Added _UNFINISHED_ water, beaches and mantle

- Refactored terrain generation
- Added PiecewiseLinearFunction
- Added some placeholder content
  - Added Test:Water, the solid, opaque water
  - Added beaches
  - Added Test:Mantle
- Tweaked rock distribution parameters

src/main/java/ru/windcorp/progressia/common/util/math/FloatFunction.java

@@ -0,0 +1,25 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util.math;
+
+@FunctionalInterface
+public interface FloatFunction {
+
+	float apply(float x);
+	
+}

src/main/java/ru/windcorp/progressia/common/util/math/FloatFunction2D.java

@@ -0,0 +1,24 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util.math;
+
+public interface FloatFunction2D {
+	
+	float apply(float x, float y);
+
+}

src/main/java/ru/windcorp/progressia/common/util/math/FloatFunction3D.java

@@ -0,0 +1,24 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util.math;
+
+public interface FloatFunction3D {
+	
+	float apply(float x, float y, float z);
+
+}

src/main/java/ru/windcorp/progressia/common/util/math/PiecewiseLinearFunction.java

@@ -0,0 +1,124 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util.math;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+
+import glm.vec._2.Vec2;
+
+public class PiecewiseLinearFunction implements FloatFunction {
+	
+	public static class Builder {
+		
+		private final List<Vec2> points = new ArrayList<>();
+		private float slopeAtNegInf = 0;
+		private float slopeAtPosInf = 0;
+		
+		public Builder add(float x, float y) {
+			points.add(new Vec2(x, y));
+			return this;
+		}
+		
+		public Builder setNegativeSlope(float slope) {
+			slopeAtNegInf = slope;
+			return this;
+		}
+		
+		public Builder setPositiveSlope(float slope) {
+			slopeAtPosInf = slope;
+			return this;
+		}
+		
+		public Builder setDefaultUndefined() {
+			slopeAtPosInf = Float.NaN;
+			slopeAtNegInf = Float.NaN;
+			return this;
+		}
+		
+		public PiecewiseLinearFunction build() {
+			float[] pointXs = new float[points.size()];
+			float[] pointYs = new float[points.size()];
+			
+			points.sort(Comparator.comparingDouble(v -> v.x));
+			for (int i = 0; i < points.size(); ++i) {
+				pointXs[i] = points.get(i).x;
+				pointYs[i] = points.get(i).y;
+			}
+			
+			return new PiecewiseLinearFunction(pointXs, pointYs, slopeAtNegInf, slopeAtPosInf);
+		}
+		
+	}
+	
+	public static Builder builder() {
+		return new Builder();
+	}
+	
+	/**
+	 * The set of the X coordinates of all defining points, sorted in increasing order
+	 */
+	private final float[] pointXs;
+	
+	/**
+	 * The set of the Y coordinates of all defining points, sorted to match the order of {@link #pointXs}
+	 */
+	private final float[] pointYs;
+	
+	/**
+	 * Slope of the segment (-inf; x[0]), or NaN to exclude the segment from the function
+	 */
+	private final float slopeAtNegInf;
+	
+	/**
+	 * Slope of the segment (x[x.length - 1]; +inf), or NaN to exclude the segment from the function
+	 */
+	private final float slopeAtPosInf;
+
+	protected PiecewiseLinearFunction(float[] pointXs, float[] pointYs, float slopeAtNegInf, float slopeAtPosInf) {
+		this.pointXs = pointXs;
+		this.pointYs = pointYs;
+		this.slopeAtNegInf = slopeAtNegInf;
+		this.slopeAtPosInf = slopeAtPosInf;
+	}
+
+	@Override
+	public float apply(float x) {
+		int index = Arrays.binarySearch(pointXs, x);
+		
+		if (index >= 0) {
+			// Wow, exact match, me surprised
+			return pointYs[index];
+		}
+		
+		int bigger = -index - 1;
+		int smaller = bigger - 1;
+		
+		if (smaller == -1) {
+			return pointYs[bigger] + (x - pointXs[bigger]) * slopeAtNegInf;
+		} else if (bigger == pointXs.length) {
+			return pointYs[smaller] + (x - pointXs[smaller]) * slopeAtPosInf;
+		} else {
+			float t = (x - pointXs[smaller]) / (pointXs[bigger] - pointXs[smaller]);
+			return pointYs[smaller] * (1 - t) + pointYs[bigger] * t;
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/server/world/generation/planet/PlanetGenerator.java

@@ -24,7 +24,6 @@ import java.util.List;
 
 import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.util.FloatRangeMap;
 import ru.windcorp.progressia.common.util.VectorUtil;
 import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
@@ -32,7 +31,7 @@ import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.generation.AbstractWorldGenerator;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceFeature;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceFloatField;
-import ru.windcorp.progressia.server.world.generation.surface.TerrainLayer;
+import ru.windcorp.progressia.server.world.generation.surface.TerrainSupplier;
 
 public class PlanetGenerator extends AbstractWorldGenerator<Boolean> {
 
@@ -46,7 +45,7 @@ public class PlanetGenerator extends AbstractWorldGenerator<Boolean> {
 		Server server,
 		Planet planet,
 		SurfaceFloatField heightMap,
-		FloatRangeMap<TerrainLayer> layers,
+		TerrainSupplier terrain,
 		List<SurfaceFeature> features
 	) {
 		super(id, server, Boolean.class, "Test:PlanetGravityModel");
@@ -56,7 +55,7 @@ public class PlanetGenerator extends AbstractWorldGenerator<Boolean> {
 		PlanetGravityModel model = (PlanetGravityModel) this.getGravityModel();
 		model.configure(planet.getGravityModelSettings());
 
-		this.terrainGenerator = new PlanetTerrainGenerator(this, heightMap, layers);
+		this.terrainGenerator = new PlanetTerrainGenerator(this, heightMap, terrain);
 		this.featureGenerator = new PlanetFeatureGenerator(this, features);
 	}
 

src/main/java/ru/windcorp/progressia/server/world/generation/planet/PlanetTerrainGenerator.java

@@ -21,7 +21,6 @@ import java.util.Map;
 
 import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.util.FloatRangeMap;
 import ru.windcorp.progressia.common.util.VectorUtil;
 import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.Coordinates;
@@ -33,7 +32,7 @@ import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.generation.surface.Surface;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceFloatField;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceTerrainGenerator;
-import ru.windcorp.progressia.server.world.generation.surface.TerrainLayer;
+import ru.windcorp.progressia.server.world.generation.surface.TerrainSupplier;
 
 class PlanetTerrainGenerator {
 
@@ -43,7 +42,7 @@ class PlanetTerrainGenerator {
 	public PlanetTerrainGenerator(
 		PlanetGenerator generator,
 		SurfaceFloatField heightMap,
-		FloatRangeMap<TerrainLayer> layers
+		TerrainSupplier terrain
 	) {
 		this.parent = generator;
 
@@ -53,7 +52,7 @@ class PlanetTerrainGenerator {
 			face -> new SurfaceTerrainGenerator(
 				new Surface(face, seaLevel),
 				heightMap,
-				layers
+				terrain
 			)
 		);
 	}

src/main/java/ru/windcorp/progressia/server/world/generation/surface/SurfaceTerrainGenerator.java

@@ -19,7 +19,6 @@ package ru.windcorp.progressia.server.world.generation.surface;
 
 import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.util.FloatRangeMap;
 import ru.windcorp.progressia.common.util.Vectors;
 import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.block.BlockData;
@@ -33,12 +32,12 @@ public class SurfaceTerrainGenerator {
 	private final Surface surface;
 
 	private final SurfaceFloatField heightMap;
-	private final FloatRangeMap<TerrainLayer> layers;
+	private final TerrainSupplier terrain;
 
-	public SurfaceTerrainGenerator(Surface surface, SurfaceFloatField heightMap, FloatRangeMap<TerrainLayer> layers) {
+	public SurfaceTerrainGenerator(Surface surface, SurfaceFloatField heightMap, TerrainSupplier terrain) {
 		this.surface = surface;
 		this.heightMap = heightMap;
-		this.layers = layers;
+		this.terrain = terrain;
 	}
 
 	public void generateTerrain(Server server, DefaultChunkData chunk) {
@@ -74,7 +73,7 @@ public class SurfaceTerrainGenerator {
 			location.set(north, west, altitude);
 			SurfaceBlockContext blockContext = context.push(location);
 			
-			BlockData block = layers.get(depth).get(blockContext, depth);
+			BlockData block = terrain.get(blockContext, depth);
 			
 			blockContext.pop();
 

src/main/java/ru/windcorp/progressia/server/world/generation/surface/TerrainSupplier.java

@@ -21,7 +21,7 @@ import ru.windcorp.progressia.common.world.block.BlockData;
 import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
 
 @FunctionalInterface
-public interface TerrainLayer {
+public interface TerrainSupplier {
 
 	BlockData get(SurfaceBlockContext context, float depth);
 	

src/main/java/ru/windcorp/progressia/test/TestContent.java

@@ -104,6 +104,8 @@ public class TestContent {
 		registerSimplestBlock("Dirt");
 		registerSimplestBlock("Chernozem");
 		registerSimplestBlock("Stone");
+		registerSimplestBlock("Mantle");
+		registerSimplestBlock("Water");
 		registerSimplestBlock("Brick");
 		registerSimplestBlock("BrickWhite");
 		registerSimplestBlock("Sand");

src/main/java/ru/windcorp/progressia/test/gen/TestGenerationConfig.java

@@ -24,21 +24,18 @@ import java.util.List;
 import java.util.function.Function;
 
 import ru.windcorp.progressia.common.Units;
-import ru.windcorp.progressia.common.util.ArrayFloatRangeMap;
-import ru.windcorp.progressia.common.util.FloatRangeMap;
 import ru.windcorp.progressia.common.util.noise.discrete.WorleyProceduralNoise;
 import ru.windcorp.progressia.common.world.Coordinates;
-import ru.windcorp.progressia.common.world.block.BlockData;
-import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.generation.WorldGenerator;
 import ru.windcorp.progressia.server.world.generation.planet.Planet;
 import ru.windcorp.progressia.server.world.generation.planet.PlanetGenerator;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceFeature;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceFloatField;
-import ru.windcorp.progressia.server.world.generation.surface.TerrainLayer;
-import ru.windcorp.progressia.test.Rocks.RockVariant;
+import ru.windcorp.progressia.test.Rocks.Rock;
 import ru.windcorp.progressia.test.TestContent;
+import ru.windcorp.progressia.test.gen.feature.*;
+import ru.windcorp.progressia.test.gen.terrain.*;
 
 public class TestGenerationConfig {
 
@@ -62,47 +59,45 @@ public class TestGenerationConfig {
 
 		TestHeightMap heightMap = new TestHeightMap(planet, planet.getRadius() / 4, FIELDS);
 
-		FloatRangeMap<TerrainLayer> layers = new ArrayFloatRangeMap<>();
-		registerTerrainLayers(layers);
+		LayeredTerrain terrain = new LayeredTerrain();
+		registerTerrainLayers(terrain);
 
 		List<SurfaceFeature> features = new ArrayList<>();
 		registerFeatures(features);
 
-		return server -> new PlanetGenerator("Test:PlanetGenerator", server, planet, heightMap, layers, features);
+		return server -> new PlanetGenerator("Test:PlanetGenerator", server, planet, heightMap, terrain, features);
 
 	}
 
-	private static void registerTerrainLayers(FloatRangeMap<TerrainLayer> layers) {
-		BlockData dirt = BlockDataRegistry.getInstance().get("Test:Dirt");
-		BlockData air = BlockDataRegistry.getInstance().get("Test:Air");
-
+	private static void registerTerrainLayers(LayeredTerrain terrain) {
 		SurfaceFloatField cliffs = FIELDS.get("Test:Cliff");
+		SurfaceFloatField beaches = FIELDS.register(
+			"Test:Beach",
+			f -> multiply(
+				anti(FIELDS.get("Test:Cliff", f))
+			)
+		);
+		RockStrata rockStrata = createStrata();
+
+		terrain.addLayer(new AirLayer("Test:Air"));
+		terrain.addLayer(new MantleLayer("Test:Mantle"));
+		terrain.addLayer(new CrustLayer("Test:Crust", rockStrata));
+		terrain.addLayer(new WaterLayer("Test:Water"));
+		terrain.addLayer(new SoilLayer("Test:Soil"));
+		terrain.addLayer(new CliffLayer("Test:Cliffs", cliffs, rockStrata));
+		terrain.addLayer(new BeachLayer("Test:Beaches", beaches, rockStrata));
+	}
+	
+	private static RockStrata createStrata() {
+		WorleyProceduralNoise.Builder<Rock> builder = WorleyProceduralNoise.builder();
+		TestContent.ROCKS.getRocks().forEach(rock -> builder.add(rock, 1));
 		
-		WorleyProceduralNoise.Builder<TerrainLayer> builder = WorleyProceduralNoise.builder();
-		TestContent.ROCKS.getRocks().forEach(rock -> {
-			builder.add((c, d) -> {
-				if (c.getRandom().nextInt(3) == 0) {
-					return rock.getBlock(RockVariant.CRACKED);
-				} else {
-					return rock.getBlock(RockVariant.MONOLITH);
-				}
-			}, 1);
-		});
 		SurfaceFloatField rockDepthOffsets = FIELDS.register(
 			"Test:RockDepthOffsets",
 			() -> tweak(FIELDS.primitive(), 40, 5)
 		);
-		RockLayer rockLayer = new RockLayer(builder.build(SEED), rockDepthOffsets);
 		
-		layers.put(Float.NEGATIVE_INFINITY, 0, (c, d) -> air);
-		layers.put(0, 4, (c, d) -> {
-			if (cliffs.get(c.getSurface().getUp(), c.getLocation().x, c.getLocation().y) > 0) {
-				return rockLayer.get(c, d);
-			} else {
-				return dirt;
-			}
-		});
-		layers.put(4, Float.POSITIVE_INFINITY, rockLayer);
+		return new RockStrata(builder.build(SEED), rockDepthOffsets);
 	}
 
 	private static void registerFeatures(List<SurfaceFeature> features) {

src/main/java/ru/windcorp/progressia/test/gen/feature/MultiblockVegetationFeature.java

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package ru.windcorp.progressia.test.gen;
+package ru.windcorp.progressia.test.gen.feature;
 
 import java.util.Set;
 import java.util.function.Consumer;

src/main/java/ru/windcorp/progressia/test/gen/feature/TestBushFeature.java

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package ru.windcorp.progressia.test.gen;
+package ru.windcorp.progressia.test.gen.feature;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.world.block.BlockData;

src/main/java/ru/windcorp/progressia/test/gen/feature/TestFlowerFeature.java

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package ru.windcorp.progressia.test.gen;
+package ru.windcorp.progressia.test.gen.feature;
 
 import java.util.Set;
 import java.util.function.Function;

src/main/java/ru/windcorp/progressia/test/gen/feature/TestGrassFeature.java

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package ru.windcorp.progressia.test.gen;
+package ru.windcorp.progressia.test.gen.feature;
 
 import java.util.List;
 import java.util.Set;
@@ -104,7 +104,17 @@ public class TestGrassFeature extends SurfaceTopLayerFeature {
 	}
 
 	private void growGrass(SurfaceBlockContext context, double grassiness) {
-		TileData flatGrass = flatGrasses.get((float) grassiness);
+		
+		double flatGrassiness = grassiness;
+		BlockData soil = context.getBlock();
+		if (soil.getId().endsWith("Sand")) {
+			flatGrassiness = flatGrassiness / 2 - 0.2;
+			if (flatGrassiness < 0) {
+				flatGrassiness = 0;
+			}
+		}
+		
+		TileData flatGrass = flatGrasses.get((float) flatGrassiness);
 		if (flatGrass != null) {
 			for (RelFace face : RelFace.getFaces()) {
 				if (face == RelFace.DOWN)

src/main/java/ru/windcorp/progressia/test/gen/feature/TestTreeFeature.java

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package ru.windcorp.progressia.test.gen;
+package ru.windcorp.progressia.test.gen.feature;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.world.block.BlockData;

src/main/java/ru/windcorp/progressia/test/gen/terrain/AirLayer.java

@@ -0,0 +1,42 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+
+public class AirLayer extends TerrainLayer {
+	
+	private final BlockData air = BlockDataRegistry.getInstance().get("Test:Air");
+
+	public AirLayer(String id) {
+		super(id);
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		return air;
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		return depth <= 0 ? 1 : 0;
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/BeachLayer.java

@@ -0,0 +1,55 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.server.world.generation.surface.SurfaceFloatField;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+import ru.windcorp.progressia.test.Rocks.RockVariant;
+
+public class BeachLayer extends TerrainLayer {
+
+	private final SurfaceFloatField beachSelector;
+	private final RockStrata strata;
+
+	public BeachLayer(String id, SurfaceFloatField beachSelector, RockStrata strata) {
+		super(id);
+		this.beachSelector = beachSelector;
+		this.strata = strata;
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		return strata.get(context, depth).getBlock(RockVariant.SAND);
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		if (depth < 0 || depth > 3) {
+			return 0;
+		}
+		
+		float altitude = context.getLocation().z;
+		if (altitude < -5| altitude > 1) {
+			return 0;
+		}
+		
+		return 3 * beachSelector.get(context);
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/CliffLayer.java

@@ -0,0 +1,64 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.server.world.generation.surface.SurfaceFloatField;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+import ru.windcorp.progressia.test.Rocks.RockVariant;
+
+public class CliffLayer extends TerrainLayer {
+
+	private final SurfaceFloatField cliffSelector;
+	private final RockStrata strata;
+
+	public CliffLayer(String id, SurfaceFloatField cliffSelector, RockStrata strata) {
+		super(id);
+		this.cliffSelector = cliffSelector;
+		this.strata = strata;
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		
+		RockVariant variant;
+		switch (context.getRandom().nextInt(4)) {
+		case 0:
+			variant = RockVariant.GRAVEL;
+			break;
+		case 1:
+			variant = RockVariant.MONOLITH;
+			break;
+		default:
+			variant = RockVariant.CRACKED;
+			break;
+		}
+		
+		return strata.get(context, depth).getBlock(variant);
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		if (depth < 0 || depth > 7) {
+			return 0;
+		}
+		
+		return 100 * cliffSelector.get(context);
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/CrustLayer.java

@@ -0,0 +1,69 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.util.ArrayFloatRangeMap;
+import ru.windcorp.progressia.common.util.FloatRangeMap;
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+import ru.windcorp.progressia.test.Rocks.RockVariant;
+
+public class CrustLayer extends TerrainLayer {
+
+	private static final FloatRangeMap<RockVariant> WEAR_TABLE = new ArrayFloatRangeMap<>();
+	static {
+		WEAR_TABLE.put(Float.NEGATIVE_INFINITY, 0.25f, RockVariant.MONOLITH);
+		WEAR_TABLE.put(0.25f, 0.5f, RockVariant.CRACKED);
+		WEAR_TABLE.put(0.5f, 0.75f, RockVariant.GRAVEL);
+		WEAR_TABLE.put(0.75f, Float.POSITIVE_INFINITY, RockVariant.SAND);
+	}
+	
+	private final RockStrata strata;
+
+	public CrustLayer(String id, RockStrata strata) {
+		super(id);
+		this.strata = strata;
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		
+		RockVariant variant;
+		if (depth < 8) {
+			float wear = 1 - depth / 8;
+			float offset = (context.getRandom().nextFloat() * 2 - 1) * 0.5f;
+			variant = WEAR_TABLE.get(wear + offset);
+		} else {
+			variant = RockVariant.MONOLITH;
+		}
+		
+		return strata.get(context, depth).getBlock(variant);
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		if (depth < 0) {
+			return 0;
+		} else if (context.getLocation().z > -100) {
+			return 1;
+		} else {
+			return 0;
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/LayeredTerrain.java

@@ -0,0 +1,61 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.server.world.generation.surface.TerrainSupplier;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+
+public class LayeredTerrain implements TerrainSupplier {
+	
+	private final List<TerrainLayer> layers = new ArrayList<>();
+	
+	public void addLayer(TerrainLayer layer) {
+		this.layers.add(layer);
+	}
+
+	@Override
+	public BlockData get(SurfaceBlockContext context, float depth) {
+		TerrainLayer layer = null;
+		float intensity = 0;
+		
+		for (int i = 0; i < layers.size(); ++i) {
+			TerrainLayer currentLayer = layers.get(i);
+			
+			float currentIntensity = currentLayer.getIntensity(context, depth);
+			if (currentIntensity <= 0) {
+				continue;
+			}
+			
+			if (intensity < currentIntensity) {
+				intensity = currentIntensity;
+				layer = currentLayer;
+			}
+		}
+		
+		if (layer == null) {
+			layer = layers.get(0);
+		}
+		
+		return layer.generate(context, depth, intensity);
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/MantleLayer.java

@@ -0,0 +1,42 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+
+public class MantleLayer extends TerrainLayer {
+
+	private final BlockData material = BlockDataRegistry.getInstance().get("Test:Mantle");
+	
+	public MantleLayer(String id) {
+		super(id);
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		return material;
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		return context.getLocation().z <= -100 ? 1 : 0;
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/RockStrata.java

@@ -15,43 +15,38 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-package ru.windcorp.progressia.test.gen;
+package ru.windcorp.progressia.test.gen.terrain;
 
 import ru.windcorp.progressia.common.util.noise.discrete.DiscreteNoise;
-import ru.windcorp.progressia.common.world.block.BlockData;
 import ru.windcorp.progressia.server.world.generation.surface.SurfaceFloatField;
-import ru.windcorp.progressia.server.world.generation.surface.TerrainLayer;
 import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+import ru.windcorp.progressia.test.Rocks.Rock;
 
-public class RockLayer implements TerrainLayer {
+public class RockStrata {
 	
-	private final DiscreteNoise<TerrainLayer> strata;
+	private final DiscreteNoise<Rock> distribution;
 	private final SurfaceFloatField depthOffsets;
 	
-	private final double horizontalScale = 200;
-	private final double verticalScale = 10;
-	private final double depthInfluense = 0.1;
+	private final double horizontalScale = 800;
+	private final double verticalScale = 20;
+	private final double depthInfluence = 0.1;
 
-	public RockLayer(DiscreteNoise<TerrainLayer> strata, SurfaceFloatField depthOffsets) {
-		this.strata = strata;
+	public RockStrata(DiscreteNoise<Rock> distribution, SurfaceFloatField depthOffsets) {
+		this.distribution = distribution;
 		this.depthOffsets = depthOffsets;
 	}
 	
-	@Override
-	public BlockData get(SurfaceBlockContext context, float depth) {
-		
+	public Rock get(SurfaceBlockContext context, float depth) {
 		double z = context.getLocation().z;
-		z -= depth * depthInfluense;
+		z -= depth * depthInfluence;
 		z += depthOffsets.get(context);
 		z /= verticalScale;
 		
-		return strata
-			.get(
+		return distribution.get(
 				context.getLocation().x / horizontalScale,
 				context.getLocation().y / horizontalScale,
 				z
-			)
-			.get(context, depth);
+		);
 	}
 
 }

src/main/java/ru/windcorp/progressia/test/gen/terrain/SoilLayer.java

@@ -0,0 +1,59 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.Units;
+import ru.windcorp.progressia.common.util.math.PiecewiseLinearFunction;
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+
+public class SoilLayer extends TerrainLayer {
+
+	private static final PiecewiseLinearFunction THICKNESS = PiecewiseLinearFunction.builder()
+		.add(Units.get("-5 m"), Units.get("1 m"))
+		.add(Units.get("0 m"), Units.get("4 m"))
+		.add(Units.get("5 km"), Units.get("0 m"))
+		.build();
+	
+	private final BlockData soil = BlockDataRegistry.getInstance().get("Test:Dirt");
+
+	public SoilLayer(String id) {
+		super(id);
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		return soil;
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		if (depth < 0) return 0;
+		
+		float altitude = context.getLocation().z;
+		float thickness = THICKNESS.apply(altitude);
+		
+		if (depth < thickness) {
+			return 2;
+		} else {
+			return 0;
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/TerrainLayer.java

@@ -0,0 +1,34 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.util.namespaces.Namespaced;
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+
+public abstract class TerrainLayer extends Namespaced {
+
+	public TerrainLayer(String id) {
+		super(id);
+	}
+	
+	public abstract BlockData generate(SurfaceBlockContext context, float depth, float intensity);
+	
+	public abstract float getIntensity(SurfaceBlockContext context, float depth);
+
+}

src/main/java/ru/windcorp/progressia/test/gen/terrain/WaterLayer.java

@@ -0,0 +1,45 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.test.gen.terrain;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
+import ru.windcorp.progressia.server.world.generation.surface.context.SurfaceBlockContext;
+
+public class WaterLayer extends TerrainLayer {
+	
+	private final BlockData water = BlockDataRegistry.getInstance().get("Test:Water");
+
+	public WaterLayer(String id) {
+		super(id);
+	}
+
+	@Override
+	public BlockData generate(SurfaceBlockContext context, float depth, float intensity) {
+		return water;
+	}
+
+	@Override
+	public float getIntensity(SurfaceBlockContext context, float depth) {
+		if (depth <= 0 && context.getLocation().z <= 0) {
+			return 2;
+		}
+		return 0;
+	}
+
+}