Rarity System

src/main/java/ninja/bytecode/iris/layer/GenLayerBiome.java

@@ -11,15 +11,16 @@ import ninja.bytecode.iris.util.BiomeResult;
 import ninja.bytecode.iris.util.CellGenerator;
 import ninja.bytecode.iris.util.GenLayer;
 import ninja.bytecode.iris.util.RNG;
+import ninja.bytecode.iris.util.RarityCellGenerator;
 import ninja.bytecode.shuriken.collections.KList;
 
 public class GenLayerBiome extends GenLayer
 {
 	private CellGenerator region;
 	private CellGenerator bridge;
-	private CellGenerator land;
+	private RarityCellGenerator<IrisBiome> land;
-	private CellGenerator shore;
+	private RarityCellGenerator<IrisBiome> shore;
-	private CellGenerator sea;
+	private RarityCellGenerator<IrisBiome> sea;
 	private DimensionChunkGenerator iris;
 
 	public GenLayerBiome(DimensionChunkGenerator iris, RNG rng)
@@ -28,9 +29,9 @@ public class GenLayerBiome extends GenLayer
 		this.iris = iris;
 		region = new CellGenerator(rng.nextParallelRNG(1188519));
 		bridge = new CellGenerator(rng.nextParallelRNG(1541462));
-		land = new CellGenerator(rng.nextParallelRNG(9045162));
+		land = new RarityCellGenerator<>(rng.nextParallelRNG(9045162));
-		shore = new CellGenerator(rng.nextParallelRNG(2342812));
+		shore = new RarityCellGenerator<>(rng.nextParallelRNG(2342812));
-		sea = new CellGenerator(rng.nextParallelRNG(6135621));
+		sea = new RarityCellGenerator<>(rng.nextParallelRNG(6135621));
 	}
 
 	public IrisRegion getRegion(double bx, double bz)

src/main/java/ninja/bytecode/iris/object/IrisBiome.java

@@ -10,6 +10,7 @@ import lombok.EqualsAndHashCode;
 import ninja.bytecode.iris.util.CNG;
 import ninja.bytecode.iris.util.CellGenerator;
 import ninja.bytecode.iris.util.Desc;
+import ninja.bytecode.iris.util.IRare;
 import ninja.bytecode.iris.util.RNG;
 import ninja.bytecode.shuriken.collections.KList;
 import ninja.bytecode.shuriken.logging.L;
@@ -17,11 +18,14 @@ import ninja.bytecode.shuriken.logging.L;
 @Desc("Represents a biome in iris.")
 @Data
 @EqualsAndHashCode(callSuper = false)
-public class IrisBiome extends IrisRegistrant
+public class IrisBiome extends IrisRegistrant implements IRare
 {
 	@Desc("This is the human readable name for this biome. This can and should be different than the file name. This is not used for loading biomes in other objects.")
 	private String name = "A Biome";
 
+	@Desc("The weight of this biome. Higher than 1 is more common, less than 1 (above 0) is rarer")
+	private double weight = 1D;
+
 	@Desc("This changes the dispersion of the biome colors if multiple derivatives are chosen")
 	private Dispersion biomeDispersion = Dispersion.SCATTER;
 

src/main/java/ninja/bytecode/iris/util/IRare.java

@@ -0,0 +1,6 @@
+package ninja.bytecode.iris.util;
+
+public interface IRare
+{
+	public double getWeight();
+}

src/main/java/ninja/bytecode/iris/util/RarityCellGenerator.java

@@ -0,0 +1,50 @@
+package ninja.bytecode.iris.util;
+
+import org.apache.commons.lang.math.DoubleRange;
+
+import ninja.bytecode.shuriken.collections.KList;
+import ninja.bytecode.shuriken.collections.KMap;
+
+public class RarityCellGenerator<T extends IRare> extends CellGenerator
+{
+	public RarityCellGenerator(RNG rng)
+	{
+		super(rng);
+	}
+
+	public T get(double x, double z, KList<T> t)
+	{
+		int totalWeight = 0;
+		KMap<DoubleRange, T> ranges = new KMap<>();
+
+		for(T i : t)
+		{
+			int weight = (int) Math.round(1000 * i.getWeight());
+
+			if(weight < 1)
+			{
+				continue;
+			}
+
+			ranges.put(new DoubleRange(totalWeight, totalWeight + weight), i);
+			totalWeight += weight;
+		}
+
+		int r = getIndex(x, z, totalWeight);
+
+		for(DoubleRange i : ranges.keySet())
+		{
+			if(i.containsDouble(r))
+			{
+				return ranges.get(i);
+			}
+		}
+
+		if(!t.isEmpty())
+		{
+			return t.get(0);
+		}
+
+		return null;
+	}
+}