env_headcrabcanister is a point entity available in the Half-Life 2 series. The canister is a mortar shell containing a payload of headcrabs. The mortar shell inflicts damage within a radius of where it lands and releases headcrabs after impact. Inputs and keyvalues offer control over impact damage and when the headcrabs are released, among other options.
For an example of their use, see the shantytown in
In code, it is represented by class
CEnvHeadcrabCanister, defined in
|ConVar/Command||Parameters or default value||Descriptor||Effect|
|Arbitrary decimal (float)||Crash effect's shake amplitude. Though the default is 50, the shake amplitude can only go up to 16.|
|Hammer units||Radius the player must be within for the screen shake effect to occur. Shake amplitude is gradually decreased the farther away from the explosion the player is.|
|Hammer units||As above, but when in a vehicle.|
- 1: No Impact Sound
- 2: No Launch Sound
- 4096: Start Impacted
- 8192: Land at initial position
- 16384: Wait for input to open
- 32768: Wait for input to spawn headcrabs
- 65536: No smoke
- 131072: No shake
- 262144: Remove on impact
- 524288: No impact effects
- Which headcrab to Spawn? (HeadcrabType)
- Select which headcrab will jump out the canister.
- 0: Normal headcrabs
- 1: Fast Headcrabs
- 2: Poison Headcrabs
- Headcrab count (HeadcrabCount)
- Number of headcrabs to spawn on impact.
- Min Refire time (MinSkyboxRefireTime)
- Min number of seconds before the canister is refired. This will only work for canisters placed in the skybox.
- Max Refire time (MaxSkyboxRefireTime)
- Max number of seconds before the canister is refired. This will only work for canisters placed in the skybox.
- Canister count (SkyboxCannisterCount)
- Number of canisters to produce and fire across the skybox. The target should be positioned inside the skybox. 0 means fire continuously, forever.
- Impact damage (Damage)
- Max damage the canister applies on impact.
- Impact damage Radius (DamageRadius)
- Max radius of the impact damage for the canister.
- Smoke duration (SmokeLifetime)
- Duration that the canister smokes. -1 means always smoke.
- Launch Position Name (LaunchPositionName)
- If the canister should launch to its origin from another point within the world, this should specify an
info_targetat the launch origin.
- Flight Speed (FlightSpeed)
- Speed to fly through the air.
- Flight Time (FlightTime)
- Time to fly through the air in seconds.
- Starting Height (StartingHeight)
- Relative height from the landing position at which the canister should be launched. Positive values mean launch it above the impact point, negative values mean launch it below.
- World Model (model)
- The model this entity should appear as. 128-character limit.
- Skin (skin or ModelSkin )
- Some models have multiple skins. This value selects from the index, starting with 0.
- Collisions (solid)
- Method of collision for this entity.
- Body Group (body or SetBodyGroup)
- Sets the the active $bodygroup.
- Hitbox Set (hitboxset)
- Sets the $hboxset to use.
- Sequence (sequence)
- Default animation sequence for the model to be playing after spawning.
- Playback Rate (playbackrate)
- A multiplier of the framerate at which animations are played, negative values are accepted. Default is 1.0
- Cycle (cycle)
- The current frame of the currently playing animation, on a range from 0-1.
- Lighting Origin (LightingOrigin)
- Select an entity (not
info_lighting!) from which to sample lighting instead of the entity's origin.
- Lighting Origin Offset (LightingOriginHack)
info_lighting_relativefrom which to sample lighting instead of the entity's origin. Not in .
- Damage Filter Name (damagefilter)
- When this entity receives damage, it will filter by this entity.
- Start Fade Distance (fademindist)
- Distance at which the entity starts fading. If <0, the entity will disappear instantly when end fade is hit. The value will scale appropriately if the entity is in a 3D Skybox.
- End Fade Distance (fademaxdist)
- Distance at which the entity ends fading. If <0, the entity won't disappear at all. The value will scale appropriately if the entity is in a 3D Skybox.
- Fade Scale (fadescale)
- If specified in the
worldspawn, or if the engine is running below DirectX 8, entities will fade out even if the fade distances above aren't specified. This value gives more control over when this happens: numbers smaller than 1 cause the entity to fade out at further distances, and greater than 1 cause it to fade out at closer distances. Using 0 turns off the forced fade altogether. See also
- Render Mode (rendermode)
- Set a non-standard rendering mode on this entity.
- Render FX / Transparency (0 - 255) (renderamt)
- Transparency amount, requires a Render Mode other than Normal. 0 is invisible, 255 is fully visible.
- Render Color (R G B) (rendercolor)
- Color tint.
- Render FX (renderfx)
- Preset pattern of appearance effects.
<float>(New with Half-Life 2: Episode Two / Source 2007) !FGD
- Classname (classname)
- The classname defines the type of entity. Classnames can be changed using
AddOutput, which will influence how the engine deals with the entity in certain circumstances.
- Name (targetname)
- The name that other entities refer to this entity by.
- Global Entity Name (globalname)
- Name by which this entity is linked to another entity in a different map. When the player transitions to a new map, entities in the new map with globalnames matching entities in the previous map will have the previous map's state copied over their state.
- Parent (parentname)
- Specifies a movement parent. An entity will maintain its initial offset from its parent. An attachment point can be added to the end of the name, separated by a comma. Every entity can be parented, even point entities. Entities which are parented will be forced to transition to the next map, such as from a
trigger_transition. Some entities which aren't intended to be parented may not function correctly.
phys_constraintcan be used as a workaround to parenting.
- Origin (X Y Z) (origin)
- The position of this entity's center in the world. Rotating entities typically rotate around their origin.
- Pitch Yaw Roll (X Y Z) (angles)
- This entity's orientation in the world. Pitch is rotation around the Y axis, yaw is the rotation around the Z axis, roll is the rotation around the X axis.Note:This works on brush entities, although Hammer doesn't show the new angles.
- Flags (spawnflags)
- Toggles features of an entity, its specific number is determined by the combination of flags added.
- Response Contexts (ResponseContext)
- Pre-defined response system contexts for this entity. Format is
key:value,key:value,.... Contexts may be filtered.
- Effects (effects)
- Combination of effect flags to use.
- Local Time (ltime)
- The local time of the entity, independent of the global clock. Used mainly for physics calculations.
- Next Think (nextthink)
- Amount of time before the entity thinks again.
- Hammer ID (hammerid)
- The entity's Hammer ID. Mainly used by plugins and debugging commands, such as
ent_keyvalue. Can be manually assigned with the "hammerid" or "id" keyvalue. Entities spawned at run-time are not assigned any Hammer ID.
- Fires the canister.
- Opens the canister (must be called after the
OnImpactedoutput is fired).
- Spawns headcrabs (must be called after the
OnImpactedoutput is fired and after
OpenCanisteris triggered, if the Wait for Input to open' flag is checked).)
- Causes the smoke effect to stop.
- Selects a skin from the model's index, starting with 0.
- Sets the the active $bodygroup.
- Makes the entity catch on fire indefinitely.
- Makes the entity catch on fire for a given amount of time.
- Makes the entity catch on fire with a given number of hitbox fire particles. Does not function correctly in onward.
- Makes the entity catch on fire with a given scale for hitbox fire particles. Does not function correctly in onward.
- Kills the entity and creates a client-side ragdoll from the model. Input is only passed if the model contains $collisionjoints, for other models phys_convert can be used instead.
- Sets the entity's lighting origin to use this entity's position.
- Offsets the entity's lighting origin by their distance from an
- Sets distance at which the entity starts fading. If <0, the entity will disappear instantly when end fade is hit. The value will scale appropriately if the entity is in a 3D Skybox.
- Sets distance at which the entity ends fading. If <0, the entity won't disappear at all. The value will scale appropriately if the entity is in a 3D Skybox.
- Only available for . Multiplies the size of the model. Does not alter the physics collisions in most cases, however. Negative values are accepted. Takes two values separated by a space. The first is the target model scale. The second value is the number of seconds the change in scale will be spread over.
modelscalekeyvalue can be AddOutputed as a workaround for other games with this input missing.
Warning: Negative or extremely high values can cause crashes!
- Sets the entity's transparency to a number from 0 (invisible) to 255 (fully visible). Requires the entity to have its Render Mode (rendermode) set to a number other than
- Swaps the rendering order of the entity. Used to attempt to fix sorting problems when rendering, for example an object rendering in front of translucent materials.
- Sets an RGB color for the entity.
- Sets a filter for this entity for when it receives damage.
- Allows the entity to be pushed by damage done to it (usually force amount correlates with the damage done).
- Prevents the entity from being pushed by damage done to it.
- Allows the entity to draw a render target shadow.
- Prevents the entity from drawing a render target shadow.
- Removes this entity and any entities parented to it from the world.
- Functions the same as
Kill, although this entity and any entities parented to it are killed on the same frame.
- Move with this entity. See Entity Hierarchy (parenting).
- Change this entity to attach to a specific attachment point on its parent. The entity will teleport so that the position of its root bone matches that of the attachment. Entities must be parented before being sent this input.
- As above, but without teleporting. The entity retains its position relative to the attachment at the time of the input being received.
- Removes this entity from the the movement hierarchy, leaving it free to move independently.
- Evaluates a keyvalue/output on this entity.
<output name> <targetname>:<inputname>:<parameter>:<delay>:<max times to fire, -1 means infinite>
- Fire the
OnUseroutputs; see User Inputs and Outputs.
- Same as a player invoking +use; may not do anything. Can also be invoked by creating an output that does not specify an input.
This input is not included in Valve's FGDs.
- Dispatches a special effect from the entity's origin. Removed and replaced entirely by the particle system since .
- Dispatches a response to the entity. See Response and Concept.
- Adds to the entity's list of response contexts. Format is
- Remove a context from this entity's list. The name should match the key of an existing context.
- Removes all contexts from this entity's list.
- Fired when the canister is launched. This output automatically puts the targetname of the canister into the parameter box for inputs, if the mapper does not override the parameter with something else.
- Fires when canister hits the ground.
- Fires when canister has finished opening.
- Fired when the entity catches fire, such as from an
- These outputs each fire in response to the firing of the like-numbered
FireUser4Input; see User Inputs and Outputs.