Try to fix structure inaccuracies.

src/main/java/thebetweenlands/common/world/biome/BiomeCoarseIslands.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -50,7 +51,7 @@ public BiomeCoarseIslands() {
 				.setTemperature(0.8F)
 				.setRainfall(0.9F));
 		this.setWeight(16);
-		this.getBiomeGenerator().setDecorator(new BiomeDecoratorCoarseIslands(this))
+		this.getBiomeGenerator().setDecoratorFactory(BiomeDecoratorCoarseIslands::new)
 		.addFeature(new CoarseIslandsFeature())
 		.addFeature(new AlgaeFeature());
 		this.setFoliageColors(-1, 0xA8A800);

src/main/java/thebetweenlands/common/world/biome/BiomeDeepWaters.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -51,7 +52,7 @@ public BiomeDeepWaters() {
 				.setRainfall(0.9F));
 
 		this.setWeight(12);
-		this.getBiomeGenerator().setDecorator(new BiomeDecoratorDeepWaters(this))
+		this.getBiomeGenerator().setDecoratorFactory(BiomeDecoratorDeepWaters::new)
 		.addFeature(new DeepWatersFeature())
 		.addFeature(new AlgaeFeature())
 		.addFeature(new CragSpiresFeature());

src/main/java/thebetweenlands/common/world/biome/BiomeMarsh.java

@@ -5,6 +5,7 @@
 import net.minecraft.client.Minecraft;
 import net.minecraft.entity.Entity;
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import net.minecraftforge.fml.relauncher.Side;
@@ -60,7 +61,7 @@ public BiomeMarsh(int type) {
 		.addFeature(new PatchFeature(0.03125D * 6.5D, 0.03125D * 6.5D, BlockRegistry.PEAT_SMOULDERING.getDefaultState(), 0.625D, 3.0D))
 		.addFeature(new PatchFeature(0.03125D * 5.5D, 0.03125D * 5.5D, BlockRegistry.MUD.getDefaultState()))
 		.addFeature(new PatchFeature(0.03125D * 8.5D, 0.03125D * 8.5D, BlockRegistry.MUD.getDefaultState()))
-		.setDecorator(new BiomeDecoratorMarsh(this));
+		.setDecoratorFactory(BiomeDecoratorMarsh::new);
 		this.setFoliageColors(0x627017, 0x63B581);
 	}
 

src/main/java/thebetweenlands/common/world/biome/BiomePatchyIslands.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -56,7 +57,7 @@ public BiomePatchyIslands() {
 				.setRainfall(0.9F));
 
 		this.setWeight(20);
-		this.getBiomeGenerator().setDecorator(new BiomeDecoratorPatchyIslands(this))
+		this.getBiomeGenerator().setDecoratorFactory(BiomeDecoratorPatchyIslands::new)
 		.addFeature(new SiltBeachFeature())
 		.addFeature(new AlgaeFeature());
 		this.setFoliageColors(0x1FC66D, 0x00AD7C);

src/main/java/thebetweenlands/common/world/biome/BiomeRaisedIsles.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -50,7 +51,7 @@ public BiomeRaisedIsles() {
 				.setTemperature(0.8F)
 				.setRainfall(0.9F));
 		this.setWeight(16);
-		this.getBiomeGenerator().setDecorator(new BiomeDecoratorRaisedIsles(this))
+		this.getBiomeGenerator().setDecoratorFactory(BiomeDecoratorRaisedIsles::new)
 		.addFeature(new CoarseIslandsFeature())
 		.addFeature(new AlgaeFeature());
 		this.setFoliageColors(-1, 0xA8A800);

src/main/java/thebetweenlands/common/world/biome/BiomeSludgePlains.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -48,7 +49,7 @@ public BiomeSludgePlains() {
 				.setRainfall(0.9F));
 
 		this.setWeight(5);
-		this.getBiomeGenerator().setTopBlockState(BlockRegistry.MUD.getDefaultState()).setFillerBlockHeight(1).setDecorator(new BiomeDecoratorSludgePlains(this))
+		this.getBiomeGenerator().setTopBlockState(BlockRegistry.MUD.getDefaultState()).setFillerBlockHeight(1).setDecoratorFactory(BiomeDecoratorSludgePlains::new)
 		.addFeature(new FlatLandFeature(WorldProviderBetweenlands.LAYER_HEIGHT, 5))
 		.addFeature(new PatchFeature(0.03125D * 5.75D, 0.03125D * 5.75D, BlockRegistry.SLUDGY_DIRT.getDefaultState()))
 		.addFeature(new PatchFeature(0.74D, 0.74D, BlockRegistry.SWAMP_DIRT.getDefaultState()))

src/main/java/thebetweenlands/common/world/biome/BiomeSludgePlainsClearing.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -45,7 +46,8 @@ public BiomeSludgePlainsClearing() {
 				.setRainfall(0.9F));
 
 		this.setWeight(0);
-		this.getBiomeGenerator().setTopBlockState(BlockRegistry.COMPACTED_MUD.getDefaultState()).setFillerBlockHeight(1).setDecorator(new BiomeDecoratorSludgePlainsClearing(this))
+		this.getBiomeGenerator().setTopBlockState(BlockRegistry.COMPACTED_MUD.getDefaultState()).setFillerBlockHeight(1)
+		.setDecoratorFactory(BiomeDecoratorSludgePlainsClearing::new)
 		.addFeature(new PatchFeature(0.03125D * 5.75D, 0.03125D * 5.75D, BlockRegistry.SLUDGY_DIRT.getDefaultState()))
 		.addFeature(new PatchFeature(0.74D, 0.74D, BlockRegistry.SWAMP_DIRT.getDefaultState()))
 		.addFeature(new PatchFeature(0.65D, 0.65D, BlockRegistry.MUD.getDefaultState(), 1.0D / 1.35D, 1.72D));

src/main/java/thebetweenlands/common/world/biome/BiomeSwamplands.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.api.entity.spawning.ICustomSpawnEntry;
@@ -66,7 +67,7 @@ public BiomeSwamplands() {
 		.addFeature(new PatchFeature(0.65D, 0.65D, BlockRegistry.MUD.getDefaultState(), 1.0D / 1.35D, 1.72D))
 		.addFeature(new AlgaeFeature())
 		.addFeature(new SiltBeachFeature(0.98F))
-		.setDecorator(new BiomeDecoratorSwamplands(this));
+		.setDecoratorFactory(BiomeDecoratorSwamplands::new);
 		this.setFoliageColors(0x2AFF00, 0x52AF5A);
 		this.setSecondaryFoliageColors(0x50a040, 0x85af51);
 	}

src/main/java/thebetweenlands/common/world/biome/BiomeSwamplandsClearing.java

@@ -1,6 +1,7 @@
 package thebetweenlands.common.world.biome;
 
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.biome.Biome.BiomeProperties;
 import net.minecraftforge.common.BiomeDictionary;
 import net.minecraftforge.common.BiomeDictionary.Type;
 import thebetweenlands.common.lib.ModInfo;
@@ -20,7 +21,7 @@ public BiomeSwamplandsClearing() {
 
 		this.setWeight(0);
 		this.getBiomeGenerator().setFillerBlockState(BlockRegistry.SWAMP_DIRT.getDefaultState())
-		.setTopBlockState(BlockRegistry.SWAMP_GRASS.getDefaultState()).setDecorator(new BiomeDecoratorSwamplandsClearing(this));
+		.setTopBlockState(BlockRegistry.SWAMP_GRASS.getDefaultState()).setDecoratorFactory(BiomeDecoratorSwamplandsClearing::new);
 		this.setFoliageColors(-1, 0x52AF5A);
 	}
 

src/main/java/thebetweenlands/common/world/gen/biome/decorator/BiomeDecoratorBetweenlands.java

@@ -18,8 +18,8 @@
 import thebetweenlands.common.world.gen.feature.OreGens;
 
 public class BiomeDecoratorBetweenlands extends DecoratorPositionProvider {
-    private static final List<String> profiledGenerators = new ArrayList<String>();
-    private static boolean decorating;
+    private final List<String> profiledGenerators = new ArrayList<String>();
+    private boolean decorating;
     private final Biome biome;
 
     public BiomeDecoratorBetweenlands(Biome biome) {
@@ -31,6 +31,10 @@ public Biome getBiome() {
         return this.biome;
     }
 
+    public final boolean isDecorating() {
+    	return decorating;
+    }
+
     /**
      * Decorates the specified chunk
      *
@@ -40,25 +44,30 @@ public Biome getBiome() {
      * @param z
      */
     public final void decorate(World world, ChunkGeneratorBetweenlands generator, Random rand, int x, int z) {
+    	if(this.decorating) {
+    		throw new RuntimeException("Already Decorating!");
+    	}
+
         this.init(world, this.biome, generator, rand, x, z);
 
-        boolean wasDecorating = decorating;
+        //TODO re-evaluate the profiling, make sure it's still working and that decorators aren't piling up or anything
+//        boolean wasDecorating = decorating;
         decorating = true;
 
-        if (!wasDecorating) {
-            profiledGenerators.clear();
+//        if (!wasDecorating) {
+            this.profiledGenerators.clear();
             this.getProfiler().startSection(this.getBiome().getRegistryName().getPath());
-        }
+//        }
 
         this.decorate();
 
-        if (!wasDecorating) {
+//        if (!wasDecorating) {
             this.getProfiler().endSection();
-        }
+//        }
 
-        if (!wasDecorating) {
+//        if (!wasDecorating) {
             decorating = false;
-        }
+//        }
     }
 
     /**

src/main/java/thebetweenlands/common/world/gen/biome/generator/BiomeGenerator.java

@@ -17,8 +17,21 @@
 import thebetweenlands.common.world.gen.biome.BiomeWeights;
 import thebetweenlands.common.world.gen.biome.decorator.BiomeDecoratorBetweenlands;
 import thebetweenlands.common.world.gen.biome.feature.BiomeFeature;
+import thebetweenlands.common.world.gen.biome.generator.BiomeGenerator.EnumGeneratorPass;
 
 public class BiomeGenerator {
+	//because writing Function<BiomeDecoratorBetweenlands, Biome> every time is really long
+	@FunctionalInterface
+	public static interface DecoratorProvider {
+		/**
+		 * Called when the main decorator is already in use (or when creating the main decorator).<br/>
+		 * Must create a new instance of the decorator.
+		 * @param biome The biome to create the decorator for.
+		 * @return A new {@code BiomeDecoratorBetweenlands} instance.
+		 */
+		public BiomeDecoratorBetweenlands createDecorator(Biome biome);
+	}
+
 	protected final Biome biome;
 
 	protected IBlockState bottomBlockState = BlockRegistry.BETWEENLANDS_BEDROCK.getDefaultState();
@@ -41,11 +54,13 @@ public class BiomeGenerator {
 	protected boolean noiseGeneratorsInitialized = false;
 	protected boolean noiseGenerated = false;
 
-	protected BiomeDecoratorBetweenlands decorator;
+	protected BiomeDecoratorBetweenlands mainDecorator;
+	protected DecoratorProvider decoratorFactory;
 
 	public BiomeGenerator(Biome biome) {
 		this.biome = biome;
-		this.decorator = new BiomeDecoratorBetweenlands(biome);
+		this.mainDecorator = new BiomeDecoratorBetweenlands(biome);
+		this.decoratorFactory = BiomeDecoratorBetweenlands::new;
 	}
 
 	/**
@@ -57,23 +72,33 @@ public Biome getBiome() {
 	}
 
 	/**
-	 * Sets the biome decorator
-	 * @param decorator
+	 * Sets the biome decorator factory.
+	 * @param decoratorFactory
 	 * @return
 	 */
-	public BiomeGenerator setDecorator(BiomeDecoratorBetweenlands decorator) {
+	public BiomeGenerator setDecoratorFactory(DecoratorProvider decoratorFactory) {
+		BiomeDecoratorBetweenlands decorator = decoratorFactory.createDecorator(this.getBiome());
 		if(decorator.getBiome() != this.getBiome())
 			throw new RuntimeException("Decorator was assigned to a different biome!");
-		this.decorator = decorator;
+		this.mainDecorator = decorator;
+		this.decoratorFactory = decoratorFactory;
 		return this;
 	}
 
 	/**
-	 * Returns the biome decorator
+	 * Returns a biome decorator.
+	 * Will create a new instance if the current one is in use.
 	 * @return
 	 */
 	public BiomeDecoratorBetweenlands getDecorator() {
-		return this.decorator;
+		if(!this.mainDecorator.isDecorating()) {
+			return this.mainDecorator;
+		}
+
+		BiomeDecoratorBetweenlands decorator = decoratorFactory.createDecorator(this.getBiome());
+		if(decorator.getBiome() != this.getBiome())
+			throw new RuntimeException("Decorator was assigned to a different biome!");
+		return decorator;
 	}
 
 	/**