Use this skill when implementing player input with Unreal Engine's Enhanced Input system. Also use when the user mentions 'Enhanced Input', 'input', 'input action', 'InputAction', 'mapping context', 'InputMappingContext', 'input binding', 'key binding', 'input trigger', 'input modifier', 'gamepad',

UE Enhanced Input System You are an expert in Unreal Engine's Enhanced Input system. Context Check Read .agents/ue project context.md before proceeding. Confirm: EnhancedInput plugin is listed as enabled Target platforms (affects which modifiers are needed per platform) Whether CommonUI is in use (it manages input mode switching automatically) Whether the project still uses legacy input (migration may be needed) Information Gathering Ask the developer: what actions are needed and their value types (Bool/Axis1D/Axis2D/Axis3D), which platforms, any complex input requirements (hold to charge, double tap, combos, chord shortcuts), and whether multiple input modes are required (gameplay vs UI vs vehicle). Enhanced Input Setup Plugin and Module .uproject : add { "Name": "EnhancedInput", "Enabled": true } to Plugins. Build.cs : add "EnhancedInput" to PublicDependencyModuleNames . DefaultInput.ini : UInputAction Asset UInputAction : UDataAsset . Create one per logical player action. Key properties (from InputAction.h ): UInputMappingContext Asset UInputMappingContext : UDataAsset . Maps physical keys to actions. DefaultKeyMappings.Mappings — TArray<FEnhancedActionKeyMapping of key to action entries MappingProfileOverrides — per profile key overrides for player remapping support RegistrationTrackingMode : Untracked (default, first Remove wins) or CountRegistrations (IMC stays until Remove called N times, safe when multiple systems share it) Binding Actions in C++ SetupPlayerInputComponent Callback Signatures BindAction accepts four delegate signatures: Storing and removing a binding: Trigger Events (ETriggerEvent) Bitmask enum from InputTriggers.h : Event State Transition Use for Started None Ongoing/Triggered First frame of input; press once actions Triggered Triggered, Triggered Triggered Every active frame; continuous movement Ongoing Ongoing Ongoing Held but not yet triggered (charge build up) Canceled Ongoing None Released before trigger threshold Completed Triggered None Input released after triggering; stop continuous actions Note: Completed does not fire if any trigger on the same action reports Ongoing that frame. Built in Triggers Full parameter listings in references/input action reference.md . Class Name Behavior UInputTriggerDown Down Every frame input exceeds threshold (implicit default) UInputTriggerPressed Pressed Once on first actuation; holding does not repeat UInputTriggerReleased Released Once when input drops below threshold after actuation UInputTriggerHold Hold After HoldTimeThreshold s; bIsOneShot=false repeats every frame UInputTriggerHoldAndRelease Hold And Release On release after holding HoldTimeThreshold s UInputTriggerTap Tap Released within TapReleaseTimeThreshold s UInputTriggerRepeatedTap Repeated Tap N taps within RepeatDelay ( NumberOfTapsWhichTriggerRepeat=2 for double tap) UInputTriggerPulse Pulse Repeatedly at Interval s while held; optional TriggerLimit UInputTriggerChordAction Chorded Action Only fires while ChordAction is active (Implicit type; auto blocks solo key) UInputTriggerCombo Combo (Beta) All ComboActions completed in order within TimeToPressKey windows Trigger type rules for multi trigger evaluation: Explicit (default, at least one must fire), Implicit (all must fire), Blocker (blocks everything if active). Built in Modifiers Applied in array order. Mapping level modifiers run before action level modifiers. Class Name Effect UInputModifierDeadZone Dead Zone Zero input below LowerThreshold ; remap to 1 at UpperThreshold . Types: Axial, Radial, UnscaledRadial UInputModifierScalar Scalar Multiply per axis by FVector Scalar UInputModifierScaleByDeltaTime Scale By Delta Time Multiply by frame DeltaTime UInputModifierNegate Negate Invert selected axes ( bX , bY , bZ ) UInputModifierSwizzleAxis Swizzle Input Axis Values Reorder axes; YXZ (default) swaps X/Y — maps 1D key onto Y of Axis2D action UInputModifierSmooth Smooth Rolling average over recent samples UInputModifierSmoothDelta Smooth Delta Smoothed normalized delta; configurable interpolation ( Lerp , Interp To , ease curves) UInputModifierResponseCurveExponential Response Curve Exponential sign(x) x ^CurveExponent per axis UInputModifierResponseCurveUser Response Curve User Defined Separate UCurveFloat per axis UInputModifierFOVScaling FOV Scaling Scale by camera FOV for consistent angular speed across zoom levels UInputModifierToWorldSpace To World Space 2D axis world space (up/down = world X, left/right = world Y) WASD Axis2D recipe ( AccumulationBehavior = Cumulative ): W : SwizzleAxis(YXZ) → Y=+1 S : SwizzleAxis(YXZ) + Negate(bY) → Y= 1 D : none → X=+1 A : Negate(bX) → X= 1 Gamepad stick : DeadZone(Radial, LowerThreshold=0.2) per stick mapping. Mouse look : [Scalar(0.4,0.4,1), Smooth, FOVScaling] per mapping. Mapping Context Priority When bConsumeInput = true on a UInputAction (the default), a higher priority context that maps the same physical key will consume it, blocking all lower priority bindings to that key from firing. This is intentional: use priority layering and bConsumeInput together to prevent input conflicts between modes (e.g., a vehicle context consuming Spacebar so the character's Jump action never fires while driving). Split Screen / Multiple Local Players In split screen, each local player has their own UEnhancedInputLocalPlayerSubsystem . Mapping contexts are per player — adding a context to one player's subsystem does not affect others. To target a specific player, retrieve their subsystem directly from their ULocalPlayer : Custom Triggers Subclass UInputTrigger ; override UpdateState Implementation returning ETriggerState::None / Ongoing / Triggered : UInputTriggerTimedBase provides HeldDuration and CalculateHeldDuration for time based triggers. Custom Modifiers Subclass UInputModifier ; override ModifyRaw Implementation : Common Mistakes Mapping context not added : Add via subsystem in BeginPlay /after Possess , not in SetupPlayerInputComponent (called earlier on some paths). Legacy binding on UEnhancedInputComponent : BindAction(FName,...) and BindAxis are = delete . Compile error. Set DefaultInputComponentClass in DefaultInput.ini . Triggered for a button press : Triggered fires every active frame. Use Started for press once, Completed for release. Completed not firing with Ongoing : If any trigger reports Ongoing that frame, Completed is suppressed. Use separate actions for clean press/release events. No dead zone on gamepad sticks : Sticks produce non zero resting values. Always add DeadZone(Radial) per stick mapping. Missing SwizzleAxis for WASD to 2D : Keyboard produces 1D. Without SwizzleAxis(YXZ) on W/S, forward/backward stays on X and is ignored by Axis2D forward movement. Replicating input actions : Input is client local. Replicate results (movement, ability activation), not trigger events. MapKey/UnmapKey at runtime for rebinding : These are editor/config screen helpers. Use subsystem player mappable key APIs or swap contexts instead. Wrong trigger type for intent : Using Down when Hold is needed, or Triggered when Started is needed. Match trigger type to the interaction pattern: Started for single press, Triggered for continuous, Hold for delayed activation. Legacy Input Migration To migrate from the legacy input system to Enhanced Input: search for InputComponent BindAction and InputComponent BindAxis calls and replace each with UEnhancedInputComponent::BindAction . Create a UInputAction data asset for every old action name, choosing the appropriate ValueType (Boolean for buttons, Axis1D for single axis, Axis2D for stick/WASD). Create a UInputMappingContext asset and add key mappings corresponding to the old DefaultInput.ini ActionMappings / AxisMappings entries. Set DefaultInputComponentClass in DefaultInput.ini and enable the EnhancedInput plugin. UI Input Mode Without CommonUI, manage input modes manually via APlayerController::SetInputMode() : CommonUI automates input routing through UCommonActivatableWidget stacks and eliminates most manual SetInputMode calls — see ue ui umg slate . Related Skills ue gameplay framework — PlayerController input lifecycle, Possess / UnPossess , SetupPlayerInputComponent ue ui umg slate — SetInputMode(FInputModeUIOnly()) / FInputModeGameAndUI() , cursor visibility, CommonUI UCommonActivatableWidget stacks ue gameplay abilities — binding Enhanced Input actions to GAS ability activation via input ID tags

ue-input-system