v+

3.6.4

build.gradle

@@ -33,7 +33,7 @@ plugins {
 }
 
 
-version '3.6.0-1.20.1-1.21.4'
+version '3.6.4-1.20.1-1.21.4'
 
 // ADD YOURSELF AS A NEW LINE IF YOU WANT YOUR OWN BUILD TASK GENERATED
 // ======================== WINDOWS =============================

core/build.gradle

@@ -62,7 +62,7 @@ dependencies {
 
     // Third Party Integrations
     compileOnly 'com.ticxo.playeranimator:PlayerAnimator:R1.2.7'
-    compileOnly 'com.nexomc:nexo:0.6.0-dev.0'
+    compileOnly 'com.nexomc:nexo:1.0.0-dev.38'
     compileOnly 'com.github.LoneDev6:api-itemsadder:3.4.1-r4'
     compileOnly 'com.github.PlaceholderAPI:placeholderapi:2.11.3'
     compileOnly 'com.github.Ssomar-Developement:SCore:4.23.10.8'

core/src/main/java/com/volmit/iris/Iris.java

@@ -32,8 +32,10 @@ import com.volmit.iris.core.nms.v1X.NMSBinding1X;
 import com.volmit.iris.core.pregenerator.LazyPregenerator;
 import com.volmit.iris.core.service.StudioSVC;
 import com.volmit.iris.core.tools.IrisToolbelt;
+import com.volmit.iris.core.tools.IrisWorldCreator;
 import com.volmit.iris.engine.EnginePanic;
 import com.volmit.iris.engine.object.IrisCompat;
+import com.volmit.iris.engine.object.IrisContextInjector;
 import com.volmit.iris.engine.object.IrisDimension;
 import com.volmit.iris.engine.object.IrisWorld;
 import com.volmit.iris.engine.platform.BukkitChunkGenerator;
@@ -101,8 +103,6 @@ import static com.volmit.iris.core.safeguard.ServerBootSFG.passedserversoftware;
 
 @SuppressWarnings("CanBeFinal")
 public class Iris extends VolmitPlugin implements Listener {
-    public static final String OVERWORLD_TAG = "31010";
-
     private static final Queue<Runnable> syncJobs = new ShurikenQueue<>();
 
     public static Iris instance;
@@ -467,6 +467,7 @@ public class Iris extends VolmitPlugin implements Listener {
         configWatcher = new FileWatcher(getDataFile("settings.json"));
         services.values().forEach(IrisService::onEnable);
         services.values().forEach(this::registerListener);
+        registerListener(new IrisContextInjector());
         J.s(() -> {
             J.a(() -> PaperLib.suggestPaper(this));
             J.a(() -> IO.delete(getTemp()));
@@ -516,10 +517,10 @@ public class Iris extends VolmitPlugin implements Listener {
                 Iris.info("Loading World: %s | Generator: %s", s, generator);
 
                 Iris.info(C.LIGHT_PURPLE + "Preparing Spawn for " + s + "' using Iris:" + generator + "...");
-                new WorldCreator(s)
+                WorldCreator c = new WorldCreator(s)
                         .generator(getDefaultWorldGenerator(s, generator))
-                        .environment(IrisData.loadAnyDimension(generator).getEnvironment())
-                        .createWorld();
+                        .environment(IrisData.loadAnyDimension(generator).getEnvironment());
+                INMS.get().createWorld(c);
                 Iris.info(C.LIGHT_PURPLE + "Loaded " + s + "!");
             }
         } catch (Throwable e) {

core/src/main/java/com/volmit/iris/core/IrisSettings.java

@@ -181,6 +181,7 @@ public class IrisSettings {
         public boolean splashLogoStartup = true;
         public boolean useConsoleCustomColors = true;
         public boolean useCustomColorsIngame = true;
+        public boolean adjustVanillaHeight = false;
         public String forceMainWorld = "";
         public int spinh = -20;
         public int spins = 7;

core/src/main/java/com/volmit/iris/core/ServerConfigurator.java

@@ -28,20 +28,27 @@ import com.volmit.iris.engine.object.IrisBiomeCustom;
 import com.volmit.iris.engine.object.IrisDimension;
 import com.volmit.iris.engine.object.IrisRange;
 import com.volmit.iris.util.collection.KList;
+import com.volmit.iris.util.collection.KMap;
 import com.volmit.iris.util.collection.KSet;
 import com.volmit.iris.util.format.C;
 import com.volmit.iris.util.plugin.VolmitSender;
 import com.volmit.iris.util.scheduling.J;
+import lombok.Data;
+import lombok.NonNull;
 import org.bukkit.Bukkit;
 import org.bukkit.configuration.InvalidConfigurationException;
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.List;
+import java.util.Arrays;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Stream;
+
+import static com.volmit.iris.core.nms.datapack.IDataFixer.Dimension.*;
 
 public class ServerConfigurator {
     public static void configure() {
@@ -84,7 +91,7 @@ public class ServerConfigurator {
         }
     }
 
-    private static List<File> getDatapacksFolder() {
+    private static KList<File> getDatapacksFolder() {
         if (!IrisSettings.get().getGeneral().forceMainWorld.isEmpty()) {
             return new KList<File>().qadd(new File(Bukkit.getWorldContainer(), IrisSettings.get().getGeneral().forceMainWorld + "/datapacks"));
         }
@@ -99,57 +106,17 @@ public class ServerConfigurator {
 
     public static void installDataPacks(IDataFixer fixer, boolean fullInstall) {
         Iris.info("Checking Data Packs...");
-        File packs = new File("plugins/Iris/packs");
-        double ultimateMaxHeight = 0;
-        double ultimateMinHeight = 0;
-        if (packs.exists() && packs.isDirectory()) {
-            for (File pack : packs.listFiles()) {
-                IrisData data = IrisData.get(pack);
-                if (pack.isDirectory()) {
-                    File dimensionsFolder = new File(pack, "dimensions");
-                    if (dimensionsFolder.exists() && dimensionsFolder.isDirectory()) {
-                        for (File file : dimensionsFolder.listFiles()) {
-                            if (file.isFile() && file.getName().endsWith(".json")) {
-                                IrisDimension dim = data.getDimensionLoader().load(file.getName().split("\\Q.\\E")[0]);
-                                if (ultimateMaxHeight < dim.getDimensionHeight().getMax()) {
-                                    ultimateMaxHeight = dim.getDimensionHeight().getMax();
-                                }
-                                if (ultimateMinHeight > dim.getDimensionHeight().getMin()) {
-                                    ultimateMinHeight = dim.getDimensionHeight().getMin();
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-        }
-
-        if (packs.exists()) {
-            for (File i : packs.listFiles()) {
-                if (i.isDirectory()) {
-                    Iris.verbose("Checking Pack: " + i.getPath());
-                    IrisData data = IrisData.get(i);
-                    File dims = new File(i, "dimensions");
-
-                    if (dims.exists()) {
-                        for (File j : dims.listFiles()) {
-                            if (j.getName().endsWith(".json")) {
-                                IrisDimension dim = data.getDimensionLoader().load(j.getName().split("\\Q.\\E")[0]);
-
-                                if (dim == null) {
-                                    continue;
-                                }
+        DimensionHeight height = new DimensionHeight(fixer);
+        KList<File> folders = getDatapacksFolder();
+        KMap<String, KSet<String>> biomes = new KMap<>();
 
+        allPacks().flatMap(height::merge)
+                .parallel()
+                .forEach(dim -> {
                     Iris.verbose("  Checking Dimension " + dim.getLoadFile().getPath());
-                                for (File dpack : getDatapacksFolder()) {
-                                    dim.installDataPack(fixer, () -> data, dpack, ultimateMaxHeight, ultimateMinHeight);
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-        }
+                    dim.installBiomes(fixer, dim::getLoader, folders, biomes.computeIfAbsent(dim.getLoadKey(), k -> new KSet<>()));
+                });
+        IrisDimension.writeShared(folders, height);
 
         Iris.info("Data Packs Setup!");
 
@@ -158,37 +125,21 @@ public class ServerConfigurator {
     }
 
     private static void verifyDataPacksPost(boolean allowRestarting) {
-        File packs = new File("plugins/Iris/packs");
+        boolean bad = allPacks()
+                .map(data -> {
+                    Iris.verbose("Checking Pack: " + data.getDataFolder().getPath());
+                    var loader = data.getDimensionLoader();
+                    return loader.loadAll(loader.getPossibleKeys())
+                            .stream()
+                            .map(ServerConfigurator::verifyDataPackInstalled)
+                            .toList()
+                            .contains(false);
+                })
+                .toList()
+                .contains(true);
+        if (!bad) return;
 
-        boolean bad = false;
-        if (packs.exists()) {
-            for (File i : packs.listFiles()) {
-                if (i.isDirectory()) {
-                    Iris.verbose("Checking Pack: " + i.getPath());
-                    IrisData data = IrisData.get(i);
-                    File dims = new File(i, "dimensions");
 
-                    if (dims.exists()) {
-                        for (File j : dims.listFiles()) {
-                            if (j.getName().endsWith(".json")) {
-                                IrisDimension dim = data.getDimensionLoader().load(j.getName().split("\\Q.\\E")[0]);
-
-                                if (dim == null) {
-                                    Iris.error("Failed to load " + j.getPath() + " ");
-                                    continue;
-                                }
-
-                                if (!verifyDataPackInstalled(dim)) {
-                                    bad = true;
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-        }
-
-        if (bad) {
         if (allowRestarting) {
             restart();
         } else if (INMS.get().supportsDataPacks()) {
@@ -210,7 +161,6 @@ public class ServerConfigurator {
             J.sleep(3000);
         }
     }
-    }
 
     public static void restart() {
         J.s(() -> {
@@ -218,7 +168,7 @@ public class ServerConfigurator {
             Iris.warn("This will only happen when your pack changes (updates/first time setup)");
             Iris.warn("(You can disable this auto restart in iris settings)");
             J.s(() -> {
-                Iris.warn("Looks like the restart command diddn't work. Stopping the server instead!");
+                Iris.warn("Looks like the restart command didn't work. Stopping the server instead!");
                 Bukkit.shutdown();
             }, 100);
             Bukkit.dispatchCommand(Bukkit.getConsoleSender(), "restart");
@@ -226,22 +176,24 @@ public class ServerConfigurator {
     }
 
     public static boolean verifyDataPackInstalled(IrisDimension dimension) {
-        IrisData idm = IrisData.get(Iris.instance.getDataFolder("packs", dimension.getLoadKey()));
         KSet<String> keys = new KSet<>();
         boolean warn = false;
 
-        for (IrisBiome i : dimension.getAllBiomes(() -> idm)) {
+        for (IrisBiome i : dimension.getAllBiomes(dimension::getLoader)) {
             if (i.isCustom()) {
                 for (IrisBiomeCustom j : i.getCustomDerivitives()) {
                     keys.add(dimension.getLoadKey() + ":" + j.getId());
                 }
             }
         }
+        String key = getWorld(dimension.getLoader());
+        if (key == null) key = dimension.getLoadKey();
+        else key += "/" + dimension.getLoadKey();
 
         if (!INMS.get().supportsDataPacks()) {
             if (!keys.isEmpty()) {
                 Iris.warn("===================================================================================");
-                Iris.warn("Pack " + dimension.getLoadKey() + " has " + keys.size() + " custom biome(s). ");
+                Iris.warn("Pack " + key + " has " + keys.size() + " custom biome(s). ");
                 Iris.warn("Your server version does not yet support datapacks for iris.");
                 Iris.warn("The world will generate these biomes as backup biomes.");
                 Iris.warn("====================================================================================");
@@ -260,10 +212,74 @@ public class ServerConfigurator {
         }
 
         if (warn) {
-            Iris.error("The Pack " + dimension.getLoadKey() + " is INCAPABLE of generating custom biomes");
+            Iris.error("The Pack " + key + " is INCAPABLE of generating custom biomes");
             Iris.error("If not done automatically, restart your server before generating with this pack!");
         }
 
         return !warn;
     }
+
+    public static Stream<IrisData> allPacks() {
+        return Stream.concat(listFiles(new File("plugins/Iris/packs")),
+                        listFiles(Bukkit.getWorldContainer()).map(w -> new File(w, "iris/pack")))
+                .filter(File::isDirectory)
+                .map(IrisData::get);
+    }
+
+    @Nullable
+    public static String getWorld(@NonNull IrisData data) {
+        String worldContainer = Bukkit.getWorldContainer().getAbsolutePath();
+        if (!worldContainer.endsWith(File.separator)) worldContainer += File.separator;
+        
+        String path = data.getDataFolder().getAbsolutePath();
+        if (!path.startsWith(worldContainer)) return null;
+        int l = path.endsWith(File.separator) ? 11 : 10;
+        return path.substring(worldContainer.length(), path.length() - l);
+    }
+
+    private static Stream<File> listFiles(File parent) {
+        var files = parent.listFiles();
+        return files == null ? Stream.empty() : Arrays.stream(files);
+    }
+
+    @Data
+    public static class DimensionHeight {
+        private final IDataFixer fixer;
+        private IrisRange overworld = new IrisRange();
+        private IrisRange nether = new IrisRange();
+        private IrisRange end = new IrisRange();
+        private int logicalOverworld = 0;
+        private int logicalNether = 0;
+        private int logicalEnd = 0;
+
+        public Stream<IrisDimension> merge(IrisData data) {
+            Iris.verbose("Checking Pack: " + data.getDataFolder().getPath());
+            var loader = data.getDimensionLoader();
+            return loader.loadAll(loader.getPossibleKeys())
+                    .stream()
+                    .peek(this::merge);
+        }
+
+        public void merge(IrisDimension dimension) {
+            overworld.merge(dimension.getDimensionHeight());
+            nether.merge(dimension.getDimensionHeight());
+            end.merge(dimension.getDimensionHeight());
+
+            logicalOverworld = Math.max(logicalOverworld, dimension.getLogicalHeight());
+            logicalNether = Math.max(logicalNether, dimension.getLogicalHeightNether());
+            logicalEnd = Math.max(logicalEnd, dimension.getLogicalHeightEnd());
+        }
+
+        public String overworldType() {
+            return fixer.createDimension(OVERRWORLD, overworld, logicalOverworld).toString(4);
+        }
+
+        public String netherType() {
+            return fixer.createDimension(NETHER, nether, logicalNether).toString(4);
+        }
+
+        public String endType() {
+            return fixer.createDimension(THE_END, end, logicalEnd).toString(4);
+        }
+    }
 }

core/src/main/java/com/volmit/iris/core/commands/CommandIris.java

@@ -21,6 +21,7 @@ package com.volmit.iris.core.commands;
 import com.volmit.iris.Iris;
 import com.volmit.iris.core.IrisSettings;
 import com.volmit.iris.core.loader.IrisData;
+import com.volmit.iris.core.nms.INMS;
 import com.volmit.iris.core.pregenerator.ChunkUpdater;
 import com.volmit.iris.core.service.StudioSVC;
 import com.volmit.iris.core.tools.IrisBenchmarking;
@@ -412,7 +413,7 @@ public class CommandIris implements DecreeExecutor {
     ) {
         sender().sendMessage(C.GREEN + "Downloading pack: " + pack + "/" + branch + (trim ? " trimmed" : "") + (overwrite ? " overwriting" : ""));
         if (pack.equals("overworld")) {
-            String url = "https://github.com/IrisDimensions/overworld/releases/download/" + Iris.OVERWORLD_TAG + "/overworld.zip";
+            String url = "https://github.com/IrisDimensions/overworld/releases/download/" + INMS.OVERWORLD_TAG + "/overworld.zip";
             Iris.service(StudioSVC.class).downloadRelease(sender(), url, trim, overwrite);
         } else {
             Iris.service(StudioSVC.class).downloadSearch(sender(), "IrisDimensions/" + pack + "/" + branch, trim, overwrite);
@@ -598,10 +599,10 @@ public class CommandIris implements DecreeExecutor {
                     continue;
                 }
                 Iris.info(C.LIGHT_PURPLE + "Preparing Spawn for " + s + "' using Iris:" + generator + "...");
-                new WorldCreator(s)
+                WorldCreator c = new WorldCreator(s)
                         .generator(getDefaultWorldGenerator(s, generator))
-                        .environment(IrisData.loadAnyDimension(generator).getEnvironment())
-                        .createWorld();
+                        .environment(IrisData.loadAnyDimension(generator).getEnvironment());
+                INMS.get().createWorld(c);
                 Iris.info(C.LIGHT_PURPLE + "Loaded " + s + "!");
             }
         } catch (Throwable e) {

core/src/main/java/com/volmit/iris/core/link/NexoDataProvider.java

@@ -125,7 +125,7 @@ public class NexoDataProvider extends ExternalDataProvider {
     @NotNull
     @Override
     public Identifier[] getBlockTypes() {
-        return Arrays.stream(NexoItems.itemNames())
+        return NexoItems.itemNames().stream()
                 .map(i -> new Identifier("nexo", i))
                 .filter(i -> {
                     try {
@@ -140,7 +140,7 @@ public class NexoDataProvider extends ExternalDataProvider {
     @NotNull
     @Override
     public Identifier[] getItemTypes() {
-        return Arrays.stream(NexoItems.itemNames())
+        return NexoItems.itemNames().stream()
                 .map(i -> new Identifier("nexo", i))
                 .filter(i -> {
                     try {

core/src/main/java/com/volmit/iris/core/nms/INMS.java

@@ -23,6 +23,7 @@ import com.volmit.iris.core.IrisSettings;
 import com.volmit.iris.core.nms.v1X.NMSBinding1X;
 import org.bukkit.Bukkit;
 
+import java.util.List;
 import java.util.Map;
 
 public class INMS {
@@ -35,8 +36,15 @@ public class INMS {
             "1.21.3", "v1_21_R2",
             "1.21.4", "v1_21_R3"
     );
+    private static final List<Version> PACKS = List.of(
+            new Version(21, 4, "31010"),
+            new Version(21, 2, "31000"),
+            new Version(20, 1, "3910")
+    );
+
     //@done
     private static final INMSBinding binding = bind();
+    public static final String OVERWORLD_TAG = getOverworldTag();
 
     public static INMSBinding get() {
         return binding;
@@ -87,4 +95,26 @@ public class INMS {
 
         return new NMSBinding1X();
     }
+
+    private static String getOverworldTag() {
+        var version = Bukkit.getServer().getBukkitVersion().split("-")[0].split("\\.", 3);
+        int major = 0;
+        int minor = 0;
+
+        if (version.length > 2) {
+            major = Integer.parseInt(version[1]);
+            minor = Integer.parseInt(version[2]);
+        } else if (version.length == 2) {
+            major = Integer.parseInt(version[1]);
+        }
+
+        for (var p : PACKS) {
+            if (p.major > major || p.minor > minor)
+                continue;
+            return p.tag;
+        }
+        return "3910";
+    }
+
+    private record Version(int major, int minor, String tag) {}
 }

core/src/main/java/com/volmit/iris/core/nms/INMSBinding.java

@@ -18,7 +18,9 @@
 
 package com.volmit.iris.core.nms;
 
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
+import com.volmit.iris.core.nms.container.Pair;
 import com.volmit.iris.core.nms.datapack.DataVersion;
 import com.volmit.iris.engine.framework.Engine;
 import com.volmit.iris.util.collection.KList;
@@ -91,8 +93,10 @@ public interface INMSBinding {
     MCABiomeContainer newBiomeContainer(int min, int max);
 
     default World createWorld(WorldCreator c) {
+        try (var ignored = injectLevelStems()) {
             return c.createWorld();
         }
+    }
 
     int countCustomBiomes();
 
@@ -125,4 +129,12 @@ public interface INMSBinding {
     }
 
     KList<String> getStructureKeys();
+
+    default AutoClosing injectLevelStems() {
+        return new AutoClosing(() -> {});
+    }
+
+    default Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        return new Pair<>(0, injectLevelStems());
+    }
 }

core/src/main/java/com/volmit/iris/core/nms/container/AutoClosing.java

@@ -0,0 +1,22 @@
+package com.volmit.iris.core.nms.container;
+
+import com.volmit.iris.util.function.NastyRunnable;
+import lombok.AllArgsConstructor;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+@AllArgsConstructor
+public class AutoClosing implements AutoCloseable {
+    private final AtomicBoolean closed = new AtomicBoolean();
+    private final NastyRunnable action;
+
+    @Override
+    public void close() {
+        if (closed.getAndSet(true)) return;
+        try {
+            action.run();
+        } catch (Throwable e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

core/src/main/java/com/volmit/iris/core/nms/datapack/IDataFixer.java

@@ -1,11 +1,28 @@
 package com.volmit.iris.core.nms.datapack;
 
 import com.volmit.iris.engine.object.IrisBiomeCustom;
+import com.volmit.iris.engine.object.IrisRange;
 import com.volmit.iris.util.json.JSONObject;
 
 public interface IDataFixer {
 
-    JSONObject fixCustomBiome(IrisBiomeCustom biome, JSONObject json);
+    default JSONObject fixCustomBiome(IrisBiomeCustom biome, JSONObject json) {
+        return json;
+    }
 
-    JSONObject fixDimension(JSONObject json);
+    JSONObject rawDimension(Dimension dimension);
+
+    default JSONObject createDimension(Dimension dimension, IrisRange height, int logicalHeight) {
+        JSONObject obj = rawDimension(dimension);
+        obj.put("min_y", height.getMin());
+        obj.put("height", height.getMax() - height.getMin());
+        obj.put("logical_height", logicalHeight);
+        return obj;
+    }
+
+    enum Dimension {
+        OVERRWORLD,
+        NETHER,
+        THE_END
+    }
 }

core/src/main/java/com/volmit/iris/core/nms/datapack/v1192/DataFixerV1192.java

@@ -1,18 +1,81 @@
 package com.volmit.iris.core.nms.datapack.v1192;
 
 import com.volmit.iris.core.nms.datapack.IDataFixer;
-import com.volmit.iris.engine.object.IrisBiomeCustom;
 import com.volmit.iris.util.json.JSONObject;
+import java.util.Map;
 
 public class DataFixerV1192 implements IDataFixer {
 
-    @Override
-    public JSONObject fixCustomBiome(IrisBiomeCustom biome, JSONObject json) {
-        return json;
+    private static final Map<Dimension, String> DIMENSIONS = Map.of(
+            Dimension.OVERRWORLD, """
+            {
+              "ambient_light": 0.0,
+              "bed_works": true,
+              "coordinate_scale": 1.0,
+              "effects": "minecraft:overworld",
+              "has_ceiling": false,
+              "has_raids": true,
+              "has_skylight": true,
+              "infiniburn": "#minecraft:infiniburn_overworld",
+              "monster_spawn_block_light_limit": 0,
+              "monster_spawn_light_level": {
+                "type": "minecraft:uniform",
+                "value": {
+                  "max_inclusive": 7,
+                  "min_inclusive": 0
                 }
+              },
+              "natural": true,
+              "piglin_safe": false,
+              "respawn_anchor_works": false,
+              "ultrawarm": false
+            }""",
+            Dimension.NETHER, """
+            {
+              "ambient_light": 0.1,
+              "bed_works": false,
+              "coordinate_scale": 8.0,
+              "effects": "minecraft:the_nether",
+              "fixed_time": 18000,
+              "has_ceiling": true,
+              "has_raids": false,
+              "has_skylight": false,
+              "infiniburn": "#minecraft:infiniburn_nether",
+              "monster_spawn_block_light_limit": 15,
+              "monster_spawn_light_level": 7,
+              "natural": false,
+              "piglin_safe": true,
+              "respawn_anchor_works": true,
+              "ultrawarm": true
+            }""",
+            Dimension.THE_END, """
+            {
+              "ambient_light": 0.0,
+              "bed_works": false,
+              "coordinate_scale": 1.0,
+              "effects": "minecraft:the_end",
+              "fixed_time": 6000,
+              "has_ceiling": false,
+              "has_raids": true,
+              "has_skylight": false,
+              "infiniburn": "#minecraft:infiniburn_end",
+              "monster_spawn_block_light_limit": 0,
+              "monster_spawn_light_level": {
+                "type": "minecraft:uniform",
+                "value": {
+                  "max_inclusive": 7,
+                  "min_inclusive": 0
+                }
+              },
+              "natural": false,
+              "piglin_safe": false,
+              "respawn_anchor_works": false,
+              "ultrawarm": false
+            }"""
+    );
 
     @Override
-    public JSONObject fixDimension(JSONObject json) {
-        return json;
+    public JSONObject rawDimension(Dimension dimension) {
+        return new JSONObject(DIMENSIONS.get(dimension));
     }
 }

core/src/main/java/com/volmit/iris/core/nms/datapack/v1206/DataFixerV1206.java

@@ -1,6 +1,6 @@
 package com.volmit.iris.core.nms.datapack.v1206;
 
-import com.volmit.iris.core.nms.datapack.IDataFixer;
+import com.volmit.iris.core.nms.datapack.v1192.DataFixerV1192;
 import com.volmit.iris.engine.object.IrisBiomeCustom;
 import com.volmit.iris.engine.object.IrisBiomeCustomSpawn;
 import com.volmit.iris.engine.object.IrisBiomeCustomSpawnType;
@@ -10,7 +10,7 @@ import com.volmit.iris.util.json.JSONObject;
 
 import java.util.Locale;
 
-public class DataFixerV1206 implements IDataFixer {
+public class DataFixerV1206 extends DataFixerV1192 {
     @Override
     public JSONObject fixCustomBiome(IrisBiomeCustom biome, JSONObject json) {
         int spawnRarity = biome.getSpawnRarity();
@@ -45,7 +45,8 @@ public class DataFixerV1206 implements IDataFixer {
     }
 
     @Override
-    public JSONObject fixDimension(JSONObject json) {
+    public JSONObject rawDimension(Dimension dimension) {
+        JSONObject json = super.rawDimension(dimension);
         if (!(json.get("monster_spawn_light_level") instanceof JSONObject lightLevel))
             return json;
         var value = (JSONObject) lightLevel.remove("value");

core/src/main/java/com/volmit/iris/core/service/StudioSVC.java

@@ -24,6 +24,7 @@ import com.volmit.iris.Iris;
 import com.volmit.iris.core.IrisSettings;
 import com.volmit.iris.core.ServerConfigurator;
 import com.volmit.iris.core.loader.IrisData;
+import com.volmit.iris.core.nms.INMS;
 import com.volmit.iris.core.pack.IrisPack;
 import com.volmit.iris.core.project.IrisProject;
 import com.volmit.iris.core.tools.IrisToolbelt;
@@ -64,7 +65,7 @@ public class StudioSVC implements IrisService {
             if (!f.exists()) {
                 Iris.info("Downloading Default Pack " + pack);
                 if (pack.equals("overworld")) {
-                    String url = "https://github.com/IrisDimensions/overworld/releases/download/" + Iris.OVERWORLD_TAG + "/overworld.zip";
+                    String url = "https://github.com/IrisDimensions/overworld/releases/download/" + INMS.OVERWORLD_TAG + "/overworld.zip";
                     Iris.service(StudioSVC.class).downloadRelease(Iris.getSender(), url, false, false);
                 } else {
                     downloadSearch(Iris.getSender(), pack, false);

core/src/main/java/com/volmit/iris/core/tools/IrisCreator.java

@@ -22,6 +22,7 @@ import com.google.common.util.concurrent.AtomicDouble;
 import com.volmit.iris.Iris;
 import com.volmit.iris.core.IrisSettings;
 import com.volmit.iris.core.ServerConfigurator;
+import com.volmit.iris.core.nms.INMS;
 import com.volmit.iris.core.pregenerator.PregenTask;
 import com.volmit.iris.core.service.StudioSVC;
 import com.volmit.iris.engine.object.IrisDimension;
@@ -170,7 +171,7 @@ public class IrisCreator {
 
         try {
             J.sfut(() -> {
-                world.set(wc.createWorld());
+                world.set(INMS.get().createWorld(wc));
             }).get();
         } catch (Throwable e) {
             e.printStackTrace();

core/src/main/java/com/volmit/iris/core/tools/IrisWorldCreator.java

@@ -21,10 +21,13 @@ package com.volmit.iris.core.tools;
 import com.volmit.iris.core.loader.IrisData;
 import com.volmit.iris.engine.object.*;
 import com.volmit.iris.engine.platform.BukkitChunkGenerator;
+import com.volmit.iris.util.reflect.WrappedField;
 import org.bukkit.Bukkit;
 import org.bukkit.World;
 import org.bukkit.WorldCreator;
+import org.bukkit.WorldType;
 import org.bukkit.generator.ChunkGenerator;
+import sun.misc.Unsafe;
 
 import java.io.File;
 

core/src/main/java/com/volmit/iris/engine/IrisWorldManager.java

@@ -62,6 +62,7 @@ import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -299,28 +300,6 @@ public class IrisWorldManager extends EngineAssignedWorldManager {
             energy += 1.2;
         }
 
-        //@builder
-        IrisBiome biome = IrisSettings.get().getWorld().isAnbientEntitySpawningSystem()
-                ? getEngine().getSurfaceBiome(c) : null;
-        IrisEntitySpawn v = IrisSettings.get().getWorld().isAnbientEntitySpawningSystem()
-                ? spawnRandomly(Stream.concat(getData().getSpawnerLoader()
-                                .loadAll(getDimension().getEntitySpawners())
-                                .shuffleCopy(RNG.r).stream()
-                                .filter(this::canSpawn)
-                                .filter((i) -> i.isValid(biome))
-                                .flatMap((i) -> stream(i, initial)),
-                        Stream.concat(getData().getSpawnerLoader()
-                                        .loadAll(getEngine().getRegion(c.getX() << 4, c.getZ() << 4).getEntitySpawners())
-                                        .shuffleCopy(RNG.r).stream().filter(this::canSpawn)
-                                        .flatMap((i) -> stream(i, initial)),
-                                getData().getSpawnerLoader()
-                                        .loadAll(getEngine().getSurfaceBiome(c.getX() << 4, c.getZ() << 4).getEntitySpawners())
-                                        .shuffleCopy(RNG.r).stream().filter(this::canSpawn)
-                                        .flatMap((i) -> stream(i, initial))))
-                .collect(Collectors.toList()))
-                .popRandom(RNG.r) : null;
-        //@done
-
         if (IrisSettings.get().getWorld().isMarkerEntitySpawningSystem()) {
             getSpawnersFromMarkers(c).forEach((blockf, spawners) -> {
                 if (spawners.isEmpty()) {
@@ -335,16 +314,39 @@ public class IrisWorldManager extends EngineAssignedWorldManager {
             });
         }
 
-        if (v != null && v.getReferenceSpawner() != null) {
-            int maxEntCount = v.getReferenceSpawner().getMaxEntitiesPerChunk();
-
-            for (Entity i : c.getEntities()) {
-                if (i instanceof LivingEntity) {
-                    if (-maxEntCount <= 0) {
+        if (!IrisSettings.get().getWorld().isAnbientEntitySpawningSystem()) {
             return;
         }
-                }
-            }
+
+        //@builder
+        Predicate<IrisSpawner> filter = i -> i.canSpawn(getEngine(), c.getX(), c.getZ());
+        ChunkCounter counter = new ChunkCounter(c.getEntities());
+
+        IrisBiome biome = getEngine().getSurfaceBiome(c);
+        IrisEntitySpawn v = spawnRandomly(Stream.concat(getData().getSpawnerLoader()
+                                .loadAll(getDimension().getEntitySpawners())
+                                .shuffleCopy(RNG.r)
+                                .stream()
+                                .filter(filter)
+                                .filter((i) -> i.isValid(biome)),
+                        Stream.concat(getData()
+                                        .getSpawnerLoader()
+                                        .loadAll(getEngine().getRegion(c.getX() << 4, c.getZ() << 4).getEntitySpawners())
+                                        .shuffleCopy(RNG.r)
+                                        .stream()
+                                        .filter(filter),
+                                getData().getSpawnerLoader()
+                                        .loadAll(getEngine().getSurfaceBiome(c.getX() << 4, c.getZ() << 4).getEntitySpawners())
+                                        .shuffleCopy(RNG.r)
+                                        .stream()
+                                        .filter(filter)))
+                .filter(counter)
+                .flatMap((i) -> stream(i, initial))
+                .collect(Collectors.toList()))
+                .getRandom();
+        //@done
+        if (v == null || v.getReferenceSpawner() == null)
+            return;
 
         try {
             spawn(c, v);
@@ -352,77 +354,27 @@ public class IrisWorldManager extends EngineAssignedWorldManager {
             J.s(() -> spawn(c, v));
         }
     }
-    }
 
     private void spawn(Chunk c, IrisEntitySpawn i) {
-        boolean allow = true;
-
-        if (!i.getReferenceSpawner().getMaximumRatePerChunk().isInfinite()) {
-            allow = false;
-            IrisEngineChunkData cd = getEngine().getEngineData().getChunk(c.getX(), c.getZ());
-            IrisEngineSpawnerCooldown sc = null;
-            for (IrisEngineSpawnerCooldown j : cd.getCooldowns()) {
-                if (j.getSpawner().equals(i.getReferenceSpawner().getLoadKey())) {
-                    sc = j;
-                    break;
-                }
-            }
-
-            if (sc == null) {
-                sc = new IrisEngineSpawnerCooldown();
-                sc.setSpawner(i.getReferenceSpawner().getLoadKey());
-                cd.getCooldowns().add(sc);
-            }
-
-            if (sc.canSpawn(i.getReferenceSpawner().getMaximumRatePerChunk())) {
-                sc.spawn(getEngine());
-                allow = true;
-            }
-        }
-
-        if (allow) {
+        IrisSpawner ref = i.getReferenceSpawner();
         int s = i.spawn(getEngine(), c, RNG.r);
         actuallySpawned += s;
         if (s > 0) {
-                getCooldown(i.getReferenceSpawner()).spawn(getEngine());
-                energy -= s * ((i.getEnergyMultiplier() * i.getReferenceSpawner().getEnergyMultiplier() * 1));
-            }
-        }
-    }
-
-    private void spawn(IrisPosition c, IrisEntitySpawn i) {
-        boolean allow = true;
-
-        if (!i.getReferenceSpawner().getMaximumRatePerChunk().isInfinite()) {
-            allow = false;
-            IrisEngineChunkData cd = getEngine().getEngineData().getChunk(c.getX() >> 4, c.getZ() >> 4);
-            IrisEngineSpawnerCooldown sc = null;
-            for (IrisEngineSpawnerCooldown j : cd.getCooldowns()) {
-                if (j.getSpawner().equals(i.getReferenceSpawner().getLoadKey())) {
-                    sc = j;
-                    break;
+            ref.spawn(getEngine(), c.getX(), c.getZ());
+            energy -= s * ((i.getEnergyMultiplier() * ref.getEnergyMultiplier() * 1));
         }
     }
 
-            if (sc == null) {
-                sc = new IrisEngineSpawnerCooldown();
-                sc.setSpawner(i.getReferenceSpawner().getLoadKey());
-                cd.getCooldowns().add(sc);
-            }
+    private void spawn(IrisPosition pos, IrisEntitySpawn i) {
+        IrisSpawner ref = i.getReferenceSpawner();
+        if (!ref.canSpawn(getEngine(), pos.getX() >> 4, pos.getZ()))
+            return;
 
-            if (sc.canSpawn(i.getReferenceSpawner().getMaximumRatePerChunk())) {
-                sc.spawn(getEngine());
-                allow = true;
-            }
-        }
-
-        if (allow) {
-            int s = i.spawn(getEngine(), c, RNG.r);
+        int s = i.spawn(getEngine(), pos, RNG.r);
         actuallySpawned += s;
         if (s > 0) {
-                getCooldown(i.getReferenceSpawner()).spawn(getEngine());
-                energy -= s * ((i.getEnergyMultiplier() * i.getReferenceSpawner().getEnergyMultiplier() * 1));
-            }
+            ref.spawn(getEngine(), pos.getX() >> 4, pos.getZ() >> 4);
+            energy -= s * ((i.getEnergyMultiplier() * ref.getEnergyMultiplier() * 1));
         }
     }
 
@@ -450,31 +402,6 @@ public class IrisWorldManager extends EngineAssignedWorldManager {
         return rarityTypes;
     }
 
-    public boolean canSpawn(IrisSpawner i) {
-        return i.isValid(getEngine().getWorld().realWorld())
-                && getCooldown(i).canSpawn(i.getMaximumRate());
-    }
-
-    private IrisEngineSpawnerCooldown getCooldown(IrisSpawner i) {
-        IrisEngineData ed = getEngine().getEngineData();
-        IrisEngineSpawnerCooldown cd = null;
-
-        for (IrisEngineSpawnerCooldown j : ed.getSpawnerCooldowns().copy()) {
-            if (j.getSpawner().equals(i.getLoadKey())) {
-                cd = j;
-            }
-        }
-
-        if (cd == null) {
-            cd = new IrisEngineSpawnerCooldown();
-            cd.setSpawner(i.getLoadKey());
-            cd.setLastSpawn(M.ms() - i.getMaximumRate().getInterval());
-            ed.getSpawnerCooldowns().add(cd);
-        }
-
-        return cd;
-    }
-
     @Override
     public void onTick() {
 
@@ -708,4 +635,27 @@ public class IrisWorldManager extends EngineAssignedWorldManager {
 
         return (double) entityCount / (getEngine().getWorld().realWorld().getLoadedChunks().length + 1) * 1.28;
     }
+
+    @Data
+    private static class ChunkCounter implements Predicate<IrisSpawner> {
+        private final Entity[] entities;
+        private transient int index = 0;
+        private transient int count = 0;
+
+        @Override
+        public boolean test(IrisSpawner spawner) {
+            int max = spawner.getMaxEntitiesPerChunk();
+            if (max <= count)
+                return false;
+
+            while (index < entities.length) {
+                if (entities[index++] instanceof LivingEntity) {
+                    if (++count >= max)
+                        return false;
+                }
+            }
+
+            return true;
+        }
+    }
 }

core/src/main/java/com/volmit/iris/engine/object/IrisContextInjector.java

@@ -0,0 +1,67 @@
+package com.volmit.iris.engine.object;
+
+import com.volmit.iris.core.nms.INMS;
+import com.volmit.iris.core.nms.container.AutoClosing;
+import com.volmit.iris.util.misc.ServerProperties;
+import org.bukkit.Bukkit;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.world.WorldInitEvent;
+
+import java.util.List;
+
+import static com.volmit.iris.Iris.instance;
+
+public class IrisContextInjector implements Listener {
+    private AutoClosing autoClosing = null;
+    private final int totalWorlds;
+    private int worldCounter = 0;
+
+    public IrisContextInjector() {
+        if (!Bukkit.getWorlds().isEmpty()) {
+            totalWorlds = 0;
+            return;
+        }
+
+        String levelName = ServerProperties.LEVEL_NAME;
+        List<String> irisWorlds = irisWorlds();
+        boolean overworld = irisWorlds.contains(levelName);
+        boolean nether = irisWorlds.contains(levelName + "_nether");
+        boolean end = irisWorlds.contains(levelName + "_end");
+
+        int i = 1;
+        if (Bukkit.getAllowNether()) i++;
+        if (Bukkit.getAllowEnd()) i++;
+
+        if (overworld || nether || end) {
+            var pair = INMS.get().injectUncached(overworld, nether, end);
+            i += pair.getA() - 3;
+            autoClosing = pair.getB();
+        }
+
+        totalWorlds = i;
+    }
+
+    @EventHandler
+    public void on(WorldInitEvent event) {
+        if (++worldCounter < totalWorlds) return;
+        if (autoClosing != null) {
+            autoClosing.close();
+            autoClosing = null;
+        }
+        instance.unregisterListener(this);
+    }
+
+    private List<String> irisWorlds() {
+        var config = YamlConfiguration.loadConfiguration(ServerProperties.BUKKIT_YML);
+        ConfigurationSection section = config.getConfigurationSection("worlds");
+        if (section == null) return List.of();
+
+        return section.getKeys(false)
+                .stream()
+                .filter(k -> section.getString(k + ".generator", "").startsWith("Iris"))
+                .toList();
+    }
+}

core/src/main/java/com/volmit/iris/engine/object/IrisDimension.java

@@ -19,6 +19,8 @@
 package com.volmit.iris.engine.object;
 
 import com.volmit.iris.Iris;
+import com.volmit.iris.core.IrisSettings;
+import com.volmit.iris.core.ServerConfigurator.DimensionHeight;
 import com.volmit.iris.core.loader.IrisData;
 import com.volmit.iris.core.loader.IrisRegistrant;
 import com.volmit.iris.core.nms.INMS;
@@ -26,6 +28,7 @@ import com.volmit.iris.core.nms.datapack.IDataFixer;
 import com.volmit.iris.engine.data.cache.AtomicCache;
 import com.volmit.iris.engine.object.annotations.*;
 import com.volmit.iris.util.collection.KList;
+import com.volmit.iris.util.collection.KSet;
 import com.volmit.iris.util.data.DataProvider;
 import com.volmit.iris.util.io.IO;
 import com.volmit.iris.util.json.JSONObject;
@@ -54,73 +57,6 @@ import java.io.IOException;
 public class IrisDimension extends IrisRegistrant {
     public static final BlockData STONE = Material.STONE.createBlockData();
     public static final BlockData WATER = Material.WATER.createBlockData();
-    private static final String DP_OVERWORLD_DEFAULT = """
-            {
-              "ambient_light": 0.0,
-              "bed_works": true,
-              "coordinate_scale": 1.0,
-              "effects": "minecraft:overworld",
-              "has_ceiling": false,
-              "has_raids": true,
-              "has_skylight": true,
-              "infiniburn": "#minecraft:infiniburn_overworld",
-              "monster_spawn_block_light_limit": 0,
-              "monster_spawn_light_level": {
-                "type": "minecraft:uniform",
-                "value": {
-                  "max_inclusive": 7,
-                  "min_inclusive": 0
-                }
-              },
-              "natural": true,
-              "piglin_safe": false,
-              "respawn_anchor_works": false,
-              "ultrawarm": false
-            }""";
-
-    private static final String DP_NETHER_DEFAULT = """
-            {
-              "ambient_light": 0.1,
-              "bed_works": false,
-              "coordinate_scale": 8.0,
-              "effects": "minecraft:the_nether",
-              "fixed_time": 18000,
-              "has_ceiling": true,
-              "has_raids": false,
-              "has_skylight": false,
-              "infiniburn": "#minecraft:infiniburn_nether",
-              "monster_spawn_block_light_limit": 15,
-              "monster_spawn_light_level": 7,
-              "natural": false,
-              "piglin_safe": true,
-              "respawn_anchor_works": true,
-              "ultrawarm": true
-            }""";
-
-    private static final String DP_END_DEFAULT = """
-            {
-              "ambient_light": 0.0,
-              "bed_works": false,
-              "coordinate_scale": 1.0,
-              "effects": "minecraft:the_end",
-              "fixed_time": 6000,
-              "has_ceiling": false,
-              "has_raids": true,
-              "has_skylight": false,
-              "infiniburn": "#minecraft:infiniburn_end",
-              "monster_spawn_block_light_limit": 0,
-              "monster_spawn_light_level": {
-                "type": "minecraft:uniform",
-                "value": {
-                  "max_inclusive": 7,
-                  "min_inclusive": 0
-                }
-              },
-              "natural": false,
-              "piglin_safe": false,
-              "respawn_anchor_works": false,
-              "ultrawarm": false
-            }""";
     private final transient AtomicCache<Position2> parallaxSize = new AtomicCache<>();
     private final transient AtomicCache<CNG> rockLayerGenerator = new AtomicCache<>();
     private final transient AtomicCache<CNG> fluidLayerGenerator = new AtomicCache<>();
@@ -443,61 +379,35 @@ public class IrisDimension extends IrisRegistrant {
         return landBiomeStyle;
     }
 
-    public boolean installDataPack(IDataFixer fixer, DataProvider data, File datapacks, double ultimateMaxHeight, double ultimateMinHeight) {
-        boolean write = false;
-        boolean changed = false;
-
-        IO.delete(new File(datapacks, "iris/data/" + getLoadKey().toLowerCase()));
-
-        for (IrisBiome i : getAllBiomes(data)) {
-            if (i.isCustom()) {
-                write = true;
-
-                for (IrisBiomeCustom j : i.getCustomDerivitives()) {
-                    File output = new File(datapacks, "iris/data/" + getLoadKey().toLowerCase() + "/worldgen/biome/" + j.getId() + ".json");
-
-                    if (!output.exists()) {
-                        changed = true;
+    public void installBiomes(IDataFixer fixer, DataProvider data, KList<File> folders, KSet<String> biomes) {
+        getAllBiomes(data)
+                .stream()
+                .filter(IrisBiome::isCustom)
+                .map(IrisBiome::getCustomDerivitives)
+                .flatMap(KList::stream)
+                .parallel()
+                .forEach(j -> {
+                    String json = j.generateJson(fixer);
+                    synchronized (biomes) {
+                        if (!biomes.add(j.getId())) {
+                            Iris.verbose("Duplicate Data Pack Biome: " + getLoadKey() + "/" + j.getId());
+                            return;
                         }
+                    }
+
+                    for (File datapacks : folders) {
+                        File output = new File(datapacks, "iris/data/" + getLoadKey().toLowerCase() + "/worldgen/biome/" + j.getId() + ".json");
 
                         Iris.verbose("    Installing Data Pack Biome: " + output.getPath());
                         output.getParentFile().mkdirs();
                         try {
-                        IO.writeAll(output, j.generateJson(fixer));
+                            IO.writeAll(output, json);
                         } catch (IOException e) {
                             Iris.reportError(e);
                             e.printStackTrace();
                         }
                     }
-            }
-        }
-
-        if (!dimensionHeight.equals(new IrisRange(-64, 320)) && this.name.equalsIgnoreCase("overworld")) {
-            Iris.verbose("    Installing Data Pack Dimension Types: \"minecraft:overworld\", \"minecraft:the_nether\", \"minecraft:the_end\"");
-            dimensionHeight.setMax(ultimateMaxHeight);
-            dimensionHeight.setMin(ultimateMinHeight);
-            changed = writeDimensionType(fixer, changed, datapacks);
-        }
-
-        if (write) {
-            File mcm = new File(datapacks, "iris/pack.mcmeta");
-            try {
-                IO.writeAll(mcm, """
-                        {
-                            "pack": {
-                                "description": "Iris Data Pack. This pack contains all installed Iris Packs' resources.",
-                                "pack_format": {}
-                            }
-                        }
-                        """.replace("{}", INMS.get().getDataVersion().getPackFormat() + ""));
-            } catch (IOException e) {
-                Iris.reportError(e);
-                e.printStackTrace();
-            }
-            Iris.verbose("    Installing Data Pack MCMeta: " + mcm.getPath());
-        }
-
-        return changed;
+                });
     }
 
     @Override
@@ -515,66 +425,55 @@ public class IrisDimension extends IrisRegistrant {
 
     }
 
-    public boolean writeDimensionType(IDataFixer fixer, boolean changed, File datapacks) {
-        File dimTypeOverworld = new File(datapacks, "iris/data/minecraft/dimension_type/overworld.json");
-        if (!dimTypeOverworld.exists())
-            changed = true;
-        dimTypeOverworld.getParentFile().mkdirs();
+    public static void writeShared(KList<File> folders, DimensionHeight height) {
+        Iris.verbose("    Installing Data Pack Dimension Types: \"iris:overworld\", \"iris:the_nether\", \"iris:the_end\"");
+        for (File datapacks : folders) {
+            write(datapacks, "overworld", height.overworldType());
+            write(datapacks, "the_nether", height.netherType());
+            write(datapacks, "the_end", height.endType());
+        }
+
+        String raw = """
+                        {
+                            "pack": {
+                                "description": "Iris Data Pack. This pack contains all installed Iris Packs' resources.",
+                                "pack_format": {}
+                            }
+                        }
+                        """.replace("{}", INMS.get().getDataVersion().getPackFormat() + "");
+
+        for (File datapacks : folders) {
+            File mcm = new File(datapacks, "iris/pack.mcmeta");
             try {
-            IO.writeAll(dimTypeOverworld, generateDatapackJsonOverworld(fixer));
+                IO.writeAll(mcm, raw);
+            } catch (IOException e) {
+                Iris.reportError(e);
+                e.printStackTrace();
+            }
+            Iris.verbose("    Installing Data Pack MCMeta: " + mcm.getPath());
+        }
+    }
+
+    private static void write(File datapacks, String type, String json) {
+        File dimType = new File(datapacks, "iris/data/iris/dimension_type/" + type + ".json");
+        File dimTypeVanilla = new File(datapacks, "iris/data/minecraft/dimension_type/" + type + ".json");
+
+        dimType.getParentFile().mkdirs();
+        try {
+            IO.writeAll(dimType, json);
         } catch (IOException e) {
             Iris.reportError(e);
             e.printStackTrace();
         }
 
-
-        File dimTypeNether = new File(datapacks, "iris/data/minecraft/dimension_type/the_nether.json");
-        if (!dimTypeNether.exists())
-            changed = true;
-        dimTypeNether.getParentFile().mkdirs();
+        if (IrisSettings.get().getGeneral().adjustVanillaHeight || dimTypeVanilla.exists()) {
+            dimTypeVanilla.getParentFile().mkdirs();
             try {
-            IO.writeAll(dimTypeNether, generateDatapackJsonNether(fixer));
+                IO.writeAll(dimTypeVanilla, json);
             } catch (IOException e) {
                 Iris.reportError(e);
                 e.printStackTrace();
             }
-
-
-        File dimTypeEnd = new File(datapacks, "iris/data/minecraft/dimension_type/the_end.json");
-        if (!dimTypeEnd.exists())
-            changed = true;
-        dimTypeEnd.getParentFile().mkdirs();
-        try {
-            IO.writeAll(dimTypeEnd, generateDatapackJsonEnd(fixer));
-        } catch (IOException e) {
-            Iris.reportError(e);
-            e.printStackTrace();
         }
-
-        return changed;
-    }
-
-    private String generateDatapackJsonOverworld(IDataFixer fixer) {
-        JSONObject obj = new JSONObject(DP_OVERWORLD_DEFAULT);
-        obj.put("min_y", dimensionHeight.getMin());
-        obj.put("height", dimensionHeight.getMax() - dimensionHeight.getMin());
-        obj.put("logical_height", logicalHeight);
-        return fixer.fixDimension(obj).toString(4);
-    }
-
-    private String generateDatapackJsonNether(IDataFixer fixer) {
-        JSONObject obj = new JSONObject(DP_NETHER_DEFAULT);
-        obj.put("min_y", dimensionHeightNether.getMin());
-        obj.put("height", dimensionHeightNether.getMax() - dimensionHeightNether.getMin());
-        obj.put("logical_height", logicalHeightNether);
-        return fixer.fixDimension(obj).toString(4);
-    }
-
-    private String generateDatapackJsonEnd(IDataFixer fixer) {
-        JSONObject obj = new JSONObject(DP_END_DEFAULT);
-        obj.put("min_y", dimensionHeightEnd.getMin());
-        obj.put("height", dimensionHeightEnd.getMax() - dimensionHeightEnd.getMin());
-        obj.put("logical_height", logicalHeightEnd);
-        return fixer.fixDimension(obj).toString(4);
     }
 }

core/src/main/java/com/volmit/iris/engine/object/IrisEngineChunkData.java

@@ -1,43 +0,0 @@
-/*
- * Iris is a World Generator for Minecraft Bukkit Servers
- * Copyright (c) 2022 Arcane Arts (Volmit Software)
- *
- * 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 com.volmit.iris.engine.object;
-
-import com.volmit.iris.engine.framework.Engine;
-import com.volmit.iris.util.collection.KList;
-import lombok.Data;
-
-@Data
-public class IrisEngineChunkData {
-    private long chunk;
-    private KList<IrisEngineSpawnerCooldown> cooldowns = new KList<>();
-
-    public void cleanup(Engine engine) {
-        for (IrisEngineSpawnerCooldown i : getCooldowns().copy()) {
-            IrisSpawner sp = engine.getData().getSpawnerLoader().load(i.getSpawner());
-
-            if (sp == null || i.canSpawn(sp.getMaximumRate())) {
-                getCooldowns().remove(i);
-            }
-        }
-    }
-
-    public boolean isEmpty() {
-        return cooldowns.isEmpty();
-    }
-}

core/src/main/java/com/volmit/iris/engine/object/IrisEngineData.java

@@ -20,51 +20,31 @@ package com.volmit.iris.engine.object;
 
 import com.volmit.iris.engine.data.cache.Cache;
 import com.volmit.iris.engine.framework.Engine;
-import com.volmit.iris.util.collection.KList;
+import com.volmit.iris.util.collection.KMap;
 import lombok.Data;
+import lombok.EqualsAndHashCode;
 
 @Data
-public class IrisEngineData {
+@EqualsAndHashCode(callSuper = true)
+public class IrisEngineData extends IrisSpawnerCooldowns {
     private IrisEngineStatistics statistics = new IrisEngineStatistics();
-    private KList<IrisEngineSpawnerCooldown> spawnerCooldowns = new KList<>();
-    private KList<IrisEngineChunkData> chunks = new KList<>();
+    private KMap<Long, IrisSpawnerCooldowns> chunks = new KMap<>();
     private Long seed = null;
 
     public void removeChunk(int x, int z) {
-        long k = Cache.key(x, z);
-        chunks.removeWhere((i) -> i.getChunk() == k);
+        chunks.remove(Cache.key(x, z));
     }
 
-    public IrisEngineChunkData getChunk(int x, int z) {
-        long k = Cache.key(x, z);
-
-        for (IrisEngineChunkData i : chunks) {
-            if (i.getChunk() == k) {
-                return i;
-            }
-        }
-
-        IrisEngineChunkData c = new IrisEngineChunkData();
-        c.setChunk(k);
-        chunks.add(c);
-        return c;
+    public IrisSpawnerCooldowns getChunk(int x, int z) {
+        return chunks.computeIfAbsent(Cache.key(x, z), k -> new IrisSpawnerCooldowns());
     }
 
     public void cleanup(Engine engine) {
-        for (IrisEngineSpawnerCooldown i : getSpawnerCooldowns().copy()) {
-            IrisSpawner sp = engine.getData().getSpawnerLoader().load(i.getSpawner());
+        super.cleanup(engine);
 
-            if (sp == null || i.canSpawn(sp.getMaximumRate())) {
-                getSpawnerCooldowns().remove(i);
-            }
-        }
-
-        for (IrisEngineChunkData i : chunks.copy()) {
-            i.cleanup(engine);
-
-            if (i.isEmpty()) {
-                getChunks().remove(i);
-            }
-        }
+        chunks.values().removeIf(chunk -> {
+            chunk.cleanup(engine);
+            return chunk.isEmpty();
+        });
     }
 }

core/src/main/java/com/volmit/iris/engine/object/IrisRange.java

@@ -50,4 +50,10 @@ public class IrisRange {
     public boolean contains(int v) {
         return v >= min && v <= max;
     }
+
+    public IrisRange merge(IrisRange other) {
+        min = Math.min(min, other.min);
+        max = Math.max(max, other.max);
+        return this;
+    }
 }

core/src/main/java/com/volmit/iris/engine/object/IrisRate.java

@@ -43,7 +43,7 @@ public class IrisRate {
     }
 
     public long getInterval() {
-        long t = per.getMilliseconds() / (amount == 0 ? 1 : amount);
+        long t = per.toMilliseconds() / (amount == 0 ? 1 : amount);
         return Math.abs(t <= 0 ? 1 : t);
     }
 

core/src/main/java/com/volmit/iris/engine/object/IrisSpawner.java

@@ -19,6 +19,7 @@
 package com.volmit.iris.engine.object;
 
 import com.volmit.iris.core.loader.IrisRegistrant;
+import com.volmit.iris.engine.framework.Engine;
 import com.volmit.iris.engine.object.annotations.ArrayType;
 import com.volmit.iris.engine.object.annotations.Desc;
 import com.volmit.iris.util.collection.KList;
@@ -95,6 +96,37 @@ public class IrisSpawner extends IrisRegistrant {
         return timeBlock.isWithin(world) && weather.is(world);
     }
 
+    public boolean canSpawn(Engine engine) {
+        if (!isValid(engine.getWorld().realWorld()))
+            return false;
+
+        var rate = getMaximumRate();
+        return rate.isInfinite() || engine.getEngineData().getCooldown(this).canSpawn(rate);
+    }
+
+    public boolean canSpawn(Engine engine, int x, int z) {
+        if (!canSpawn(engine))
+            return false;
+
+        var rate = getMaximumRatePerChunk();
+        return rate.isInfinite() || engine.getEngineData().getChunk(x, z).getCooldown(this).canSpawn(rate);
+    }
+
+    public void spawn(Engine engine) {
+        if (getMaximumRate().isInfinite())
+            return;
+
+        engine.getEngineData().getCooldown(this).spawn(engine);
+    }
+
+    public void spawn(Engine engine, int x, int z) {
+        spawn(engine);
+        if (getMaximumRatePerChunk().isInfinite())
+            return;
+
+        engine.getEngineData().getChunk(x, z).getCooldown(this).spawn(engine);
+    }
+
     @Override
     public String getFolderName() {
         return "spawners";

core/src/main/java/com/volmit/iris/engine/object/IrisSpawnerCooldowns.java

@@ -0,0 +1,34 @@
+package com.volmit.iris.engine.object;
+
+import com.volmit.iris.engine.framework.Engine;
+import com.volmit.iris.util.collection.KMap;
+import lombok.EqualsAndHashCode;
+import lombok.NonNull;
+
+@EqualsAndHashCode
+public class IrisSpawnerCooldowns {
+    private final KMap<String, IrisEngineSpawnerCooldown> cooldowns = new KMap<>();
+
+    public IrisEngineSpawnerCooldown getCooldown(@NonNull IrisSpawner spawner) {
+        return getCooldown(spawner.getLoadKey());
+    }
+
+    public IrisEngineSpawnerCooldown getCooldown(@NonNull String loadKey) {
+        return cooldowns.computeIfAbsent(loadKey, k -> {
+            IrisEngineSpawnerCooldown cd = new IrisEngineSpawnerCooldown();
+            cd.setSpawner(loadKey);
+            return cd;
+        });
+    }
+
+    public void cleanup(Engine engine) {
+        cooldowns.values().removeIf(cd -> {
+            IrisSpawner sp = engine.getData().getSpawnerLoader().load(cd.getSpawner());
+            return sp == null || cd.canSpawn(sp.getMaximumRate());
+        });
+    }
+
+    public boolean isEmpty() {
+        return cooldowns.isEmpty();
+    }
+}

core/src/main/java/com/volmit/iris/util/misc/ServerProperties.java

@@ -0,0 +1,39 @@
+package com.volmit.iris.util.misc;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Properties;
+
+public class ServerProperties {
+    public static final Properties DATA = new Properties();
+    public static final File SERVER_PROPERTIES;
+    public static final File BUKKIT_YML;
+
+    public static final String LEVEL_NAME = DATA.getProperty("level-name", "world");
+
+    static {
+        String[] args = ProcessHandle.current()
+                .info()
+                .arguments()
+                .orElse(new String[0]);
+
+        String propertiesPath = "server.properties";
+        String bukkitYml = "bukkit.yml";
+
+        for (int i = 0; i < args.length - 1; i++) {
+            switch (args[i]) {
+                case "-c", "--config" -> propertiesPath = args[i + 1];
+                case "-b", "--bukkit-settings" -> bukkitYml = args[i + 1];
+            }
+        }
+
+        SERVER_PROPERTIES = new File(propertiesPath);
+        BUKKIT_YML = new File(bukkitYml);
+        try (FileInputStream in = new FileInputStream(SERVER_PROPERTIES)){
+            DATA.load(in);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

nms/v1_20_R1/src/main/java/com/volmit/iris/core/nms/v1_20_R1/NMSBinding.java

@@ -2,8 +2,10 @@ package com.volmit.iris.core.nms.v1_20_R1;
 
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Lifecycle;
 import com.volmit.iris.Iris;
 import com.volmit.iris.core.nms.INMSBinding;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
 import com.volmit.iris.engine.data.cache.AtomicCache;
 import com.volmit.iris.engine.framework.Engine;
@@ -20,14 +22,16 @@ import com.volmit.iris.util.nbt.mca.palette.*;
 import com.volmit.iris.util.nbt.tag.CompoundTag;
 import com.volmit.iris.util.scheduling.J;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
-import net.minecraft.core.BlockPos;
-import net.minecraft.core.Holder;
+import lombok.SneakyThrows;
+import net.minecraft.core.*;
 import net.minecraft.core.Registry;
-import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.nbt.*;
 import net.minecraft.nbt.Tag;
+import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.tags.TagKey;
@@ -41,6 +45,8 @@ import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.chunk.ChunkAccess;
 import net.minecraft.world.level.chunk.ChunkStatus;
 import net.minecraft.world.level.chunk.LevelChunk;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -73,11 +79,10 @@ import java.io.DataOutputStream;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Vector;
+import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
 public class NMSBinding implements INMSBinding {
 
@@ -85,9 +90,11 @@ public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -568,6 +575,9 @@ public class NMSBinding implements INMSBinding {
 
     public void inject(long seed, Engine engine, World world) {
         var chunkMap = ((CraftWorld)world).getHandle().getChunkSource().chunkMap;
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
         chunkMap.generator = new IrisChunkGenerator(chunkMap.generator, seed, engine, world);
     }
 
@@ -628,4 +638,98 @@ public class NMSBinding implements INMSBinding {
             }
         }
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public com.volmit.iris.core.nms.container.Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                        old.resources(),
+                        old.dataConfiguration(),
+                        old.datapackWorldgen(),
+                        createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().registryOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new com.volmit.iris.core.nms.container.Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.registryOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.registryOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.registry(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.getHolderOrThrow(ResourceKey.create(Registries.DIMENSION_TYPE, new ResourceLocation("iris", key.location().getPath()))),
+                levelStems.getOrThrow(key).generator()
+        ), Lifecycle.stable());
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.registryKeySet().forEach(key -> {
+            var value = source.get(key);
+            var info = source.lifecycle(value);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }

nms/v1_20_R2/src/main/java/com/volmit/iris/core/nms/v1_20_R2/NMSBinding.java

@@ -8,21 +8,29 @@ import java.io.DataOutputStream;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Vector;
+import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
 import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Lifecycle;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
 import com.volmit.iris.util.scheduling.J;
+import lombok.SneakyThrows;
+import net.minecraft.core.*;
+import net.minecraft.core.Registry;
 import net.minecraft.nbt.*;
 import net.minecraft.nbt.Tag;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.tags.TagKey;
 import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.block.EntityBlock;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -61,10 +69,6 @@ import com.volmit.iris.util.nbt.mca.palette.*;
 import com.volmit.iris.util.nbt.tag.CompoundTag;
 
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
-import net.minecraft.core.BlockPos;
-import net.minecraft.core.Holder;
-import net.minecraft.core.Registry;
-import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
@@ -83,9 +87,11 @@ public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -538,6 +544,9 @@ public class NMSBinding implements INMSBinding {
 
     public void inject(long seed, Engine engine, World world) {
         var chunkMap = ((CraftWorld)world).getHandle().getChunkSource().chunkMap;
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
         chunkMap.generator = new IrisChunkGenerator(chunkMap.generator, seed, engine, world);
     }
 
@@ -630,4 +639,98 @@ public class NMSBinding implements INMSBinding {
     public static Holder<net.minecraft.world.level.biome.Biome> biomeToBiomeBase(Registry<net.minecraft.world.level.biome.Biome> registry, Biome biome) {
         return registry.getHolderOrThrow(ResourceKey.create(Registries.BIOME, CraftNamespacedKey.toMinecraft(biome.getKey())));
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public com.volmit.iris.core.nms.container.Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                        old.resources(),
+                        old.dataConfiguration(),
+                        old.datapackWorldgen(),
+                        createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().registryOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new com.volmit.iris.core.nms.container.Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.registryOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.registryOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.registry(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.getHolderOrThrow(ResourceKey.create(Registries.DIMENSION_TYPE, new ResourceLocation("iris", key.location().getPath()))),
+                levelStems.getOrThrow(key).generator()
+        ), Lifecycle.stable());
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.registryKeySet().forEach(key -> {
+            var value = source.get(key);
+            var info = source.lifecycle(value);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }

nms/v1_20_R3/src/main/java/com/volmit/iris/core/nms/v1_20_R3/NMSBinding.java

@@ -8,21 +8,29 @@ import java.io.DataOutputStream;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Vector;
+import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
 import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Lifecycle;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
 import com.volmit.iris.util.scheduling.J;
+import lombok.SneakyThrows;
+import net.minecraft.core.*;
+import net.minecraft.core.Registry;
 import net.minecraft.nbt.*;
 import net.minecraft.nbt.Tag;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.tags.TagKey;
 import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.block.EntityBlock;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -61,10 +69,6 @@ import com.volmit.iris.util.nbt.mca.palette.*;
 import com.volmit.iris.util.nbt.tag.CompoundTag;
 
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
-import net.minecraft.core.BlockPos;
-import net.minecraft.core.Holder;
-import net.minecraft.core.Registry;
-import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
@@ -83,9 +87,11 @@ public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -538,6 +544,9 @@ public class NMSBinding implements INMSBinding {
 
     public void inject(long seed, Engine engine, World world) {
         var chunkMap = ((CraftWorld)world).getHandle().getChunkSource().chunkMap;
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
         chunkMap.generator = new IrisChunkGenerator(chunkMap.generator, seed, engine, world);
     }
 
@@ -631,4 +640,98 @@ public class NMSBinding implements INMSBinding {
     public static Holder<net.minecraft.world.level.biome.Biome> biomeToBiomeBase(Registry<net.minecraft.world.level.biome.Biome> registry, Biome biome) {
         return registry.getHolderOrThrow(ResourceKey.create(Registries.BIOME, CraftNamespacedKey.toMinecraft(biome.getKey())));
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public com.volmit.iris.core.nms.container.Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                        old.resources(),
+                        old.dataConfiguration(),
+                        old.datapackWorldgen(),
+                        createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().registryOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new com.volmit.iris.core.nms.container.Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.registryOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.registryOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.registry(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.getHolderOrThrow(ResourceKey.create(Registries.DIMENSION_TYPE, new ResourceLocation("iris", key.location().getPath()))),
+                levelStems.getOrThrow(key).generator()
+        ), Lifecycle.stable());
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.registryKeySet().forEach(key -> {
+            var value = source.get(key);
+            var info = source.lifecycle(value);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }

nms/v1_20_R4/src/main/java/com/volmit/iris/core/nms/v1_20_R4/NMSBinding.java

@@ -6,12 +6,17 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
 import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Lifecycle;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
 import com.volmit.iris.core.nms.datapack.DataVersion;
 import com.volmit.iris.util.nbt.tag.CompoundTag;
 import com.volmit.iris.util.scheduling.J;
+import lombok.SneakyThrows;
 import net.minecraft.core.*;
 import net.minecraft.core.Registry;
 import net.minecraft.core.component.DataComponents;
@@ -25,6 +30,8 @@ import net.minecraft.nbt.LongTag;
 import net.minecraft.nbt.ShortTag;
 import net.minecraft.nbt.StringTag;
 import net.minecraft.nbt.Tag;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.server.commands.data.DataCommands;
 import net.minecraft.server.level.ServerLevel;
@@ -34,6 +41,8 @@ import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.block.EntityBlock;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.chunk.status.ChunkStatus;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -86,9 +95,11 @@ public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -544,6 +555,10 @@ public class NMSBinding implements INMSBinding {
 
     public void inject(long seed, Engine engine, World world) {
         var chunkMap = ((CraftWorld)world).getHandle().getChunkSource().chunkMap;
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
+
         chunkMap.generator = new IrisChunkGenerator(chunkMap.generator, seed, engine, world);
     }
 
@@ -650,4 +665,98 @@ public class NMSBinding implements INMSBinding {
 
         return keys;
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public com.volmit.iris.core.nms.container.Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                        old.resources(),
+                        old.dataConfiguration(),
+                        old.datapackWorldgen(),
+                        createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().registryOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new com.volmit.iris.core.nms.container.Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.registryOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.registryOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.registry(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.getHolder(new ResourceLocation("iris", key.location().getPath())).orElseThrow(),
+                levelStems.getOrThrow(key).generator()
+        ), RegistrationInfo.BUILT_IN);
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.registryKeySet().forEach(key -> {
+            var value = source.get(key);
+            var info = source.registrationInfo(key).orElse(null);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }

nms/v1_21_R1/src/main/java/com/volmit/iris/core/nms/v1_21_R1/NMSBinding.java

@@ -10,14 +10,23 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
 import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Lifecycle;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
 import com.volmit.iris.core.nms.datapack.DataVersion;
 import com.volmit.iris.util.scheduling.J;
+import lombok.SneakyThrows;
+import net.minecraft.core.*;
+import net.minecraft.core.Registry;
 import net.minecraft.core.component.DataComponents;
 import net.minecraft.nbt.*;
 import net.minecraft.nbt.Tag;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.server.level.ChunkMap;
 import net.minecraft.tags.TagKey;
@@ -26,6 +35,8 @@ import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.block.EntityBlock;
 import net.minecraft.world.level.chunk.status.ChunkStatus;
 import net.minecraft.world.level.chunk.status.WorldGenContext;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -64,10 +75,6 @@ import com.volmit.iris.util.nbt.mca.palette.*;
 import com.volmit.iris.util.nbt.tag.CompoundTag;
 
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
-import net.minecraft.core.BlockPos;
-import net.minecraft.core.Holder;
-import net.minecraft.core.Registry;
-import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
@@ -85,9 +92,11 @@ public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -546,6 +555,9 @@ public class NMSBinding implements INMSBinding {
         var worldGenContextField = getField(chunkMap.getClass(), WorldGenContext.class);
         worldGenContextField.setAccessible(true);
         var worldGenContext = (WorldGenContext) worldGenContextField.get(chunkMap);
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
 
         var newContext = new WorldGenContext(
                 worldGenContext.level(), new IrisChunkGenerator(worldGenContext.generator(), seed, engine, world),
@@ -657,4 +669,98 @@ public class NMSBinding implements INMSBinding {
 
         return keys;
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public com.volmit.iris.core.nms.container.Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                        old.resources(),
+                        old.dataConfiguration(),
+                        old.datapackWorldgen(),
+                        createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().registryOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new com.volmit.iris.core.nms.container.Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.registryOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.registryOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.registry(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.getHolder(ResourceLocation.fromNamespaceAndPath("iris", key.location().getPath())).orElseThrow(),
+                levelStems.getOrThrow(key).generator()
+        ), RegistrationInfo.BUILT_IN);
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.registryKeySet().forEach(key -> {
+            var value = source.get(key);
+            var info = source.registrationInfo(key).orElse(null);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }

nms/v1_21_R2/src/main/java/com/volmit/iris/core/nms/v1_21_R2/NMSBinding.java

@@ -6,15 +6,23 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
+import com.mojang.serialization.Lifecycle;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
+import com.volmit.iris.core.nms.container.Pair;
 import com.volmit.iris.core.nms.datapack.DataVersion;
 import com.volmit.iris.util.scheduling.J;
+import lombok.SneakyThrows;
 import net.minecraft.core.*;
 import net.minecraft.core.Registry;
 import net.minecraft.core.component.DataComponents;
 import net.minecraft.nbt.*;
 import net.minecraft.nbt.Tag;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.tags.TagKey;
 import net.minecraft.world.item.component.CustomData;
@@ -22,6 +30,8 @@ import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.block.EntityBlock;
 import net.minecraft.world.level.chunk.status.ChunkStatus;
 import net.minecraft.world.level.chunk.status.WorldGenContext;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -72,9 +82,11 @@ public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -533,6 +545,9 @@ public class NMSBinding implements INMSBinding {
         var worldGenContextField = getField(chunkMap.getClass(), WorldGenContext.class);
         worldGenContextField.setAccessible(true);
         var worldGenContext = (WorldGenContext) worldGenContextField.get(chunkMap);
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
 
         var newContext = new WorldGenContext(
                 worldGenContext.level(), new IrisChunkGenerator(worldGenContext.generator(), seed, engine, world),
@@ -644,4 +659,98 @@ public class NMSBinding implements INMSBinding {
 
         return keys;
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                        old.resources(),
+                        old.dataConfiguration(),
+                        old.datapackWorldgen(),
+                        createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().lookupOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.lookupOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.lookupOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.lookup(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.get(ResourceLocation.fromNamespaceAndPath("iris", key.location().getPath())).orElseThrow(),
+                levelStems.getValueOrThrow(key).generator()
+        ), RegistrationInfo.BUILT_IN);
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.listElementIds().forEach(key -> {
+            var value = source.getValue(key);
+            var info = source.registrationInfo(key).orElse(null);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }

nms/v1_21_R3/src/main/java/com/volmit/iris/core/nms/v1_21_R3/NMSBinding.java

@@ -1,9 +1,12 @@
 package com.volmit.iris.core.nms.v1_21_R3;
 
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import com.mojang.serialization.Lifecycle;
 import com.volmit.iris.Iris;
 import com.volmit.iris.core.nms.INMSBinding;
+import com.volmit.iris.core.nms.container.AutoClosing;
 import com.volmit.iris.core.nms.container.BiomeColor;
+import com.volmit.iris.core.nms.container.Pair;
 import com.volmit.iris.core.nms.datapack.DataVersion;
 import com.volmit.iris.engine.data.cache.AtomicCache;
 import com.volmit.iris.engine.framework.Engine;
@@ -19,6 +22,7 @@ import com.volmit.iris.util.nbt.mca.palette.*;
 import com.volmit.iris.util.nbt.tag.CompoundTag;
 import com.volmit.iris.util.scheduling.J;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
+import lombok.SneakyThrows;
 import net.minecraft.core.Registry;
 import net.minecraft.core.*;
 import net.minecraft.core.component.DataComponents;
@@ -27,6 +31,8 @@ import net.minecraft.nbt.Tag;
 import net.minecraft.nbt.*;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.WorldLoader;
 import net.minecraft.server.commands.data.BlockDataAccessor;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.tags.TagKey;
@@ -41,6 +47,8 @@ import net.minecraft.world.level.chunk.ChunkAccess;
 import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.level.chunk.status.ChunkStatus;
 import net.minecraft.world.level.chunk.status.WorldGenContext;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
 import org.bukkit.*;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -66,14 +74,18 @@ import java.lang.reflect.Modifier;
 import java.util.List;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 
 public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
+    private final AtomicCache<WorldLoader.DataLoadContext> dataLoadContext = new AtomicCache<>();
     private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
     private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
     private final AtomicCache<RegistryAccess> registryAccess = new AtomicCache<>();
+    private final ReentrantLock dataContextLock = new ReentrantLock(true);
     private final AtomicCache<Method> byIdRef = new AtomicCache<>();
     private Field biomeStorageCache = null;
 
@@ -532,6 +544,9 @@ public class NMSBinding implements INMSBinding {
         var worldGenContextField = getField(chunkMap.getClass(), WorldGenContext.class);
         worldGenContextField.setAccessible(true);
         var worldGenContext = (WorldGenContext) worldGenContextField.get(chunkMap);
+        var dimensionType = chunkMap.level.dimensionTypeRegistration().unwrapKey().orElse(null);
+        if (dimensionType != null && !dimensionType.location().getNamespace().equals("iris"))
+            Iris.error("Loaded world %s with invalid dimension type! (%s)", world.getName(), dimensionType.location().toString());
 
         var newContext = new WorldGenContext(
                 worldGenContext.level(), new IrisChunkGenerator(worldGenContext.generator(), seed, engine, world),
@@ -643,4 +658,98 @@ public class NMSBinding implements INMSBinding {
 
         return keys;
     }
+
+    @Override
+    public AutoClosing injectLevelStems() {
+        return inject(this::supplier);
+    }
+
+    @Override
+    @SneakyThrows
+    public Pair<Integer, AutoClosing> injectUncached(boolean overworld, boolean nether, boolean end) {
+        var reg = registry();
+        var field = getField(RegistryAccess.ImmutableRegistryAccess.class, Map.class);
+        field.setAccessible(true);
+
+        AutoClosing closing = inject(old -> new WorldLoader.DataLoadContext(
+                    old.resources(),
+                    old.dataConfiguration(),
+                    old.datapackWorldgen(),
+                    createRegistryAccess(old.datapackDimensions(), true, overworld, nether, end)
+                )
+        );
+
+        var injected = ((CraftServer) Bukkit.getServer()).getServer().worldLoader.datapackDimensions().lookupOrThrow(Registries.LEVEL_STEM);
+        var old = (Map<ResourceKey<? extends Registry<?>>, Registry<?>>) field.get(reg);
+        var fake = new HashMap<>(old);
+        fake.put(Registries.LEVEL_STEM, injected);
+        field.set(reg, fake);
+
+        return new Pair<>(
+                injected.size(),
+                new AutoClosing(() -> {
+                    closing.close();
+                    field.set(reg, old);
+                }));
+    }
+
+    private WorldLoader.DataLoadContext supplier(WorldLoader.DataLoadContext old) {
+        return dataLoadContext.aquire(() -> new WorldLoader.DataLoadContext(
+                old.resources(),
+                old.dataConfiguration(),
+                old.datapackWorldgen(),
+                createRegistryAccess(old.datapackDimensions(), false, true, true, true)
+        ));
+    }
+
+    @SneakyThrows
+    private AutoClosing inject(Function<WorldLoader.DataLoadContext, WorldLoader.DataLoadContext> transformer) {
+        if (!dataContextLock.tryLock()) throw new IllegalStateException("Failed to inject data context!");
+
+        var server = ((CraftServer) Bukkit.getServer());
+        var field = getField(MinecraftServer.class, WorldLoader.DataLoadContext.class);
+        var nmsServer = server.getServer();
+        var old = nmsServer.worldLoader;
+
+        field.setAccessible(true);
+        field.set(nmsServer, transformer.apply(old));
+
+        return new AutoClosing(() -> {
+            field.set(nmsServer, old);
+            dataContextLock.unlock();
+        });
+    }
+
+    private RegistryAccess.Frozen createRegistryAccess(RegistryAccess.Frozen datapack, boolean copy, boolean overworld, boolean nether, boolean end) {
+        var access = registry();
+        var dimensions = access.lookupOrThrow(Registries.DIMENSION_TYPE);
+        var levelStems = access.lookupOrThrow(Registries.LEVEL_STEM);
+
+        var fake = new MappedRegistry<>(Registries.LEVEL_STEM, Lifecycle.experimental());
+        if (overworld) register(fake, levelStems, dimensions, LevelStem.OVERWORLD);
+        if (nether) register(fake, levelStems, dimensions, LevelStem.NETHER);
+        if (end) register(fake, levelStems, dimensions, LevelStem.END);
+        copy(fake, datapack.lookup(Registries.LEVEL_STEM).orElse(null));
+
+        if (copy) copy(fake, levelStems);
+
+        return new RegistryAccess.Frozen.ImmutableRegistryAccess(List.of(fake.freeze())).freeze();
+    }
+
+    private void register(MappedRegistry<LevelStem> target, Registry<LevelStem> levelStems, Registry<DimensionType> dimensions, ResourceKey<LevelStem> key) {
+        target.register(key, new LevelStem(
+                dimensions.get(ResourceLocation.fromNamespaceAndPath("iris", key.location().getPath())).orElseThrow(),
+                levelStems.getValueOrThrow(key).generator()
+        ), RegistrationInfo.BUILT_IN);
+    }
+
+    private void copy(MappedRegistry<LevelStem> target, Registry<LevelStem> source) {
+        if (source == null) return;
+        source.listElementIds().forEach(key -> {
+            var value = source.getValue(key);
+            var info = source.registrationInfo(key).orElse(null);
+            if (value != null && info != null && !target.containsKey(key))
+                target.register(key, value, info);
+        });
+    }
 }