[Scummvm-devel] Non-hardcoded gameids

[Marcus Comstedt]

David Given <dg at cowlark.com> writes:

> Sorry, that's not quite what I meant --- if the overlay's colour format
> doesn't have an alpha channel, how do you tell the compositor which bits
> should be transparent or not? Or does the colour format *always* have an alpha
> channel?

If there is no alpha support in the overlay, there is no "compositor"
to tell anything.  When you call clearOverlay(), the game graphics
will actually be _copied_ to the overlay, to emulate a transparent
overlay.  You can then overpaint any parts you like, with or without
alpha blending (which you then have to implement yourself), using
grabOverlay() and copyRectToOverlay().


  // Marcus