game-input-and-accessibility

Game Input and Accessibility

Overview

Players use keyboards, mice, gamepads, touch screens and adaptive controllers, with different hands, eyes and ears. Code that reads KeyCode.Space directly cannot be rebound, cannot be driven by a gamepad without a second branch, and cannot be tested without a keyboard. Gameplay reads named actions; devices map to actions in one place.

Core principle: Gameplay never sees a key code. Every action is rebindable, every essential cue reaches the player through more than one sense, and motion and flashing can be turned down.

Actions, per engine

// ❌ Unity legacy, device-bound, unrebindable
if (Input.GetKeyDown(KeyCode.Space)) Jump();

// ✅ Unity Input System action (from the .inputactions asset or its generated class)
[SerializeField] InputActionReference jump;
void OnEnable()  { jump.action.performed += OnJump; jump.action.Enable(); }
void OnDisable() { jump.action.performed -= OnJump; }
void OnJump(InputAction.CallbackContext _) => _intents.Jump();

# Godot: actions from the InputMap, never physical keys in gameplay
func _unhandled_input(event: InputEvent) -> void:
    if event.is_action_pressed("jump"):
        intents.jump()

// Unreal Enhanced Input
void AHeroCharacter::SetupPlayerInputComponent(UInputComponent* Input) {
    auto* EIC = CastChecked<UEnhancedInputComponent>(Input);
    EIC->BindAction(JumpAction, ETriggerEvent::Started, this, &AHeroCharacter::OnJump);
    EIC->BindAction(MoveAction, ETriggerEvent::Triggered, this, &AHeroCharacter::OnMove);
}
// The mapping context is added through UEnhancedInputLocalPlayerSubsystem::AddMappingContext.

// Web: map KeyboardEvent.code (layout-independent position) to actions; poll gamepads each frame
const bindings: Record<string, Action> = { Space: "jump", KeyW: "up", ArrowUp: "up" };
window.addEventListener("keydown", (e) => { const a = bindings[e.code]; if (a) input.press(a); });
// in the loop: for (const pad of navigator.getGamepads()) if (pad?.buttons[0].pressed) input.press("jump");