Skill: Setup Enhanced Input

Description

Configure the Enhanced Input system with Input Actions, Mapping Contexts, key mapping Modifiers, and Triggers.

Arguments

• {{arg}}: The action name to set up (e.g., Jump, Sprint, Interact, Move)

Steps

1. Create Input Action Asset: Use the create_input_action MCP tool to create /Game/Input/Actions/IA_{{arg}}:

   {
     "PackagePath": "/Game/Input/Actions",
     "ActionName": "IA_{{arg}}",
     "ValueType": "Digital"
   }
   

   (Supported ValueType options: Digital, Axis1D, Axis2D, Axis3D)

2. Add Key Mapping to Input Mapping Context:

   • If /Game/Input/IMC_Default does not exist, create it via create_input_mapping_context:

     {
       "PackagePath": "/Game/Input",
       "ContextName": "IMC_Default"
     }
     

   • Bind the target key mapping using add_input_mapping:

     {
       "ContextAsset": "/Game/Input/IMC_Default",
       "InputActionAsset": "/Game/Input/Actions/IA_{{arg}}",
       "Key": "SpaceBar"
     }
     

3. Configure Key Mapping Modifiers & Triggers: Attach key modifiers (e.g. Negate, SwizzleAxis) and trigger conditions (e.g. Pressed, Hold, Tap) using configure_input_mapping_modifiers_triggers:

   • Example 1: Axis Negation (e.g. Move Backward 'S' key):

     {
       "ContextAsset": "/Game/Input/IMC_Default",
       "InputActionAsset": "/Game/Input/Actions/IA_Move",
       "Key": "S",
       "Modifiers": [ { "Type": "Negate" } ]
     }
     

   • Example 2: 2D Vector Swizzle (e.g. Move Forward 'W' key):

     {
       "ContextAsset": "/Game/Input/IMC_Default",
       "InputActionAsset": "/Game/Input/Actions/IA_Move",
       "Key": "W",
       "Modifiers": [ { "Type": "SwizzleAxis", "Order": "YXZ" } ]
     }
     

   • Example 3: Hold Trigger (e.g. Charge Attack / Sprint Hold):

     {
       "ContextAsset": "/Game/Input/IMC_Default",
       "InputActionAsset": "/Game/Input/Actions/IA_Sprint",
       "Key": "LeftShift",
       "Triggers": [ { "Type": "Hold", "HoldTimeThreshold": 0.5, "bIsOneShot": true } ]
     }
     

4. In the character/pawn header, add:

   UPROPERTY(EditDefaultsOnly, Category="Input")
   TObjectPtr<UInputAction> {{arg}}Action;
   void Handle{{arg}}(const FInputActionValue& Value);
   

5. In the character/pawn class, override SetupPlayerInputComponent to bind the action:

   // Header
   virtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;
   
   // Source
   void AMyCharacter::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
   {
       Super::SetupPlayerInputComponent(PlayerInputComponent);
       
       if (UEnhancedInputComponent* EIC = Cast<UEnhancedInputComponent>(PlayerInputComponent))
       {
           EIC->BindAction({{arg}}Action, ETriggerEvent::Triggered, this, &AMyCharacter::Handle{{arg}});
       }
   }
   

6. Implement the handler function in C++:

   void AMyCharacter::Handle{{arg}}(const FInputActionValue& Value)
   {
       // Retrieve input value (e.g. float or Vector2D depending on configuration)
       // float AxisValue = Value.Get<float>();
   }
   

7. Blueprint Binding Alternative:

   • In a Blueprint Character graph, right-click and search for "EnhancedAction IA_{{arg}}".
   • Add the Enhanced Action IA_{{arg}} node.
   • Wire your game logic nodes to the Triggered or Started / Completed pins.

Notes

• Ensure "EnhancedInput" is added to PublicDependencyModuleNames in the project's .Build.cs file.
• Include EnhancedInput/Public/EnhancedInputComponent.h.
• The project must have the EnhancedInput plugin enabled.
• Python API Tip (UE 5.8): When mapping keys via Unreal Python, instantiate unreal.Key() with key.set_editor_property('key_name', 'Space'), construct mapping = unreal.EnhancedActionKeyMapping(), set action and key, and append mapping to imc.get_editor_property('mappings') before calling unreal.EditorAssetLibrary.save_loaded_asset(imc).