[Freeciv-Dev] Re: (PR#3936) introducing native coordinates

[Jason Dorje Short <vze49r5w@xxxxxxxxxxx>]

Raimar Falke wrote:
> On Thu, Apr 24, 2003 at 08:58:16AM -0500, Jason Dorje Short wrote:
>
> > > > > - which iso variants do we support (IMHO both)
> > > > Hmm?  The "variants" you talk about in the file are just a different 
> > > > numbering system; there's nothing fundamentally different between them.
> > >
> > > You can't express every instance of variant1 with an instance of
> > > variant2. Example: try to build a variant1 map (width and height
> > > searched) which looks the same like the variant2 map of size (9x5)
> > > (picture in the page). IMHO this isn't possible. Because the "wdith"
> > > of variant1 is always even.
> > True (and vice versa), but that's not really worth worrying over.  Who 
> > really needs a 99x49 map when you can have a 100x50 one?
> That is probably right. But this is a decision you (or some other
> made) and didn't document. I wonder what other decisions are made
> without documenting.
Yes.

> > On a related note, if you specify an odd ysize in an iso-map that wraps 
> > in the y direction, you will get very odd behavior.  You have to have an 
> > even dimension to wrap in a particular direction.  Your variant1 (the 
> > same as gen-topology uses) enforces this by compressing in the x 
> > direction; your variant2 compresses in the y.  But neither accounts for 
> > the other direction.
> Ahh yes that is another point which I think your gen_topo patch is
> bad. It should not accept certain wrappings or sizes or should correct
> the size by adding one.
Yes, this is a definite bug.

There are also bugs in clip_mapview_window() and map scrolling.  And 
note that only gui-gtk is supported.
> > > Question: is wrapping defined in compact form the same as
> > > wrapping defined in iso-view form? IMHO yes but I'm not sure.
> > Again you've lost me.  What is the iso-view form?  The form you get by 
> > looking at it in an isometric-view client?  This is the "natural" view 
> > of an iso map; the wrapping here is identical except that the scale is 
> > different.
>
> Well the neighborhood in both forms is different. See
> http://www.freeciv.org/~rfalke/grid_pics2/grid_iso1_wn.png and
> http://www.freeciv.org/~rfalke/grid_pics2/grid_compact_wn.png. But it
> looks that these difference don't matter for the wrapping case. In the
> above case this means that if you start at the blue point and goes
> west wards (NW, W and SW) you will reach the same tile no matter if
> you go in the iso-view form or the compact form.
But these are the "natural" and "native" form, and neither are used for 
finding adjacent tiles.  In particular the natural form isn't used at 
all, and the adjacent tiles can't be determined from the native form at 
all.  The DIR8 directions, therefore, are only of use (in the core code) 
for the "map" form.
jason