[DGD] the building blocks of grandiose worlds: geometry

[Raymond Jennings]

I should probably point out that in this process I'm trusting geometry
queries to be honest.  Real geometry is consistent and allows for this to
work.  This scheme will fail in a hurry if geometry handlers lie to the
relation processing.


On Tue, Aug 27, 2013 at 11:07 AM, Raymond Jennings <shentino at gmail.com>wrote:

> I agree, it's vague ^^  I'm still trying to come up with the terminology
> too.
>
> The basic idea is that I keep track of geometric (topologic?) relations
> between neighboring objects.
>
> WRT one object that holds the relation mapping, another object can be:
>
> 1.  An insider (completely contained by us)
> 2.  An intersecter (our boundaries criss cross)
> 3.  An outsider (completely containing us)
> 4.  An overlapper (our boundaries are perfectly congruent)
> 0.  No relation at all
>
> The default is 0, which as a nil is not even tracked, and any object not
> in our relation map is assumed to be 0.
>
> Now the immediately useful part:
>
> First, direct neighbors:
>
> Objects in sets 1, 2, or 4 have parts of themselves inside us, and qualify
> for internal actions.
> Objects in sets 2, 3, or 4 have parts of themselves outside us, and
> qualify for external actions.
>
> Second, indirect neighbors:
>
> Additionally, objects in sets 2, 3, or 4 may have objects of their own
> inside them, or in their own 1-, 2-, or 4- set.
>
> The 1's, 2's, and 4's of our 2's, 3's, and 4's are external neighbors.
>
> The 2's, 3's, and 4's of our 1's, 2,s and 4's are our internal neighbors,
> and the rules of geometry (I think anyway) imply that those indirect
> relations will also show up in our own 1's, 2's, or 4's
>
> By querying these lists, I can find neighbors.  This collection of
> neighbors is the list of candidates for things like visibility,
> interaction, targeting by nouns, and so on.
>
> That is the immediate usefulness.
>
> The second intended benefit:  Any outsider or insider acts as a veil which
> hides everything behind it from processing, which in a sizable world can
> obviously cut way down on the O(N^2) potentials, since anything affecting
> us from beyond that veil (no sirius black jokes please) has to go through
> the veil to get to us, and since the outsider or insider is already keeping
> track of us in its own relation list, anything that cares to find us can do
> so easily once it hits the veil and peeks behind it.
>
> This veiling effect also helps save on processing time when geometry
> relations need to be checked for updating after an object moves.  I don't
> have to do a nasty O(N^2) check against everything else.  If I change from
> a 1 to a 2 for object B, I only have to look at object B's 1's and 2's and
> 4's to see who my new relations might be.  Similiarly, if I become a 1 of
> object B, I never have to look outside object B again to check anything.
>
> This is all theoretical so far, but my prototype is working well enough
> even now for the time being.
>
> As a quick and dirty example, let's say you have a few objects:
>
> object A is Fort Providence, and is a municipal zone.
> object B is the county of Kolechistan
> object C is Kolechistan's first police precinct
> object D is Kolechistan's fourth fire district
> object E is the state of Imporiton
> object F is the great and glorious nation of Triskellia
> object G is the state of Oregon.
>
> A is completely inside B, and also completely inside C and D
> B is completely inside E, and contains C and D
> C and D, being under different departments of Kolechistan, are
> intersecting each other, completely contain A, and are completely inside B
> E contains A
> F contains E
> F contains G
>
> Now, I have some optimizations already.
>
> Because E completely surrounds B, it doesn't even show up as a relation at
> all for A, C, or D.  A, C, and D list B as their ousider, and can safely
> ignore anything outside of B.  Which means that anything inside Kolechistan
> doesn't have to worry about the rest of Imporiton, or for that matter,
> anything outside it such as F (Triskellia) and G (oregon).  Object B acts
> as a veil that hides objects E, F, and G from objects B and C, and
> therefore from object A.
>
> Additinally, anything outside of Kolechistan doesn't need to worry about
> anything inside of it.  Objects E, F, and G can completely ignore object
> B's contents, since object E acts as a veil.
>
> Now if due to political events, the borders change, I can run a geometry
> check on any objects.  If the check brings in new neighbors, I can check
> against them as well, and if relations change I can then look for more
> candidates.
>
> However, I only have to check my neighbors.  If after checking them, no
> new candidates pop up, I can stop.  Anything that remains an outsider
> cannot possibly have anything interesting outside itself, and likewise for
> insiders.
>
> Now, if something happened outside that needed our attention, that
> something would first have to pierce the borders of our outsiders, and if
> it did that, it would then check our outsider's relations (including us).
>
> or, to put it back in the example, if a rocket was launched from China and
> made its way to Fort Providence, you can bet your bones that Triskellia's
> air force radar would find out about it and the air force would warn
> Imporiton's governor.  Imporiton's governor, in turn would probably put the
> police precinct and fire district on high alert by the time the rocket
> impacted.  Which is to say, that the rocket would have to go through
> Triskellia's borders before Imporiton even saw it, and likewise through
> Imporiton's borders before the police and fire districts saw it, and then
> likewise for Fort Providence itself.  Each penetration of a veil brings up
> new objects to check for relations, and this process can recurse as needed
> until everything resolves.
>
> Since the police and fire zones intersect though, Fort Providence still
> has to put up with jurisdictional squabbles.
>
> I hope this clarifies my idea better.
>
>
> On Mon, Aug 26, 2013 at 11:08 AM, Natasha Koroleva <
> natasha.i.koroleva at gmail.com> wrote:
>
>> Kind of vague description. I wonder there is a direction attribute for
>> the relation (I assume this will be used for to handle exits)? Overlap
>> includes some sort of index so that you know what is above and below
>> the object?
>>
>> On Mon, Aug 26, 2013 at 10:51 AM, Raymond Jennings <shentino at gmail.com>
>> wrote:
>> > Ok, so I just implemented very basic geometry processing, that makes
>> sets
>> > of objects that are inside, outside, intersecting, overlapping, or not
>> > related at all.
>> >
>> > This is the foundation for delegation and object hiding in my "colossal
>> > galaxy with detail down to the room" scheme.
>> >
>> > The gist is that for any two objects, object B can be inside object A,
>> > outside it, intersecting it, or overlapping it (same position and shape)
>> >
>> > Ultimately, the relation list will seed the candidate list when checking
>> > for neighbors.
>> >
>> > Can anyone see any flaws in this design?
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>
>