Path: utzoo!mnetor!uunet!husc6!think!ames!ptsfa!well!ewhac
From: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Newsgroups: comp.sys.amiga
Subject: Re: Need MORE HELP on GAME DEVELOPMENT on the Amiga
Message-ID: <5038@well.UUCP>
Date: 20 Jan 88 08:13:52 GMT
References: <1617@ssc-vax.UUCP>
Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Organization: Speak Before You Think Enterprises
Lines: 37
Keywords: Just one more question (or two)...

In article <1617@ssc-vax.UUCP> dmg@ssc-vax.UUCP (David Geary) writes:
>In article 4972, Leo Schwab writes:
>>  You should be able to get away with 8 colors on an arkanoid clone.
>>  Open a 4-plane screen (16 colors), then make colors 8-15 dimmer versions
>>  of colors 0-7.  Then, when you want to render a shadow, set your
>>  RastPort.Mask value to 0x08, and draw a slightly offset rectangle...
>
>Leo's suggestion sounds good to me except that I will have a pattern on
>the background that I want to show through.  Should I copy a rectangle
>from the playfield into a buffer, set the RastPort.Mask to 0x08, and
>then render the rectangle I copied back on to the screen?

	No.  You'd do something like this:

	/*
	 * Example assumes that colors 8-15 are dimmer versions of
	 * colors 0-7.
	 */
	SetAPen (RastPort, 0xffL);	/*  Set all bits  */
	RastPort.Mask = 0x08;		/*  Set high bit  */
	/*  Draw shadow over whatever's there.  */
	RectFill (RastPort, x1, y1, x2, y2);

>Another consideration is that the shadows for the boxes can all be rendered
>with rectangles, but the baton's shadow is odd shaped.  How do I
>deal with that?  [ ... ]

	You'd OR all the bitplanes in the baton to create a single bitplane
shadow mask.  Then you'd blit it into the most significant bitplane in your
playfield.  Poof!

_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
Leo L. Schwab -- The Guy in The Cape	ihnp4!ptsfa -\
 \_ -_		Recumbent Bikes:	      dual ---> !{well,unicom}!ewhac
O----^o	      The Only Way To Fly.	      hplabs / (pronounced "AE-wack")
"Simplicity and clarity should be your theme in dress."
		-- A fortune cookie I got in LA's Atomic Cafe.