/// <summary>
/// Generate rain shadow for given latitude line
/// </summary>
protected void GenerateShadowLine(int y)
{
var currentRain = this.InitialRainAmount;
var sourceRange = new Range(this.Elevation.SeaThreshold, this.Elevation.LandThreshold);
var destRange = new Range(this.MinRainLoss, this.MaxRainLoss);
for (var ix = 0; ix < this.Dimensions.Width; ++ix)
{
// Retrieve elevation
var elevation = this.Elevation[ix, y];
// Are we over water?
if (elevation < this.Elevation.SeaThreshold)
{
// Accumulate more rain by evaporation of ocean water
currentRain *= this.RainGain;
currentRain = Math.Clamp(currentRain, this.MinRainAmount, this.MaxRainAmount);
}
else if (elevation <= this.Elevation.LandThreshold) // Are we over land?
{
// Percentage of how much water is lost from the cloud and rained down
var factor = MathUtil.Map(elevation, sourceRange, destRange);
var loss = currentRain * factor;
currentRain *= 1.0f - factor;
this.RainShadow[ix, y] = loss;
// This isnt realistic, but to make maps less weird looking we add a fixed amount of water to the cloud
// each tile it travels.
currentRain += this.FlatRainGain;
if (currentRain < this.MinRainAmount)
{
currentRain = this.MinRainAmount;
}
}
else
{
// Loose rain at max rate
var loss = currentRain * this.MountainRainLoss;
currentRain *= 1.0f - this.MountainRainLoss;
this.RainShadow[ix, y] = loss; // DEBUG remove this, because it skews the threshold calculations
if (currentRain < this.MinRainAmount)
{
currentRain = this.MinRainAmount;
}
}
}
}
/// <summary>
/// Map all biomes.
/// </summary>
protected void MapBiomes()
{
var rng = new Random(this.Seed + 13185);
// Chance ranges for broad leaf forest generation, pulled out of the loops to avoid repeated heap allocations
//var sourceRange = new Range(this.Temperature.ColderThreshold, this.Temperature.ColdThreshold);
// Alternative: Source range starting at 0.0f. Causes forests to almost never be 100% coniferous
var coniferousSrcRange = new Range(this.Temperature.ColdestThreshold, this.Temperature.ColdThreshold);
var destRange = new Range(0.0f, 1.0f);
var difference = this.Temperature.WarmThreshold - this.Temperature.ColdThreshold;
var jungleSrcRange = new Range(this.Temperature.ColdThreshold + (difference / 2), this.Temperature.WarmThreshold);
var climateZoneSrcRange = jungleSrcRange;
for (var ix = 0; ix < this.Dimensions.Width; ++ix)
{
for (var iy = 0; iy < this.Dimensions.Height; ++iy)
{
var elevation = this.Elevation.HeightLevels[ix, iy];
var drainage = this.Drainage[ix, iy];
var temperature = this.Temperature.TemperatureLevels[ix, iy];
var rawTemperature = this.Temperature[ix, iy];
var rainfall = this.Rainfall[ix, iy];
// Determine rough climate zone.
var climateZone = ClimateZone.Temperate;
// Warmer and warmest temperatures are always tropical
if (temperature == TemperatureLevel.Warmer ||
temperature == TemperatureLevel.Warmest)
{
climateZone = ClimateZone.Tropical;
}
else if (temperature == TemperatureLevel.Warm) // Smoothly transition in warm temperature zone
{
var tropicalChance = MathUtil.Map(rawTemperature, climateZoneSrcRange, destRange);
if (rng.NextDouble() <= tropicalChance)
{
climateZone = ClimateZone.Tropical;
}
}
var type = TerrainType.Unknown;
if (elevation == HeightLevel.Sea)
{
if (temperature == TemperatureLevel.Coldest)
{
type = TerrainType.Glacier;
}
else if (temperature == TemperatureLevel.Colder)
{
type = TerrainType.SeaIce;
}
else
{
type = TerrainType.Ocean;
}
}
else if (elevation == HeightLevel.Land)
{
if (temperature == TemperatureLevel.Coldest)
{
type = TerrainType.Glacier;
}
else if (temperature == TemperatureLevel.Colder)
{
type = TerrainType.Tundra;
}
else
{
// Very dry region
if (rainfall < 0.1f)
{
if (climateZone == ClimateZone.Tropical)
{
// Tropical zones have little bad lands, but lots of deserts and rocky
// wastelands
if (drainage < 0.85f)
{
type = TerrainType.SandDesert;
}
else
{
type = TerrainType.RockyWasteland;
}
}
else
{
// Temperate regions have no deserts
if (drainage < 0.65f)
{
type = TerrainType.RockyWasteland;
}
else
{
type = TerrainType.BadLands;
}
}
}
else if (rainfall < 0.66f)
{
if (climateZone == ClimateZone.Tropical)
{
// Since evaporation is high, even moderately high rainfall levels will still result
// in arid biomes
if (rainfall < 0.30f)
{
type = TerrainType.SandDesert;
}
else if (rainfall < 0.45f)
{
if (drainage < 0.5)
{
type = TerrainType.Steppe;
}
else
{
type = TerrainType.HillySteppe;
}
}
else if (rainfall < 0.55f)
{
if (drainage < 0.5)
{
type = TerrainType.SavannaDry;
}
else
{
type = TerrainType.HillsDry;
}
}
else
{
if (drainage < 0.5)
{
type = TerrainType.Savanna;
}
else
{
type = TerrainType.HillySavanna;
}
}
}
else // Temperate climate
{
// In a temperate climate, evaporation is low. Thus, only areas with very little
// rainfall will develop arid biomes
if (rainfall < 0.20f)
{
if (drainage < 0.5)
{
type = TerrainType.ShrublandDry;
}
else
{
type = TerrainType.HillsDry;
}
}
else if (rainfall < 0.40f)
{
if (drainage < 0.5)
{
type = TerrainType.Shrubland;
}
else
{
type = TerrainType.Hills;
}
}
else if (rainfall > 0.55 && drainage < 0.15f)
{
type = TerrainType.Marsh;
}
else
{
if (drainage < 0.5)
{
type = TerrainType.Grassland;
}
else
{
type = TerrainType.HillyGrassland;
}
}
}
}
// Grasslands region
/*else if (rainfall < 0.2f)
* {
* if (drainage < 0.5f)
* {
* type = TerrainType.Grassland;
* }
* else
* {
* type = TerrainType.Hills;
* }
* }
* // Savanna region
* else if (rainfall < 0.33f)
* {
* if (drainage < 0.5f)
* {
* type = TerrainType.Savanna;
* }
* else
* {
* type = TerrainType.HillsDry;
* }
* }
* // Marsh, shrubland region
* else if (rainfall < 0.66f)
* {
* if (drainage < 0.12f)
* type = TerrainType.Marsh;
* else if (drainage < 0.5f)
* {
* if (temperature == TemperatureLevel.Warmer ||
* temperature == TemperatureLevel.Warmest)
* type = TerrainType.ShrublandDry;
* else
* type = TerrainType.Shrubland;
* }
* else
* {
* if (temperature == TemperatureLevel.Warmer ||
* temperature == TemperatureLevel.Warmest)
* type = TerrainType.HillsDry;
* else
* type = TerrainType.Hills;
* }
* }*/
// Forest/Swamp region
else
{
if (drainage < 0.12f /*0.10f*/)
{
type = TerrainType.Swamp;
}
else
{
if (temperature == TemperatureLevel.Warmer ||
temperature == TemperatureLevel.Warmest)
{
type = TerrainType.TropicalBroadleafForest;
}
else if (temperature == TemperatureLevel.Warm)
{
var jungleChance = MathUtil.Map(rawTemperature, jungleSrcRange, destRange);
if (rng.NextDouble() <= jungleChance)
{
type = TerrainType.TropicalBroadleafForest;
}
else
{
type = TerrainType.TemperateBroadleafForest;
}
}
else
{
// In colder climates, we use a scaling chance of generation broad leaf forests
// to smoothly transition from temperate zones with broad leaf forests to
// more colder zones with coniferous forests
var broadleafChance = MathUtil.Map(rawTemperature, coniferousSrcRange, destRange);
// broadleafChance *= broadleafChance;
if (rng.NextDouble() <= broadleafChance)
{
type = TerrainType.TemperateBroadleafForest;
}
else
{
type = TerrainType.ConiferousForest;
}
}
}
}
}
}
else if (elevation == HeightLevel.LowMountain)
{
type = TerrainType.MountainsLow;
}
else if (elevation == HeightLevel.MediumMountain)
{
type = TerrainType.MountainsMed;
}
else if (elevation == HeightLevel.HighMountain)
{
type = TerrainType.MountainsHigh;
}
else if (elevation == HeightLevel.MountainPeak)
{
type = TerrainType.MountainPeak;
}
this.TerrainTypes[ix, iy] = type;
}
}
}