[Freeciv-Dev] Re: (PR#9135) Roadstyle 2

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9135 >

John Bauman wrote:

>>- I really don't like the separation of diagonal and cardinal roads in
>>the tileno.  Rather than "r.road_n0s1e0w1_n1s1e0w0" I'd rather have
>>"r.road_01001110" or "r.road_n0ne1e0se0s1sw1w1nw0".  Note the use of a
>>rotational ordering, which I suspect will be very helpful later on.
> 
> Do you have a good idea for a name? I think I'll go with the second choice
> you
> gave.  Rotational ordering would make much sense than what we have now.

Yes, rotational ordering is nice for tilesets.  Problem is the direction 
enumeration doesn't guarantee it.

What do you mean by a "good idea for a name"?


Side note...

I think the tileset code needs to use directional indices rather than 
directions directly.  That way we can guarantee that the indices are 
rotational and that the cardinal indices correspond to the cardinal 
directions in the tileset rather than the cardinal directions in the map.

   bool is_valid_tileset_dir(enum direction8 dir)
   {
     if (is_hex) {
       if (hex_width > 0) {
         return (dir != DIR8_NORTHEAST && dir != DIR8_SOUTHWEST);
       } else {
         return (dir != DIR8_SOUTHEAST && dir != DIR8_NORTHWEST);
       }
     } else {
       return TRUE;
     }
   }

   bool is_cardinal_tileset_dir(enum direction8 dir)
   {
     if (is_hex) {
       return is_valid_tileset_dir(enum direction8 dir);
     } else {
       return DIR_IS_CARDINAL(dir);
     }
   }

   num_valid_tileset_dirs = 0;
   num_cardinal_tileset_dirs = 0;
   dir = DIR8_NORTH;
   do {
     if (is_valid_tileset_dir(dir)) {
       valid_tileset_dirs[num_valid_tileset_dirs]++ = dir;
     }
     if (is_cardinal_tileset_dir(dir)) {
       cardinal_tileset_dirs[num_cardinal_tileset_dirs++] = dir;
     }
     dir = DIR_CW(dir);
   } while (dir != DIR8_NORTH);

>>- Think about hexagonal tilesets.  Here we only have six directions.
>>How will this be coded?  (Note that all the other directional tileset
>>code doesn't really support hex tilesets either.  The hex author figured
>>out ways around it in the tileset.)  (As a side note, the NSEW should be
>>changed to be rotational as well.)
> 
> I imagine that the tileset author could just ignore the directions that
> don't exist.

Yes but this is ugly since it requires 4x more tileset tags than are 
needed.  (As a side note, making a "good" hex tileset should be much 
easier than making a "good" rectangular tileset.)

> How do the other roadstyles work with hexagonal topologies now (in the
> patch for those toplogies, at least)?

I assume he just ignores the extra directions.  For roads this is easy, 
but for cell-based terrains or river graphics (which are based on 
cardinal directions) it doesn't work well.

jason