Command functions are traditionally named like the command shortened
to four characters. When this name collides with a keyword or library
function, we abbreviate more: brea(), rea(). A few are unabbreviated,
e.g. execute(). A few have different names, e.g. explain(), not
list().
Commit 23726b379 (v4.3.0) suppressed a GCC warning about carg()
colliding with its built-in function.
Ron Koenderink reported Microsoft Visual Studio 2019 fails to link:
"_carg already defined in ucrtd.lib(ucrtbased.dll)".
Time to clean this up: rename the functions to c_FOO(), where FOO is
the unabbreviated name of the command.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
When the lot being bid for goes away and gets reused while the player
is at the prompt for the destination sector, comm.com_amount gets
stale. We use it before we detect the change and fail the command
This can lead to a misleading ""You don't have that much to spend!"
error. Messed up when the code was fixed to deal with lot changes in
4.0.2.
Fix by checking for lot change earlier.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
When the lot being bid for changes while the player is at the "How
much" prompt, we report "Commodity #%d has changed!", and continue
with the changed lot.
If continuing is okay, we should keep quiet. We did that until commit
40b11c098 "Fix buy not to wipe out concurrent updates", v4.3.27. Okay
when only the lot's price changed.
However, the lot could have gone away, or even be reused for something
else. Failing the command seems safest for the player, so do that.
It's how we use the check_FOO_ok() elsewhere.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Engineers can work even when loaded on a ship or land unit. They
happily raise sea sector efficiency. That's just wrong. It's
questionable even on land, because unloading need not be possible.
Has been that way since the command was added in Empire 2.
Add the missing check.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The work required for building sea sectors is zero in sect.config.
When a deity runs neweff or production on a sea sector, e.g. with
"neweff *", buildeff() divides by zero. Same when a player or deity
runs work with an engineer in a sea sector. Broken in commit
2ffd7b948 "config: Make work to build sectors configurable", v4.4.0
Fix buildeff() to avoid the division. Change the required work to 100
in sect.config for good measure.
Cover deity use of neweff and production in tests/update.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Each point of gold resource is worth 5d. Except for mountains, where
it's just 3.75d. This is because a mountain's process efficiency is
only 75%. Has been that way since Empire 3 made mountains mine gold.
This is actually a needless complication: a sector with 75% process
efficiency produces just like one with 100% process efficiency and 75%
of the resource.
Increase mountain process efficiency to 100%. Deities may want to
compensate by adjusting mountains' gold resources.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The work required for a product is traditionally the amount of raw
materials, plus 1 for resource usage, or 1 if using neither. Make it
independently configurable instead, via new product selector bwork,
backed by new struct pchrstr member p_bwork. Keep the required work
exactly the same in the default configuration.
Clients that compute work from materials need to be updated. Easy,
since build work is now exposed in xdump.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
External use of prod_materials_cost(), prod_resource_limit() went away
in commit 4a714a37d "production: Use update code instead of
duplicating it", v4.4.0.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
We reject satellites, ABMs, anti-ship missiles, and SAMs. That's
enumerating badness. More robust replacement: accept only bomber,
tactical, cargo, except for anti-ship missiles.
Throw in PLN_LAUNCHED sanity checking while there.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Any plane may have capabilities VTOL, helo, light.
Capability missile requires VTOL.
Anti-ballistic missiles have capabilities missile, SDI.
Anti-satellite missiles have capabilities missile, satellite.
Surface-to-air missiles have capabilities missile, intercept.
Anti-ship missiles have capabilities missile, marine, and may have
tactical.
Surface-to-surface missiles have capability missile, and may have
tactical.
Satellites have capability satellite, and may have spy, image.
Ordinary planes may have capabilities bomber, tactical, intercept,
cargo, spy, image, ASW, para, escort, mine, sweep. Capability para
requires cargo; see para().
Only "missile requires VTOL" is enforced. Enforce the rest.
Excluding P_O when asking for P_N is now redundant. Drop that from
msl_abm_intercept().
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Their impact on the target does not depend on shell load (it sometimes
did for a-sats until commit cf960a573 "Make anti-sat launch consistent
with interception", v4.3.23). The shell use is logistical busy-work,
and economically irrelevant. Remove it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The asat's impact on the target does not depend on its shell load (it
sometimes did until commit cf960a573 "Make anti-sat launch consistent
with interception", v4.3.23). The shell use is logistical busy-work,
and economically irrelevant. Remove it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Marine missiles can't actually support, see perform_mission(). Make
the mission command reject them.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The mission code doesn't treat SAMs specially: they take off, fly out,
maybe fight, fly home, and land. Landing triggers the oops in
pln_put1().
Letting SAMs escort makes no sense. Fix the mission command to reject
them.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Option DEFENSE_INFRA was replaced in commit 4d1dd6fa6, v4.3.6. Point
to the replacement instead.
Options SHIPCHOPPERS and XLIGHT were made non-optional in Empire 2.
Don't mention them.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Unused since commit beedf8dce "retreat: Rewrite automatic retreat code
to fix its many bugs", v4.3.33.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Stale since commit 6ac9ad66e (v4.3.20) silently dropped dead code for
supply of military. Dead since commit 689f435af (v4.2.14) dropped
option GRAB_THINGS.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
get_dlist() collects defending land units in a list, and resupplies
them. Bug: it uses a local copy instead of the one in the list. When
att_fight() writes back the list, the commodities supplied get wiped
out, triggering a seqno oops. Broken in commit 62b9399cd "subs:
Factor lnd_insque() out of lnd_sel(), ask_olist(), ...", v4.3.33.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Commit 555de3100 (v4.3.0) added these macros so xdump tables loan and
treaty can share an agreement_statuses table. Treaties are gone since
commit a109de948 (v4.3.33). Drop the macros.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Portability issue: prototypes.h uses enum ns_seltype, defined in
nsc.h. GCC is fine with that; it supports incomplete enum types as an
extension. Broken in commit 157ae8ec2 "Clean up superfluous include
of nsc.h in prototypes.h", v4.3.27. Moving sarg.c stuff to nsc.h
fixes it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
C99 requires at least one argument for the "..." in a variadic macro.
GCC and Clang don't care, but warn with -pedantic. Solaris cc warns.
The warning is easy to avoid, so do it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
MY_LIB_READLINE tries each readline-compatible library with a sequence
of additional libraries, starting with none. If the check with none
fails, all the others checks reuse the cached result, and also fail.
Broken in commit 1cbda2c7d "client: Rewrite readline configuration",
v4.4.0.
Avoid the unwanted chaching.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The test scripts need a POSIX-compliant Bourne shell. /bin/sh isn't
on some systems, such as Solaris. Run them with $(SHELL).
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The default SHELL isn't POSIX on some systems, such as Solaris. Use
the one Autoconf chooses instead of the default.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Solaris 10's nroff can't deal with the lengthy .NF ... .FI: it
complains, writes truncated output, and terminates
successfully (*boggle*). Split the .NF ... .FI in two.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Commit 23373d01d "configure: Test compiler flags" (v4.4.0) made
configure test whether compiler flags work, to let us use flags that
work only for some compilers.
Unfortunately, the Sun C compiler accepts invalid options with a
warning, breaking the test. Observed on Solaris 10.
Fix by testing the compiler flags only when AC_PROG_CC detected GCC.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
plane damage() prints @noisy with snprintf() even when it's null. It
doesn't actually use the output then. Some systems (GNU, Windows)
deal gracefully with printing null strings, others crash. @noisy is
null when bombers or missiles miss and do collateral damage. Affects
bomb, launch, and interdiction missions. Broken in commit 820d755e5
"subs: Change pln_damage()'s parameter noisy to string prefix",
v4.3.33.
Fix by guarding the snprintf().
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Document the need for the XSI Extension. Don't list curses as
required, it's actually optional. Correct advice for Solaris. Add
advice for AIX. Drop references to C89; we actually require C99, and
POSIX.1-2001 provides it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
We require POSIX.1-2001. Some systems provide it only with feature
test macro _POSIX_C_SOURCE defined to 200112L. Since we don't define
it, the build fails there. Observed on Solaris 10.
We actually require the XSI extension. The GNU C Library provides it
by default. With _POSIX_C_SOURCE 200112L, however, you have to define
feature test macro _XOPEN_SOURCE to get it. But then _POSIX_C_SOURCE
is redundant.
Make configure put #define _XOPEN_SOURCE 600 into config.h. Drop the
two existing #define _XOPEN_SOURCE 500 in .c files.
Now Solaris cc refuses to play ball unless switched to C99. Replace
AC_PROG_CC by AC_PROG_CC_STDC to mollify it.
Unfortunately, use of _XOPEN_SOURCE exposes bugs in AIX libc and old
versions of GNU libc:
* AIX defines struct in6_addr's member s6_addr as a macro expanding
into the actual member. Without _ALL_SOURCE (the default), the
expansion is wrong and doesn't compile. Observed with AIX V7.2.
* GNU lib's IN6_IS_ADDR_V4MAPPED() is unusable without
_DEFAULT_SOURCE (default) or _GNU_SOURCE. Observed with Debian 8.
Tracked at <https://sourceware.org/bugzilla/show_bug.cgi?id=16421>,
fixed in version 2.25.
Affects just sockaddr_ntop()'s special case from commit 372cdb136 "Use
IPv4 format for IPv4-mapped addresses", v4.3.31. Disable the special
case and use IPv6 format on such systems. This is a very minor
usability regression. Could be avoided, I guess, but it's not worth
the trouble.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
getpass() is traditional Unix, but has been withdrawn from POSIX. We
still use it when it's available, and fall back to portable code only
when it's not.
The portable code behaves differently: it reads stdin instead of
/dev/tty, and in noncanonical mode.
Simplify things: always use the replacement.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
getpass() is traditional Unix, but has been withdrawn from POSIX. We
provide a replacement in case it's missing. The one for Windows
suppresses echo, like getpass() does. Implement that for POSIX. The
other differences to getpass() remain.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
I'm going to drop use of getpass(). As a first step, weaken the bond
by hiding it in a separate function.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
lwpSigWait() was designed to resemble sigwait(). It doesn't anymore.
Drop the awkward argument, and use the return value instead.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
LWP's use of sigset_t is problematic.
To iterate over a sigset_t, it uses NSIG, which is not portable: BSD
and System V provide it, but it's not POSIX.
To record signals caught, it updates a sigset_t variable from a signal
handler. The variable isn't volatile, because we'd have to cast away
volatile for sigaddset().
Replace sigset_t by an array of signal numbers terminated with 0.
Since lwpInitSigWait() needs to store the signal set for
lwpCatchAwaitedSig() anyway, there is no need to pass it to
lwpSigWait(). Drop its parameter.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
lwpSigWait() clears LwpSigCheck even when signals remain in
LwpSigCaught. The next empth_wait_for_signal() will then wait until
another one gets caught. Broken in commit fe2de3d74, v4.3.10.
Fix by clearing it only when LwpSigCaught is empty.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
sigismember() fails when passed an invalid or unsupported signal
number. lwpInitSigWait() and lwpGetSig() treat sigismember() failure
like "is a member". lwpInitSigWait() will then sigaction()
unsuccessfully. Harmless. lwpGetSig() returns the bad signal number
when it's greater than any caught signal's number. The bad signal
number then gets returned to main(), which shuts down the server.
Fix by treating failure like "is not a member".
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
lwpCatchAwaitedSig() is not reentrant. lwpInitSigWait() attempts to
protect it by setting an appropriate signal mask, but screws up. This
could conceivably lose signals. Messed up when it got added in commit
7183516d9, v4.3.6. Fix it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
lwpSigWait()'s contract specifies failure, which means oopsing is
wrong. Harmless, as its only caller empth_wait_for_signal() oopses on
failure. Drop it anyway.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
We get strncasecmp() from <string.h>. This is a BSDism; POSIX
provides it in <strings.h>. Missed in commit 8fdd0259f2, v4.2.19.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Commit fad8e7f7b "Move auxiliary build tools to build-aux/" moved
depcomp, but neglected to adjust Make.mk. This broke the build with
tool chains that actually use depcomp. Modern GCC and Clang don't.
Fix the obvious way.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Configuration tables product, sect-chr, ship-chr, plane-chr, land-chr,
nuke-chr have a bit of extra space deities can use for customizing
their games. Give them more: enlarge product from 23 to 31
entries (plus one sentinel), sect-chr from 39 to 63, ship-chr from 47
to 127, plane-chr from 47 to 127, land-chr from 31 to 127, and
nuke-chr from 20 to 63.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Macros LND_TYPE_MAX, N_MAXNUKE, PLN_TYPE_MAX, P_MAX, SCT_TYPE_MAX,
SHP_TYPE_MAX are only used to size a single array each. Eliminate.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Don't use ALL CAPS for headings. Reformat them in the style
recommended by doc/coding. Drop a few comments that aren't pulling
their weight, and fix the odd typo.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
qprint() was carelessly added at the end of the file in Empire 2,
where it's under the "Write a script for placing capitals" headline.
Move it to a more sensible place.
NUMTRIES was added behind the global variables in Empire 2. Move it
before them, and reformat its comment.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Replace own[x][y] by own[XYOFFSET(x, y)], and narrow the element type
from int to short. Takes a fourth the space.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The previous commit's interpolation tables reproduce the historical
linear functions faithfully. This exact fit requires an awkward data
point in each of the tables for iron fertility and oil. Drop them.
No double-valued data points remain. Adjust struct resource_point
member @res to int.
This results in slightly less rural iron (33 elevations down one
point), fertility (10 elevations down one point) and oil (14
elevations down one point, 5 down two points). Only resource values
less than 100 are affected.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The functions mapping elevation to resources are piecewise linear.
Replace them by linear interpolation on data points defined in tables.
Tables are easier to tweak for deities than code.
The data points are a bit awkward because the functions they replace
are. The next commit will tweak them to address that.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The functions mapping elevation to resources are piecewise linear,
except for set_oil(), which randomly adds 1 to sea oil, and
set_gold(), which is isn't linear for mountains, but very close.
Drop the random oil bit, and replace the non-liner gold function by a
linear one. Both resources decrease at most by one point.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Land elevation is computed by first placing mountains, then elevating
land to fit.
Mountains placement is a weighted random sampling. A sector's weight
is its distance to sea capped at five and squared.
Non-mountain, non-capital sectors get assigned equidistant elevations
from 1 up to 97 rounded to integer in an order that depends on
distance to mountain and distance to sea, both capped at 5. Mountains
get equidistant elevations starting at 98 (see recent commit
"fairland: Fair mountain resources"). Capitals get 36.
Sea elevation is randomly chosen from a range that depends on the
sector's distance to land. The range increases from [-27,-1] next to
land to [-127,-1] for distance 5 and up.
Without mountains, the result is boring: elevation increases pretty
much linearly with the distance from the coast, i.e. each islands is a
single cone. With mountains, we get one cone per mountain. The sea
sea elevations are basically noise.
Worse, it's buggy: mountain placement can place fewer mountains than
requested. The weighted random sampling assigns weights even to
sectors that cannot be picked (capitals and sectors that have been
picked already). When the dice land on such a sector, it instead
picks the next one (in island growth order) that can be picked. If
there is no next one, the mountain is not placed. This is a fairness
issue.
Impact varies with fairland parameters. For 60 sector islands with 5%
mountains, around one in 10000 islands is short one mountain in my
testing. For 10 sector islands with 50% mountains, some 760 out of
10000 islands are short one sector, 80 short two, and five short
three. The numbers get worse as spikiness increases.
Undocumented misfeature: the placement loop is limited to 1000
iterations, supposedly to catch a runaway loop. Since the loop
iterates exactly once per mountain, all this accomplishes it limiting
mountains to 1000 per island.
When too few mountains are placed, the loop assigning elevations to
non-mountain, non-capital decrements elevations below 1. Since
Chainsaw 3, such elevations then get mapped to 1, plastering over the
bug. We get non-mountain sectors with elevation 1 instead of
mountains.
Rewrite as follows.
Use a simple random hill algorithm to assign raw elevations:
initialize elevation to zero, then randomly raise circular hills on
land / lower circular depressions at sea. Their size and height
depends on the distance to the coast, capped at 3. After a sufficient
number of iterations, the resulting terrain has a "natural" look.
This is elevate_prep().
elevate_land() then sorts non-capital sectors by raw elevation. The
highest become mountains. Sectors get assigned the same equidistant
elevations as before, just in raw elevation order.
elevate_sea() simply normalizes raw elevation to [-127,-1].
Elevations now show a nice undulating pattern independent of mountain
percentage.
Implementation detail: replace elev[x][y] by elev[XYOFFSET(x, y)], and
narrow the element type from int to short. Takes a fourth the space.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
elevate_land() computes the sequence of elevations 97, 97 - delta,
... in fixed point with a scaling factor of 100. Switch to
floating-point, because it's simpler. Elevations (and thus resources)
change slightly due to reduced rounding errors.
Note that we map elevations less than 1 to 1 both before and after the
patch. Odd. Turns out this mitigates a bug: mountain placement can
place fewer mountains than it should, and when that happens,
elevations go below 1 here. The next commit will fix this.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Elevations 34 and 35 are reserved for coastal mountains. When an
elevation computed for a non-mountain falls in that band, it's
adjusted to 36.
This is unnecessary since the previous commit; drop. Test output
shows the dropped elevation adjustment.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
For fairness, fairland aims to make islands of the same size consist
of the exact same sectors, just individually arranged.
It fails to achieve its aim for mountains: their elevation is random,
34 or 35 for coastal mountains, and between 98 and 254 (two dice) for
non-coastal ones. Elevation determines resources. Mountains get 89
gold on average (between 80 and 93), except for coastal mountains,
which get none. It didn't really matter until Empire 3 made mountains
produce gold dust. Since then, it's unfair.
Set mountain elevation to 98 + i * delta, where i is the mountain
number (starting at zero), delta is (127 - 98) / max_mn, and max_mn is
the maximum number of mountains an island could have. This puts the
highest mountains on the largest islands.
Non-coastal mountains have slightly less gold than before, coastal
mountains have much more.
Mountains can still be unfair, because fairland can screw up their
number. To be fixed soon.
Avoid elevations 34 and 35 for non-mountain, non-capital sectors
doesn't make sense anymore. The next commit will get rid of it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
distance_to_land() searches for closest land sector, and
distance_to_sea() for the closest sea sector. We already have a more
efficient alternative: the breadth-first search recently added for
spheres of influence can precompute these distances. Put it to use,
and retire distance_to_land() and distance_to_sea().
distance_to_what() could now be simplified. Don't bother, because
it'll soon be deleted entirely.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
When an island gets placed too close to the edge of the sphere of
influence, its side facing the edge will likely be formed by the edge.
Looks unnatural, and can give a clue on the location of the other
continent.
Make place_island() prefer sectors away from the edge: instead of
picking one of the admissible sectors with equal probability, reduce
the probability as we get closer to the edge.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Planned island sizes are random with an expected value that matches
the average size requested by the user. Can be off quite a bit when
the number of islands is small. Also, actual island size can be
smaller than planned size when space is tight.
Instead of picking random island sizes independently, pick a random
split of their requested total size.
To reduce the probability of islands not growing to their planned
size, grow large islands before smaller ones.
To compensate for inability to grow, carry the difference over to the
next island size.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The previous commit reduced the difference in island size within the
same batch of islands to at most one. Eliminate the remaining
difference by shrinking the bigger islands by one sector.
This invalidates the precomputed exclusive zones, so recompute them.
fairland-test needs a tweak to avoid loss of test coverage.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The previous commits changed grow_island() to create islands in
batches consisting of one island per continent, all of the same
planned size. grow_island() still places and grows one island after
the other. When an island can't grow to the actual size, the others
in the same batch are not affected. Island size can therefore differ
a lot within the same batch.
Change grow_island() to interleave the work on a batch's island: first
place them all, then add one sector to each in turn. Stop after all
reached the planned size, or one or more could not be grown further.
This is similar to how we grow continents: drift() places them all,
and grow_continent() adds one sector to each continent in turn.
Island size within the same batch can now differ at most by one
sector. The next commit will eliminate that remaining difference.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The previous two commits put the same number of islands closest to
each continent. This one makes their planned sizes match: instead of
rolling dice separately for each island's size, we roll dice only for
the first continent's islands. The other continent's islands get the
same sizes.
Actual island sizes still differ when islands can't be grown to their
planned size. To be addressed next.
fairland-test needs a tweak to avoid loss of test coverage.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The previous commit made island distribution more fair by placing
islands close to a continent in turn. This is still unfair when
fairland can't place all the islands.
Make grow_islands() fail when it can't place all islands, and main()
start over then, just like it does when grow_continents() fails.
Deities can no longer fill the world with islands by asking for a
impossibly high number of islands. Tolerable loss, I think.
fairland-test needs a tweak to avoid loss of test coverage.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
fairland places islands of random size in random places, subject to
minimum distances. Results are often less than fair, in particular
when the number of islands per continent is low: some continents have
more land nearby than others. Increasing distances between islands
doesn't help much. Deities commonly run fairland until they find the
result acceptable.
The next few commits will tackle this issue. As a first step, this
one places islands closest to continents in turn, so that each
continent is closest to the same number of islands. A continent is
closest to an island when it is closest to each of its sectors.
The number of islands must be a multiple of the number of continents
now.
Since fairland may be unable to place all islands, a continent may
still get fewer islands than it should. The next commit will address
that.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
A continent's sphere of influence is the set of sectors closer to it
than to any other continent. The next commit needs this. Compute the
spheres with a breadth-first search.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
dirx[] and diry[] are redundant with diroff[][]. Convert the
remaining uses, and drop the arrays.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
grow_one_sector() picks a coastal start sector, then moves along the
coast trying to add an adjacent sector to the island.
It operates in spiking mode with a chance of @sp percent.
When spiking, the neighbors with sea on both sides are preferred. For
instance, when the area around the sector being considered looks like
this
- .
- - .
- .
then the neighbor in direction j is preferred, because it has sea in
directions u and n. No other neighbor is preferred.
The start sector is the first coastal sector found in a linear search
in growth order, starting at the last sector grown when spiking, or
else at a random sector. This is new_try().
grow_one_sector() tries adding a neighbor in clockwise order, starting
with a random direction. When spiking, it goes around the clock two
times, trying only preferred sectors in the first round.
When it can't add a neighbor, it moves to the next coastal sector with
next_coast().
Taken together, this randomly picks one element from the set of
pairs (S, D) where the sector in direction D off base sector S can be
added to the island. How does the probability distribution look like?
Bias: a sector's probability to be added to the island land increases
with the number of base sectors it is adjacent to. This tends to fill
in bays and lakes, which is fine.
Bias: coastal sectors following runs of non-coastal ones are more
likely to be picked as start sector. Perhaps less of an issue when
spiking, where the pick is not intended to be random.
Bias: a pair (S, D) is more likely to be picked when base sector S
follows a run of coastal sectors that aren't base sectors, or
direction D follows a a run of directions that don't permit growth.
The impact of these two biases is not obvious. I suspect they are the
reason behind the tendency of large islands to curve around obstacles
in a counterclockwise direction. This can result in multiple islands
wrapping around a central one like layers of an onion.
Bug: the move along the coast is broken. next_coast() searches for
the first adjacent sea in clockwise order, starting in direction g,
then from there clockwise for a sector belonging to the island.
Amazingly, this does move along the coast in a clockwise direction.
It can get caught in a loop, though. Consider this island:
-
- - -
-
If we start at the central sector (marked 0), the search along the
coast progresses like this:
1
- 0 2
-
It reaches the central sector again after three moves (to 1, to 2,
back to 0), and stops without having reached the two sectors on the
left.
If we start with the leftmost sector, the search loops: 0, 1, 2, 3, 1,
...
2
0 1 3
-
grow_one_sector() ensures termination by giving up after 200 moves.
Nuts!
Because of this, grow_one_sector() can fail when it shouldn't, either
because the search along the coast stops early, or goes into a loop,
or simply because there's too much coast. The latter should not
happen in common usage, where island sizes are in the tens, not the
hundreds.
Clean up this hot mess by rewriting grow_one_sector() to pick a sector
adjacent to the island with a clearly defined probability, as follows.
Use weighted random sampling to pick one sector from the set of
possible adjacent sectors.
When spiking, a sector's weight increases with number of adjacent sea
sectors. This directs the growth away from land, resulting in spikes.
When not spiking, the weight increases with the number of adjacent
land sectors. This makes the island more rounded.
To visit the adjacent sectors, grow_one_sector() iterates over the
neighbors of all island sectors, skipping neighbors that have been
visited already.
This produces comparable results for low spike percentages. The weird
onions are gone, though.
Noticeable differences emerge as the spike percentage grows. Whereas
the old one produces long snakes that tend to curve into themselves,
the new one produces shorter spikes extending from a core, a bit like
tentacles. Moreover, islands are more centered on their first sector
now. The probability for coastal capitals is lower, in particular for
moderate spike percentages.
I consider this improvements.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
2021-01-05 10:41:36 +01:00
45 changed files with 163 additions and 281 deletions
