docs: Improve //noise2d documentation

Thanks to @notsowow for pointing out that it didn't make sense!
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Starbeamrainbowlabs 2023-12-26 19:07:41 +00:00
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@ -16,6 +16,7 @@ Note to self: See the bottom of this file for the release template text.
### Bugfixes and changes
- Don't warn on failed registration of `//flora` → [`//bonemeal`](https://worldeditadditions.mooncarrot.space/Reference/#bonemeal) if the `bonemeal` mod isn't installed (e.g. in MineClone2) - thanks @VorTechnix in #106
- Improve documentation of [`//noise2d`](https://worldeditadditions.mooncarrot.space/Reference/#noise2d). If it still doesn't make sense, please let me know. It's a complicated command that needs reworking a bit to be easier to use.
## v1.14.5: The multipoint update, hotfix 5 (1st August 2023)

@ -737,10 +737,32 @@ Usage examples:
### `//noise2d [<key_1> [<value_1>]] [<key_2> [<value_2>]] ...]`
Applies 2D noise to the terrain in the defined region. Like `//erode`, this command accepts a number of different key-value parameters and provides a number of different underlying algorithms.
In other words, this command changes the height of the terrain according to some noise function (e.g. Perlin noise):
![//noise2d applies 2D noise as a modifier to terrain height.](https://raw.githubusercontent.com/sbrl/Minetest-WorldEditAdditions/dev/.docs/images/reference/noise2d.jpeg)
It does so like this:
1. Take coordinates of each column
2. Plug them through a noise function (see below)
3. Apply the generated noise value to the terrain.
`//noise2d` has a number of parameters that let you adjust the mathematical properties of step 2, which are explained in the table below.
Some terms that are useful to know:
- **Scale:** How big or small the noise is. Lower values stretch it out to be bigger, and higher values squash it in.
- **Offset:** Noise is calculated by passing some coordinates into a function.
- **Perlin:** A noise algorithm. `//noise2d` defaults to this.
#### Table of parameters
Parameter | Type | Default Value | Description
------------|-----------|---------------|-----------------------
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.
scale | `float` | 1 | Sets `scalex`, `scaley`, and `scalez` all at once. Consider also `//apply`.
scalex | `float` | 1 | The scale of the noise on the x axis.
scaley | `float` | 1 | The scale of the noise on the y axis.
scalez | `float` | 1 | The scale of the noise on the z axis.
@ -751,12 +773,29 @@ exponent | `float` | 0 | Raise the generated noise value (with a range of 0 t
multiply | `float` | 1 | Multiply the generated noise value by this number
add | `float` | 0 | Add this number to the generated noise value.
#### Apply
Different values of the `apply` parameter result in the generated noise values being applied in different ways:
- An integer indicates that the noise should be rescaled to a given amplitude (equal parts of the range above and below 0) before being added to the terrain heightmap.`
- The exact string `add`: Noise values are added to each heightmap pixel.
- The exact string `multiply`: Each heightmap pixel is multiplied by the corresponding noise value.
1. An integer indicates that the noise should be rescaled to a given amplitude (equal parts of the range above and below 0) before being added to the terrain heightmap.`
2. The exact string `add`: Noise values are added to each heightmap pixel.
3. The exact string `multiply`: Each heightmap pixel is multiplied by the corresponding noise value.
An integer is the most common way to use `//noise2d`. So, for example:
```weacmd
//noise2d apply 5
```
...would alter the height of each column of nodes by at most 5 blocks either side, while:
```weacmd
//noise2d apply 10
```
...would alter the height by 10 blocks instead of 5.
#### Types of noise
Another thing that can be changed is the noise algorithm. This changes what the noise that is applied to the terrain looks like.
The following algorithms are currently available:
@ -765,7 +804,7 @@ Algorithm | Description
`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.
`white` | Random white noise. In other words, just random values.
`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).
`infrared` | Even smoother than red noise. Tends to also be quite flat unless you use a slightly higher `apply` value (e.g. `20`).
@ -776,6 +815,7 @@ When specifying algorithm names, the `algorithm` parameter name is optional. For
//noise2d offsetx 4 algorithm perlin scale 0.2
```
#### Further examples
Example invocations:
```weacmd