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Recipe: Bind Ability to Input

Goal: Press a button, activate an ability.

Prerequisites: Enhanced Input plugin enabled. A character with an ASC. An ability to bind. See Input Binding for the full architecture and complete code examples.

Quick Version

There are two approaches to input binding in GAS. Pick the one that fits your project -- both are covered in detail on the Input Binding page.

InputID Tag-Based
Complexity Lower Higher
Scalability Fixed enum slots Unlimited tags
Ability task support Automatic Manual (AbilitySpecInputPressed/Released)
Works well for Fixed input layouts Dynamic ability sets, loadouts

Steps (InputID Approach)

1. Create the Input Action

  1. Content Browser > right-click > Input > Input Action
  2. Name it: IA_Attack
  3. Set Value Type to Digital (Bool)

2. Add to Input Mapping Context

  1. Open your IMC (e.g., IMC_Default)
  2. Add a mapping: Input Action = IA_Attack, Key = Left Mouse Button

3. Define an Input Enum (C++)

If you haven't already, create an EAbilityInput enum with entries for each bindable slot (PrimaryAttack, Dodge, Jump, etc.). See Input Binding -- Step 1 for the full enum.

4. Map InputAction to InputID

Add an entry to your character's AbilityInputBindings array (in Class Defaults or C++):

Input Action InputID
IA_Attack PrimaryAttack

5. Wire SetupPlayerInputComponent (C++)

Your character class needs a SetupPlayerInputComponent override that loops through the bindings and calls AbilityLocalInputPressed / AbilityLocalInputReleased on the ASC. See Input Binding -- Steps 3-4 for the complete code.

6. Grant the Ability with InputID

When granting the ability, pass the InputID to the FGameplayAbilitySpec constructor:

FGameplayAbilitySpec Spec(AbilityClass, 1, static_cast<int32>(EAbilityInput::PrimaryAttack), this);
AbilitySystemComponent->GiveAbility(Spec);

7. Test

  1. PIE
  2. Press the bound key
  3. Verify the ability activates (showdebug abilitysystem)
  4. Release the key -- verify held abilities respond to release
  5. Check Stamina/cooldown if the ability has cost/cooldown effects

Checklist

  • Input Action created (IA_)
  • Input Action added to Input Mapping Context with a key
  • Input enum defined with an entry for this ability
  • InputAction mapped to InputID (character array or data asset)
  • SetupPlayerInputComponent wires the binding loop (C++)
  • Ability granted with the correct InputID
  • Tested in PIE

Using Tag-Based Routing Instead?

Follow the same first two steps (create IA, add to IMC), then:

  • Create an InputTag (e.g., InputTag.Attack)
  • Map the IA to the tag in your character's input config
  • Grant the ability with the tag added to DynamicSpecSourceTags
  • Call AbilitySpecInputPressed/Released in your routing callbacks -- without this, WaitInputRelease breaks silently

See Input Binding -- Tag-Based Routing for the complete walkthrough and The Critical Detail for why the AbilitySpecInputPressed call matters.