unity-input-correctness

Input System (New) -- Correctness Patterns

Prerequisite skills: unity-input (Input System API, actions, bindings, PlayerInput component)

These patterns target the most common Input System bugs: wrong reading method for the action type, mixing old/new APIs, losing rebindings, and mishandling multiplayer device assignment.

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PATTERN: Reading Input -- triggered vs IsPressed vs WasPressedThisFrame

WHEN: Reading button/action state at runtime

WRONG (Claude default):

// Using .triggered for continuous input (only fires once per press)
if (fireAction.triggered)
    rb.AddForce(Vector3.forward * force); // Only fires one frame, not while held

// Using .IsPressed() for one-shot actions (fires every frame while held)
if (jumpAction.IsPressed())
    Jump(); // Jumps every frame the button is held!

RIGHT:

// One-shot actions (jump, interact, fire single bullet):
if (jumpAction.WasPressedThisFrame())  // True for exactly ONE frame
    Jump();

// Or use .triggered (same as WasPressedThisFrame for Button actions with default interaction)
if (jumpAction.triggered)
    Jump();

// Continuous actions (sprint, aim, hold to charge):
if (sprintAction.IsPressed())  // True every frame while held
    moveSpeed = sprintSpeed;

// Value reading (stick, mouse delta):
Vector2 moveInput = moveAction.ReadValue<Vector2>();  // Continuous value

GOTCHA: .triggered respects Interactions (Hold, Tap, etc.) -- it fires when the interaction completes. .WasPressedThisFrame() fires on raw press regardless of interactions. .IsPressed() returns true every frame while actuated above the press threshold. For Button type actions without interactions, .triggered == .WasPressedThisFrame(). For Value type actions, .triggered fires when the value changes from zero to non-zero.

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PATTERN: Action Map Switching

WHEN: Switching between action maps (e.g., Gameplay -> UI -> Vehicle)

WRONG (Claude default):

// Forgetting that SwitchCurrentActionMap disables the previous map
playerInput.SwitchCurrentActionMap("UI");
// All "Gameplay" actions are now DISABLED -- callbacks won't fire
// If you cached Gameplay actions, they silently stop working