Features

Noises

mapgen.noise2d

To get a 2D perlin noise map.

Arguments :

• minp (position) : Minimal corner of the perlin noise map
• maxp (position) : Maximal corner of the perlin noise map
• offset (number) : The noise offset
• scale (number) : The scale of the noise
• spread (table) : This table has the same format than a position. It define how slow/fast the value changes in 2 dimensions
• seed (number) : Each seed generate a different noise
• octaves (number) : A high value result of more details but is slower
• persist (number) : Depth of the details evoked previously

Return :

• noise (table) : An array of values starting at index 1

mapgen.noise3d

Same as above, but in 3D.

Arguments :

• minp (position) : Minimal corner of the perlin noise map
• maxp (position) : Maximal corner of the perlin noise map
• offset (number) : The noise offset
• scale (number) : The scale of the noise
• spread (table) : This table has the same format than a position. It define how slow/fast the value changes in 3 dimensions
• seed (number) : Each seed generate a different noise
• octaves (number) : A high value result of more details but is slower
• persist (number) : Depth of the details evoked previously

Return :

• noise (table) : An array of values starting at index 1

VoxelArea:noise

It returns a perlin noise map from a voxel area. Then you can use VoxelArea:index(pos) to get the noise value matching the position pos.

Arguments :

• offset (number) : The noise offset
• scale (number) : The scale of the noise
• spread (table) : This table has the same format than a position. It define how slow/fast the value changes.
• seed (number) : Each seed generate a different noise
• octaves (number) : A high value result of more details but is slower
• persist (number) : Depth of the details evoked previously

Return :

• noise (table) : An array of values starting at index 1

Equivalent in 2D : FlatArea:noise

VoxelAreas

VoxelArea:altitude

To get only the y coordinate (altitude) at index i, faster than pos = VoxelArea:position(i) if we want only the y.

Arguments :

• i (number) : index of the VoxelArea

Return :

• alt (number) : the y value (the altitude) of the position matching index i

minetest.voxel_area

Just a shortcut for VoxelArea:new({MinEdge = minp, MaxEdge = maxp})

Arguments :

• minp (position) : The corner of the VoxelArea which has the smaller coordinates
• maxp (position) : The opposite corner

Return :

• o (VoxelArea) : The new voxel area

FlatArea

Same but in 2D. It has the same methods than a VoxelArea except altitude.

minetest.flat_area

Just a shortcut for FlatArea:new({MinEdge = minp, MaxEdge = maxp}).

Arguments :

• minp (position) : The corner of the VoxelArea which has the smaller coordinates
• maxp (position) : The opposite corner

Return :

• o (FlatArea) : The new voxel area

mapgen.translate

Takes an index of area1 and return the index matching the same position for area2.

Arguments :

• area1 (VoxelArea or FlatArea) : The first area (input)
• area2 (VoxelArea or FlatArea) : The second area (output)
• i (number) : An index of area1 which will be convert to index of area2
• alt (number) : Only when area1 is a FlatArea and area2 is a VoxelArea. It is the altitude (y coordinate) of the point.

Return :

• i (number) : The index of area2 which matches the same position for area1

You can also use VoxelArea:translate(area2, i) or FlatArea:translate(area2, i, alt).

Map Metadata

You can store map metadata in the file mapgen.txt placed in the world folder. The 3 following functions are used to store these metadata. Not that these metadata are set on shutting down : if it crash, they aren't saved.

mapgen.set_map_meta

To set to value the metadata with field as name.

Arguments :

• field (string, number or boolean) : The name of the metadata to set
• value (table, string, number, boolean or nil) : Value to give to the metadata

No return

minetest.define_map_meta

Same as above, but don't change anything if this metadata is already defined.

Arguments :

• field (string, number or boolean) : The name of the metadata to set
• value (table, string, number, boolean or nil) : Value to give to the metadata

No return

minetest.increment_map_meta

Increment the involved metadata by 1 (must be a number).

Arguments :

• field (string, number or boolean) : The name of the metadata to increment

No return

minetest.get_map_meta

Returns the map meta with field as name.

Arguments :

• field (string, number or boolean) : The name of the metadata to get

No return

Others mapgen-related features

mapgen.get_voxel_manip

Return a VoxelManip object and his VoxelArea.

Arguments :

• minp (position) : minimal corner of the area
• maxp (position) : maximal corner of the area

Return :

• vm (VoxelManip) : The VoxelManip object, which has already read the chunk
• area (VoxelArea) : A VoxelManip matching the VM.

mapgen.get_ids

Converts nodenames to content ids

Arguments :

• node1, node2, node3 ... (string or table) : Name of the nodes to convert to ids, or table containing these names

Return :

• id1, id2, id3 ... (number or table) : If number, the content id ; if table, array of ids, with exactely the same structure than the argument table

For example mapgen.get_ids(nodename1, nodename2, {nodename3, {nodename4}, stuff = nodename5}, nodename6) returns id_of_node1, id_of_node2, {id_of_node3, {id_of_node4}, stuff = id_of_node5}, id_of_node6

mapgen.average_time

Returns average generation time

No arguments

Return :

• t (number) : The average generation time in seconds

Others

pos2d

Convert a standard pos to a 2D pos with {x = pos.x, y = pos.z}.

Arguments :

• pos_in (position) : The position to convert ; if already 2D, the same is returned

Return :

• pos_out (2D position) : The 2D position

pos3d

Convert a 2D pos to 3D, reverse of the previous function

Arguments :

• pos_in (2D position) : The position to convert ; if already 3D, the same is returned
• alt (number) : Altitude (y coordinate) of your future 3D position

Return :

• pos_out (position) : The 3D position

load_modfile

Loads a file in your mod.

Arguments :

• path (string) : Path of the file from the mod folder (for example file.lua or scripts/generate.lua)

No return

mapgen.send

Send a message to the main player, or all players, and print it on debug.txt.

Arguments :

• text (string) : The text to send
• all (boolean) : If true, will be sent to all players, if false or omitted, only sent to the main player

No return

math.round

Round a number to the nearest multiple.

Arguments :

• n (number) : The number to round
• div (number) : n is rounded to the nearest multiple of div ; if omitted, set to 1

Return :

• rn (number) : The rounded number

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TO MAKE A MAPGEN :

Write a lua file which defines the following functions. These functions are not functions that mapgen_lib defines and you call, it's the contrary ! If you omit one of them, this poses no problem.

mapgen.on_generated

Used to make the base map with the VoxelManipulator.

Arguments :

• minp (position) : The corner of the generated chunk which has the smallest coordinates
• maxp (position) : The opposite corner
• data (table) : A huge array containing the ids of all nodes in the chunk
• param (table) : Same as above, but contains the param (light) levels ; integers from 0 to 255 (day light + night light * 16)
• param2 (table) : Same as above, but contains the param2 values
• area (VoxelArea) : A Voxel Area to help you ; you can use area:iterp(minp, maxp) or area:index(pos) for example
• seed (number) : The seed of the world ; currently a 32-bit integer

Return :

• data (table) : The content id array
• param (table or boolean) : The light data array ; if you returns the boolean true instead of the array, light is calculated automatically.
• param2 (table) : Array containing the param2 values

mapgen.after_generated

Called after the base map generation by the VoxelManip. Used to generate complementary structures like trees or villages.

Arguments :

• minp (position) : The corner of the generated chunk which has the smallest coordinates
• maxp (position) : The opposite corner
• seed (number) : The seed of the world ; currently a 32-bit integer

No return

mapgen.spawn_player

Used to define where the player is spawned in the world. You can also generate structures like platforms by minetest.set_node.

Arguments :

• player (ObjectRef) : The player to spawn
• seed (number) : The seed of the world ; currently a 32-bit integer

Return :

• pos (position) : The position at which the player appears

Params formspec

You can define mapgen.params_formspec, if any, it is shown after choosing the mapgen and before generating map. The sent fields are stored in metadata. To get the field which has been sent from a given widget, do mapgen.get_map_meta("name_of_the_widget").

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When all is done, create a folder "mapgen" in your mod folder and put this lua file in it.