Deregister empty scenes if a player leaves them

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

@@ -117,6 +117,7 @@ public class GenshinScene {
 	}
 	
 	public void removePlayer(GenshinPlayer player) {
+		// Remove player from scene
 		getPlayers().remove(player);
 		player.setScene(null);
 		
@@ -127,6 +128,11 @@ public class GenshinScene {
 		for (EntityGadget gadget : player.getTeamManager().getGadgets()) {
 			this.removeEntity(gadget);
 		}
+		
+		// Deregister scene if not in use
+		if (this.getEntities().size() <= 0) {
+			this.getWorld().deregisterScene(this);
+		}
 	}
 	
 	private void setupPlayerAvatars(GenshinPlayer player) {

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

@@ -111,7 +111,7 @@ public class World implements Iterable<GenshinPlayer> {
 		SceneData sceneData = GenshinData.getSceneDataMap().get(sceneId);
 		if (sceneData != null) {
 			scene = new GenshinScene(this, sceneData);
-			this.getScenes().put(sceneId, scene);
+			this.registerScene(scene);
 			return scene;
 		}
 		
@@ -198,6 +198,14 @@ public class World implements Iterable<GenshinPlayer> {
 		}
 	}
 	
+	public void registerScene(GenshinScene scene) {
+		this.getScenes().put(scene.getId(), scene);
+	}
+	
+	public void deregisterScene(GenshinScene scene) {
+		this.getScenes().remove(scene.getId());
+	}
+	
 	public boolean transferPlayerToScene(GenshinPlayer player, int sceneId, Position pos) {
 		if (player.getScene().getId() == sceneId || GenshinData.getSceneDataMap().get(sceneId) == null) {
 			return false;