Write custom processors

You can write custom processors to use with bindings, actions and controls in your Project. Custom processors are available in the UI and code in the same way as the built-in processors.

To create a custom processor:

1. Add a processor class and method
2. Register the new processor to the Input System
3. Customize the Editor UI for the new processor, if necessary.

Add a processor class and method

1. Add a class derived from InputProcessor<TValue>, and implement the Process method:

public class MyValueShiftProcessor : InputProcessor<float>
{
    [Tooltip("Number to add to incoming values.")]
    public float valueShift = 0;

    public override float Process(float value, InputControl control)
    {
        return value + valueShift;
    }
}

Important

Processors must be stateless, because they are not part of the input state that the Input System keeps. For this reason, you can't store local states in a processor if the processor changes based on the input value.

Register the new processor to the Input System

Register the new processor to the Input System. Call InputSystem.RegisterProcessor in your initialization code. You can do this locally within the Processor class:

#if UNITY_EDITOR
[InitializeOnLoad]
#endif
public class MyValueShiftProcessor : InputProcessor<float>
{
    #if UNITY_EDITOR
    static MyValueShiftProcessor()
    {
        Initialize();
    }
    #endif

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
    static void Initialize()
    {
        InputSystem.RegisterProcessor<MyValueShiftProcessor>();
    }

    //...
}

Your new Processor is now available in the in the Input Actions Editor and you can also add it in code like this:

var action = new InputAction(processors: "myvalueshift(valueShift=2.3)");

Customize the Editor UI

To customize the UI for editing your Processor, create a custom InputParameterEditor class for it:

// No registration is necessary for an InputParameterEditor.
// The system automatically finds subclasses based on the
// <..> type parameter.
#if UNITY_EDITOR
public class MyValueShiftProcessorEditor : InputParameterEditor<MyValueShiftProcessor>
{
    private GUIContent m_SliderLabel = new GUIContent("Shift By");

    public override void OnEnable()
    {
        // Put initialization code here. Use 'target' to refer
        // to the instance of MyValueShiftProcessor that is being
        // edited.
    }

    public override void OnGUI()
    {
        // Define your custom UI here using EditorGUILayout.
        target.valueShift = EditorGUILayout.Slider(m_SliderLabel,
            target.valueShift, 0, 10);
    }
}
#endif