SlipperyFeet

Based on game build 722832 | Last updated: 2026-04-27

Overview

SlipperyFeet tracks slip accumulation for entities moving across icy or slippery terrain. It monitors nearby slipperyfeettarget entities (ice patches, frozen surfaces) and nonslipgritpool entities (grit that reduces slip), accumulating slip based on movement speed and decaying over time. When slip exceeds a threshold, the component pushes a feetslipped event to trigger slip animations or effects. The component uses a source modifier system to track multiple slip sources simultaneously.

Usage example

local inst = CreateEntity()
inst:AddComponent("slipperyfeet")

-- Start a slip source (e.g., standing on ice)
inst.components.slipperyfeet:StartSlipperySource("ice_entity")

-- Check current slip level
local slip = inst.components.slipperyfeet.slippiness
local threshold = inst.components.slipperyfeet.threshold

-- Stop slip source when leaving ice
inst.components.slipperyfeet:StopSlipperySource("ice_entity")

Dependencies & tags

External dependencies:

• util/sourcemodifierlist -- manages multiple slip source modifiers with boolean values

Components used:

• slipperyfeettarget -- checked on nearby entities to determine slip zones; calls GetSlipperyRate() and IsSlipperyAtPosition()
• nonslipgritpool -- checked on nearby entities to detect anti-slip grit zones; calls IsGritAtPosition()
• nonslipgrituser -- checked on self entity; calls DoDelta() when grit is active but not at position
• physics -- calls GetMotorSpeed() to calculate slip accumulation rate
• transform -- calls GetWorldPosition() for spatial queries
• stategraph -- checks state tags "running", "spinning", "noslip" via inst.sg

Tags:

• slipperyfeettarget -- searched for in radius to detect slip zones
• nonslipgritpool -- searched for in radius to detect grit zones

Properties

Property	Type	Default Value	Description
inst	entity	---	The owning entity instance.
_sources	SourceModifierList	---	Tracks active slip sources with boolean modifiers.
_updating	table	{}	Tracks which update loops are active by reason key.
onicetile	boolean	false	Whether the entity is currently on an ocean ice tile.
started	boolean	false	Whether the component has started listening for state changes.
threshold	number	TUNING.WILSON_RUN_SPEED * 4	Slip value at which feetslipped event is pushed.
decay_accel	number	TUNING.WILSON_RUN_SPEED * 2	Acceleration rate for slip decay speed.
decay_spd	number	0	Current decay speed used in DoDecay() calculations.
slippiness	number	0	Current accumulated slip value.
inittask	task	nil	Delayed initialization task handle.
checknearbyentitytask	task	nil	Slow update check task handle for nearby entity detection.

Main functions

OnInit(inst)

• Description: Initializes the component after a short delay. Sets up ocean ice tile event listener and checks initial position for ice. Schedules slow update check if not on ocean ice.
• Parameters: inst -- the owning entity instance
• Returns: nil
• Error states: Errors if inst.components.slipperyfeet is nil when accessing self via inst.components.slipperyfeet — no nil guard present.

OnOceanIce(inst, on_ocean_ice)

• Description: Callback for ocean ice tile changes. Starts slip source when entering ocean ice, stops when leaving. Manages checkice update loop based on tile state.
• Parameters:
  • inst -- the owning entity instance
  • on_ocean_ice -- boolean indicating if entity is on ocean ice tile
• Returns: nil
• Error states: Errors if inst.components.slipperyfeet is nil when accessing self — no nil guard present.

SlowUpdateCheck(inst)

• Description: Periodic check for nearby slippery entities. Reschedules itself if no entities found, or starts faster checkiceentity update loop when entities are detected.
• Parameters: inst -- the owning entity instance
• Returns: nil
• Error states: Errors if inst.components.slipperyfeet is nil when accessing self — no nil guard present.

OnLoad()

• Description: Restore hook called when entity loads from save. Cancels pending init task and runs OnInit() immediately if task exists.
• Parameters: None
• Returns: nil
• Error states: None

OnRemoveFromEntity()

• Description: Cleanup hook called when component is removed from entity. Cancels all pending tasks, removes event listeners, and stops all internal update loops.
• Parameters: None
• Returns: nil
• Error states: None

StartSlipperySource(src, key)

• Description: Activates a slip source by setting a modifier in _sources. Calls Start_Internal() to begin state tracking if this is the first source.
• Parameters:
  • src -- string identifier for the slip source (e.g., "ice_entity", "ocean_ice")
  • key -- optional key for distinguishing multiple sources of same type
• Returns: nil
• Error states: None

StopSlipperySource(src, key)

• Description: Removes a slip source modifier. Calls Stop_Internal() if no sources remain active.
• Parameters:
  • src -- string identifier for the slip source
  • key -- optional key matching the source started
• Returns: nil
• Error states: None

GetSlipperyAndNearbyEnts()

• Description: Searches within SLIPPERY_CHECK_RADIUS for entities with slipperyfeettarget component. Returns the first entity that is slippery at the current position, plus the first nearby entity found.
• Parameters: None
• Returns: Two values: slippery entity (or nil), first nearby entity (or nil)
• Error states: Errors if self.inst.Transform is nil when calling GetWorldPosition() — no nil guard present.

Start_Internal()

• Description: Begins component state tracking. Sets started flag, registers newstate event listener, and calls OnNewState() to initialize accumulation state based on current stategraph tags.
• Parameters: None
• Returns: nil
• Error states: Errors if inst.sg is nil when calling HasAnyStateTag() or HasStateTag() — no nil guard present.

Stop_Internal()

• Description: Stops component state tracking. Clears started flag, removes newstate event listener, and disables accumulation via SetAccumulating_Internal(false).
• Parameters: None
• Returns: nil
• Error states: None

SetAccumulating_Internal(accumulating)

• Description: Controls whether slip is accumulating based on movement. Starts or stops the accumulate update loop. Resets decay_spd to 0 when toggling state.
• Parameters: accumulating -- boolean to enable or disable accumulation
• Returns: nil
• Error states: None

SetCurrent(val)

• Description: Sets the current slip value directly. Starts decay update loop if value is positive. Pushes feetslipped event if value meets or exceeds threshold.
• Parameters: val -- number representing slip value
• Returns: nil
• Error states: None

DoDelta(delta)

• Description: Applies a delta to current slip value. Positive deltas reset decay_spd to 0. Negative deltas are clamped to minimum 0 via math.max().
• Parameters: delta -- number to add to current slippiness (can be negative)
• Returns: nil
• Error states: None

CalcAccumulatingSpeed()

• Description: Calculates slip accumulation rate based on entity movement speed. Applies curved formula (speed * speed) / TUNING.WILSON_RUN_SPEED. Reduces speed for spinning state using TUNING.WX78_SPIN_RUNSPEED_MULT and TUNING.WX78_SPIN_SLIPPERY.
• Parameters: None
• Returns: number representing accumulation speed
• Error states: Errors if inst.Physics is nil when calling GetMotorSpeed() — no nil guard present. Errors if inst.sg is nil when calling HasStateTag() — no nil guard present.

StartUpdating_Internal(reason)

• Description: Registers an update loop by reason key. Starts component updating via StartUpdatingComponent() if this is the first active update. Cancels checknearbyentitytask when starting.
• Parameters: reason -- string key identifying the update loop (e.g., "accumulate", "decay", "checkice")
• Returns: nil
• Error states: Errors if self.inst is nil when calling StartUpdatingComponent() — no nil guard present.

StopUpdating_Internal(reason)

• Description: Unregisters an update loop by reason key. Stops component updating via StopUpdatingComponent() if no updates remain. Reschedules checknearbyentitytask when all updates stop.
• Parameters: reason -- string key identifying the update loop to stop
• Returns: nil
• Error states: None — includes nil guard checking self.inst.components.slipperyfeet ~= nil before rescheduling task.

DoDecay(dt)

• Description: Applies slip decay over time. Uses average speed calculation: (speed + decay_spd) / 2. Increases decay_spd by decay_accel * dt each call. Calls DoDelta() with negative value.
• Parameters: dt -- delta time in seconds
• Returns: nil
• Error states: None

OnUpdate(dt)

• Description: Main update loop called every frame when component is updating. Checks ocean ice tile status, nearby ice entities, and grit pools. Accumulates slip based on movement speed or decays existing slip. Applies random variation (0.7 + 0.3 * math.random()) to accumulation rate.
• Parameters: dt -- delta time in seconds
• Returns: nil
• Error states: Errors if TheWorld.Map is nil when calling IsOceanTileAtPoint() or IsVisualGroundAtPoint() — no nil guard present. Errors if self.inst.Transform is nil when calling GetWorldPosition() — no nil guard present.

LongUpdate(dt)

• Description: Less frequent update loop for when entity is idle. Accumulates slip for one frame only if accumulating, or continues decay if slip exists. Uses FRAMES constant instead of dt for accumulation.
• Parameters: dt -- delta time in seconds
• Returns: nil
• Error states: None

GetDebugString()

• Description: Returns formatted debug string showing current slip, threshold, and accumulation/decay rate. Format: slippiness/threshold (+/-rate/s).
• Parameters: None
• Returns: string for debug display
• Error states: None

Events & listeners

• Listens to: on_OCEAN_ICE_tile -- triggers OnOceanIce() when entity enters/exits ocean ice tiles
• Listens to: newstate -- triggers OnNewState() to update accumulation state based on stategraph tags
• Pushes: feetslipped -- fired when slippiness reaches or exceeds threshold