[crossfire] weather, lattitude, town location, and the world

Mark Wedel mwedel at sonic.net
Tue Nov 15 02:05:19 CST 2005


>
      That could work, particularly if canals were added later, so that
     >
      boats could travel across much of the continent (your movement code
     >
      reworking could make it possible then to have narrowboats to travel
     >
      between cities).
     
  I'd personally think that canals on that scale would be more modern than what 
crossfire is really set in.

  However, connecting the cities via roads would certainly make sense.

>
     
     >>
        But point here is that this is still creating a map with actual forest spaces
     >>
      and whatnot - you use a dynamic process to create a static map.
     >
     
     >
      Yes, and thereafter are forced to use that static version to edit it,
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      this is an issue if there is a change that would be easy to make with
     >
      a heightmap, but which would require extensive modification otherwise.
     
  I'd make the case that any changes via heightmap, when interacting with 
weather, would be fairly unpredictable.  Heightmap has all sorts of different 
effects - changing the elevation of some spaces could result in a whole host of 
changes (rivers changing course, etc).

>
     
     >
      Incidentally, it also strikes me that the best way to get a height map
     >
      would be from a grayscale image. - simply say that brightness is
     >
      altitude, and then lots of adjustments could be made with the use of
     >
      gimp filters.
     
  Maybe.  It'd depend on the source of that grayscale image.  If you just used 
general blur routines, then you'd just get a very aged world (gentle slopes).

  But typically you do want some extremes - ranges of high points.  That said, 
may be able to hand draw your rough idea what the continent in gimp is, use 
blending, etc.


>>
        In geological terms, rivers will carve out valleys.  So in those cases where a
     >>
      river flows into what would form a lake, see where the water would flow out and
     >>
      make some random determination if the ground in that area is hard (rock) or soft
     >>
      (earth/gravel/whatever), and thus a gorge would get eroded away to let the water
     >>
      out, and you don't have a lake anymore.
     >
     
     >
      The issue with doing that is that it would require playing with the
     >
      sea levels as water evaporates, to compensate for the water falling as
     >
      rain. As long as the world is mostly land, and not water, then that
     >
      will be a significant effect.
     
For simplicity, I'd say that is not necessary.

  We have a height map.  At some level, we are making a decision at what 
altitude is sea level and what isn't.  Saying sea level is 10' lower after 
weather iterations isn't likely to make any radical changes on the map, and if 
you really wanted to, could make that adjustment before running the weather code 
(it really comes down to how much water you want).

  We're not trying to mimic an entire planet creation - what we're really 
wanting to do is run the weather code to fill in some of the features.

  If we start worrying about sea level, then you could start making cases like 
lots of forest would reduce CO2 content, thus making the area colder.  Its 
easier to just start with some constants, like sea level is X (on earth, only 3% 
of the water is fresh water, and of that 3%, 69% is locked as glacier and 
icecaps (I'd venture amount if glaciers is relatively low)).  So if doing a 
continent not at the polar regions, only talking about maybe 1% of the water 
being on that continent?


>
     
     >
      hmm, hacking the weather code to include a water table would have some
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      merit to it (for one thing, the quick hack would be to determine
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      porous rock depth by archetype, so deserts might still get rain, but
     >
      they would have lots of porous rock, so the water would never stay on
     >
      the surface (yes, I realise that is not even vaguely what deserts
     >
      actually are, but it would at least stop puddles forming....)
     
  There is certainly some evaporative effect.

  That said, I don't really know if we need to know how porous the rock is - I'd 
just assume go without that and see what we get.

  Swamp would more be determined by water sitting there, eg, ground is flat 
enough that the water doesn't really have anyplace to flow, and temperature is 
such that the water doesn't evaporate.

  Adding porous seems to add yet another complication which I'm not sure we need 
- we're not trying to perfectly imitate earth here, were just trying to get a 
system that seems to work good enough.

  I never really liked the puddles much - perhaps because they were just so 
oversized related to the actual terrain (in some cases, being the size of 
lakes).  I personally don't think  we need that visual indicator, but rather, 
knowing rainfall and potentially having terrain evolve (or more appropriate, 
grow plants and herbs) would be the more interesting bits.

  That's actually one reason I play without weather - I just found all the 
puddles to be visually distracting without adding much.


    


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