Calculate 'i' inside 'y' loop to avoid 'i' and 'y' becoming
out of step due to the uses of 'continue'.
Simplify calculation of 'p2d' when coordinates are inverted.
Remove some unnecessary and unreliable 'index out of
voxelmanip' checks.
Move calculation of '&em' out of loops.
For 'Loop further down until not air' code, use y coordinate
to detect being out of voxelmanip, instead of checking index
which did not detect that.
Add and improve comments.
Indent the 'for (;; y--) {' loop.
Improve format and fix codestyle issues.
In MapgenV6::flowMud(), the previous implementation of coordinate
inversion caused the 2 inverted mudflow iterations (out of the 3
iterations) to not loop over the area, so only 1 non-inverted
iteration occurred.
Fix this bug but only iterate mudflow twice, as mapgen v6 has only
had 1 iteration for many years. There is now a good balance of 1
non-inverted iteration and 1 inverted iteration.
Re-add the random size range for large rooms.
Remove 'first_room_large' bool.
Add 'large_room_chance' parameter that can disable large rooms,
specify 1 large room, or specify a chance for large rooms.
If 1 or a chance is specified, the first generated room is large,
to take advantage of the intersection checks that are done for the
1st room only.
Move 'num_dungeons' to 'DungeonParams'.
Add new parameter 'num_rooms' to replace 'rooms_min' and 'rooms_max',
so that the mapgen has complete control over the number of rooms.
Add new bool 'first_room_large' so that the mapgen chooses this
instead of a hardcoded 1 in 4 chance.
Add new parameter 'room_size_large' to replace 'room_size_large_min'
and 'room_size_large_max', so that the mapgen has complete control
over this.
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 only 'mapgen water source' and 'mapgen river water source'
were checked for. Games can use multiple liquid nodes defined for biomes,
many of which will not be aliased to those 2 mapgen aliases, causing
floating dungeons to generate in some liquids.
Now we check for liquid drawtype instead, so can remove liquid nodes
from dungeonparams.
Also check for 'airlike' drawtype instead of 'CONTENT_AIR' to avoid
generation in 'airlike' nodes in some rare situations. This will also be
needed for when we add definable biome air nodes.
* Rename IWritableNodeDefManager to NodeDefManager
* Make INodeDefManager functions const
* Use "const *NodeDefManager" instead of "*INodeDefManager"
* Remove unused INodeDefManager class
* Merge NodeDefManager and CNodeDefManager
* Document NodeDefManager
