LandClasses

LandClasses are regions specified by the LandControl PQSMod that can locally customize several features of the local terrain. To put it very, very simply: LandControl's LandClasses are what you get when you take the concept of HeightColorMap and empower it with greater control over local colors, the ability to place detail objects called terrain scatters (examples are grass, trees and boulders) and even an ability to adjust the local elevation of the terrain.

Similarly to HeightColorMap, the LandClasses are limited by altitude, but unlike HeightColorMap, LandControl also lets you limit the latitude and longitude range(s) wherein a LandClass should act.

Subnodes - Both are defined under the main table.

LerpRange { } = Defines the range along the given coordinate axes wherein a LandClass should act.
Scatters { } = Defines the terrain scatters that may spawn in this LandClass, and the prominence of each.

Example

cfg

LandControl
{
  LandClasses
  {
    Value
    {
      alterApparentHeight = 100
      alterRealHeight = 10
      color = 1,1,1,0
      coverageBlend = 1
      coverageFrequency = 12	
      coverageOctaves = 6
      coveragePersistance = 0.5
      coverageSeed = 234124
      name = IceCaps
      latDelta = 0
      latitudeDouble = True
      lonDelta = 1
      minimumRealHeight = 20
      noiseBlend = 0.25
      noiseColor = 0.552238822,0.519182861,0.480795324,0
      noiseFrequency = 24
      noiseOctaves = 8
      noisePersistance = 0.5
      noiseSeed = 5646345
      altitudeRange
      {
        endEnd = 2
        endStart = 2
        startEnd = -0.5
        startStart = -0.5
      }
      latitudeRange
      {
        endEnd = 0.0414999984204769
        endStart = 0.0399999991059303
        startEnd = -10
        startStart = -10
      }
      latitudeDoubleRange
      {
        endEnd = 11
        endStart = 11
        startEnd = 0.96000000089407
        startStart = 0.958500001579523
      }
      longitudeRange
      {
        endEnd = 10
        endStart = 10
        startEnd = -10
        startStart = -10
      }
      Scatters
      {
        Value
        {
          density = -1
          scatterName = BrownRock
          delete = False
        }
      }
    }
  }
}

Parameters

Similar to the article on the base mod, we'll separate the parameters for a LandClass into categories:

Coverage Control: parameters that apply further control to the coverage of a LandClass.
Color Control: parameters that specify the colors that a LandClass may apply to the terrain.
Elevation Control: parameters that control the local elevation of terrain that falls under the given LandClass.
Range Control: parameters that specify the range of altitudes, latitudes and longitudes that the LandClass should cover.

One parameter does not fall into any of these categories: name, which is useful in distinguishing LandClasses. Naming LandClasses is up to user preference, pick any name that seems applicable and intuitive.

We shall now discuss each category in turn.

(Note: the parameters latDelta and lonDelta also appear in exports from Kittopia. These are used internally by KSP and should not actually be set from config files. Ignore these.)

Coverage Control

Similar to how the base mod applies a Simplex noise to the altitude, latitude and longitude, each LandClass may apply a Simplex noise to the computed coverage.

To be specific, LandControl first obtains a normalized value for altitude, latitude and longitude from the input vertex. It then applies a simplex noise to each of these coordinates just to shake things up a little and avoid obvious 'zones'.

The resulting shifted coordinates are then compared to the altitude, latitude and longitude ranges specified in each LandClass. The per-coordinate-axis contributions are multiplied together to get the overall coverage of the LandClass. A simplex noise can be applied to this coverage multiplicatively for further detail. The below parameters control this noise.

For a more detailed explanation of simplex noise parameters, see the main mod article.

Property	Format	Description
coverageBlend	Decimal	The strength of the simplex noise. This linearly scales the strength of the simplex noise multiplication.
coverageFrequency	Decimal	The initial size of the simplex noise.
coverageOctaves	Integer	The number of simplex noise iterations.
coveragePersistance	Decimal	The multiplicative falloff of noise strength for each successive octave.
coverageSeed	Integer	A seed for the simplex noise generator, to produce different patterns.

Color Control

Unlike HeightColorMap, which only allows for a single color value per region, LandControl allows for two color values, between which it interpolates with yet another Simplex noise.

Property	Format	Description
color	Color	The main color of the region.
noiseColor	Color	A secondary color for the region.
noiseBlend	Decimal	A multiplicative strength value for the Simplex noise.
noiseFrequency	Decimal	The size of the color noise. As frequency gets bigger, size gets smaller.
noiseOctaves	Integer	The number of color noise octaves.
noisePersistance	Decimal	The falloff of successive noise iterations.
noiseSeed	Integer	The seed of the simplex noise.

Elevation Control

As an extra luxury, LandControl also allows for limited adjustments to local elevation.

Property	Format	Description
alterApparentHeight	Decimal	LandControl writes the normalized altitude to the alpha channel of the vertex color. Should you want to, then you can use this parameter to adjust the normalized altitude within this LandClass, but only insofar as the vertex color is concerned.
alterRealHeight	Decimal	An absolute offset (IE it is applied additively) to the terrain elevation within this LandClass, scaled by the coverage of the LandClass.
minimumRealHeight	Decimal	If not set to zero: if the altitude of the input vertex relative to sea level is less than this value (yes, this value describes a sea level relative elevation) then the vertex' elevation is raised to this value, depending on the LandClass coverage.

Range Control

At first glance the parameters for a LerpRange may seem a bit confusing. In essence, Kerbal Space Program performs a double linear interpolation.

Think of each LerpRange one at a time. For example, picture in your head a 2D grid, like a map. The horizontal axis of that map will be the planet's longitude, progressing from zero on the left, to one on the right. Similarly, the vertical axis represents latitude, from zero at the bottom to one at the top. As with a heightmap, you can imagine the brightness of points in the grid as the elevation.

Each LerpRange essentially defines a region along one of these axes. Let's take the horizontal or 'longitude' axis. The parameters supplied to longitudeRange will create a vertical 'band' in the 2D grid where intensity increases from zero to one, and then from one to zero again.

The same will apply to the latitude and the altitude, and the product of these three 'bands' is the coverage - changes from the coverage noise notwithstanding.

Note that the latitude actually specifies two ranges: latitudeRange and latitudeDoubleRange. This second range goes unused unless the latitudeDouble parameter is set to True. It is used to create a second latitude range for this LandClass. KSP will take the largest value of the two latitude ranges as the coverage for that coordinate axis. A notable use of this feature is the polar ice caps of Kerbin.

Property	Format	Description
latitudeDouble	Boolean	Whether to use a second latitude range. Example use case: mirroring over the equator.
altitudeRange	LerpRange	Determines the heights at which the LandClass has dominion.
latitudeRange	LerpRange	Determines the latitudes at which the LandClass has dominion.
latitudeDoubleRange	LerpRange	Optionally, a second latitude range over which the LandClass has dominion. Only used if `latitudeDouble` is true.
longitudeRange	LerpRange	Determines the longitudes at which the LandClass has dominion.

LerpRange

Each LerpRange { } node describes a range of numbers to encompass, or lerp over. They contain four values: startStart, startEnd, endStart and endEnd. These names a perhaps a bit confusing so let's discuss them in detail.

Property	Format	Description
startStart	Decimal	The true start of the LandClass coverage. Coverage before this point is non-existent, while coverage after this point is sparse.
startEnd	Decimal	The end of the starting area of the LandClass coverage. Coverage before this point is sparse, while coverage after this point is complete.
endStart	Decimal	The start of the ending area of the LandClass coverage. Coverage before this point is complete, while coverage after this point is sparse.
endEnd	Decimal	The true end of the LandClass coverage. Coverage before this point is sparse, while coverage after this point is non-existent.

Scatters

LandClasses may specify which terrain scatters may spawn in the area that they have dominion over, as well as a relative density for these whitelisted terrain scatters. This takes the form of one Scatters { } node containing Value { } nodes.

Each Value { } node references a terrain scatter from the main Scatters { } (as defined under in the LandControl node) by name. Example:

cfg

LandControl
{
    // The 'main' scatters node. This DEFINES the terrain scatters.
    Scatters
    {
        Value
        {
            name = Example_Scatter
        }
    }
    LandClasses
    {
        Value
        {
            name = Example_LandClass
            // This REFERENCES the defined terrain scatters.
            Scatters
            {
                Value
                {
                    // Reference defined scatters by name.
                    scatterName = Example_Scatter
                    density = 0.5
                }
            }
        }
    }
}

Property	Format	Description
density	Decimal	The relative density for this terrain scatter.
scatterName	Text	The name of the scatter to spawn in this LandClass.

How precisely does density work?

LandControl first checks which LandClasses are relevant to a given vertex. It keeps track of these and their contribution values, which it turns into a weighted sum.

Later, if spawning scatters is requested, it tracks density per terrain scatter. For some, this will be zero. The density value of a LandClass' terrain scatter reference is added to a terrain scatter's density tally, multiplied by the weighted contribution of the LandClass, as well as the terrain scatter density as set by the player in the game's settings.

Finally, terrain scatters are created using the sum density for each scatter, which gets multiplied with their densityFactor and maxScatter parameters. This seems to form the basis for whatever scatter distribution system KSP uses. More info on the parameters for terrain scatters themselves can be found in the main article on terrain scatters.

LandClasses ​

Subnodes - Both are defined under the main table. ​

Example ​

Parameters ​

Coverage Control ​

Color Control ​

Elevation Control ​

Range Control ​

LerpRange ​

Scatters ​

How precisely does density work? ​