//noiseapply2d: document

Chat-Command-Reference.md

@@ -505,7 +505,7 @@ Applies 2D noise to the terrain in the defined region. Like `//erode`, this comm
 
 Parameter	| Type		| Default Value	| Description
 ------------|-----------|---------------|-----------------------
-algorithm	| `string`	| perlin		| The 2D noise algorithm to apply - see below.
+algorithm	| `string`	| perlinmt		| The 2D noise algorithm to apply - see below.
 apply		| `string|integer` | 5		| How to apply the noise to the terrain - see below.
 scalex		| `float`	| 1				| The scale of the noise on the x axis.
 scaley		| `float`	| 1				| The scale of the noise on the y axis.
@@ -528,7 +528,8 @@ The following algorithms are currently available:
 
 Algorithm	| Description
 ------------|--------------------------
-`perlin`	| Perlin noise. Functional, but currently contains artefacts I'm having difficulty tracking down.
+`perlinmt`  | **Default**.Perlin noise, backed by Minetest's inbuilt `PerlinNoise` class.
+`perlin`	| Perlin noise, backed by a pure Lua perlin noise implementation. Functional, but currently contains artefacts I'm having difficulty tracking down.
 `sin`		| A sine wave created with `math.sin()`.
 `white`		| Random white noise.
 `red`		| Red noise - has a lower frequency than white noise. Ref [Noise Functions and Map Generation by Red Blob Games](https://www.redblobgames.com/articles/noise/introduction.html).
@@ -654,6 +655,21 @@ As with `//ellipsoidapply` for advanced users `//multi` is also supported - but
 ```
 
 
+## `//noiseapply2d <threshold> <scale> <command_name> <args>`
+Like [`//ellipsoidapply`](#ellipsoidapply), but instead only keeps changes where a noise function (defaults to `perlinmt`, see [`//noise2d`](#noise2d)) returns a value greater than a given threshold value.
+
+Also takes a scale value that controls the scale of the noise - -higher values result in smaller "blobs". If you're operating on small areas, then a value of at least 10 is advised as "blobs" are by default on the scale of ~50 nodes.
+
+As with `//ellipsoidapply` for advanced users `//multi` is also supported - but make sure your modifications stay within the defined region - otherwise they be kept regardless, as `//noiseapply2d` only applies the masking to the nodes in the defined region.
+
+Any suggestions on  how to provide more customisability without making this command more difficult to use or significantly more inconsistent with other `//*apply` functions are welcome - please [open an issue](https://github.com/sbrl/Minetest-WorldEditAdditions/issues/new).
+
+```weacmd
+//noiseapply2d 0.5 10 set dirt
+//noiseapply2d 0.4 3 layers dirt_with_snow dirt 3 stone 10
+```
+
+
 ## `//scol [<axis1> ] <length>`
 Short for _select column_. Sets the pos2 at a set distance along 1 axis from pos1. If the axis isn't specified, defaults the direction you are facing. Implementation thanks to @VorTechnix.
 

README.md

@@ -49,6 +49,7 @@ The detailed explanations have moved! Check them out [here](https://github.com/s
  - [`//fillcaves [<node_name>]`](https://worldeditadditions.mooncarrot.space/Reference/#fillcaves)
  - [`//convolve <kernel> [<width>[,<height>]] [<sigma>]`](https://worldeditadditions.mooncarrot.space/Reference/#convolve)
  - [`//erode [<snowballs|river> [<key_1> [<value_1>]] [<key_2> [<value_2>]] ...]`](https://worldeditadditions.mooncarrot.space/Reference/#erode) **experimental**
+ - [`//noise2d [<key_1> [<value_1>]] [<key_2> [<value_2>]] ...]`](https://worldeditadditions.mooncarrot.space/Reference/#noise2d)
 
 ### Flora
  - [`//bonemeal [<strength> [<chance>]]`](https://github.com/sbrl/Minetest-WorldEditAdditions/blob/main/Chat-Command-Reference.md#bonemeal-strength-chance)
@@ -82,7 +83,7 @@ The detailed explanations have moved! Check them out [here](https://github.com/s
  - [`//subdivide <size_x> <size_y> <size_z> <cmd_name> <args>`](https://worldeditadditions.mooncarrot.space/Reference/#subdivide)
  - [`//ellipsoidapply <command_name> <args>`](https://worldeditadditions.mooncarrot.space/Reference/#ellipsoidapply) _(new in v1.9)_
  - [`//airapply <command_name> <args>`](https://worldeditadditions.mooncarrot.space/Reference/#airapply) _(new in v1.9)_
- - [`//noiseapply2d <command_name> <args>`](https://worldeditadditions.mooncarrot.space/Reference/#noiseapply2d) _(new in v1.13)_
+ - [`//noiseapply2d <threshold> <scale> <command_name> <args>`](https://worldeditadditions.mooncarrot.space/Reference/#noiseapply2d) _(new in v1.13)_
 
 ### Extras
  - [`//y`](https://github.com/sbrl/Minetest-WorldEditAdditions/blob/main/Chat-Command-Reference.md#y)