Merge pull request #256 from Grasscutters/dev-entity

Implement natural spawns

build.gradle

@@ -37,6 +37,7 @@ dependencies {
 	implementation group: 'dev.morphia.morphia', name: 'morphia-core', version: '2.2.6'
 
     implementation group: 'org.greenrobot', name: 'eventbus-java', version: '3.3.1'
+    implementation group: 'org.danilopianini', name: 'java-quadtree', version: '0.1.9'
 }
 
 application {

src/main/java/emu/grasscutter/data/GenshinData.java

@@ -60,7 +60,8 @@ public class GenshinData {
 	private static final Int2ObjectMap<FetterData> fetterDataMap = new Int2ObjectOpenHashMap<>();
 	private static final Int2ObjectMap<FetterCharacterCardData> fetterCharacterCardDataMap = new Int2ObjectOpenHashMap<>();
 	private static final Int2ObjectMap<RewardData> rewardDataMap = new Int2ObjectOpenHashMap<>();
-
+	private static final Int2ObjectMap<WorldLevelData> worldLevelDataMap = new Int2ObjectOpenHashMap<>();
+	
 	// Cache
 	private static Map<Integer, List<Integer>> fetters = new HashMap<>();
 	
@@ -260,4 +261,8 @@ public class GenshinData {
 
 		return fetters;
 	}
+
+	public static Int2ObjectMap<WorldLevelData> getWorldLevelDataMap() {
+		return worldLevelDataMap;
+	}
 }

src/main/java/emu/grasscutter/data/GenshinDepot.java

@@ -3,9 +3,14 @@ package emu.grasscutter.data;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.danilopianini.util.FlexibleQuadTree;
+import org.danilopianini.util.SpatialIndex;
+
 import emu.grasscutter.Grasscutter;
 import emu.grasscutter.data.def.ReliquaryAffixData;
 import emu.grasscutter.data.def.ReliquaryMainPropData;
+import emu.grasscutter.game.world.SpawnDataEntry;
+import emu.grasscutter.game.world.SpawnDataEntry.SpawnGroupEntry;
 import emu.grasscutter.utils.WeightedList;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
@@ -14,6 +19,8 @@ public class GenshinDepot {
 	private static Int2ObjectMap<WeightedList<ReliquaryMainPropData>> relicMainPropDepot = new Int2ObjectOpenHashMap<>();
 	private static Int2ObjectMap<List<ReliquaryAffixData>> relicAffixDepot = new Int2ObjectOpenHashMap<>();
 	
+	private static Int2ObjectMap<SpatialIndex<SpawnGroupEntry>> spawnLists = new Int2ObjectOpenHashMap<>();
+	
 	public static void load() {
 		for (ReliquaryMainPropData data : GenshinData.getReliquaryMainPropDataMap().values()) {
 			if (data.getWeight() <= 0 || data.getPropDepotId() <= 0) {
@@ -46,4 +53,12 @@ public class GenshinDepot {
 	public static List<ReliquaryAffixData> getRandomRelicAffixList(int depot) {
 		return relicAffixDepot.get(depot);
 	}
+	
+	public static Int2ObjectMap<SpatialIndex<SpawnGroupEntry>> getSpawnLists() {
+		return spawnLists;
+	}
+	
+	public static SpatialIndex<SpawnGroupEntry> getSpawnListById(int sceneId) {
+		return getSpawnLists().computeIfAbsent(sceneId, id -> new FlexibleQuadTree<>());
+	}
 }

src/main/java/emu/grasscutter/data/ResourceLoader.java

@@ -19,6 +19,8 @@ import emu.grasscutter.data.common.ScenePointConfig;
 import emu.grasscutter.data.custom.AbilityEmbryoEntry;
 import emu.grasscutter.data.custom.OpenConfigEntry;
 import emu.grasscutter.data.custom.ScenePointEntry;
+import emu.grasscutter.game.world.SpawnDataEntry;
+import emu.grasscutter.game.world.SpawnDataEntry.SpawnGroupEntry;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 
 public class ResourceLoader {
@@ -49,6 +51,8 @@ public class ResourceLoader {
 		loadScenePoints();
 		// Process into depots
 		GenshinDepot.load();
+		// Load spawn data
+		loadSpawnData();
 		// Custom - TODO move this somewhere else
 		try {
 			GenshinData.getAvatarSkillDepotDataMap().get(504).setAbilities(
@@ -233,6 +237,33 @@ public class ResourceLoader {
 		}
 	}
 	
+	private static void loadSpawnData() {
+		// Read from cached file if exists
+		File spawnDataEntries = new File(Grasscutter.getConfig().DATA_FOLDER + "Spawns.json");
+		List<SpawnGroupEntry> spawnEntryList = null;
+		
+		if (spawnDataEntries.exists()) {
+			// Load from cache
+			try (FileReader fileReader = new FileReader(spawnDataEntries)) {
+				spawnEntryList = Grasscutter.getGsonFactory().fromJson(fileReader, TypeToken.getParameterized(Collection.class, SpawnGroupEntry.class).getType());
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+		}
+		
+		if (spawnEntryList == null || spawnEntryList.isEmpty()) {
+			Grasscutter.getLogger().error("No spawn data loaded!");
+			return;
+		}
+
+		for (SpawnGroupEntry entry : spawnEntryList) {
+			entry.getSpawns().stream().forEach(s -> {
+				s.setGroup(entry);
+			});
+			GenshinDepot.getSpawnListById(entry.getSceneId()).insert(entry, entry.getPos().getX(), entry.getPos().getZ());
+		}
+	}
+	
 	private static void loadOpenConfig() {
 		// Read from cached file if exists
 		File openConfigCache = new File(Grasscutter.getConfig().DATA_FOLDER + "OpenConfig.json");

src/main/java/emu/grasscutter/data/def/WorldLevelData.java

@@ -0,0 +1,24 @@
+package emu.grasscutter.data.def;
+
+import emu.grasscutter.data.GenshinResource;
+import emu.grasscutter.data.ResourceType;
+
+@ResourceType(name = "WorldLevelExcelConfigData.json")
+public class WorldLevelData extends GenshinResource {
+	private int Level;
+	private int MonsterLevel;
+	    
+	@Override
+	public int getId() {
+		return this.Level;
+	}
+
+	public int getMonsterLevel() {
+		return MonsterLevel;
+	}
+
+	@Override
+	public void onLoad() {
+		
+	}
+}

src/main/java/emu/grasscutter/game/GenshinPlayer.java

@@ -195,11 +195,11 @@ public class GenshinPlayer {
 		this.world = world;
 	}
 
-	public GenshinScene getScene() {
+	public synchronized GenshinScene getScene() {
 		return scene;
 	}
 
-	public void setScene(GenshinScene scene) {
+	public synchronized void setScene(GenshinScene scene) {
 		this.scene = scene;
 	}
 

src/main/java/emu/grasscutter/game/GenshinScene.java

@@ -3,19 +3,32 @@ package emu.grasscutter.game;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Set;
 
+import org.danilopianini.util.SpatialIndex;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.data.GenshinData;
+import emu.grasscutter.data.GenshinDepot;
+import emu.grasscutter.data.GenshinResource;
+import emu.grasscutter.data.def.MonsterData;
 import emu.grasscutter.data.def.SceneData;
+import emu.grasscutter.data.def.WorldLevelData;
 import emu.grasscutter.game.entity.EntityAvatar;
 import emu.grasscutter.game.entity.EntityClientGadget;
 import emu.grasscutter.game.entity.EntityGadget;
+import emu.grasscutter.game.entity.EntityMonster;
 import emu.grasscutter.game.entity.GenshinEntity;
 import emu.grasscutter.game.props.ClimateType;
 import emu.grasscutter.game.props.FightProperty;
 import emu.grasscutter.game.props.LifeState;
 import emu.grasscutter.game.props.SceneType;
+import emu.grasscutter.game.world.SpawnDataEntry;
+import emu.grasscutter.game.world.SpawnDataEntry.SpawnGroupEntry;
 import emu.grasscutter.net.packet.GenshinPacket;
 import emu.grasscutter.net.proto.AttackResultOuterClass.AttackResult;
 import emu.grasscutter.net.proto.VisionTypeOuterClass.VisionType;
@@ -23,7 +36,9 @@ import emu.grasscutter.server.packet.send.PacketEntityFightPropUpdateNotify;
 import emu.grasscutter.server.packet.send.PacketLifeStateChangeNotify;
 import emu.grasscutter.server.packet.send.PacketSceneEntityAppearNotify;
 import emu.grasscutter.server.packet.send.PacketSceneEntityDisappearNotify;
+import emu.grasscutter.utils.Utils;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMaps;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class GenshinScene {
@@ -32,6 +47,10 @@ public class GenshinScene {
 	private final List<GenshinPlayer> players;
 	private final Int2ObjectMap<GenshinEntity> entities;
 	
+	private final Set<SpawnDataEntry> spawnedEntities;
+	private final Set<SpawnDataEntry> deadSpawnedEntities;
+	private boolean dontDestroyWhenEmpty;
+	
 	private int time;
 	private ClimateType climate;
 	private int weather;
@@ -40,10 +59,13 @@ public class GenshinScene {
 		this.world = world;
 		this.sceneData = sceneData;
 		this.players = Collections.synchronizedList(new ArrayList<>());
-		this.entities = new Int2ObjectOpenHashMap<>();
+		this.entities = Int2ObjectMaps.synchronize(new Int2ObjectOpenHashMap<>());
 
 		this.time = 8 * 60;
 		this.climate = ClimateType.CLIMATE_SUNNY;
+		
+		this.spawnedEntities = new HashSet<>();
+		this.deadSpawnedEntities = new HashSet<>();
 	}
 	
 	public int getId() {
@@ -102,11 +124,27 @@ public class GenshinScene {
 		this.weather = weather;
 	}
 
+	public boolean dontDestroyWhenEmpty() {
+		return dontDestroyWhenEmpty;
+	}
+
+	public void setDontDestroyWhenEmpty(boolean dontDestroyWhenEmpty) {
+		this.dontDestroyWhenEmpty = dontDestroyWhenEmpty;
+	}
+
+	public Set<SpawnDataEntry> getSpawnedEntities() {
+		return spawnedEntities;
+	}
+
+	public Set<SpawnDataEntry> getDeadSpawnedEntities() {
+		return deadSpawnedEntities;
+	}
+
 	public boolean isInScene(GenshinEntity entity) {
 		return this.entities.containsKey(entity.getId());
 	}
 	
-	public void addPlayer(GenshinPlayer player) {
+	public synchronized void addPlayer(GenshinPlayer player) {
 		// Check if player already in
 		if (getPlayers().contains(player)) {
 			return;
@@ -125,7 +163,7 @@ public class GenshinScene {
 		this.setupPlayerAvatars(player);
 	}
 	
-	public void removePlayer(GenshinPlayer player) {
+	public synchronized void removePlayer(GenshinPlayer player) {
 		// Remove player from scene
 		getPlayers().remove(player);
 		player.setScene(null);
@@ -139,7 +177,7 @@ public class GenshinScene {
 		}
 		
 		// Deregister scene if not in use
-		if (this.getEntities().size() <= 0) {
+		if (this.getEntities().size() <= 0 && !this.dontDestroyWhenEmpty()) {
 			this.getWorld().deregisterScene(this);
 		}
 	}
@@ -277,6 +315,80 @@ public class GenshinScene {
 		target.onDeath(attackerId);
 	}
 	
+	public void onTick() {
+		this.checkSpawns();
+	}
+	
+	// TODO - Test
+	public void checkSpawns() {
+		SpatialIndex<SpawnGroupEntry> list = GenshinDepot.getSpawnListById(this.getId());
+		Set<SpawnDataEntry> visible = new HashSet<>();
+		
+		for (GenshinPlayer player : this.getPlayers()) {
+			int RANGE = 100;
+			Collection<SpawnGroupEntry> entries = list.query(
+				new double[] {player.getPos().getX() - RANGE, player.getPos().getZ() - RANGE}, 
+				new double[] {player.getPos().getX() + RANGE, player.getPos().getZ() + RANGE}
+			);
+			
+			for (SpawnGroupEntry entry : entries) {
+				for (SpawnDataEntry spawnData : entry.getSpawns()) {
+					visible.add(spawnData);
+				}
+			}
+		}
+		
+		// World level
+		WorldLevelData worldLevelData = GenshinData.getWorldLevelDataMap().get(getWorld().getWorldLevel());
+		int worldLevelOverride = 0;
+		
+		if (worldLevelData != null) {
+			worldLevelOverride = worldLevelData.getMonsterLevel();
+		}
+				
+		// Todo
+		List<GenshinEntity> toAdd = new LinkedList<>();
+		List<GenshinEntity> toRemove = new LinkedList<>();
+		
+		for (SpawnDataEntry entry : visible) {
+			if (!this.getSpawnedEntities().contains(entry) && !this.getDeadSpawnedEntities().contains(entry)) {
+				// Spawn entity
+				MonsterData data = GenshinData.getMonsterDataMap().get(entry.getMonsterId());
+				
+				if (data == null) {
+					continue;
+				}
+				
+				EntityMonster entity = new EntityMonster(this, data, entry.getPos(), worldLevelOverride > 0 ? worldLevelOverride : entry.getLevel());
+				entity.getRotation().set(entry.getRot());
+				entity.setGroupId(entry.getGroup().getGroupId());
+				entity.setPoseId(entry.getPoseId());
+				entity.setConfigId(entry.getConfigId());
+				entity.setSpawnEntry(entry);
+				
+				toAdd.add(entity);
+				
+				// Add to spawned list
+				this.getSpawnedEntities().add(entry);
+			}
+		}
+		
+		for (GenshinEntity entity : this.getEntities().values()) {
+			if (entity.getSpawnEntry() != null && !visible.contains(entity.getSpawnEntry())) {
+				toRemove.add(entity);
+			}
+		}
+		
+		if (toAdd.size() > 0) {
+			toAdd.stream().forEach(this::addEntityDirectly);
+			this.broadcastPacket(new PacketSceneEntityAppearNotify(toAdd, VisionType.VisionBorn));
+		}
+		if (toRemove.size() > 0) {
+			toRemove.stream().forEach(this::removeEntityDirectly);
+			this.broadcastPacket(new PacketSceneEntityDisappearNotify(toRemove, VisionType.VisionRemove));
+		}
+	}
+	
 	// Gadgets
 	
 	public void onPlayerCreateGadget(EntityClientGadget gadget) {

src/main/java/emu/grasscutter/game/World.java

@@ -37,6 +37,7 @@ import emu.grasscutter.server.packet.send.PacketWorldPlayerInfoNotify;
 import emu.grasscutter.server.packet.send.PacketWorldPlayerRTTNotify;
 import emu.grasscutter.utils.Position;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMaps;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class World implements Iterable<GenshinPlayer> {
@@ -58,11 +59,13 @@ public class World implements Iterable<GenshinPlayer> {
 	public World(GenshinPlayer player, boolean isMultiplayer) {
 		this.owner = player;
 		this.players = Collections.synchronizedList(new ArrayList<>());
-		this.scenes = new Int2ObjectOpenHashMap<>();
+		this.scenes = Int2ObjectMaps.synchronize(new Int2ObjectOpenHashMap<>());
 		
 		this.levelEntityId = getNextEntityId(EntityIdType.MPLEVEL);
 		this.worldLevel = player.getWorldLevel();
 		this.isMultiplayer = isMultiplayer;
+		
+		this.owner.getServer().registerWorld(this);
 	}
 	
 	public GenshinPlayer getHost() {
@@ -212,19 +215,29 @@ public class World implements Iterable<GenshinPlayer> {
 			return false;
 		}
 		
-		Integer oldSceneId = null;
+		GenshinScene oldScene = null;
 
 		if (player.getScene() != null) {
-			oldSceneId = player.getScene().getId();
-			player.getScene().removePlayer(player);
+			oldScene = player.getScene();
+			
+			// Dont deregister scenes if the player is going to tp back into them
+			if (oldScene.getId() == sceneId) {
+				oldScene.setDontDestroyWhenEmpty(true);
+			}
+			
+			oldScene.removePlayer(player);
 		}
 		
-		GenshinScene scene = this.getSceneById(sceneId);
-		scene.addPlayer(player);
+		GenshinScene newScene = this.getSceneById(sceneId);
+		newScene.addPlayer(player);
 		player.getPos().set(pos);
 		
+		if (oldScene != null) {
+			oldScene.setDontDestroyWhenEmpty(false);
+		}
+		
 		// Teleport packet
-		if (oldSceneId.equals(sceneId)) {
+		if (oldScene == newScene) {
 			player.sendPacket(new PacketPlayerEnterSceneNotify(player, EnterType.EnterGoto, EnterReason.TransPoint, sceneId, pos));
 		} else {
 			player.sendPacket(new PacketPlayerEnterSceneNotify(player, EnterType.EnterJump, EnterReason.TransPoint, sceneId, pos));
@@ -263,6 +276,12 @@ public class World implements Iterable<GenshinPlayer> {
     	}
 	}
 	
+	public void onTick() {
+		for (GenshinScene scene : this.getScenes().values()) {
+			scene.onTick();
+		}
+	}
+	
 	public void close() {
 		
 	}

src/main/java/emu/grasscutter/game/entity/EntityMonster.java

@@ -37,6 +37,10 @@ public class EntityMonster extends GenshinEntity {
 	private final int level;
 	private int weaponEntityId;
 	
+	private int groupId;
+	private int configId;
+	private int poseId;
+	
 	public EntityMonster(GenshinScene scene, MonsterData monsterData, Position pos, int level) {
 		super(scene);
 		this.id = getWorld().getNextEntityId(EntityIdType.MONSTER);
@@ -100,9 +104,35 @@ public class EntityMonster extends GenshinEntity {
 		return this.getFightProperty(FightProperty.FIGHT_PROP_CUR_HP) > 0f;
 	}
 	
+	public int getGroupId() {
+		return groupId;
+	}
+
+	public void setGroupId(int groupId) {
+		this.groupId = groupId;
+	}
+
+	public int getConfigId() {
+		return configId;
+	}
+
+	public void setConfigId(int configId) {
+		this.configId = configId;
+	}
+
+	public int getPoseId() {
+		return poseId;
+	}
+
+	public void setPoseId(int poseId) {
+		this.poseId = poseId;
+	}
+	
 	@Override
 	public void onDeath(int killerId) {
-		
+		if (this.getSpawnEntry() != null) {
+			this.getScene().getDeadSpawnedEntities().add(getSpawnEntry());
+		}
 	}
 	
 	public void recalcStats() {
@@ -190,11 +220,11 @@ public class EntityMonster extends GenshinEntity {
 		
 		SceneMonsterInfo.Builder monsterInfo = SceneMonsterInfo.newBuilder()
 				.setMonsterId(getMonsterId())
-				.setGroupId(133003095)
-				.setConfigId(95001)
+				.setGroupId(this.getGroupId())
+				.setConfigId(this.getConfigId())
 				.addAllAffixList(getMonsterData().getAffix())
 				.setAuthorityPeerId(getWorld().getHostPeerId())
-				.setPoseId(0)
+				.setPoseId(this.getPoseId())
 				.setBlockId(3001)
 				.setBornType(MonsterBornType.MonsterBornDefault)
 				.setSpecialNameId(40);

src/main/java/emu/grasscutter/game/entity/GenshinEntity.java

@@ -4,6 +4,7 @@ import emu.grasscutter.game.GenshinScene;
 import emu.grasscutter.game.World;
 import emu.grasscutter.game.props.FightProperty;
 import emu.grasscutter.game.props.LifeState;
+import emu.grasscutter.game.world.SpawnDataEntry;
 import emu.grasscutter.net.proto.MotionInfoOuterClass.MotionInfo;
 import emu.grasscutter.net.proto.MotionStateOuterClass.MotionState;
 import emu.grasscutter.net.proto.SceneEntityInfoOuterClass.SceneEntityInfo;
@@ -14,6 +15,7 @@ import it.unimi.dsi.fastutil.ints.Int2FloatOpenHashMap;
 public abstract class GenshinEntity {
 	protected int id;
 	private final GenshinScene scene;
+	private SpawnDataEntry spawnEntry;
 	
 	private MotionState moveState;
 	private int lastMoveSceneTimeMs;
@@ -104,4 +106,12 @@ public abstract class GenshinEntity {
 		
 		return proto;
 	}
+
+	public SpawnDataEntry getSpawnEntry() {
+		return spawnEntry;
+	}
+
+	public void setSpawnEntry(SpawnDataEntry spawnEntry) {
+		this.spawnEntry = spawnEntry;
+	}
 }

src/main/java/emu/grasscutter/game/world/SpawnDataEntry.java

@@ -0,0 +1,80 @@
+package emu.grasscutter.game.world;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import emu.grasscutter.utils.Position;
+
+public class SpawnDataEntry {
+	private transient SpawnGroupEntry group;
+	private int monsterId;
+	private int configId;
+	private int level;
+	private int poseId;
+	private Position pos;
+	private Position rot;
+	
+	public SpawnGroupEntry getGroup() {
+		return group;
+	}
+
+	public void setGroup(SpawnGroupEntry group) {
+		this.group = group;
+	}
+
+	public int getMonsterId() {
+		return monsterId;
+	}
+	
+	public int getConfigId() {
+		return configId;
+	}
+	
+	public int getLevel() {
+		return level;
+	}
+	
+	public int getPoseId() {
+		return poseId;
+	}
+	
+	public Position getPos() {
+		return pos;
+	}
+	
+	public Position getRot() {
+		return rot;
+	}
+	
+	public static class SpawnGroupEntry {
+		private int sceneId;
+		private int groupId;
+		private int blockId;
+		private Position pos;
+		private List<SpawnDataEntry> spawns;
+		
+		public int getSceneId() {
+			return sceneId;
+		}
+
+		public int getGroupId() {
+			return groupId;
+		}
+
+		public int getBlockId() {
+			return blockId;
+		}
+
+		public void setBlockId(int blockId) {
+			this.blockId = blockId;
+		}
+
+		public Position getPos() {
+			return pos;
+		}
+
+		public List<SpawnDataEntry> getSpawns() {
+			return spawns;
+		}
+	}
+}

src/main/java/emu/grasscutter/server/dispatch/DispatchServer.java

@@ -43,6 +43,7 @@ public final class DispatchServer {
 
 	public String regionListBase64;
 	public HashMap<String, RegionData> regions;
+	private HttpServer server;
 
 	public DispatchServer() {
 		this.regions = new HashMap<String, RegionData>();
@@ -54,6 +55,10 @@ public final class DispatchServer {
 		this.initRegion();
 	}
 
+	public HttpServer getServer() {
+		return server;
+	}
+
 	public InetSocketAddress getAddress() {
 		return address;
 	}
@@ -200,7 +205,6 @@ public final class DispatchServer {
 	}
 
 	public void start() throws Exception {
-		HttpServer server;
 		if (Grasscutter.getConfig().getDispatchOptions().UseSSL) {
 			HttpsServer httpsServer = HttpsServer.create(getAddress(), 0);
 			SSLContext sslContext = SSLContext.getInstance("TLS");

src/main/java/emu/grasscutter/server/game/GameServer.java

@@ -10,6 +10,7 @@ import emu.grasscutter.command.CommandMap;
 import emu.grasscutter.database.DatabaseHelper;
 import emu.grasscutter.game.Account;
 import emu.grasscutter.game.GenshinPlayer;
+import emu.grasscutter.game.World;
 import emu.grasscutter.game.dungeons.DungeonManager;
 import emu.grasscutter.game.gacha.GachaManager;
 import emu.grasscutter.game.managers.ChatManager;
@@ -26,6 +27,7 @@ public final class GameServer extends MihoyoKcpServer {
 	private final GameServerPacketHandler packetHandler;
 
 	private final Map<Integer, GenshinPlayer> players;
+	private final Set<World> worlds;
 	
 	private final ChatManager chatManager;
 	private final InventoryManager inventoryManager;
@@ -50,6 +52,7 @@ public final class GameServer extends MihoyoKcpServer {
 		this.address = address;
 		this.packetHandler = new GameServerPacketHandler(PacketHandler.class);
 		this.players = new ConcurrentHashMap<>();
+		this.worlds = Collections.synchronizedSet(new HashSet<>());
 		
 		this.chatManager = new ChatManager(this);
 		this.inventoryManager = new InventoryManager(this);
@@ -84,6 +87,10 @@ public final class GameServer extends MihoyoKcpServer {
 		return players;
 	}
 
+	public Set<World> getWorlds() {
+		return worlds;
+	}
+
 	public ChatManager getChatManager() {
 		return chatManager;
 	}
@@ -161,12 +168,32 @@ public final class GameServer extends MihoyoKcpServer {
 	}
 	
 	public void onTick() throws Exception {
+		Iterator<World> it = this.getWorlds().iterator();
+		while (it.hasNext()) {
+			World world = it.next();
+			
+			if (world.getPlayerCount() == 0) {
+				it.remove();
+			}
+			
+			world.onTick();
+		}
+		
 		for (GenshinPlayer player : this.getPlayers().values()) {
 			player.onTick();
 		}
 
 		OnGameServerTick.post(new GameServerTickEvent());
 	}
+	
+	public void registerWorld(World world) {
+		this.getWorlds().add(world);
+	}
+	
+	public void deregisterWorld(World world) {
+		// TODO Auto-generated method stub
+		
+	}
 
 	@Override
 	public void onStartFinish() {

src/main/java/emu/grasscutter/server/packet/send/PacketSceneEntityDisappearNotify.java

@@ -1,5 +1,8 @@
 package emu.grasscutter.server.packet.send;
 
+import java.util.Collection;
+import java.util.List;
+
 import emu.grasscutter.game.entity.GenshinEntity;
 import emu.grasscutter.net.packet.GenshinPacket;
 import emu.grasscutter.net.packet.PacketOpcodes;
@@ -18,4 +21,15 @@ public class PacketSceneEntityDisappearNotify extends GenshinPacket {
 
 		this.setData(proto);
 	}
+	
+	public PacketSceneEntityDisappearNotify(Collection<GenshinEntity> entities, VisionType disappearType) {
+		super(PacketOpcodes.SceneEntityDisappearNotify);
+
+		SceneEntityDisappearNotify.Builder proto = SceneEntityDisappearNotify.newBuilder()
+				.setDisappearType(disappearType);
+		
+		entities.forEach(e -> proto.addEntityList(e.getId()));
+
+		this.setData(proto);
+	}
 }

src/main/java/emu/grasscutter/utils/Utils.java

@@ -10,6 +10,7 @@ import emu.grasscutter.Grasscutter;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
+
 import org.slf4j.Logger;
 
 @SuppressWarnings({"UnusedReturnValue", "BooleanMethodIsAlwaysInverted"})
@@ -24,6 +25,19 @@ public final class Utils {
 		return random.nextFloat() * (max - min) + min;
 	}
 	
+	public static double getDist(Position pos1, Position pos2) {
+		double xs = pos1.getX() - pos2.getX();
+		xs = xs * xs;
+		
+		double ys = pos1.getY() - pos2.getY();
+		ys = ys * ys;
+
+		double zs = pos1.getZ() - pos2.getZ();
+		zs = zs * zs;
+
+		return Math.sqrt(xs + zs + ys);
+	}
+
 	public static int getCurrentSeconds() {
 		return (int) (System.currentTimeMillis() / 1000.0);
 	}