[Freeciv-Dev] Re: (PR#2957) is ocean as a function with oceanness read from ruleset

["kayeats@xxxxxxxxxxxxxxxxxxxxxxxxx via RT" <rt@xxxxxxxxxxxxxx>]

Here is my vision of things which I think answers both your concerns.

In the foreseeable (though not immediate) future it should be possible
that there be no references to T_<terraintype>.  It will necessitate new
ruleset flags, but the result would be a lot less hard-coded stuff so much
more exotic modpacks could be easily made.  Also there are interesting
steps along the way (like ocean shelf done properly).  If terrains are
going to be in the ruleset it makes sense to me that they be as fully in
the ruleset as possible -- at least as a long-ish term goal.

Take a look at the code; terrain types are only specifically referenced in
a manageable number of places:

<DETAILS: skip to END to get back to general discussion>

client/tilespec.c: used for various display reasons, I don't know this
code at all, so this is the one case I can't vouch for being able to do
away with.

common/map.c:
        terrain_is_clean, and is_starter_close: need to know the good base
terrain types (grass and plains), this can either be calculated somewhere
based on f/p/t of each type or could be a flag.  Also need to know about
rivers (one flag).
        is_good_tile, something comparable should be calculable from the
f/p/t of each type; it's only used to place starting positions.
        is_water_adjacent_to_tile, river and ocean flag needed
That's all for map: between 2 and 3 ruleset flags needed (including ocean)

common/terrain.h
        T_'s are defined here

server/mapgen.c
        make_<terrain>: two possible solutions to this.
                1) if something similar to my mapgen patches #2749 +- 1
gets in (incidentally Ross Wetmore had a good suggestion on how to fix his
largest concern with that patch which I intend to code up soon...) then
a half dozen or so parameters are sufficient to determine the placement of
a given terrain, along with a river flag and a polar flag to make the
polar strips.  I was working on a prototype of this but it isn't ready
yet.
                2) ultimately a mapgen which calls external stuff would
certainly solve the problem, no extra parameters needed since external
programs special to particular modified rulesets could be used.

        river code: again two solutions, or some combination of the two
                1) make rivers from the height_map, no flags needed
                2) use the new river flag to determine the affinity of a
terrain for rivers rather than as a boolean

        make_passable: This needs to know something about how to treat the
different types of ocean.  A non-boolean ocean flag should do the trick,
or it might be deduceable from the placing functions of each ocean type, at
worst an extra "default ocean" flag could do the trick.
        make_fair: needs to know a suitable non-base (not grass/plains)
terrain type to break up clumps of the base with.  Either calculable
from the f/p/t or at absolute worst another flag.  Really I don't see why
we couldn't do away with this function all together.
        make_huts: has a check for T_ARCTIC.  I'm not sure why that's
worthwhile but a polar flag should be good enough.
        gens 2-4 terrain placing: the placing function info used in the
make_<terrain> should be sufficient here also.

so we're up to a total of between 9 and 12 flags.  That's starting to get
a bit big.  The 6 terrain placing parameters could be combined together
into a string or list which would get parsed up.

server/maphand.c
        is_terrain_ecologically_wet: river and ocean flags would suffice
        global_warming and nuclear_winter: probably another ruleset
parameter each, though possibly deducible from what the terrains can be
transformed into along with f/p/t to make sure the players lose.  A proper
climate model would of course also do the trick but I don't expect that
anytime soon.

so we're up to something like 11 flags (best case 9 worst 14), or with the
terrain placing stuck together as one more complicated variable: 6.

server/sanitycheck.c one reference to T_ARCTIC which should be T_FIRST

server/settlers.c on a philosophical level the settlers should be able to
behave correctly just from info about terrain types.  This is probably a
longer term goal, though I don't know this code either so I can't really
say.

The sdl gui also uses the terrain types lightly, but the others do not so
it can't be unavoidable.

<END of DETAILS>


So this is what I see as possible and worthwhile.  Doing it all at once
would be unreasonable.  However it seems to me it can be done piecemeal.
This patch is one part which as well as being part of the large goal is
also a step towards the possible subgoal of ocean shelf.  6 or 11 new
flags is a fairly large number, but not unmanageably so.  Whether all this
would be worthwhile is of course not my decision to make.

Karen