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plantlife_modpack/API.txt
Vanessa Ezekowitz 94770d713b extended the API again - this time adding a function to allow a custom check
for air surrounding the plant spawn location (defaults to 1, just the target
node).  Values of 1 and 9 for the two new variables would check the 3x3 area
around the spawn location.  Don't make these numbers too large or it will
slow the abm down.
2013-01-11 11:52:34 -05:00

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This document briefly describes the Plantlife API.
=========
Functions
=========
There are five main functions defined by the main "plants_lib" mod:
spawn_on_surfaces()
grow_plants()
plant_valid_wall()
is_node_loaded()
dbg()
-----
The first of these, spawn_on_surfaces() is defined with quite a large number
of variables. All of the variables below, if specified at all, must be
specified exactly in the order given here. This function has no return value.
spawn_on_surfaces = function(sdelay, splant, sradius, schance, ssurface,
savoid, seed_diff, lightmin, lightmax, nneighbors,
ocount, facedir, depthmax, altitudemin, altitudemax)
The first several of these are all required, and are from the last version of
the flowers mod, so this part of the API should be the same as before.
sdelay: The value passed to the ABM's interval parameter, usually
in the 1000-3000 range.
splant: The node name of the item to spawn (e.g.
"flowers:flower_rose"). Note that if the plant is
"poisonivy:seedling", and it's next to a wall at spawn
time, it automatically becomes the wall-climbing variety.
A plant will of course only be spawned if the node about
to be replaced is air.
sradius: Don't spawn within this many nodes of the avoid items
mentioned below.
schance: The value passed to the ABM's chance parameter, normally
in the 10-100 range.
ssurface: Table with the names of the nodes on which to spawn the
plant in question, such as {"default:sand",
"default:dirt_with_grass"}. It is not recommended to put
"default:dirt" or "default:stone" into this table if you
can do without it, as this will cause the engine to
process potentially large numbers of such nodes when
deciding when to execute the ABM and where it should
operate.
savoid: Table with a list of groups and/or node names to avoid
when spawning the plant, such as {"group:flowers",
"default:tree"}.
From here down are several optional parameters. You can use as many as you
need, but you must specify them in order (so if you want lightmax, you need
lightmin and seed_diff also, but not the rest).
seed_diff: The perlin seed difference value passed to the
minetest.env:get_perlin() function. Used along with the
global perlin controls below to create the "biome" in
which the plants will spawn. Usually a value of somewhere
in the 10 to 100 range is good. Defaults to 0 if not
provided.
lightmin: Minimum amount of light necessary to make a plant spawn.
Defaults to 0.
lightmax: Maximum amount of light present to allow a plant to spawn.
Defaults to the engine's MAX_LIGHT value of 14.
nneighbors: Table with a list of neighboring nodes, passed to the ABM
as the "neighbors" parameter, indicating what needs to be
next to the node the plant is about to spawn on, such as
{"default:stone","default:water_source"}. Defaults to the
value of ssurface if not provided.
ocount: There must be at least this many of the above neighbors in
the eight spaces immediately surrounding the node the
plant is about to spawn on for it to happen. Defaults to
0.
facedir: The value passed to the param2 variable when adding the
plant node to the map. Defaults to 0.
depthmax: If a node spawns on top of a water source, the water must
be at most this deep. Defaults to 1 node.
altitudemin: Items must be at this altitude or higher to spawn at all.
Defaults to -31000.
altitudemax: But no higher than this altitude. Defaults to +31000.
sbiome: List of nodes that must be somewhere in the vicinity in
order for the plant to spawn. Typically this would be
something like "default:water_source" or "default:sand".
Defaults to the value of ssurface if not provided.
sbiomesize: How large of an area to check for the above node.
Specifically, this checks a cuboid area centered on the
node to be spawned on, 3 tall and this wide/long.
Defaults to 0.
sbiomecount: How many of the above nodes must be within that radius.
Defaults to 1.
airradius: How large of an area to check for air around the target.
Defaults to 0 (only check the target).
aircount: How many of the surrounding nodes need to be air for the
above check to return true. Defaults to 1.
By default, if a biome node, size, and count are not defined, the biome
checking is disabled. Same holds true for the nneighbors bit above that.
-----
The second function, grow_plants() is used to turn the spawned nodes above
into something else over time. This function has no return value, and is
defined like so:
grow_plants = function(gdelay, gchance, gplant, gresult, dry_early_node,
grow_nodes, facedir, need_wall, grow_vertically, height_limit,
ground_nodes, grow_function)
gdelay: Passed as the ABM "interval" parameter, as with spawning.
gchance: Passed as the ABM "chance" parameter.
gplant: Name of the node being grown. This value is passed as the
only item in the table given to the ABM as the nodenames
parameter, so it is the plants themselves that are the ABM
trigger, rather than the ground they spawned on. A plant
will only grow if the node above it is air.
gresult: Name of the node into which the above should transform
when the ABM executes.
dry_early_node: This value is ignored except for jungle grass, where it
indicates which node the grass must be on in order for it
to turn from "short" to default:dry_shrub.
grow_nodes: This node must be under the plant in order for it to grow
at all. Normally this should be the same as the list of
surfaces passed to the spawning ABM as the "nodenames"
parameter, such as {"default:dirt_with_grass",
"default:sand"}. This is so that the plant can be
manually placed on something like a flower pot or
something without it growing and eventually dieing.
facedir: Same as with spawning a plant. If supplied, this value is
passed to the param2 variable when changing the plant. If
nil or left out, no new param2 value is applied.
need_wall: Set this to true if you the plant needs to grow against a
wall. Defaults to false.
grow_vertically: Set this to true if the plant needs to grow vertically, as
in climbing poison ivy. Defaults to false.
height_limit: Just how tall can a vertically-growing plant go? Set this
accordingly. The mod will search straight down from the
position being spawned at to find a ground node, below.
Defaults to 62000 (unlimited).
ground_nodes: What nodes should be treated as "the ground" below a
vertically-growing plant. Usually this will be the same
as the grow_nodes table, but might also include, for
example, water or some other surrounding material.
Defaults to "default:dirt_with_grass".
grow_function: Execute the named function (which must be supplied as just
the name of the function as a string) when growing this
node, rather than using the method provided by the default
growing code. Note that if this is specified, only the
gdelay, gchance, and gplant variables will be used, the
rest will be ignored by the growing ABM. You can still
read them from within the function if you need to. The
function will be passed two parameters in order: The
position of the node to be "grown" (in the usual table
format), and the Perlin noise value at the location in
question.
seed_diff: The perlin seed diff to be use to calculate the noise
value given to the above grow_function. Should be the
same as the seed diff used when first spawning the plant
that's being grown.
-----
plant_valid_wall() expects only a single parameter, "pos", which is the usual
table indicating the coordinates around which to search for adjacent walls.
This function returns the location of the first wall found as a facedir value,
or nil if there are no adjacent walls.
-----
is_node_loaded() is defined in exactly the same manner (that is, "node_pos" is
a set of coordinates), and acts as a wrapper for the
minetest.env:get_node_or_nil(node_pos) function. Returns true if the node in
question is already loaded, or false if not.
-----
dbg() is a simple debug output function which takes one string parameter. It
just checks if plantlife_debug is true and outputs the phrase "[Plantlife] "
followed by the supplied string, via the print() function.
===============
Global Settings
===============
Enable this if you want the mod to spam your console with debug info :-)
plantlife_debug = false
The mod uses perlin noise to create "biomes" of the various plants. Aside
from plantlife_seed_diff (see below), these values are the ones plugged
directly into the minetest.env:get_perlin() function. For more information on
how perlin noise is generated, you will need to search the web, as these
default values were arrived at through trial and error.
plantlife_seed_diff = 123
perlin_octaves = 3
perlin_persistence = 0.2
perlin_scale = 25
This value is compared against the output of the above perlin noise function
to decide when to actually place a plant. Smaller numbers mean larger biomes
and more abundant plants.
plantlife_limit = 0.6
These three are pretty obvious. Basically they control the shape and
distribution of the biomes in which the various plants will appear.
flowers_seed_diff = plantlife_seed_diff
junglegrass_seed_diff = plantlife_seed_diff + 10
poisonivy_seed_diff = plantlife_seed_diff + 10
==============
Local settings
==============
Each of the three components of this modpack has an init.lua file, as usual,
and at the top of those files are four variables that affect how and when the
ABMs are run. In each one, the spawn_delay value is used as the 'interval'
parameter and controls how often to run the ABM (in in-game tenths of
seconds), while spawn_chance is used for the ABM's "chance" parameter, and is
basically how likely the ABM is to actually execute (a 1 to (1/chance)
probability).
spawn_delay = 2000
spawn_chance = 100
The other two in each init.lua file control the same two settings used by the
growing ABM.
grow_delay = 1000
grow_chance = 10