The fire command requires at least one gun for depth charging, but
missions and return fire don't. Has always been that way, except
between 4.0.6 and commit a3ad623 (v4.3.12), when depth charging worked
exactly like gun fire, and guns were consistently required.
Require guns for all ways to drop depth charges.
Why upgrade? I'm not a lawyer, but here's my take on the differences
to version 2:
* Software patents: better protection against abuse of patents to
prevent users from exercising the rights under the GPL. I doubt
we'll get hit with a patent suit, but it's a good move just on
general principles.
* License compatibility: compatible with more free licenses, i.e. can
"steal" more free software for use in Empire. I don't expect to steal
much, but it's nice to have the option.
* Definition of "source code": modernization of some details for today's
networked world, to make it easier to distribute the software. Not
really relevant to us now, as we normally distribute full source code.
* Tivoization: this is about putting GPL-licensed software in hardware,
then make the hardware refuse to run modified software. "Neat" trick
to effectively deny its users their rights under the GPL. Abuse was
"pioneered" by TiVo (popular digital video recorders). GPLv3 forbids
it. Unlikely to become a problem for us.
* Internationalization: more careful wording, to harden the license
outside the US. The lawyers tell us it better be done that way.
* License violations: friendlier way to deal with license violations.
This has come out of past experience enforcing the GPL.
* Additional permissions: Probably not relevant to us.
Also include myself in the list of principal authors.
The automatic supply interface has design flaws that make it hard to
use correctly. Its current uses are in fact all wrong (until commit
0179fd86, the update had a few uses that might have been correct).
Some of the bugs can only bite with land unit capability combinations
that don't exist in the stock game, though.
Automatic supply draws supplies from supply sources in range. Since
that can update any supply source in range, all copies of potential
supply sources a caller may keep can get invalidated. Writing back
such an invalid copy wipes out the deduction of supplies and mobility
from a source, triggering a seqno mismatch oops.
This commit redesigns the interface so that callers can safely keep a
copy of the object drawing the supplies (the "supply sink"). The idea
is to pass the sink to the supply code, so it can avoid using it as
source. The actual avoiding will be implemented in a later commit.
Copies other than the supply sink still need to be eliminated. See
commit 65410d16 for an example.
Other improvements to help avoid common errors:
* Supply functions are commonly used to ensure the sink has a certain
amount of supplies. A common error is to fetch that amount
regardless of how many the sink already has. It's more convenient
for such users to pass how many they need to have instead of how
many to get.
* A common use of supply functions is to get supplies for immediate
use. If that use turns out not to be possible after all, the
supplies need to be added somewhere, which is all too easy to
forget. Many bugs of this kind have been fixed over time, and there
are still some left. This class of bugs can be avoided by adding
the supplies to the sink automatically.
In fact, this commit fixes precisely such bugs in mission_pln_equip()
and shp_missile_defense(): plane interception and support missions,
missile interception (abms), launch of ballistic missiles and
anti-sats could all lose shells, or supply more than needed.
Replace supply_commod() by new sct_supply(), shp_supply(),
lnd_supply(), and resupply_all() by new lnd_supply_all(). Simplify
users accordingly.
There's just one use of resupply_commod() left, in landmine(). Use
lnd_supply_all() there, and remove resupply_commod().
Commit a3ad623b (v4.3.12) made depth charging fail when there's just
one shell. This let players find all submarine uids. It basically
reopened the loophole closed in commit aa26c53e (v4.2.20).
Fix by making shp_dchrg() with just one shell succeed and return
damage like fire from one gun.
Checking l_ammo before lnd_dam() oopses when something attempts to
fire from a land unit type that can't fire (l_dam == 0) and uses no
ammo. Such usage is perfectly fine. Move the check to the correct
place.
New lnd_att(), lnd_def(), lnd_vul(), lnd_spd(), lnd_vis(), lnd_frg(),
lnd_acc(), lnd_dam(), lnd_aaf() replace the struct lndstr members with
the same names.
Make land unit selectors att, def, vul, spd, vis, frg, acc, dam, aaf
virtual.
This takes care of a number of bugs / inconsistencies:
* Resupply before fire: fire command did not require unit to be in
supply, and resupplied shells. Everywhere else (return fire,
support and interdiction) the land unit had to be in supply after
resupply of everything. Unify not to resupply anything and not to
require being in supply. This is consistent with ships and sectors.
* Resupply after fire: fire command resupplied shells after active
fire. Unify not to do that. This is consistent with ships and
sectors.
* When a land unit returned fire to multiple attackers, quiet_bigdef()
charged it ammo for each one. Finally, it was charged one shell
more by use_ammo(). Except only the first land unit got charged
there in fact, because buggy add_to_fired_queue() entered only the
first land unit into the defender list. Fix add_to_fired_queue()
and change quiet_bigdef() not to charge ammo, just like for ships
and sectors. This charges only one shell instead of the true ammo
use, which is wrong, but consistent with ships.
* lnd_support() tallied support damage unrounded. Unify to round
before tally.
This takes care of a number of bugs / inconsistencies:
* Submarines with zero mobility could interdict. Change to require
positive mobility.
* Submarines with zero firing range could not interdict. Fix by
dropping the test from perform_mission(). No ships in the stock
game are affected.
* Submarines without capability torp could fire return torpedoes and
interdict. Stock sbc, nm and msb were affected by the return fire
bug. Closes bug#950936.
* Shell resupply bugs: quiet_bigdef(), fire_torp() and
perform_mission() resupplied before checking all other requirements
and could thus get more shells than actually needed.
torp() no longer resupplies shells. It's hardly worth the bother, and
fire doesn't do it either.
This takes care of a number of bugs / inconsistencies:
* Ships with zero firing range could return fire and fire support, but
not fire actively or interdict. Fix by testing for gun limit
instead in multifire() and mission(). No ships in the stock game
are affected.
* Required gun crew was inconsistent: multifire() let N military fire
max(1,floor(N/2)) guns for active fire. Ditto perform_mission() for
interdiction. quiet_bigdef() let them fire N guns for returning gun
fire. Ditto sd() for firing support and firing at boarding parties.
fire_dchrg() let them fire floor(N/2) for returning fire to
torpedoes. Unify to let N military fire floor((N+1)/2) guns.
* Shell use was inconsistent: sd() and perform_mission() used one
shell per gun, everything else one per two guns. Unify to one shell
per two guns.
* Shell resupply bugs: multifire() got two shells regardless of actual
ammo use. quiet_bigdef() got one shell (but use_ammo() uses only
one, which is a bug). sd() and perform_mission() resupplied before
checking all other requirements and could thus get more shells than
actually needed.
Before 4.0.6, depth charges required no guns, one military, did damage
like shell fire from two guns, and used two shells. Missions were not
quite consistent with that (bug). 4.0.6 changed depth charges to work
exactly like shell fire (but without updating documentation
accordingly): require guns and gun crew, non-zero firing range, scale
damage and ammunition use with guns.
Go back to the old model, but with damage like three guns, to avoid
changing the stock game's dd now (three gun damage for two shells).
Stock game's af changes from two gun damage for one shell, and nas
from four gun damage for two shells.
Factor out common depth-charging code into shp_dchrg().
This takes care of a number of bugs / inconsistencies:
* sb() fired support even when there were not enough mil.
* Shell resupply bugs: multifire() and quiet_bigdef() resupplied
shells before checking all other requirements and could thus get
more shells than actually needed.
Rename landgun() to fortgun() for consistency.
other. Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special). New header types.h to
help avoid inclusion cycles. Sort include directives. Remove some
superflous includes.
(ltend, multifire, quite_bigdef, mine, landmine)
(do_loan, prod, printdiff, sell, sona, stre)
(tend, fire_dchrg, vers, work, ac_planedamage)
(ac_shipflak, ask_off, get_mine_dsupport, att_fight)
(ask_move_in_off, detonate, sd, land_gun)
(land_unitgun, lnd_fort_interdiction, lnd_fortify)
(perform_mission, pln_mine, pln_mobcost)
(retreat_ship1, retreat_land1, shp_sweep)
(shp_fort_interdiction, shp_missle_defense)
(new_work, growfood, upd_land, land_repair)
(get_materials, do_mob_ship, do_mob_land)
(load_it, unload_it, prod_plane, produce)
(guerrilla, upd_buildeff, spread_fallout)
(upd_ship, ship_repair, min, dmin, MIN):
Remove min() and dmin() functions and replace
with a MIN macro in misc.h. Remove local MIN
macros and use the new one in misc.h. This
change removes the need for the special
case for _WIN32.
(fuel, look_ship, multifire, mission, sona)
(plane_sona, ef_open, player_accept, player_main)
(ac_dog, att_get_combat, calc_mobcost)
(ask_move_in_off, intelligence_report)
(build_mission_list_type, perform_mission)
(show_mission, use_supply, dodistribute)
(allocate_memory, max, dmax, MAX):
Remove max() and dmax() functions and replace
with a MAX macro in misc.h. Remove local MAX
macros and use the new one in misc.h. This
change removes the need for the special
case for _WIN32.
