npc_alyx

For the main article about the character, see Alyx Vance.

npc_alyx is a point entity available in Half-Life 2, Half-Life 2: Episode One, Half-Life 2: Episode Two, and Half-Life 2: Deathmatch.

Class hierarchy
CNPC_Alyx ↳CNPC_PlayerCompanion ↳CAI_PlayerAlly ↳CAI BaseActor ↳CAI_ExpresserHost ↳CAI_BaseHumanoid ↳CAI_BaseHumanoidBase ↳CAI_BaseNPC ↳CBaseCombatCharacter ↳CBaseFlex ↳CBaseAnimatingOverlay ↳CBaseAnimating ↳CBaseEntity
npc_alyx.cpp

Alyx Vance is the deuteragonist of Half-Life 2 and its episodes, serving as Gordon's companion and Eli's beloved daughter. She is considered a vital ally and therefore will regenerate health overtime. She is one of the few NPCs that have weapon holster/unholster animations and the ability to use the Alyxgun. Her original Half-Life 2 appearance features few special abilities beyond her weapon, but in Half-Life 2: Episode One and Half-Life 2: Episode Two, she's literally a completely different NPC. She has more comments, can count enemies, can protect herself when she isn't being mobbed, and can perform Dynamic interactions. Use ai_goal_follow to get Alyx to follow the player.

Note:Some keyvalues, spawnflags, effect flags, inputs, or outputs might not affect an NPC, based on the functionality and coding of the NPC.

Keyvalues

Weapons ([todo internal name (i)]) <choices>

• Alyx Gun
• Shotgun
• Nothing

PlayerCompanion:

Always transition (AlwaysTransition) <boolean> (in all games since )

This NPC will always teleport to a Player Squad Transition Point if they're not within the trigger_transition.

Prevent picking up weapons? (DontPickupWeapons) <boolean> (in all games since )

This NPC will NOT be allowed to pick up weapons they find on the ground.

Is this a vital ally? (GameEndAlly) <boolean> (in all games since )

This NPC will cause the game to end if killed.

TalkNPC:

Use Sentence (UseSentence) <string>

Sentence spoken when the NPC gets +used by a player

Un-Use Sentence (UnUseSentence) <string>

Sentence spoken NPC gets used again

Don't Use Speech Semaphore (DontUseSpeechSemaphore) <boolean>

Friendly NPCs are not allowed to speak if another friendly NPC is speaking. In some cases, we don't want speaking NPCs to prevent other NPCs from speaking (for instance, if there is a friendly NPC speaking for a long time on a monitor). To make this NPC not prevent other NPCs from talking, make it not grab the semaphore when it speaks.

BaseNPC keyvalues

CBaseCombatCharacter: Relationship (Relationship) <string> !FGD <string|targetname or classname> <string|disposition> <int|rank> Changes whether this entity likes or dislikes certain other things. Used like the ai_relationship entity, with this entity as the subject. Values for disposition are: D_HT: Hate D_FR: Fear D_LI: Like D_NU: Neutral Physics Impact Damage Scale (physdamagescale) <float> Multiplier for damage amount when this entity is hit by a physics object. With a value of 0 the entity will take no damage from physics. CAI_BaseNPC: Target Path Corner (target) <targetname> The path_corner that this NPC will move to after spawning. Squad Name (squadname) <string> NPCs that are in the same squad (i.e., have matching squad names) will share information about enemies and will take turns attacking and covering each other. Hint Group (hintgroup) <string> Hint groups are used by NPCs to restrict their hint-node searching to a subset of the map's hint nodes. Only hint nodes with matching hint group names will be considered by this NPC. Hint Limit Nav (hintlimiting) <boolean> Limits NPC to using specified hint group for navigation requests. Does not limit local navigation. Sleep State (sleepstate) <choices> Holds the NPC in stasis until specified condition. See also Wake Radius and Wake Squad. 0: None 1: Waiting for threat 2: Waiting for PVS 3: Waiting for input, ignore PVS 4: Auto PVS 5: Auto PVS after PVS Wake Radius (wakeradius) <float> Auto-wake if player comes within this distance. Wake Squad (wakesquad) <boolean> Wake all of the NPCs squadmates if the NPC is woken. Enemy Filter (enemyfilter) <targetname> Filter entity to test targets against. Ignore unseen enemies (ignoreunseenenemies) <boolean> Prefers visible enemies, regardless of distance or relationship priority. DamageFilter: Damage Filter (damagefilter) <targetname> Name of the filter_damage_type entity that controls which entities can damage us.

Flags

BaseNPC flags

Wait Till Seen : [1] Prevents this NPC from seeing (or being seen) until it enters a player's viewcone. Gag : [2] Won't make IDLE sounds until it's angry. Fall to ground (unchecked means teleport to ground) : [4] Drop Healthkit : [8] Causes this NPC to drop an item_healthvial upon dying. Efficient : [16] Don't acquire enemies or avoid obstacles Wait For Script : [128] Forces this NPC to "wait" in an idle state until it finishes playing a scripted_sequence. Long Visibility/Shoot : [256] By default, increases a NPC's sight range to 6,000 units and allows it to attack from anywhere within that distance. Fade Corpse : [512] Think outside PVS : [1024] Allows this NPC to run its regular AI outside of any player's PVS. Template NPC : [2048] Marks this NPC as a template for entities like npc_template_maker. The NPC will not spawn on its own. This is not needed for point_template. Do Alternate collision for this NPC (player avoidance) : [4096] Note:This flag is disabled in episodic for player companions, because the StartScripting input does this. Don't drop weapons : [8192] Ignore player push : [16384] (in all games since ) Entity won't give way to player.

Inputs

AllowInteraction  (in all games since )

Allow Alyx's 'hacking' AI to run.

DisallowInteraction

Disallow Alyx's 'hacking' AI.

AllowDarknessSpeech <boolean> (in all games since )

Enables or disables Alyx's darkness speech ('where are you', etc).

EnterVehicle <targetname> (in all games since )

Make Alyx enter the vehicle specified by name.

ExitVehicle  (in all games since )

Make Alyx exit the vehicle she's in.

SetReadinessLow  (in all games since )

Set readiness to calmest state (Bored)

SetReadinessMedium  (in all games since )

Set readiness to moderate (Alert)

SetReadinessHigh<  (in all games since )

Set readiness to highest. (Combat imminent)

SetReadinessPanic  (in all games since )

Set readiness to panic state (Special)

LockReadiness <float> (in all games since )

PlayerCompanion

PlayerCompanion: OutsideTransition  (in all games since ) Use this input to teleport the NPC to a hint node with the "Player Squad Transition Point" hint type. EnableAlwaysTransition  (in all games since ) DisableAlwaysTransition  (in all games since ) If enabled, this NPC will always teleport to a Player Squad Transition Point even if they're not within the trigger_transition. MakeGameEndAlly  (in all games since ) MakeRegularAlly  (in all games since ) Determines whether the game should end if this character dies. EnableWeaponPickup  (in all games since ) DisableWeaponPickup  (in all games since ) Enables/disables weapon pickup. GiveWeapon <classname> (in all games since ) Gives the NPC a weapon immediately. ClearAllOutputs  (only in ) Clears every output that this NPC has.

TalkNPC:

SpeakResponseConcept <string> (in all games since )

Speak the specified response concept immediately.

BaseNPC inputs

CAI_BaseNPC: ActivateSpeedModifier  !FGD DisableSpeedModifier  !FGD Break Smash into pieces. If this is not possible, disappear. BecomeRagdoll  (in all games since ) Remove itself and instantly become a ragdoll with zero force (just go limp). OnDeath, etc. outputs will NOT be fired. ForceInteractionWithNPC <string> <string>  (in all games since ) Force the NPC to use a dynamic interaction with another NPC. Syntax is <targetname> <dynamic interaction>. ForgetEntity <targetname> Clears out the NPC's knowledge of a named entity. UpdateEnemyMemory  (in all games since ) Update (or create) this NPC's memory of of the given entity. GagEnable GagDisable Gagged NPCs won't speak (or moan, caw, etc.) unless made to be a choreographed scene. HolsterWeapon  (in all games since ) UnholsterWeapon  (in all games since ) Force the NPC to holster or unholster their weapon. Ignored if the NPC is scripting or if the NPC doesn't use weapons. HolsterAndDestroyWeapon  (in all games since ) Same as HolsterWeapon, except the weapon is destroyed once it has been concealed. IgnoreDangerSounds <float> Ignore danger sounds for the specified number of seconds. InsideTransition  !FGD OutsideTransition  !FGD SetBodyGroup <integer> HACK: Sets this NPC's body group (from 0–n). SetEnemyFilter <string> SetHealth <integer> Set the NPC's health. SetMaxLookDistance <float> (only in ) Sets the maximum look distance for the NPC. Defaults are 2048 and 6000 for long range NPCs. SetRelationship <string|targetname or classname> <string|disposition> <int|rank> Changes whether this NPC likes or dislikes certain others. Used like the ai_relationship entity, with this NPC as the subject. Values for disposition are: D_HT: Hate D_FR: Fear D_LI: Like D_NU: Neutral SetSquad <string> Change the name of this NPC's squad. Leaving the parameter blank will remove the NPC from any existing squad. StartScripting StopScripting Enter/exit scripting state, where NPCs ignore a variety of stimulus that would make them break out of their scripts. They ignore danger sounds, ignore +Use, don't idle speak or respond to other NPCs' idle speech, and so on. Wake Wakes up the NPC if it is sleeping. CBaseCombatCharacter: KilledNPC  !FGD Tells the entity it killed something. Despite the name, this can include a player. This input will be automatically sent by the victim when they die. physdamagescale <float> Scales damage energy when this character is hit by a physics object. With a value of 0 the NPC will take no damage from physics. DamageFilter: SetDamageFilter <string> Sets the entity to use as damage filter. Pass in an empty string (no parameter) to clear the damage filter.

Outputs

OnFinishInteractWithObject

Fires when Alyx finishes interacting with an object (usually hacking it).

OnPlayerUse

Fires when a player +USEs Alyx.

BaseNPC Outputs

OnDamaged Fired when this NPC takes damage (!activator is the damage inflictor). OnDamagedByPlayer Fired when this NPC is hurt by a player (!activator is the attacker or vehicle driver [if friendly fire]). OnDamagedByPlayerSquad Fired when this NPC is hurt by a player OR by one of the player's squadmates (!activator is the attacker or vehicle driver [if friendly fire]). OnDeath Fired when this NPC is killed (!activator is the killer). OnDenyCommanderUse Fired when this NPC has refused to join the player's squad. OnForcedInteractionAborted Fired when the NPC aborts a forced interaction for some reason (target NPC died, couldn't be pathed to, etc.). OnForcedInteractionStarted Fired when the NPC starts a forced interaction. OnForcedInteractionFinished "NPCs in actbusies can no longer perform dynamic interactions." Todo: What does this mean? OnHalfHealth Fired when this NPC reaches half of its maximum health. OnHearCombat Fired when this NPC hears combat sounds. OnHearPlayer Fired when this NPC hears the player. OnHearWorld Fired when this NPC hears a sound (other than combat or the player). OnFoundEnemy <targetname> Fired when this NPC establishes line of sight to its enemy. OnLostEnemy Fired when this NPC loses its enemy. Usually due to the enemy being killed/removed, or because this NPC has selected a newer, more dangerous enemy. OnLostEnemyLOS Fired when this NPC loses line of sight to its enemy. OnFoundPlayer <targetname> Fired when this NPC establishes line of sight to its enemy, and that enemy is a player. OnLostPlayer Fired when this NPC loses its enemy, and that enemy was a player. Usually due to the enemy being killed/removed, or because this NPC has selected a newer, more dangerous enemy. OnLostPlayerLOS Fired when this NPC loses line of sight to its enemy, and that enemy is a player. OnSleep Fired when this NPC enters a sleep state. OnWake Fired when this NPC comes out of a sleep state.