haha yes it works sort of

src/main/java/com/dfsek/terra/TerraWorld.java

@@ -2,8 +2,8 @@ package com.dfsek.terra;
 
 import com.dfsek.terra.api.gaea.biome.BiomeGrid;
 import com.dfsek.terra.api.generic.TerraPlugin;
-import com.dfsek.terra.api.generic.generator.TerraChunkGenerator;
 import com.dfsek.terra.api.generic.world.World;
+import com.dfsek.terra.api.implementations.bukkit.generator.BukkitChunkGenerator;
 import com.dfsek.terra.biome.BiomeZone;
 import com.dfsek.terra.biome.grid.master.TerraBiomeGrid;
 import com.dfsek.terra.biome.grid.master.TerraRadialBiomeGrid;
@@ -55,7 +55,7 @@ public class TerraWorld {
     }
 
     public static boolean isTerraWorld(World w) {
-        return w.getGenerator() instanceof TerraChunkGenerator;
+        return w.getGenerator() instanceof BukkitChunkGenerator;
     }
 
     public TerraBiomeGrid getGrid() {

src/main/java/com/dfsek/terra/api/gaea/profiler/WorldProfiler.java

@@ -1,7 +1,8 @@
 package com.dfsek.terra.api.gaea.profiler;
 
-import com.dfsek.terra.api.generic.generator.TerraChunkGenerator;
 import com.dfsek.terra.api.generic.world.World;
+import com.dfsek.terra.api.implementations.bukkit.generator.BukkitChunkGenerator;
+import com.dfsek.terra.api.implementations.bukkit.generator.BukkitChunkGeneratorWrapper;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.HashBiMap;
 import net.jafama.FastMath;
@@ -15,7 +16,7 @@ public class WorldProfiler {
     private boolean isProfiling;
 
     public WorldProfiler(World w) {
-        if(!(w.getGenerator() instanceof TerraChunkGenerator))
+        if(!(w.getGenerator() instanceof BukkitChunkGenerator))
             throw new IllegalArgumentException("Attempted to instantiate profiler on non-Gaea managed world!");
         this.addMeasurement(new Measurement(2500000, DataType.PERIOD_MILLISECONDS), "TotalChunkGenTime")
                 .addMeasurement(new Measurement(2500000, DataType.PERIOD_MILLISECONDS), "ChunkBaseGenTime")
@@ -23,7 +24,7 @@ public class WorldProfiler {
                 .addMeasurement(new Measurement(2000000, DataType.PERIOD_MILLISECONDS), "PopulationManagerTime");
         isProfiling = false;
         this.world = w;
-        ((TerraChunkGenerator) w.getGenerator()).attachProfiler(this);
+        ((BukkitChunkGeneratorWrapper) ((BukkitChunkGenerator) w.getGenerator()).getHandle()).getDelegate().attachProfiler(this);
     }
 
     public String getResultsFormatted() {

src/main/java/com/dfsek/terra/api/generic/generator/ChunkGenerator.java

@@ -22,6 +22,7 @@ public interface ChunkGenerator extends Handle {
 
     ChunkData generateChunkData(@NotNull World world, @NotNull Random random, int x, int z, @NotNull BiomeGrid biome);
 
+
     List<BlockPopulator> getDefaultPopulators(World world);
 
     interface ChunkData {

src/main/java/com/dfsek/terra/api/generic/generator/TerraChunkGenerator.java

@@ -9,7 +9,7 @@ import org.jetbrains.annotations.NotNull;
 import java.util.Random;
 
 public interface TerraChunkGenerator {
-    void generateChunkData(@NotNull World world, @NotNull Random random, int x, int z, @NotNull BiomeGrid biome, ChunkGenerator.ChunkData data);
+    ChunkGenerator.ChunkData generateChunkData(@NotNull World world, @NotNull Random random, int x, int z, @NotNull BiomeGrid biome, ChunkGenerator.ChunkData original);
 
     void attachProfiler(WorldProfiler profiler);
 
@@ -24,4 +24,5 @@ public interface TerraChunkGenerator {
     boolean shouldGenerateStructures();
 
     ConfigPack getConfigPack();
+
 }

src/main/java/com/dfsek/terra/api/implementations/bukkit/TerraBukkitPlugin.java

@@ -6,11 +6,14 @@ import com.dfsek.terra.api.GenericLoaders;
 import com.dfsek.terra.api.gaea.GaeaPlugin;
 import com.dfsek.terra.api.gaea.lang.Language;
 import com.dfsek.terra.api.generic.TerraPlugin;
+import com.dfsek.terra.api.generic.world.Biome;
 import com.dfsek.terra.api.generic.world.World;
 import com.dfsek.terra.api.generic.world.WorldHandle;
 import com.dfsek.terra.api.generic.world.block.BlockData;
 import com.dfsek.terra.api.generic.world.block.MaterialData;
+import com.dfsek.terra.api.implementations.bukkit.generator.BukkitChunkGenerator;
 import com.dfsek.terra.api.implementations.bukkit.generator.BukkitChunkGeneratorWrapper;
+import com.dfsek.terra.api.implementations.bukkit.world.BukkitBiome;
 import com.dfsek.terra.command.TerraCommand;
 import com.dfsek.terra.command.structure.LocateCommand;
 import com.dfsek.terra.config.base.ConfigPack;
@@ -24,7 +27,6 @@ import com.dfsek.terra.registry.ConfigRegistry;
 import com.dfsek.terra.util.PaperUtil;
 import org.bstats.bukkit.Metrics;
 import org.bukkit.Bukkit;
-import org.bukkit.block.Biome;
 import org.bukkit.command.PluginCommand;
 import org.bukkit.entity.EntityType;
 import org.bukkit.generator.ChunkGenerator;
@@ -130,7 +132,8 @@ public class TerraBukkitPlugin extends GaeaPlugin implements TerraPlugin {
     }
 
     public TerraWorld getWorld(World w) {
-        if(!(w.getGenerator() instanceof TerraChunkGenerator)) throw new IllegalArgumentException("Not a Terra world!");
+        if(!(w.getGenerator() instanceof BukkitChunkGenerator))
+            throw new IllegalArgumentException("Not a Terra world! " + w.getGenerator());
         if(!worlds.containsKey(w.getName())) {
             getLogger().warning("Unexpected world load detected: \"" + w.getName() + "\"");
             return new TerraWorld(w, ((TerraChunkGenerator) w.getGenerator()).getConfigPack(), this);
@@ -151,9 +154,10 @@ public class TerraBukkitPlugin extends GaeaPlugin implements TerraPlugin {
 
     @Override
     public void register(TypeRegistry registry) {
-        registry.registerLoader(Biome.class, (t, o, l) -> Biome.valueOf((String) o))
+        registry
                 .registerLoader(BlockData.class, (t, o, l) -> handle.createBlockData((String) o))
                 .registerLoader(MaterialData.class, (t, o, l) -> handle.createMaterialData((String) o))
+                .registerLoader(Biome.class, (t, o, l) -> new BukkitBiome(org.bukkit.block.Biome.valueOf((String) o)))
                 .registerLoader(EntityType.class, (t, o, l) -> EntityType.valueOf((String) o));
         genericLoaders.register(registry);
     }

src/main/java/com/dfsek/terra/api/implementations/bukkit/generator/BukkitChunkGeneratorWrapper.java

@@ -19,8 +19,11 @@ public class BukkitChunkGeneratorWrapper extends ChunkGenerator {
     @Override
     public @NotNull ChunkData generateChunkData(@NotNull World world, @NotNull Random random, int x, int z, @NotNull BiomeGrid biome) {
         BukkitWorld bukkitWorld = new BukkitWorld(world);
-        BukkitChunkGenerator.BukkitChunkData data = new BukkitChunkGenerator.BukkitChunkData(createChunkData(world));
+
-        delegate.generateChunkData(bukkitWorld, random, x, z, new BukkitBiomeGrid(biome), new BukkitChunkGenerator.BukkitChunkData(createChunkData(bukkitWorld.getHandle())));
+        return (ChunkData) delegate.generateChunkData(bukkitWorld, random, x, z, new BukkitBiomeGrid(biome), new BukkitChunkGenerator.BukkitChunkData(createChunkData(world))).getHandle();
-        return data.getHandle();
+    }
+
+    public TerraChunkGenerator getDelegate() {
+        return delegate;
     }
 }

src/main/java/com/dfsek/terra/config/loaders/MaterialSetLoader.java

@@ -5,7 +5,6 @@ import com.dfsek.tectonic.loading.ConfigLoader;
 import com.dfsek.tectonic.loading.TypeLoader;
 import com.dfsek.terra.api.generic.world.block.MaterialData;
 import com.dfsek.terra.util.MaterialSet;
-import org.bukkit.Material;
 
 import java.lang.reflect.Type;
 import java.util.List;
@@ -20,7 +19,7 @@ public class MaterialSetLoader implements TypeLoader<MaterialSet> {
         for(String string : stringData) {
             try {
                 if(string.startsWith("#")) set.addTag(string.substring(1));
-                else set.add((MaterialData) configLoader.loadType(Material.class, string));
+                else set.add((MaterialData) configLoader.loadType(MaterialData.class, string));
             } catch(NullPointerException e) {
                 throw new LoadException("Invalid data identifier \"" + string + "\"", e);
             }

src/main/java/com/dfsek/terra/config/loaders/Types.java

@@ -4,8 +4,8 @@ import com.dfsek.terra.api.gaea.math.ProbabilityCollection;
 import com.dfsek.terra.api.gaea.tree.Tree;
 import com.dfsek.terra.api.gaea.world.Flora;
 import com.dfsek.terra.api.gaea.world.palette.Palette;
+import com.dfsek.terra.api.generic.world.block.BlockData;
 import org.bukkit.Material;
-import org.bukkit.block.data.BlockData;
 
 import java.lang.reflect.Type;
 import java.util.Set;

src/main/java/com/dfsek/terra/generation/TerraChunkGenerator.java

@@ -95,8 +95,8 @@ public class TerraChunkGenerator implements com.dfsek.terra.api.generic.generato
 
 
     @Override
-    @SuppressWarnings({"deprecation", "try"})
+    @SuppressWarnings({"try"})
-    public void generateChunkData(@NotNull World world, @NotNull Random random, int chunkX, int chunkZ, @NotNull BiomeGrid biome, ChunkGenerator.ChunkData chunk) {
+    public ChunkGenerator.ChunkData generateChunkData(@NotNull World world, @NotNull Random random, int chunkX, int chunkZ, @NotNull BiomeGrid biome, ChunkGenerator.ChunkData chunk) {
         TerraWorld tw = main.getWorld(world);
         com.dfsek.terra.api.gaea.biome.BiomeGrid grid = tw.getGrid();
         try(ProfileFuture ignore = tw.getProfiler().measure("TotalChunkGenTime")) {
@@ -105,7 +105,7 @@ public class TerraChunkGenerator implements com.dfsek.terra.api.generic.generato
                 interp = new ChunkInterpolator3(world, chunkX, chunkZ, tw.getGrid());
                 if(needsLoad) load(world); // Load population data for world.
 
-                if(!tw.isSafe()) return;
+                if(!tw.isSafe()) return chunk;
                 int xOrig = (chunkX << 4);
                 int zOrig = (chunkZ << 4);
 
@@ -142,7 +142,7 @@ public class TerraChunkGenerator implements com.dfsek.terra.api.generic.generato
                                 }
                                 paletteLevel++;
                             } else if(y <= sea) {
-                                chunk.setBlock(x, y, z, seaPalette.get(sea - y, x + xOrig, z + zOrig));
+                                //chunk.setBlock(x, y, z, seaPalette.get(sea - y, x + xOrig, z + zOrig));
                                 if(justSet && c.doSlabs()) {
                                     SlabUtil.prepareBlockPartCeiling(data, chunk.getBlockData(x, y, z), chunk, new Vector3(x, y, z), c.getSlabPalettes(), c.getStairPalettes(), c.getSlabThreshold(), sampler);
                                 }
@@ -170,6 +170,7 @@ public class TerraChunkGenerator implements com.dfsek.terra.api.generic.generato
                     biome.setBiome(x << 2, z << 2, b.getVanillaBiome());
                 }
             }
+            return chunk;
         }
     }