical entities. EndTouch  (in all games since ) !FGD Behave as if !caller had just exited the trigger volume. DisableAndEndTouch  (only in ) 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

Bug:Spamming crouch jumps in a trigger can randomly fire OnStartTouch/OnEndTouch. Confirm:Is it a Multiplayer issue only?   [todo tested in ?] OnStartTouch !activator = entity that caused this output !caller = this entity Fired when a valid entity starts touching this trigger. OnStartTouchAll !activator = entity that caused this output !caller = this entity 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 !activator = entity that caused this output !caller = this entity Fired when a valid entity stops touching this trigger. Note:Will also fire for entities touching it when trigger is disabled via Disable input Warning:This includes entities which are deleted while inside the trigger. In this case !activator will be invalid. Warning:OnEndTouch can fire before OnStartTouch under certain circumstances[How?] where both are fired on the same tick and each have the same delay. Fix:Add a slight delay to OnEndTouch. OnEndTouchAll !activator = entity that caused this output !caller = this entity Fired when all valid entities stop touching this trigger. OnTouching  (in all games since ) !activator = !caller = this entity Fired if something is currently touching this trigger when TouchTest is fired. OnNotTouching  (in all games since ) !activator = !caller = this entity Fired if nothing is currently touching this trigger when TouchTest is fired.

See also

About the Trigger_Look