Low-disruption first step towards removing the hardcoded cave liquid
code. Since MT 5.0.0 cave liquids can be defined and located by
biome definitions instead.
In games that do not yet use biome definitions to define and locate
cave liquids (MTGame does), lava will now appear below
y = water_level - 256 instead of below 'lava depth' (usually y = -256).
Therefore no change in most mapgens if using the default 'lava depth'.
Add mapgen parameters to set the range of the random number of
randomwalk caves per mapchunk, and to set the proportion that are
flooded with liquids.
Default values are, for now, unchanged from the previous hardcoded
values.
Add parameters to allow small randomwalk caves
Disabled by default for now as they have never been present in the
non-mgv6 mapgens.
Add user-settable noise parameters for dungeon density to each mapgen,
except V6 which hardcodes this noise parameter.
Move the calculation of number of dungeons generated in a mapchunk out
of dungeongen.cpp and into mapgen code, to allow mapgens to generate
any desired number of dungeons in a mapchunk, instead of being forced
to have number of dungeons determined by a density noise.
This is more flexible and allows mapgens to use dungeon generation to
create custom structures, such as occasional mega-dungeons.
Shorter, simpler, clearer and more consistent with other mapgens,
while preserving functionality.
Base terrain shape is unchanged.
With the 'vary river depth' option disabled, river surface level
is unchanged.
Behaviour of the 4 heat/humidity/river depth options is very
slightly changed due to bugfixes and code cleanup (the mapgen is
'unstable').
Apply heat and humidity gradients above water_level instead of
above y = 0.
Add 2 new mapgen flags to make river depth variation and humidity drop
with altitude independently optional, instead of both being enabled by
the 'humid rivers' flag.
Simplify and clarify related code by removing a low priority
optimisation regarding 't_heat'.
Remove unnecessary optimisation bools and use spflags directly instead.
Improve and fix documentation in settingtypes.txt.
A few minor code cleanups.
Split some long lines.
Edit comments.
Remove unnecessary comments and unnecessary commented-out code.
Use std::fmax/fmin instead of MYMAX/MYMIN.
Remove scope-limiting braces.
Consistently define literals as floats, except in noise parameters.
Cleanup literals in noise parameters.
Remove unnecessary 'near_cavern' line.
Reduce max spawn y to be consistent with other mapgens.
Caverns first appeared in mgvalleys and were later added to other
mapgens as shared code. Now this shared code can replace mgvalley's
internal cavern code.
Also use shared tunnel code instead of internal code.
Changes to mapgen that will affect existing worlds (mgvalleys is not
stable):
Single lava and water sources not added in tunnels.
Previous caverns are unchanged but an equal number of new ones are
added at a distance from the previous.
From y = -256 to 192 nodes below, where the caverns taper at their
upper limit, they will have a slightly different shape as the taper
is now linear.
