[Freeciv-Dev] Re: (PR#2748) 3 mapgen patches now through rt (sorry about that) --- 1 of 3

["Ross W. Wetmore" <rwetmore@xxxxxxxxxxxx>]

At 09:45 AM 03/01/09 -0800, kayeats@xxxxxxxxxxxxxxxxxxxxxxxxx via RT wrote:
>
>>    Mapgenerators 2-4 already
>>    treat rivers as percent.
>
>Really?  I just looked at the code and all they seem to do in gens 2-4 is
>divide by 10 everwhere.  Maybe I'm not looking closely enough.
>
>Anyway, once I saw all the dividing by 10 that was already there I was
>convinced that my initial instinct to change the maximum of
>map.riverlength to be 100 like all the other terrain parameters was the
>right solution.  Attached is the new version of the patch.  I also
>followed your polar suggestion (sort-of, it isn't quite so simple as
>simply replacing everywhere because you have to compute differently with
>fixed values, so the only use of it is for clarity and hence I only used
>it local to adjust_terrain_param).  Hopefully my third patch will go
>in as well and it won't matter one bit.
>
>If I'm misunderstanding how this will interact with gens 2-4 please
>correct me.

Except for rivers, mapgenerator works in percents, so everything is 
fine here.

A better fix than the divide by 10 hack is to take the percent from
riverlength/total_land_tiles. Since most users won't understand the 
screwiness of riverlength, and the system should be percents everywhere 
anyway, the final tweak is to assume riverlength < 50 is already in 
percent. 

Conversely :-), assume it is now always in percent and for backwards
compatibility take anything greater than 50 as a real river length.

Anything much over 25% or 1 tile in 4 is bad for rivers producing
canal networks that look like AI road systems rather than single
flow reality. You certainly don't want 100% rivers except for some
wierd case.

>Karen

Cheers,
RossW
=====

This is how it generates the bucket counts. If you look carefully it
treats rivers/10 exactly the same way it treats mountain percent.

    i *= tilefactor;
    if (terrain_control.river_style==R_AS_TERRAIN) {
      riverbuck += map.riverlength / 10 * i;
      fill_island(1, &riverbuck,
                  1,1,1,1,
                  T_RIVER, T_RIVER, T_RIVER, T_RIVER,
                  pstate);
    }
    if (terrain_control.river_style==R_AS_SPECIAL) {
      riverbuck += map.riverlength / 10 * i;
      fill_island_rivers(1, &riverbuck, pstate);
    }
    mountbuck += map.mountains * i;
    fill_island(20, &mountbuck,
                3,1, 3,1,
                T_HILLS, T_MOUNTAINS, T_HILLS, T_MOUNTAINS,
                pstate);       
                                                
If you look at the adjust_parameters you need to read the comment
carefully and then understand that the adjustment is based on
percent (and map.generator 1 is never adjusted).


  /*!PS: I don't have the time to have several test runs */
  /* to find a mapping from percents to generator 1 settings. */

  if(map.generator==1){
    /*map.riverlength*= 10; */
    /*I leave this out, people will get too upset
      if they have to change all their scripts */
    return;
  }

  map.riverlength/= 10;/* left in */

    total = map.riverlength + map.mountains + map.deserts
    + map.forestsize + map.swampsize + map.grasssize;