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.
Previously dungeons > decorations > ores.
Decorations depend on the node they are placed on, and ore types are
increasingly able to place large continuous volumes of nodes, such as
strata. Decorations are increasingly being used underground.
The new order avoids a node being changed by ore generation after a
decoration has been placed on it.
The new order also avoids ores appearing in the walls of a dungeon if
the wall nodes match the local stone node.
Make tunnels wider and use the noise parameters of most other mapgens.
All other underground features are already identical to all other
non-mgv6 mapgens, this final change modernises and improves the tunnels.
Previously the only way to disable biomes was to 'clear' the registered
biomes in a mod, but this method causes large amounts of unnecessary
processing:
1. Calculation of 4 2D noises.
2. Looping through all nodes of a mapchunk replacing nodes with identical
nodes.
The new flag disables those operations.
Previously, caverns confused tunnel generation causing biome top and filler
nodes to appear in caverns.
Split 'generateCaves()' into 2 functions to separate tunnel and large
randomwalk cave generation.
In each mapgen re-order cave generation to generate tunnels before caverns.
Add new biome fields 'node_dungeon', 'node_dungeon_alt', 'node_dungeon_stair'.
If 'node_dungeon' is not defined dungeons fall back to classic behaviour.
Remove messy and imprecise dungeon material code from 'generateBiomes()'.
Code deciding dungeon materials is now in 'generateDungeons()' and uses the
biome at mapchunk centre for more precision.
Remove hardcoded 'MG_STONE' types as long intended.
