Started on a major rework of the way NPCLib handles packets.

commons/src/main/java/net/jitse/npclib/api/NPC.java

@@ -22,11 +22,12 @@ import java.util.*;
 /**
  * @author Jitse Boonstra
  */
-public abstract class NPC {
+public abstract class NPC implements PacketHandler {
 
     protected final UUID uuid = UUID.randomUUID();
     protected final String name = uuid.toString().replace("-", "").substring(0, 10);
-    protected final int entityId = (int) Math.ceil(Math.random() * 100000) + 100000;
+    // Below was previously = (int) Math.ceil(Math.random() * 100000) + 100000 (new is experimental).
+    protected final int entityId = Integer.MAX_VALUE - NPCManager.getAllNPCs().size();
 
     protected double cosFOV = Math.cos(Math.toRadians(60));
 
@@ -45,7 +46,7 @@ public abstract class NPC {
         this.plugin = plugin;
         this.skin = skin;
         this.autoHideDistance = autoHideDistance;
-        this.lines = (lines == null ? Collections.emptyList() : lines);
+        this.lines = lines == null ? Collections.emptyList() : lines;
 
         NPCManager.add(this);
     }
@@ -110,8 +111,11 @@ public abstract class NPC {
         return shown.contains(player.getUniqueId()) && !autoHidden.contains(player.getUniqueId());
     }
 
-    // Generate packets.
-    public abstract void create(Location location);
+    public void create(Location location) {
+        this.location = location;
+
+        createPackets();
+    }
 
     public void show(Player player) {
         show(player, false);
@@ -160,13 +164,9 @@ public abstract class NPC {
 
     private boolean canSeeNPC(Player player) {
         Vector dir = location.toVector().subtract(player.getEyeLocation().toVector()).normalize();
-        double dot = dir.dot(player.getLocation().getDirection());
-        return dot >= cosFOV;
+        return dir.dot(player.getLocation().getDirection()) >= cosFOV;
     }
 
-    // Internal method.
-    protected abstract void sendShowPackets(Player player);
-
     public void hide(Player player) {
         hide(player, false, true);
     }
@@ -196,7 +196,4 @@ public abstract class NPC {
             }
         }
     }
-
-    // Internal method.
-    protected abstract void sendHidePackets(Player player, boolean scheduler);
 }

commons/src/main/java/net/jitse/npclib/api/PacketHandler.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2018 Jitse Boonstra
+ */
+
+package net.jitse.npclib.api;
+
+import org.bukkit.entity.Player;
+
+/**
+ * @author Jitse Boonstra
+ */
+interface PacketHandler {
+
+    void createPackets();
+
+    void sendShowPackets(Player player);
+
+    void sendHidePackets(Player player, boolean scheduler);
+}

nms/v1_8_R1/src/main/java/net/jitse/npclib/nms/v1_8_R1/NPC_v1_8_R1.java

@@ -13,7 +13,6 @@ import net.jitse.npclib.nms.v1_8_R1.packets.PacketPlayOutScoreboardTeamWrapper;
 import net.jitse.npclib.skin.Skin;
 import net.minecraft.server.v1_8_R1.*;
 import org.bukkit.Bukkit;
-import org.bukkit.Location;
 import org.bukkit.craftbukkit.v1_8_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -37,9 +36,7 @@ public class NPC_v1_8_R1 extends NPC {
     }
 
     @Override
-    public void create(Location location) {
-        this.location = location;
-
+    public void createPackets() {
         this.hologram = new Hologram(location.clone().add(0, 0.5, 0), lines);
         hologram.generatePackets(false);