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    Interface IInputStateCallbackReceiver

    Interface for devices that implement their own state update handling.

    Namespace: UnityEngine.InputSystem.LowLevel
    Syntax
    public interface IInputStateCallbackReceiver
    Remarks

    The input system has built-in logic to automatically handle the state buffers that store input values for devices. This means that if an input event containing input state is processed, its data will be copied automatically into the state memory for the device.

    However, some devices need to apply custom logic whenever new input is received. An example of this is delta which needs to accumulate deltas as they are received within a frame and then reset the delta at the beginning of a new frame.

    This interface allows to bypass the built-in logic and instead intercept and manually handle state updates.

    Methods

    OnNextUpdate()

    A new input update begins. This means that the current state of the device is being carried over into the next frame.

    Declaration
    void OnNextUpdate()
    Remarks

    This is called without the front and back buffer for the device having been flipped. You can use Change(InputDevice, InputEventPtr, InputUpdateType) to write values into the device's state (e.g. to reset a given control to its default state) which will implicitly perform the buffer flip.

    OnStateEvent(InputEventPtr)

    A new state event has been received and is being processed.

    Declaration
    void OnStateEvent(InputEventPtr eventPtr)
    Parameters
    Type Name Description
    InputEventPtr eventPtr

    The state event. This will be either a StateEvent or a DeltaStateEvent.

    Remarks

    Use Change(InputDevice, InputEventPtr, InputUpdateType) to write state updates into the device state buffers. While nothing will prevent a device from writing directly into the memory buffers retrieved with currentStatePtr, doing so will bypass the buffer flipping logic as well as change detection from change monitors (IInputStateChangeMonitor; this will cause InputAction to not work with the device) and thus lead to incorrect behavior.

    See Also
    StateEvent
    DeltaStateEvent

    See Also

    InputDevice
    Pointer
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