Event callbacks are exposed to Blueprints. They are implemented with custom Events.

Event Callbacks

Most callbacks exposed in the C++ sound engine API are exposed to Blueprints. For more information on what the various callback types accomplish, refer to the SDK documentation.

Note: Blueprint graphs need to be executed on the game thread, so callbacks that require you to modify the AkCallbackInfo structure (AK_SpeakerVolumeMatrix, for example) cannot be exposed to Blueprints. Implement them with C++ code.

Using Event Callbacks

To subscribe to an Event callback, select it in the Callback Mask input pin dropdown. You can then implement the Blueprint graph you want to execute in the selected callback with a custom Blueprint Event:

Subscribing to Multiple Callback Types

To subscribe to more than one callback type, select multiple values in the Callback Mask input pin dropdown:

Then, in your Custom Event graph, you can use a Switch on the Callback Type variable to determine the current callback type, then cast the Callback Info class to the appropriate type:

Using MIDI Callbacks

The contents of a MIDI Event callback info class can be interpreted differently depending on the current MIDI Event type. In order to simplify parsing the MIDI callback info, a Blueprint macro, SwitchOnMidiType, is provided. It will automatically parse the callback info object and trigger the correct execution pin:

Note: The Chan member of the MIDI Callback Info class refers to the MIDI channel. Its range is from 1 to 16.