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<H1>Re: [MUD-Dev] Finding Space</H1>
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<LI><em>To</em>: MUD-Dev <<A HREF="mailto:mud-dev#null,net">mud-dev#null,net</A>></LI>
<LI><em>Subject</em>: Re: [MUD-Dev] Finding Space</LI>
<LI><em>From</em>: Nathan Yospe <<A HREF="mailto:yospe#hawaii,edu">yospe#hawaii,edu</A>></LI>
<LI><em>Date</em>: Sun, 17 Aug 1997 21:48:05 -1000</LI>
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<PRE>
On Fri, 15 Aug 1997, Michael Hohensee wrote:
:I've been working up a system in which objects take up space in a
:co-ordinate based world, and I seem to have hit a stumbling block. I
:know that others have probably solved this problem (Physmud++ *must*
:have had to solve this ;), so maybe someone can help me.
Yes and no. Same as collision detection... exactly the same, in fact, as
this is a big part of what I consider collision detection. I use spheres
around the center of volume (not to be confused with the center of mass)
of a group of objects, single composite object, individual components...
and then I assume that the particulate (smallest tracked) components are
spherical. This reduces any "will I fit?" problem to a series of fast
comparisons that only get ugly when a collision is immenent (and since I
track in four dimensions, the fourth being a minute projection forward in
time, I have a chance to prepare for collisions.)
:Here's how it works:
:We are representing a three dimensional space, but in this example we'll
:restrict it to two dimensions.
:4-----------------------------
:3------******--------**-------
:2------******-----**-**--*****
:1----*-******-----**-**-------
:0-----------------------------
: 0 2 4 6 8 1012
: 1 3 5 7 9 11
:'-' = empty space, '*' = space taken up by an object.
:For simplicity, all objects take up a cubical volume of space (square,
:in this case). Objects are held in a tree or linked list of structs
:which contain the origin point of the object, and the dimensions of the
:object. For example, the big square in the picture above would be
:Location=6,1 -- Dimensions=6,3.
First off, spheres are simpler in 3D than cubes. Little bit of advice from
a graphical engine hand. MUCH simpler.
:I can store anything to any location I want, but I want to avoid
:overlapping objects onto each other (it's bad), so I need to be able to
:find empty space between objects. I can't just try to place an object
:in every location, since there isn't any granularity to this space (I
:use floats instead of ints).
And thus the reason for spheres. Use a transform and a single calculation
gives you the shortest distance between two points. Then just check to
make sure that's more than the radius of both spheres summed.
:A friend of mine glanced at this problem and said, "Oh, that's a
:bin-stuffing problem." Of course, he didn't remember anything else
:about the problem, so here I am. :)
Um. Bin stuffing would have been ints and a grid of locations.
:Does anyone have the answer? :)
Well, if mine made any sense...
"You? We can't take you," said the Dean, glaring at the Librarian.
"You don't know a thing about guerilla warfare." - Reaper Man,
Nathan F. Yospe Registered Looney by Terry Pratchett
yospe#hawaii,edu <A HREF="http://www2.hawaii.edu/~yospe">http://www2.hawaii.edu/~yospe</A> Meow
</PRE>
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<li><strong><A NAME="00656" HREF="msg00656.html">Re: [MUD-Dev] Finding Space</A></strong>
<ul compact><li><em>From:</em> Michael Hohensee <michael#sparta,mainstream.net></li></ul>
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<LI><STRONG><A NAME="00603" HREF="msg00603.html">Finding Space</A></STRONG>
<UL><LI><EM>From:</EM> Michael Hohensee <michael#sparta,mainstream.net></LI></UL></LI>
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<ul><li>Thread context:
<BLOCKQUOTE><UL>
<LI><STRONG>Re: [MUD-Dev] Finding Space</STRONG>, <EM>(continued)</EM>
<ul compact>
<LI><strong><A NAME="00625" HREF="msg00625.html">Re: [MUD-Dev] Finding Space</A></strong>,
Ned Lovely <a href="mailto:njl#NEDS,PLACE.ORG">njl#NEDS,PLACE.ORG</a>, Sat 16 Aug 1997, 20:53 GMT
</LI>
</ul>
</LI>
<LI><strong><A NAME="00603" HREF="msg00603.html">Finding Space</A></strong>,
Michael Hohensee <a href="mailto:michael#sparta,mainstream.net">michael#sparta,mainstream.net</a>, Fri 15 Aug 1997, 14:03 GMT
<UL>
<LI><strong><A NAME="00607" HREF="msg00607.html">Re: [MUD-Dev] Finding Space</A></strong>,
Shawn Halpenny <a href="mailto:malachai#iname,com">malachai#iname,com</a>, Fri 15 Aug 1997, 18:12 GMT
<UL>
<LI><strong><A NAME="00654" HREF="msg00654.html">Re: [MUD-Dev] Finding Space</A></strong>,
Nathan Yospe <a href="mailto:yospe#hawaii,edu">yospe#hawaii,edu</a>, Mon 18 Aug 1997, 08:01 GMT
</LI>
</UL>
</LI>
<LI><strong><A NAME="00653" HREF="msg00653.html">Re: [MUD-Dev] Finding Space</A></strong>,
Nathan Yospe <a href="mailto:yospe#hawaii,edu">yospe#hawaii,edu</a>, Mon 18 Aug 1997, 07:48 GMT
<UL>
<LI><strong><A NAME="00656" HREF="msg00656.html">Re: [MUD-Dev] Finding Space</A></strong>,
Michael Hohensee <a href="mailto:michael#sparta,mainstream.net">michael#sparta,mainstream.net</a>, Mon 18 Aug 1997, 19:22 GMT
</LI>
</UL>
</LI>
<LI><strong><A NAME="00657" HREF="msg00657.html">Re: [MUD-Dev] Finding Space</A></strong>,
clawrenc <a href="mailto:clawrenc#cup,hp.com">clawrenc#cup,hp.com</a>, Tue 19 Aug 1997, 00:21 GMT
</LI>
</UL>
</LI>
<LI><strong><A NAME="00556" HREF="msg00556.html">[MUD-Dev] Spellcaster, or Waving Hands</A></strong>,
Cynbe ru Taren <a href="mailto:cynbe#laurel,actlab.utexas.edu">cynbe#laurel,actlab.utexas.edu</a>, Thu 14 Aug 1997, 17:50 GMT
<UL>
<LI><strong><A NAME="00583" HREF="msg00583.html">Re: [MUD-Dev] Spellcaster, or Waving Hands</A></strong>,
clawrenc <a href="mailto:clawrenc#cup,hp.com">clawrenc#cup,hp.com</a>, Thu 14 Aug 1997, 22:21 GMT
</LI>
</UL>
</LI>
</UL></BLOCKQUOTE>
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