Re: A83: sprite won't clear completly

Re: A83: sprite won't clear completly

• To: assembly-83@lists.ticalc.org
• Subject: Re: A83: sprite won't clear completly
• From: Indiana Zephyr <indyz@megsinet.net>
• Date: Thu, 18 Feb 1999 18:09:15 -0600
• Delivered-To: assembly-83-outgoing@towerguard.unix.edu.sollentuna.se
• Delivered-To: assembly-83@lists.ticalc.org
• References: <19990217233429.29656.qmail@hotmail.com>
• Reply-To: assembly-83@lists.ticalc.org

I think I figured it out.  First, you need to understand how XOR works:
It flips the color where it draws the sprite.  So when you draw your guy, it
flips the colors where your lines are to dark.  When you move again, it
redraws the sprite _in the same place_, thereby flipping the dark again and
making the whole area light.  Then the coordinates are moved slightly and it
starts all over.  When you change what picture you are using, the dark areas
in the picture on the screen do not match the dark areas in the new
picture.  This makes it look like XOR is screwing up when it is really doing
it's job perfectly.

You probably don't understand that, so send me some private mail if you need
more help.

=Indy Z.

• Re: A83: sprite won't clear completly
• From: matthew landry <mhlandry@bellsouth.net>

• A83: sprite won't clear completly
• From: "Cory Derenburger" <cderenburger@hotmail.com>

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