Path: mcdsun!noao!hao!hplabs!pyramid!amiga!jimm
From: jimm@amiga.UUCP (James D. Mackraz)
Newsgroups: net.micro.amiga
Subject: DUAL-PLAYFIELD Screens -- Example
Message-ID: <1596@amiga.amiga.UUCP>
Date: 2 Nov 86 21:46:38 GMT
Reply-To: jimm@homer.UUCP (Jim Mackraz)
Organization: Mitsumi Technology, Inc.
Lines: 374

::

    The following is an example of using a dual-playfield screen.
    Contrary to what it says in the Intuition Manual, the way
    to do this is to open a normal, single-playfiled screen and
    then to mutate it into a dual-playfield, providing your
    own bit map and planes, and auxilliary data structures.

    The example given performs this mutation on the workbench screen,
    but such intrusive behavior is not recommended for any purpose
    other than demonstration and playing around.  (And perhaps the
    odd subliminal message.)

    There are certain constraints which must be understood as to the
    number of bitplanes in the two playfields which are allowed, and
    the formulas for color mapping the two playfields are only hinted
    at in this example, so you must still consult the manuals.

    Note the constant FANCYVERSION, which if defined non-zero results
    in a more exciting demo than the version of this program supplied
    in the Intuition Revision notes (which are to be distributed to
    developers).

    Note also that like most of my previous examples, this program
    was produced under GreenHills C, and come with no guarantee to
    compile and run under any other system.

    Although I am no longer an employee of Commodore-Amiga, Inc., it
    is my pleasure to continue to support and be a member of the
    Amiga developers community.  See you at the Developer's Conference.

				Jim Mackraz
				(amiga!jimm)