[Freeciv-Dev] Re: [PATCH] Corecleanup_07Part2 has been putin incoming

[Jason Dorje Short <jshort@xxxxxxxxxxxxx>]

"Ross W. Wetmore" wrote:
> 
> At 10:10 AM 01/08/29 +0200, Raimar Falke wrote:

> >You have to acknowledge that casting to unsigned and comparing it is a
> >trick to gain performance and this trick isn't immediate obvious to a
> >normal programmer. It has to be documented somewhere or we went up
> >like in the ai case.
> 
> No, it can be viewed as *understanding* that real map coordinates are
> always positive and defined by an upper bound and doing the appropriate
> logical test for this condition. It is unfortunate that map coordinates
> were stored in ints instead of unsigned, but the cast corrects this.

Please, no!  Many topologies (notably the isometric ones) would be best
handled if the map coordinates went over into the negatives.  A front
end drawing a game may often want to draw negative tiles (irrelevant to
the implementation, perhaps, but important to the theory).  Under the
current topology, any negative X values doesn't prevent the tile from
being real - only the Y value matters.

Negative values are key.  We're talking about a plane; it extends
forever in every direction.  We could have negative values wrap around
to very high positive ones, but what would be the point, really?

In the current topology no negative value can ever be normal.  Is this
what you meant to say?

jason