[Freeciv-Dev] [Patch] Watchtower version 2

[Bert Buchholz <bertbuchholz@xxxxxx>]

Okay, here the second version of my watchtower patch, I hope I included
everything that was discussed so far, but after all, I'm just a German.
;-)

Features:
Well, I listed them already, no need to do this again. BUT: This patch
is not dealing with any "fine grained control over vision range" (as
Raimar called it), which I think makes sense but makes a lot of changes
necessary, that are far beyond this patch (and my insight into the
code).

Up to now, following events regarding watchtowers are handled (there may
be more to handle which I didn't see):
- A fortress is pillaged (vr reduced)
- A town is built upon a fortress (vr reduced)
- A unit steps into a fortress (vr enhanced)
- A unit steps out of a watchtower (vr reduced)
- The necessary invention is made (all units inside fortresses get
  enhanced vr)
- A fortress is built (all units on that tile get enhanced vr)

*New*:
- A unit gets killed inside a fortress (vr reduced)
- A unit getting upgraded inside a fortress (vr mostly not changing)
- A unit is created on a fortress, for example barbarians, or a unit is
  being bribed (vr enhanced)

What about loading savegames? server/savegame.c, around 1126
I'm unfogging the necessary tiles, but there's another piece of code I'm
not sure of:

    {
      int range = get_unit_type(punit->type)->vision_range;
      square_iterate(punit->x, punit->y, range, x1, y1) {
        map_set_known(x1, y1, plr);
      } square_iterate_end;
    }

Obiviously, the vision_range would be different if the unit was in a
fortress, but I'm not sure what this does anyway because loading works
without changing this. Because map_set_known() is done inside
really_unfog_area() which is called by unfog_area(), which is being used
in connection with the watchtower's visionrange. Hmm, slightly confusing
:-)

Is this just for being on the safe side or has this a reason I'm
overlooking?

Another issue: Having in mind this change of visionrange-"calculation"
to a somewhat more fine grained version, it might be useful to replace
every 

unfog_area(unit_owner(punit), punit->x, punit->y,
               get_unit_type(punit->type)->vision_range);

with something like

unfog_area(unit_owner(punit), punit->x, punit->y,
               get_vision_range(punit));
               ^^^^^^^^^^^^^^^^^^^^^^^

This function get_vision_range() could include all these calculations
and conditions, if the unit is inside a fortress or upon a mountain or
whatever or in the swamps and return the fitting vision_range_index as
suggested by Raimar, here a quote:

|If the pythagorean distance is used it has to be dense. This is to
|prevent cases like if you get an increase by one and your current
|vision is 2.
|
|index            | 0  1  2  3  4  5  6
|square if radius | 0  1  2  4  5  8  9

But this can be spared for later, for now, this function could calculate
the visionrange and return it as it is done already (simply the radius
for the square being fogged/unfogged), because this would shorten the
code and make it much easier to read. And, the best, it could easily be
changed later to adapt to this fine-grain-stuff (could someone please
find a word for that ;-) I didn't wanna put this in now already, but I
think this is worth for being considered.

Again, I attached the (same) savegame, playername is swk, move on till
1540 and have a look...

Bert

PS: I'd love to check this by using the autoplay-feature, but seemingly,
the ai doesn't build fortresses. Is that correct?

fortress_watchtower_2.diff
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civgame1500.sav.gz
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