Resolve some Volcanic Island generation issues.

- Volcanic Islands now generate in any depth of water
- Fix most "buried" Volcano structures

common/build.gradle

@@ -23,3 +23,8 @@ sourceSets {
 		}
 	}
 }
+
+dependencies {
+	// Biolith for BiomePerimeters in the VolcanoStructure
+	modImplementation "com.terraformersmc:biolith-fabric:${biolith_version}"
+}

common/src/main/java/com/terraformersmc/terrestria/feature/structure/volcano/VolcanoStructure.java

@@ -3,15 +3,21 @@
 import com.mojang.serialization.Codec;
 import com.mojang.serialization.MapCodec;
 import com.mojang.serialization.codecs.RecordCodecBuilder;
+import com.terraformersmc.biolith.api.biomeperimeters.BiomePerimeters;
 import com.terraformersmc.terrestria.Terrestria;
 import com.terraformersmc.terrestria.init.TerrestriaBiomes;
 import com.terraformersmc.terrestria.init.TerrestriaStructures;
+import net.minecraft.registry.RegistryKeys;
 import net.minecraft.registry.entry.RegistryEntry;
 import net.minecraft.structure.*;
+import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.intprovider.IntProvider;
 import net.minecraft.world.Heightmap;
 import net.minecraft.world.biome.Biome;
+import net.minecraft.world.biome.source.BiomeAccess;
 import net.minecraft.world.biome.source.BiomeCoords;
+import net.minecraft.world.biome.source.BiomeSource;
+import net.minecraft.world.biome.source.util.MultiNoiseUtil;
 import net.minecraft.world.gen.structure.Structure;
 import net.minecraft.world.gen.structure.StructureType;
 
@@ -41,11 +47,26 @@ public Optional<StructurePosition> getStructurePosition(Structure.Context contex
 		int x = context.chunkPos().getCenterX();
 		int z = context.chunkPos().getCenterZ();
 		int y = context.chunkGenerator().getHeightInGround(x, z, Heightmap.Type.OCEAN_FLOOR_WG, context.world(), context.noiseConfig());
+		int seaLevel = context.chunkGenerator().getSeaLevel();
 		RegistryEntry<Biome> biome = context.chunkGenerator().getBiomeSource().getBiome(BiomeCoords.fromBlock(x),
 				BiomeCoords.fromBlock(y), BiomeCoords.fromBlock(z), context.noiseConfig().getMultiNoiseSampler());
 
-		if (!biome.matchesKey(TerrestriaBiomes.VOLCANIC_ISLAND) &&
-				!Terrestria.getConfigManager().getGeneralConfig().areOceanVolcanoesEnabled()) {
+		if (biome.matchesKey(TerrestriaBiomes.VOLCANIC_ISLAND)) {
+			// Shore volcanoes at the edges and regular volcanoes in the center.
+			int distance = BiomePerimeters.getOrCreateInstance(
+					context.dynamicRegistryManager().get(RegistryKeys.BIOME).getOrThrow(TerrestriaBiomes.VOLCANIC_ISLAND), 40)
+					.getPerimeterDistance(new BiomeAccess(
+							new BiomeAccessStorage(context.biomeSource(), context.noiseConfig().getMultiNoiseSampler()),
+							context.seed()), new BlockPos(x, seaLevel, z));
+
+			if (this.baseY < seaLevel - 10 && distance >= 20) {
+				return Optional.empty();
+			}
+			if (this.baseY >= seaLevel - 10 && distance < 20) {
+				return Optional.empty();
+			}
+		} else if (!Terrestria.getConfigManager().getGeneralConfig().areOceanVolcanoesEnabled()) {
+			// No need to consider starting a structure outside Volcanic Island unless sea volcanoes are enabled.
 			return Optional.empty();
 		}
 
@@ -60,4 +81,12 @@ private void addPieces(StructurePiecesCollector collector, Structure.Context con
 	public StructureType<?> getType() {
 		return TerrestriaStructures.VOLCANO_STRUCTURE_TYPE;
 	}
+
+	// Shim class to instantiate a BiomeAccess.Storage from available information.
+	private record BiomeAccessStorage(BiomeSource biomeSource, MultiNoiseUtil.MultiNoiseSampler noiseSampler) implements BiomeAccess.Storage {
+		@Override
+		public RegistryEntry<Biome> getBiomeForNoiseGen(int biomeX, int biomeY, int biomeZ) {
+			return biomeSource.getBiome(biomeX, biomeY, biomeZ, noiseSampler);
+		}
+	}
 }

worldgen/src/main/java/com/terraformersmc/terrestria/TerrestriaWorldgen.java

@@ -3,9 +3,13 @@
 import com.terraformersmc.terrestria.biomegen.TerrestriaBiolithGeneration;
 import com.terraformersmc.terrestria.surfacebuilders.TerrestriaSurfaceBuilders;
 import net.fabricmc.api.ModInitializer;
+import net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents;
 import net.fabricmc.loader.api.FabricLoader;
+import net.minecraft.server.world.ServerWorld;
+import org.jetbrains.annotations.Nullable;
 
 public class TerrestriaWorldgen implements ModInitializer {
+	private static ServerWorld OVERWORLD = null;
 
 	@Override
 	public void onInitialize() {
@@ -17,5 +21,17 @@ public void onInitialize() {
 		} else {
 			Terrestria.LOGGER.warn("Terrestria world generation disabled; Biolith is not present.");
 		}
+
+		// We need access to the Overworld for some surface builders.
+		ServerLifecycleEvents.SERVER_STARTED.register(server -> {
+			OVERWORLD = server.getOverworld();
+		});
+		ServerLifecycleEvents.SERVER_STOPPED.register(server -> {
+			OVERWORLD = null;
+		});
+	}
+
+	public static @Nullable ServerWorld getOverworld() {
+		return OVERWORLD;
 	}
 }

worldgen/src/main/java/com/terraformersmc/terrestria/surfacebuilders/CanyonSurfaceBuilder.java

@@ -11,7 +11,6 @@
 import net.minecraft.world.gen.chunk.BlockColumn;
 
 public class CanyonSurfaceBuilder extends BiolithSurfaceBuilder {
-
 	private static final OpenSimplexNoise CLIFF_NOISE = new OpenSimplexNoise(346987);
 
 	private final BlockState cliffMaterial;

worldgen/src/main/java/com/terraformersmc/terrestria/surfacebuilders/DuneSurfaceBuilder.java

@@ -13,7 +13,6 @@
 import net.minecraft.world.gen.chunk.BlockColumn;
 
 public class DuneSurfaceBuilder extends BiolithSurfaceBuilder {
-
 	private static final OpenSimplexNoise NOISE = new OpenSimplexNoise(3445);
 
 	private final BlockState topMaterial;

worldgen/src/main/java/com/terraformersmc/terrestria/surfacebuilders/OceanIslandSurfaceBuilder.java

@@ -3,58 +3,68 @@
 import com.terraformersmc.biolith.api.biomeperimeters.BiomePerimeters;
 import com.terraformersmc.biolith.api.surface.BiolithSurfaceBuilder;
 import com.terraformersmc.terraform.noise.OpenSimplexNoise;
+import com.terraformersmc.terrestria.TerrestriaWorldgen;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.Blocks;
+import net.minecraft.server.world.ServerWorld;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.MathHelper;
+import net.minecraft.util.math.noise.DoublePerlinNoiseSampler;
 import net.minecraft.util.math.random.Random;
 import net.minecraft.world.Heightmap;
 import net.minecraft.world.biome.Biome;
 import net.minecraft.world.biome.source.BiomeAccess;
 import net.minecraft.world.chunk.Chunk;
 import net.minecraft.world.gen.chunk.BlockColumn;
+import net.minecraft.world.gen.noise.NoiseParametersKeys;
 
 public class OceanIslandSurfaceBuilder extends BiolithSurfaceBuilder {
 	private static final OpenSimplexNoise ISLAND_NOISE = new OpenSimplexNoise(346987);
-	private static final int DEEP_DEPTH = 32;
-	private static final int SHALLOW_DEPTH = 16;
-	private static final double HEIGHT_FACTOR = 1.1;
+	private static final int ISLAND_HEIGHT = 12;
+	private static final double NOISE_SCALE = 9.5d;
 
 	private final BlockState topMaterial;
 	private final BlockState midMaterial;
 	private final BlockState lowMaterial;
 	private final BlockState beachMaterial;
 	private final BlockState underwaterMaterial;
-	private final boolean deepOcean;
 
-	public OceanIslandSurfaceBuilder(BlockState topMaterial, BlockState midMaterial, BlockState lowMaterial, BlockState beachMaterial, BlockState underwaterMaterial, boolean deepOcean) {
+	public OceanIslandSurfaceBuilder(BlockState topMaterial, BlockState midMaterial, BlockState lowMaterial, BlockState beachMaterial, BlockState underwaterMaterial) {
 		this.topMaterial = topMaterial;
 		this.midMaterial = midMaterial;
 		this.lowMaterial = lowMaterial;
 		this.beachMaterial = beachMaterial;
 		this.underwaterMaterial = underwaterMaterial;
-		this.deepOcean = deepOcean;
 	}
 
 	@Override
 	public void generate(BiomeAccess biomeAccess, BlockColumn column, Random rand, Chunk chunk, Biome biome, int x, int z, int vHeight, int seaLevel) {
-		int delta = (int)((deepOcean ? DEEP_DEPTH : SHALLOW_DEPTH) * HEIGHT_FACTOR);
+		ServerWorld overworld = TerrestriaWorldgen.getOverworld();
+		if (overworld == null) {
+			throw new IllegalStateException("Overworld does not exist during Overworld surface generation...");
+		}
+		DoublePerlinNoiseSampler surface = overworld.getChunkManager().chunkLoadingManager.noiseConfig
+				.getOrCreateSampler(NoiseParametersKeys.SURFACE);
 
-		// We are going to accept the ocean surface noise and just raise it so we need the ocean surface.
+		// Find the original top Y value, the desired top Y value, and the delta between them.
+		// We can't trust the provided vHeight because we need the ocean floor instead of surface.
 		vHeight = chunk.sampleHeightmap(Heightmap.Type.OCEAN_FLOOR_WG, x & 0xf, z & 0xf);
+		int top = seaLevel + ISLAND_HEIGHT + (int) (NOISE_SCALE * surface.sample(x, seaLevel, z));
+		int delta = MathHelper.clamp(top - vHeight, 0, 128);
 
 		// Work around noise-adapting structures (like villages)...
-		if (vHeight >= 60) {
+		if (vHeight >= seaLevel - 2) {
 			vHeight = seaLevel - delta;
 		}
 
 		// Delta is how much we are raising the surface.  Reduce it as we approach the edge of the island biome.
 		int borderAdjustment = BiomePerimeters.getOrCreateInstance(biome, 40)
-				.getPerimeterDistance(biomeAccess, new BlockPos(x, 62, z));
+				.getPerimeterDistance(biomeAccess, new BlockPos(x, seaLevel, z));
 		if (borderAdjustment < 32) {
 			delta = delta * borderAdjustment / 32;
 		}
 
-		int top = vHeight + delta;
+		top = vHeight + delta;
 		for (int y = 0; y <= top; y++) {
 			BlockState originalState = column.getState(y);
 			if (originalState.isOf(Blocks.STONE) || originalState.isOf(Blocks.WATER) || originalState.isAir()) {

worldgen/src/main/java/com/terraformersmc/terrestria/surfacebuilders/TerrestriaSurfaceBuilders.java

@@ -37,8 +37,7 @@ public static void init() {
 						TerrestriaBlocks.ANDISOL.getDirt().getDefaultState(),
 						TerrestriaBlocks.VOLCANIC_ROCK.plain.full.getDefaultState(),
 						TerrestriaBlocks.BLACK_SAND.getDefaultState(),
-						Blocks.SAND.getDefaultState(),
-						true
+						Blocks.SAND.getDefaultState()
 				).setBiomeKey(TerrestriaBiomes.VOLCANIC_ISLAND));
 	}
 

worldgen/src/main/resources/terrestria-worldgen.accesswidener

@@ -1,2 +1,3 @@
 accessWidener	v1	named
 
+accessible field net/minecraft/server/world/ServerChunkLoadingManager noiseConfig Lnet/minecraft/world/gen/noise/NoiseConfig;