What is the second argument to ViewportResizedEvent?

Hey everyone,

Recently I had to use the FViewport::ViewportResizedEvent delegate. It is declared in the following way:

/** delegate type for viewport resize events ( Params: FViewport* Viewport, uint32 ) */
DECLARE_MULTICAST_DELEGATE_TwoParams(FOnViewportResized, FViewport*, uint32);
/** Send when a viewport is resized */
ENGINE_API static FOnViewportResized ViewportResizedEvent;

The question here is: what is the magical uint32 variable and what should it be called. The only instance where the event is being broadcast is from the UnrealClient.cpp - FViewport::UpdateViewportRHI

if ( !bDestroyed )
    // send a notification that the viewport has been resized
    ViewportResizedEvent.Broadcast(this, 0);

So what is the uint32 argument?

Not a huge issue just curiosity.

Thank you!

It’s seems always zero in 4.10.
May be it’s viewport index for further dev issues.