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<H1>Re: [MUD-Dev]  Senses &amp; geographical events</H1>
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<LI><em>To</em>: <A HREF="mailto:mud-dev#null,net">mud-dev#null,net</A></LI>
<LI><em>Subject</em>: Re: [MUD-Dev]  Senses &amp; geographical events</LI>
<LI><em>From</em>: <A HREF="mailto:clawrenc#cup,hp.com">clawrenc#cup,hp.com</A></LI>
<LI><em>Date</em>: Wed, 02 Jul 97 15:33:50 -0700</LI>
<LI><em>Reply-to</em>: <A HREF="mailto:claw#null,net">claw#null,net</A></LI>
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<PRE>
In &lt;Pine.SOL.3.94.970630191350.3527G-100000#eduserv1,rug.ac.be&gt;, on
06/30/97 
   at 11:29 AM, Wout Mertens &lt;Wout.Mertens#rug,ac.be&gt; said:

&gt;Yo!

Man!

&gt;You have a certain signal (auditory, visual, magical, ...), and a
&gt;space in which an event concerning this signal happens. Call it for
&gt;example the sensory plane. For the rest of the discussion, let's
&gt;assume it's 2D, 3D is easily derived from it. The mapping of real
&gt;world to the plane (or space) is left as an exercise for the reader,
&gt;what with all those private coordinate spaces rooms get.

&gt;Now, I assume we're working with discrete senses (floating point is
&gt;discrete, assume that I mean the smallest possible number when I say
&gt;unit), and that at a certain point the signal strength is 0.
&gt;(otherwise, don't bother with this system, right?) The signal
&gt;strength versus distance function can be any function, as long as it
&gt;goes 0 starting from some distance.

Problem:

  The sensory abilities of different creatures are different.

Thus a human will, say, not be able to see a mouse a mile distant, but
will if he's using binoculars.  Similar is true for mouse vs rabbit vs
wolf vs human vs giant, let alone the infra-red vs UV vs visible ligt.

&gt;Cover the plane with squares with sidelength 2R, centered around the
&gt;location of the objects in that plane. Then all the squares that are
&gt;overlapped by the square 2r around the source, are likely receivers,
&gt;and you only have to check those for the r+R rule.

&gt;The last problem is: How to efficiently represent such a plane?

&gt;I propose that all the objects that can sense that signal, are put in
&gt;sorted lists:

&gt;One list for the leftmost x-coordinate of the squares and one for the
&gt;rightmost x-coordinate.

&gt;Each entry contains a list for topmost y-coord and a list for
&gt;bottommost y-coord, and of course those entries refer to an object.

&gt;To find the aforementioned squares, get all the entries for which
&gt;((minx &lt;= leftx &lt;= maxx) OR (minx &lt;= rightx &lt;= maxx)) AND ((miny &lt;=
&gt;topy &lt;= maxx) OR (minx &lt;= boty &lt;= maxx))
&gt;To do this in a way that you get a unique list of candidates, maybe
&gt;use a tag field and tag the entries you visited with a timestamp (so
&gt;you don't have to keep clearing the tags)

Problem: 

  You've just recreated an object scanning loop.  

Its increasingly expensive as the number of objects in the world
grows.  Its great for a world with a few hundred objects.  Its piss
poor for a world with a few million (remember those mosquitoes?)  Now
you could attempt to order the list with morton codes -- but that
merely slows the unscalability: it doesn't cure it.

-- 
J C Lawrence                           Internet: claw#null,net
(Contractor)                           Internet: coder#ibm,net
---------------(*)               Internet: clawrenc#cup,hp.com
...Honorary Member Clan McFUD -- Teamer's Avenging Monolith...


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<ul><li>Thread context:
<BLOCKQUOTE><UL>
<LI><STRONG>Re: [MUD-Dev] RP=MUSH/PG=MUD</STRONG>, <EM>(continued)</EM>
<ul compact>
<ul compact>
<ul compact>
<ul compact>
<ul compact>
<ul compact>
<LI><strong><A NAME="01037" HREF="msg01037.html">Re: [MUD-Dev] RP=MUSH/PG=MUD</A></strong>, 
Martin Keegan <a href="mailto:martin#cam,sri.com">martin#cam,sri.com</a>, Tue 02 Sep 1997, 23:05 GMT
</LI>
</ul>
</ul>
</ul>
</ul>
</ul>
<LI><strong><A NAME="00077" HREF="msg00077.html">Re: [MUD-Dev] RP=MUSH/PG=MUD</A></strong>, 
Chris Gray <a href="mailto:cg#ami-cg,GraySage.Edmonton.AB.CA">cg#ami-cg,GraySage.Edmonton.AB.CA</a>, Fri 04 Jul 1997, 13:04 GMT
</LI>
<LI><strong><A NAME="00090" HREF="msg00090.html">Re: [MUD-Dev] RP=MUSH/PG=MUD</A></strong>, 
clawrenc <a href="mailto:clawrenc#cup,hp.com">clawrenc#cup,hp.com</a>, Wed 09 Jul 1997, 00:53 GMT
</LI>
</ul>
</LI>
<LI><strong><A NAME="00006" HREF="msg00006.html">Re: [MUD-Dev]  Senses &amp; geographical events</A></strong>, 
Chris Gray <a href="mailto:cg#ami-cg,GraySage.Edmonton.AB.CA">cg#ami-cg,GraySage.Edmonton.AB.CA</a>, Wed 02 Jul 1997, 00:18 GMT
<UL>
<li>&lt;Possible follow-up(s)&gt;<br>
<LI><strong><A NAME="00052" HREF="msg00052.html">Re: [MUD-Dev]  Senses &amp; geographical events</A></strong>, 
clawrenc <a href="mailto:clawrenc#cup,hp.com">clawrenc#cup,hp.com</a>, Thu 03 Jul 1997, 05:44 GMT
</LI>
</UL>
</LI>
<LI><strong><A NAME="00003" HREF="msg00003.html">Re: [MUD-Dev] Integrating PK</A></strong>, 
Matt Chatterley <a href="mailto:root#mpc,dyn.ml.org">root#mpc,dyn.ml.org</a>, Tue 01 Jul 1997, 21:58 GMT
<UL>
<LI><strong><A NAME="00032" HREF="msg00032.html">Re: [MUD-Dev] Integrating PK</A></strong>, 
Adam Wiggins <a href="mailto:nightfall#user1,inficad.com">nightfall#user1,inficad.com</a>, Wed 02 Jul 1997, 15:19 GMT
<UL>
<LI><strong><A NAME="00040" HREF="msg00040.html">Re: [MUD-Dev] Integrating PK</A></strong>, 
Matt Chatterley <a href="mailto:root#mpc,dyn.ml.org">root#mpc,dyn.ml.org</a>, Wed 02 Jul 1997, 22:20 GMT
</LI>
<LI><strong><A NAME="00073" HREF="msg00073.html">Re: [MUD-Dev] Integrating PK</A></strong>, 
clawrenc <a href="mailto:clawrenc#cup,hp.com">clawrenc#cup,hp.com</a>, Fri 04 Jul 1997, 05:17 GMT
</LI>
</UL>
</LI>
</UL>
</LI>
</UL></BLOCKQUOTE>

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