[MUD-Dev] Modeling spells/skills as collections of affects

[Dan Shiovitz]

On Thu, 4 Sep 1997 clawrenc at cup.hp.com wrote:
> In <199708312324.3515400 at bedford.net>, on 08/31/97 
>    at 06:41 PM, "Brian Price" <blprice at bedford.net> said:
[..]
> The model topic was debated and discussed heavily in this list in the
> early parts of last year (AlexO, Wout, ChrisG, and myself as I
> recall).  Several competing models were proposed and championed,
> variously named "affects", "Affects", and "spoofs and watchers".
[..]
>   Affect -- AlexO's contribution?  A named set of attribute weightings
> and full function bodies (weak OO model) which could be applied to a
> player or other object.  An Affect added its attribute weightings to
> the matching attribute values on the object.  Functions opaquely
> overlaid any prior methods of that name.  A later extension had
> Affects functions instead creating little function lists as they were
> applied.  Thus prior versions of the function could be called from a
> given Affect's version of the function.
> 
>   Spoofs and Watchers -- My contribution.  A spoof is an object that
> replaces another object (assumes the other object's ObjectID), while
> retaining a copy of the original object under a different (temporary)
> ObjectID.  The intent of a spoof is that all messages sent to the
> original object would instead be intercepted by the spoof object.  The
[..]
> A weakness which impacts all these models is the concept of implicit
> ordering and detection of side-effects between multiple applied
> affects/Affects/spoofs (can he be a near FireGod _and_ a water sprite
> _and_ terribly sleepy?).  I do not recall that any decent solution was
> arrived at.  My current partial solution is to use priority values for
> spoofs.  Spoofs then attempt to order themselves via insertion at
> install time on an object in priority order such that any message to
> the object goes to the lowest priority object first, then the next
> highest etc until the true original object is reached.  

I've been thinking of something vaguely like Affects for my system. I'm
still not precisely sure what to do with someone that wears cursed
gauntlets of fumbling that make her miss all the time and wields the magic 
spear Elsinore that always hits its target. I guess some sort of priority
system would be the way to go here, yes. Of course, I have no idea of a
consistent way to do so ("yes, this one makes you always hit with level
40, whereas this one makes you miss 10% more often with level 50 .. so you
add them together, and get, uh .."). I suppose that's not a terrible way
to do things: if each affect is given some sort of power level as well as
its actual effects, then when two affects contradict each other you could
let the more powerful one take effect, either at full power or at the
difference in power of the two .. so maybe in the above example you'd miss
1% more often instead of 10%.  Or maybe that's stupid, and if you're
wearing always-hit shoes and a miss-10% belt, then you should always hit. 
Or maybe I just shouldn't have any always- items in the game :)

I'm not quite clear on why spoofs are a good idea, though. It seems like
replacing the entire object just to modify its hitroll (or whatever) is a
bit excessive; can't you just have a list of affects on the object and ask
each of them if they modify its hitroll, and have queries about the
object's hitroll receive a consolidation of all that information?

> J C Lawrence                           Internet: claw at null.net
> (Contractor)                           Internet: coder at ibm.net
--
Dan Shiovitz :: scythe at u.washington.edu :: shiov at cs.washington.edu
..................................................................
"Alas, I do not rule the world and that, I am afraid, is the story
of my life: always a godmother, never a God."     -- Fran Lebowitz
...http://weber.u.washington.edu/~scythe/home.html................