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

[Raimar Falke <rf13@xxxxxxxxxxxxxxxxx>]

On Mon, Apr 14, 2003 at 12:20:47PM -0500, Jason Dorje Short wrote:
> Raimar Falke wrote:
> >On Mon, Apr 14, 2003 at 11:02:28AM -0500, Jason Dorje Short wrote:
> >>Raimar Falke wrote:
> >>>On Sun, Apr 13, 2003 at 05:37:59PM -0500, Jason Dorje Short wrote:
> 
> >>I'm not sure.  Certainly 
> >>there are some additional (non-mapview-specific) ones in mapview.
> >
> >
> >>Conversely, if we use map coordinates as standard there are just a few 
> >>places that need to convert to native coordinates.  These include a few 
> >>map.c backend functions (normalize_map_pos, map_distance_vector, 
> >>rand_map_pos, map_to_index_pos, index_to_map_pos) as well as a very few 
> >>pieces of user code (savegames, map debug output).
> >
> >
> >So we both say that our changes are minimal.
> 
> Yep.  I'm not against the idea of using native coordinates as standard. 
>  I'm just not willing to track down all the places that need to be 
> fixed for it, since I've already spent 2 years doing it the other way.
> 
> >>>- mapview: is reduced to one file (mapview_common) AFAIK
> >>
> >>Don't just lump in everything in mapview.c and mapview_common.c into 
> >>"mapview" and write it off.  mapview does have some very specialized 
> >>needs (like clipping the window), but also some generalized ones as well 
> >>(like rectangle_iterate).
> >
> >
> >You agree that all this should and can be done in mapview_common?!
> >
> >I also said in the past that the mapview_common change won't be easy.
> 
> But again you're lumping all this stuff together.  There is a discrete 
> set of changes:
> 
> - clip_mapview_window - localized and ugly.  Does not relate to the 
> current discussion.
> 
> - mapview scrolling - non-localized and ugly.  Does not relate to the 
> current discussion.
> 
> - overview window: non-localized, but fairly low-impact.
> 
> - unnormalize_map_pos: localized and complicated.  Does not relate to 
> the current discussion.
> 
> - Other misc changes.  These generally do relate to the current 
> discussion.  For instance under your system, all of the mapview 
> iterations need to be done in map coordinates and need a manual 
> conversion.  This is not localized, and cannot be written off as "part 
> of that mapview change" since it relates directly to this discussion.

I really can't say anything about mapview(_common). I don't know it at
the detail level which is needed.

> >Let me create some code so that we can have some facts. Hopefully this
> >week.
> >
> >Is there an implementation of your approach which is complete? For
> >measure of speed and general impact this doesn't have to support
> >mapview.
> 
> Excellent.  See the gen-topologies patch in freeciv-test.  It is 
> out-of-date for current CVS (by about 2 weeks, I think - I have an 
> updated patch locally).

I'm not subscribed to freeciv-test.

> You do need to support mapview.  Most of the mapview code can remain 
> unchanged (note, clip_mapview_window and mapview scrolling do not work 
> perfectly).  What you will need to fix is the fact that mapview deals 
> exclusively in map coordinates, so you'll need to convert to/from native 
> coordinates all over the place.
> 
> But you can drop all of the existing map<->native conversion operations, 
> so this will approximately balance out.  This includes huge quantities 
> of mapgen.c, some stuff in map.c, and some scattered other places.
> 
> Compared to mapgen and mapview, everything else is tiny.  So as a 
> measure of "general impact" these two are very significant.

We haven't touched the question of wrapping till now. I think that
both of http://www.freeciv.org/~rfalke/grid_pictures/grid_iso_wrap.png
and http://www.freeciv.org/~rfalke/grid_pictures/grid_iso_rot_wrap.png
are possible.

grid_iso_wrap.png is rather easy to implement and requires almost no
changes to mapgen.c (at least I think so).

        Raimar

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