[A83] hitdetection

To: "TI-83 assembly-83" <assembly-83@lists.ticalc.org>
Subject: [A83] hitdetection
From: "Jan (belgacom)" <jandebeule@belgacom.net>
Date: Sat, 21 Apr 2001 16:38:39 +0200
Importance: Normal
Reply-To: assembly-83@lists.ticalc.org

I'm working on a hitdetection-routine for a ball-game.  The balls that are
moving around the field have an equation (y(x)=ax+b) (i use left-bottom as
(0,0) and work with pixels (so x from 0 to 95 and y from 0 to 64) and every
frame I increase 'x'  1 or more times.
Now hitdetection would work this way: i check if  d(m1,m2)=r² (m1: centre of
the ball that is moving, m2: centre of ball i want to check (if hit) and r:
the radius of the ball)
Now my question is: should i work with OP1-OP6 ('cause i know they are
easily to work with (for multiplying, square root,...)) or should i work
with the usual registers: af, bc, de and hl ('cause my coordinates have to
be integers in the end)
Another problem would be that the balls aren't really circles, they're
sprites that look like circles...

Ball:
         .db     %01110000
         .db     %11111000
         .db     %11111000            :=> third number of this row would be
the centre
         .db     %11111000
         .db     %01110000
         .db     %00000000
         .db     %00000000
         .db     %00000000

Follow-Ups:

[A83] Re: hitdetection

From: Harper Maddox <gte172i@prism.gatech.edu>