Merge branch 'distant-horizons-core-serverSupport'

api/src/main/java/com/seibel/distanthorizons/api/methods/events/interfaces/IDhServerMessageReceived.java

@@ -0,0 +1,15 @@
+package com.seibel.distanthorizons.api.methods.events.interfaces;
+
+/**
+ * @author Cailin
+ */
+public interface IDhServerMessageReceived<T> extends IDhApiEvent<T>
+{
+	/**
+	 * Triggered when a plugin message is received from the server.
+	 * @param channel The name of the channel this was received on.
+	 * @param message The message sent from the server.
+	 */
+	void serverMessageReceived(String channel, byte[] message);
+	
+}

core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientApi.java

@@ -21,6 +21,9 @@ package com.seibel.distanthorizons.core.api.internal;
 
 import com.seibel.distanthorizons.api.methods.events.abstractEvents.*;
 import com.seibel.distanthorizons.api.methods.events.sharedParameterObjects.DhApiRenderParam;
+import com.seibel.distanthorizons.core.level.IServerKeyedClientLevel;
+import com.seibel.distanthorizons.core.level.IKeyedClientLevelManager;
+import com.seibel.distanthorizons.core.world.*;
 import com.seibel.distanthorizons.coreapi.DependencyInjection.ApiEventInjector;
 import com.seibel.distanthorizons.core.level.IDhClientLevel;
 import com.seibel.distanthorizons.core.config.Config;
@@ -36,64 +39,64 @@ import com.seibel.distanthorizons.coreapi.util.math.Mat4f;
 import com.seibel.distanthorizons.core.render.glObject.GLProxy;
 import com.seibel.distanthorizons.core.render.renderer.TestRenderer;
 import com.seibel.distanthorizons.core.util.RenderUtil;
-import com.seibel.distanthorizons.core.world.DhClientWorld;
-import com.seibel.distanthorizons.core.world.AbstractDhWorld;
-import com.seibel.distanthorizons.core.world.IDhClientWorld;
-import com.seibel.distanthorizons.core.world.EWorldEnvironment;
 import com.seibel.distanthorizons.core.wrapperInterfaces.chunk.IChunkWrapper;
 import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftClientWrapper;
 import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftRenderWrapper;
 import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IProfilerWrapper;
 import com.seibel.distanthorizons.core.wrapperInterfaces.world.IClientLevelWrapper;
+import io.netty.buffer.ByteBuf;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.lwjgl.glfw.GLFW;
 
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.util.concurrent.TimeUnit;
 
 /**
  * This holds the methods that should be called
  * by the host mod loader (Fabric, Forge, etc.).
  * Specifically for the client.
- * 
- * @author James Seibel
- * @version 2022-9-16
  */
 public class ClientApi
 {
 	private static final Logger LOGGER = LogManager.getLogger();
 	public static final boolean ENABLE_EVENT_LOGGING = true;
 	public static boolean prefLoggerEnabled = false;
-	
+
 	public static final ClientApi INSTANCE = new ClientApi();
 	public static TestRenderer testRenderer = new TestRenderer();
 	private static final IMinecraftClientWrapper MC = SingletonInjector.INSTANCE.get(IMinecraftClientWrapper.class);
 	private static final IMinecraftRenderWrapper MC_RENDER = SingletonInjector.INSTANCE.get(IMinecraftRenderWrapper.class);
-	
+	private static final IKeyedClientLevelManager KEYED_CLIENT_LEVEL_MANAGER = SingletonInjector.INSTANCE.get(IKeyedClientLevelManager.class);
+
 	public static final long SPAM_LOGGER_FLUSH_NS = TimeUnit.NANOSECONDS.convert(1, TimeUnit.SECONDS);
-	
+
 	private boolean configOverrideReminderPrinted = false;
 	public boolean rendererDisabledBecauseOfExceptions = false;
-	
+
 	private long lastFlushNanoTime = 0;
-	
-	
-	
+
+	private boolean isServerCommunicationEnabled = true;
+
+	private boolean serverIsMalformed = false;
+
+
 	//==============//
 	// constructors //
 	//==============//
-	
+
 	private ClientApi()
 	{
-		
+
 	}
-	
-	
-	
+
+
+
 	//========//
 	// events //
 	//========//
-	
+
 	public void onClientOnlyConnected()
 	{
 		// only continue if the client is connected to a different server
@@ -103,11 +106,11 @@ public class ClientApi
 			{
 				LOGGER.info("Client on ClientOnly mode connecting.");
 			}
-			
+
 			SharedApi.setDhWorld(new DhClientWorld());
 		}
 	}
-	
+
 	public void onClientOnlyDisconnected()
 	{
 		if (MC.clientConnectedToDedicatedServer())
@@ -119,13 +122,17 @@ public class ClientApi
 				{
 					LOGGER.info("Client on ClientOnly mode disconnecting.");
 				}
-				
+
 				world.close();
 				SharedApi.setDhWorld(null);
 			}
+			this.isServerCommunicationEnabled = false;
+			this.serverIsMalformed = false;
+			KEYED_CLIENT_LEVEL_MANAGER.setUseOverrideWrapper(false);
+			KEYED_CLIENT_LEVEL_MANAGER.setServerKeyedLevel(null);
 		}
 	}
-	
+
 	public void clientChunkLoadEvent(IChunkWrapper chunk, IClientLevelWrapper level)
 	{
 		if (SharedApi.getEnvironment() == EWorldEnvironment.Client_Only)
@@ -137,7 +144,7 @@ public class ClientApi
 			}
 		}
 	}
-	
+
 	public void clientChunkSaveEvent(IChunkWrapper chunk, IClientLevelWrapper level)
 	{
 		if (SharedApi.getEnvironment() == EWorldEnvironment.Client_Only)
@@ -149,14 +156,14 @@ public class ClientApi
 			}
 		}
 	}
-	
+
 	public void clientLevelUnloadEvent(IClientLevelWrapper level)
 	{
 		if (ENABLE_EVENT_LOGGING)
 		{
 			LOGGER.info("Client level "+level+" unloading.");
 		}
-		
+
 		AbstractDhWorld world = SharedApi.getAbstractDhWorld();
 		if (world != null)
 		{
@@ -164,12 +171,22 @@ public class ClientApi
 			ApiEventInjector.INSTANCE.fireAllEvents(DhApiLevelUnloadEvent.class, new DhApiLevelUnloadEvent.EventParam(level));
 		}
 	}
-	
+
 	public void clientLevelLoadEvent(IClientLevelWrapper level)
 	{
+		if (this.isServerCommunicationEnabled)
+		{
+			if (ENABLE_EVENT_LOGGING)
+			{
+				LOGGER.info("Server supports communication, deferring loading.");
+			}
+			return;
+		}
+		
+		
 		if (ENABLE_EVENT_LOGGING)
 		{
-			LOGGER.info("Client level "+level+" loading.");
+			LOGGER.info("Client level " + level + " loading.");
 		}
 		
 		AbstractDhWorld world = SharedApi.getAbstractDhWorld();
@@ -179,40 +196,55 @@ public class ClientApi
 			ApiEventInjector.INSTANCE.fireAllEvents(DhApiLevelLoadEvent.class, new DhApiLevelLoadEvent.EventParam(level));
 		}
 	}
-	
+
+	public void serverLevelLoadEvent(IServerKeyedClientLevel level)
+	{
+		if (ENABLE_EVENT_LOGGING)
+		{
+			LOGGER.info("Server level " + level + " (" + level.getServerLevelKey() + ") loading.");
+		}
+
+		AbstractDhWorld world = SharedApi.getAbstractDhWorld();
+		if (world != null)
+		{
+			world.getOrLoadLevel(level);
+			ApiEventInjector.INSTANCE.fireAllEvents(DhApiLevelLoadEvent.class, new DhApiLevelLoadEvent.EventParam(level));
+		}
+	}
+
 	public void rendererShutdownEvent()
 	{
 		if (ENABLE_EVENT_LOGGING)
 		{
 			LOGGER.info("Renderer shutting down.");
 		}
-		
+
 		IProfilerWrapper profiler = MC.getProfiler();
 		profiler.push("DH-RendererShutdown");
-		
+
 		profiler.pop();
 	}
-	
+
 	public void rendererStartupEvent()
 	{
 		if (ENABLE_EVENT_LOGGING)
 		{
 			LOGGER.info("Renderer starting up.");
 		}
-		
+
 		IProfilerWrapper profiler = MC.getProfiler();
 		profiler.push("DH-RendererStartup");
-		
+
 		// make sure the GLProxy is created before the LodBufferBuilder needs it
 		GLProxy.getInstance();
 		profiler.pop();
 	}
-	
+
 	public void clientTickEvent()
 	{
 		IProfilerWrapper profiler = MC.getProfiler();
 		profiler.push("DH-ClientTick");
-		
+
 		boolean doFlush = System.nanoTime() - this.lastFlushNanoTime >= SPAM_LOGGER_FLUSH_NS;
 		if (doFlush)
 		{
@@ -221,7 +253,7 @@ public class ClientApi
 		}
 		ConfigBasedLogger.updateAll();
 		ConfigBasedSpamLogger.updateAll(doFlush);
-		
+
 		IDhClientWorld clientWorld = SharedApi.getIDhClientWorld();
 		if (clientWorld != null)
 		{
@@ -230,12 +262,75 @@ public class ClientApi
 		profiler.pop();
 	}
 	
-	
-	
+	/** @param byteBuf is Netty's {@link ByteBuffer} wrapper. */
+	public void serverMessageReceived(ByteBuf byteBuf)
+	{
+		// It is important to ensure malicious server input is ignored.
+		if (this.serverIsMalformed)
+		{
+			return;
+		}
+		
+		short commandLength = byteBuf.readShort();
+		if (commandLength > 32)
+		{
+			LOGGER.error("Server sent command > 32");
+			ClientApi.INSTANCE.serverIsMalformed = true;
+			return;
+		}
+		
+		String eventType = byteBuf.readCharSequence(commandLength, StandardCharsets.UTF_8).toString();
+		switch (eventType)
+		{
+			case "ServerCommsEnabled":
+				LOGGER.info("Server supports DH protocol.");
+				ClientApi.INSTANCE.isServerCommunicationEnabled = true;
+				KEYED_CLIENT_LEVEL_MANAGER.setUseOverrideWrapper(true);
+				MC.executeOnRenderThread(() -> {
+					// Go ahead and unload the current world, because it may be wrong. We expect
+					// a followup WorldChanged event from the server soon anyways.
+					this.clientLevelUnloadEvent((IClientLevelWrapper) MC.getWrappedClientWorld());
+				});
+				break;
+				
+			case "WorldChanged":
+				short worldKeyLength = byteBuf.readShort();
+				if (worldKeyLength > 128)
+				{
+					LOGGER.error("Server sent worldKey > 128");
+					this.serverIsMalformed = true;
+					return;
+				}
+				
+				String worldKey = byteBuf.readCharSequence(worldKeyLength, StandardCharsets.UTF_8).toString();
+				if (!worldKey.matches("[a-zA-Z0-9_]+"))
+				{
+					LOGGER.error("Server sent invalid world key name, and is being ignored.");
+					this.isServerCommunicationEnabled = false;
+					this.serverIsMalformed = true;
+					return;
+				}
+				
+				LOGGER.info("Server sent world change event: " + worldKey);
+				MC.executeOnRenderThread(() -> {
+					if (MC.getWrappedClientWorld() != null)
+					{
+						this.clientLevelUnloadEvent((IClientLevelWrapper) MC.getWrappedClientWorld());
+					}
+					IServerKeyedClientLevel clientLevel = KEYED_CLIENT_LEVEL_MANAGER.getServerKeyedLevel(MC.getWrappedClientWorld(), worldKey);
+					KEYED_CLIENT_LEVEL_MANAGER.setServerKeyedLevel(clientLevel);
+					this.serverLevelLoadEvent(clientLevel);
+				});
+				break;
+		}
+	}
+
+
+
 	//===========//
 	// rendering //
 	//===========//
-	
+
 	public void renderLods(IClientLevelWrapper levelWrapper, Mat4f mcModelViewMatrix, Mat4f mcProjectionMatrix, float partialTicks)
 	{
 		if (ModInfo.IS_DEV_BUILD && !this.configOverrideReminderPrinted && MC.playerExists())
@@ -246,8 +341,8 @@ public class ClientApi
 			MC.sendChatMessage("Here be dragons!");
 			this.configOverrideReminderPrinted = true;
 		}
-		
-		
+
+
 		IProfilerWrapper profiler = MC.getProfiler();
 		profiler.pop(); // get out of "terrain"
 		profiler.push("DH-RenderLevel");
@@ -257,20 +352,20 @@ public class ClientApi
 			{
 				return;
 			}
-			
-			
+
+
 			//FIXME: Improve class hierarchy of DhWorld, IClientWorld, IServerWorld to fix all this hard casting
 			// (also in RenderUtil)
 			IDhClientWorld dhClientWorld = SharedApi.getIDhClientWorld();
 			IDhClientLevel level = dhClientWorld.getOrLoadClientLevel(levelWrapper);
-			
+
 			if (prefLoggerEnabled)
 			{
 				level.dumpRamUsage();
 			}
-			
-			
-			
+
+
+
 			profiler.push("Render" + (Config.Client.Advanced.Debugging.rendererMode.get() == ERendererMode.DEFAULT ? "-lods" : "-debug"));
 			try
 			{
@@ -280,7 +375,7 @@ public class ClientApi
 							new DhApiRenderParam(mcProjectionMatrix, mcModelViewMatrix,
 								RenderUtil.createLodProjectionMatrix(mcProjectionMatrix, partialTicks),
 								RenderUtil.createLodModelViewMatrix(mcModelViewMatrix), partialTicks);
-					
+
 					boolean renderingCanceled = ApiEventInjector.INSTANCE.fireAllEvents(DhApiBeforeRenderEvent.class, new DhApiBeforeRenderEvent.EventParam(renderEventParam));
 					if (!this.rendererDisabledBecauseOfExceptions && !renderingCanceled)
 					{
@@ -298,7 +393,7 @@ public class ClientApi
 			{
 				this.rendererDisabledBecauseOfExceptions = true;
 				LOGGER.error("Renderer thrown an uncaught exception: ", e);
-				
+
 				MC.sendChatMessage("\u00A74\u00A7l\u00A7uERROR: Distant Horizons"
 						+ " renderer has encountered an exception!");
 				MC.sendChatMessage("\u00A74Renderer is now disabled to prevent further issues.");
@@ -316,13 +411,13 @@ public class ClientApi
 			profiler.push("terrain"); // go back into "terrain"
 		}
 	}
-	
-	
-	
+
+
+
 	//=================//
 	//    DEBUG USE    //
 	//=================//
-	
+
 	/** Trigger once on key press, with CLIENT PLAYER. */
 	public void keyPressedEvent(int glfwKey)
 	{
@@ -331,8 +426,8 @@ public class ClientApi
 			// keybindings are disabled
 			return;
 		}
-		
-		
+
+
 		if (glfwKey == GLFW.GLFW_KEY_F8)
 		{
 			Config.Client.Advanced.Debugging.debugRendering.set(EDebugRendering.next(Config.Client.Advanced.Debugging.debugRendering.get()));
@@ -349,6 +444,6 @@ public class ClientApi
 			MC.sendChatMessage("P: Debug Pref Logger is " + (prefLoggerEnabled ? "enabled" : "disabled"));
 		}
 	}
-	
-	
+
+
 }

core/src/main/java/com/seibel/distanthorizons/core/api/internal/SharedApi.java

@@ -5,6 +5,7 @@ import com.seibel.distanthorizons.core.dataObjects.render.bufferBuilding.ColumnR
 import com.seibel.distanthorizons.core.dataObjects.transformers.DataRenderTransformer;
 import com.seibel.distanthorizons.core.file.fullDatafile.FullDataFileHandler;
 import com.seibel.distanthorizons.core.generation.WorldGenerationQueue;
+import com.seibel.distanthorizons.core.level.IDhClientLevel;
 import com.seibel.distanthorizons.core.world.*;
 import com.seibel.distanthorizons.core.world.*;
 
@@ -12,6 +13,7 @@ import com.seibel.distanthorizons.core.world.*;
 public class SharedApi
 {
     private static AbstractDhWorld currentWorld;
+
 	
 	
 	

core/src/main/java/com/seibel/distanthorizons/core/file/structure/ClientOnlySaveStructure.java

@@ -5,9 +5,11 @@ import com.seibel.distanthorizons.core.dependencyInjection.SingletonInjector;
 import com.seibel.distanthorizons.core.file.subDimMatching.SubDimensionLevelMatcher;
 import com.seibel.distanthorizons.core.config.Config;
 import com.seibel.distanthorizons.api.enums.config.EServerFolderNameMode;
+import com.seibel.distanthorizons.core.level.IServerKeyedClientLevel;
 import com.seibel.distanthorizons.core.util.objects.ParsedIp;
 import com.seibel.distanthorizons.core.util.LodUtil;
 import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftClientWrapper;
+import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftSharedWrapper;
 import com.seibel.distanthorizons.core.wrapperInterfaces.world.ILevelWrapper;
 
 import javax.annotation.Nullable;
@@ -25,17 +27,17 @@ public class ClientOnlySaveStructure extends AbstractSaveStructure
 {
 	final File folder;
 	private static final IMinecraftClientWrapper MC_CLIENT = SingletonInjector.INSTANCE.get(IMinecraftClientWrapper.class);
+	private static final IMinecraftSharedWrapper MC_SHARED = SingletonInjector.INSTANCE.get(IMinecraftSharedWrapper.class);
 	public static final String INVALID_FILE_CHARACTERS_REGEX = "[\\\\/:*?\"<>|]";
 
-	SubDimensionLevelMatcher fileMatcher = null;
-	final HashMap<ILevelWrapper, File> levelToFileMap = new HashMap<>();
+	SubDimensionLevelMatcher subDimMatcher = null;
+	final HashMap<ILevelWrapper, File> levelWrapperToFileMap = new HashMap<>();
 
 
 
 	public ClientOnlySaveStructure()
 	{
-		this.folder = new File(MC_CLIENT.getGameDirectory().getPath() +
-				File.separatorChar + "Distant_Horizons_server_data" + File.separatorChar + getServerFolderName());
+		this.folder = new File(getSaveStructureFolderPath());
 
 		if (!this.folder.exists())
 		{
@@ -54,34 +56,51 @@ public class ClientOnlySaveStructure extends AbstractSaveStructure
 	//================//
 
 	@Override
-	public File getLevelFolder(ILevelWrapper level)
+	public File getLevelFolder(ILevelWrapper levelWrapper)
 	{
-		return this.levelToFileMap.computeIfAbsent(level, (newLevel) ->
+		return this.levelWrapperToFileMap.computeIfAbsent(levelWrapper, (newLevelWrapper) ->
 		{
-			if (Config.Client.Advanced.Multiplayer.multiverseSimilarityRequiredPercent.get() == 0)
+			// Use the server provided key if one was provided
+			if (newLevelWrapper instanceof IServerKeyedClientLevel)
 			{
-				if (this.fileMatcher != null)
+				IServerKeyedClientLevel keyedClientLevel = (IServerKeyedClientLevel) newLevelWrapper;
+				LOGGER.info("Loading level "+newLevelWrapper.getDimensionType().getDimensionName()+" with key: "+keyedClientLevel.getServerLevelKey());
+				// This world was identified by the server directly, so we can know for sure which folder to use.
+				return new File(getSaveStructureFolderPath() + File.separatorChar + keyedClientLevel.getServerLevelKey());
+			}
+			
+			
+			// use multiverse matching if enabled
+			if (Config.Client.Advanced.Multiplayer.multiverseSimilarityRequiredPercent.get() != 0)
+			{
+				// create the matcher if one doesn't exist
+				if (this.subDimMatcher == null || !this.subDimMatcher.isFindingLevel(newLevelWrapper))
 				{
-					this.fileMatcher.close();
-					this.fileMatcher = null;
+					LOGGER.info("Loading level " + newLevelWrapper.getDimensionType().getDimensionName());
+					this.subDimMatcher = new SubDimensionLevelMatcher(newLevelWrapper, this.folder,
+							this.getMatchingLevelFolders(newLevelWrapper).toArray(new File[0] /* surprisingly we don't need to create an array of any specific size for this to work */));
 				}
-				return this.getLevelFolderWithoutSimilarityMatching(newLevel);
+				
+				File levelFile = this.subDimMatcher.tryGetLevel();
+				if (levelFile != null)
+				{
+					this.subDimMatcher.close();
+					this.subDimMatcher = null;
+				}
+				return levelFile;
 			}
-
-			if (this.fileMatcher == null || !this.fileMatcher.isFindingLevel(newLevel))
+			
+			// we aren't using multiverse matching, shut down the matcher
+			// TODO this additional call may not be needed
+			if (this.subDimMatcher != null)
 			{
-				LOGGER.info("Loading level for world " + newLevel.getDimensionType().getDimensionName());
-				this.fileMatcher = new SubDimensionLevelMatcher(newLevel, this.folder,
-						this.getMatchingLevelFolders(newLevel).toArray(new File[0] /* surprisingly we don't need to create an array of any specific size for this to work */));
+				this.subDimMatcher.close();
+				this.subDimMatcher = null;
 			}
-
-			File levelFile = this.fileMatcher.tryGetLevel();
-			if (levelFile != null)
-			{
-				this.fileMatcher.close();
-				this.fileMatcher = null;
-			}
-			return levelFile;
+			
+			
+			// get the default folder
+			return this.getLevelFolderWithoutSimilarityMatching(newLevelWrapper);
 		});
 	}
 
@@ -129,7 +148,7 @@ public class ClientOnlySaveStructure extends AbstractSaveStructure
 	@Override
 	public File getRenderCacheFolder(ILevelWrapper level)
 	{
-		File levelFolder = this.levelToFileMap.get(level);
+		File levelFolder = this.levelWrapperToFileMap.get(level);
 		if (levelFolder == null)
 		{
 			return null;
@@ -141,7 +160,7 @@ public class ClientOnlySaveStructure extends AbstractSaveStructure
 	@Override
 	public File getFullDataFolder(ILevelWrapper level)
 	{
-		File levelFolder = this.levelToFileMap.get(level);
+		File levelFolder = this.levelWrapperToFileMap.get(level);
 		if (levelFolder == null)
 		{
 			return null;
@@ -173,7 +192,16 @@ public class ClientOnlySaveStructure extends AbstractSaveStructure
 		// a valid level folder needs to have DH specific folders in it
 		return files != null && files.length != 0;
 	}
-
+	
+	
+	private static String getSaveStructureFolderPath()
+	{
+		String path = MC_SHARED.getInstallationDirectory().getPath() + File.separatorChar
+				+ "Distant_Horizons_server_data" + File.separatorChar
+				+ getServerFolderName();
+		return path;
+	}
+	
 	/** Generated from the server the client is currently connected to. */
 	private static String getServerFolderName()
 	{
@@ -213,15 +241,15 @@ public class ClientOnlySaveStructure extends AbstractSaveStructure
 		// This fixes some issues when the server is named something in other languages
 		return new PercentEscaper("", true).escape(folderName);
 	}
-
-
-
+	
+	
+	
 	//==================//
 	// override methods //
 	//==================//
 
 	@Override
-	public void close() { this.fileMatcher.close(); }
+	public void close() { this.subDimMatcher.close(); }
 
 	@Override
 	public String toString() { return "[" + this.getClass().getSimpleName() + "@" + this.folder.getName() + "]"; }

core/src/main/java/com/seibel/distanthorizons/core/level/DhClientLevel.java

@@ -4,6 +4,7 @@ import com.seibel.distanthorizons.core.dataObjects.fullData.accessor.ChunkSizedF
 import com.seibel.distanthorizons.core.file.fullDatafile.IFullDataSourceProvider;
 import com.seibel.distanthorizons.core.file.fullDatafile.RemoteFullDataFileHandler;
 import com.seibel.distanthorizons.core.file.structure.AbstractSaveStructure;
+import com.seibel.distanthorizons.core.file.structure.ClientOnlySaveStructure;
 import com.seibel.distanthorizons.core.logging.DhLoggerBuilder;
 import com.seibel.distanthorizons.core.pos.DhBlockPos;
 import com.seibel.distanthorizons.core.wrapperInterfaces.block.IBlockStateWrapper;

core/src/main/java/com/seibel/distanthorizons/core/level/IKeyedClientLevelManager.java

@@ -0,0 +1,24 @@
+package com.seibel.distanthorizons.core.level;
+
+import com.seibel.distanthorizons.core.wrapperInterfaces.world.IClientLevelWrapper;
+import com.seibel.distanthorizons.core.wrapperInterfaces.world.ILevelWrapper;
+import com.seibel.distanthorizons.coreapi.interfaces.dependencyInjection.IBindable;
+
+/**
+ * Handles level overrides initiated by servers that
+ * support differentiating between different levels.
+ */
+public interface IKeyedClientLevelManager extends IBindable
+{
+	/** Called when a client level is wrapped by a ServerEnhancedClientLevel, for integration into mod internals. */
+	void setServerKeyedLevel(IServerKeyedClientLevel clientLevel);
+	IServerKeyedClientLevel getOverrideWrapper();
+	
+	/** Returns a new instance of a ServerEnhancedClientLevel. */
+	IServerKeyedClientLevel getServerKeyedLevel(ILevelWrapper level, String serverLevelKey);
+	
+	/** Sets the LOD engine to use the override wrapper, if the server has communication enabled. */
+	void setUseOverrideWrapper(boolean useOverrideWrapper);
+	boolean getUseOverrideWrapper();
+	
+}

core/src/main/java/com/seibel/distanthorizons/core/level/IServerKeyedClientLevel.java

@@ -0,0 +1,11 @@
+package com.seibel.distanthorizons.core.level;
+
+import com.seibel.distanthorizons.core.wrapperInterfaces.world.IClientLevelWrapper;
+
+/** Enhances a {@link IClientLevelWrapper} with server provided level information. */
+public interface IServerKeyedClientLevel extends IClientLevelWrapper
+{
+    /** Returns the level key, which is used to select the correct folder on the client. */
+    String getServerLevelKey();
+	
+}

core/src/main/java/com/seibel/distanthorizons/core/world/DhClientWorld.java

@@ -45,6 +45,7 @@ public class DhClientWorld extends AbstractDhWorld implements IDhClientWorld
         return this.levels.computeIfAbsent((IClientLevelWrapper) wrapper, (clientLevelWrapper) ->
 		{
             File file = this.saveStructure.getLevelFolder(wrapper);
+
             if (file == null)
 			{
 				return null;

core/src/main/java/com/seibel/distanthorizons/core/wrapperInterfaces/minecraft/IMinecraftClientWrapper.java

@@ -138,5 +138,8 @@ public interface IMinecraftClientWrapper extends IBindable
 	void crashMinecraft(String errorMessage, Throwable exception); //FIXME: Move to IMinecraftSharedWrapper
 
     Object getOptionsObject();
+
+	/** Executes the given task on Minecraft's render thread. */
+	void executeOnRenderThread(Runnable runnable);
 	
 }