-Add: sync serverPos[XYZ] on spawning of entity

This fixes the issue that, up to 400 ticks from getting in range,
entities have a wrong offset (because server and client don't agree on
the position to calculate relative updates from)

forge/forge_client/src/net/minecraft/src/forge/PacketHandlerClient.java

@@ -51,6 +51,12 @@ public class PacketHandlerClient extends PacketHandlerBase
                     pkt.readData(data);
                     onOpenGui((PacketOpenGUI)pkt);
                     break;
+
+                case ForgePacket.TRACK:
+                    pkt = new PacketEntityTrack();
+                    pkt.readData(data);
+                    onEntityTrackPacket((PacketEntityTrack)pkt, ModLoader.getMinecraftInstance().theWorld);
+                    break;
             }
         }
         catch (IOException e)
@@ -60,6 +66,27 @@ public class PacketHandlerClient extends PacketHandlerBase
         }
     }
 
+    /**
+     * Process the Entity Track packet. This corrects the serverPos[XYZ] to match
+     *  with the server, so any following relative updates are valid.
+     * @param packet The Track Packet
+     * @param world The world the entity is in
+     */
+    public void onEntityTrackPacket(PacketEntityTrack packet, World world)
+    {
+        if (DEBUG)
+        {
+            System.out.println("S->C: " + packet.toString(true));
+        }
+
+        Minecraft mc = ModLoader.getMinecraftInstance();
+        Entity entity = ((WorldClient)world).getEntityByID(packet.entityId);
+
+        entity.serverPosX = packet.serverPosX;
+        entity.serverPosY = packet.serverPosY;
+        entity.serverPosZ = packet.serverPosZ;
+    }
+
     /**
      * Processes the Entity Spawn packet. And spawns an entity in world as needed.
      * If the client has the required client mod.

forge/forge_common/net/minecraft/src/forge/ForgeHooks.java

@@ -29,6 +29,7 @@ import net.minecraft.src.Packet250CustomPayload;
 import net.minecraft.src.World;
 import net.minecraft.src.mod_MinecraftForge;
 import net.minecraft.src.forge.packets.PacketEntitySpawn;
+import net.minecraft.src.forge.packets.PacketEntityTrack;
 import net.minecraft.src.forge.packets.PacketHandlerBase;
 
 import java.io.ByteArrayOutputStream;
@@ -710,6 +711,12 @@ public class ForgeHooks
         PacketEntitySpawn pkt = new PacketEntitySpawn(entity, info.Mod, info.ID);
         return pkt.getPacket();
     }
+    
+    public static Packet getEntityTrackPacket(int entityId, int serverPosX, int serverPosY, int serverPosZ)
+    {
+        PacketEntityTrack pkt = new PacketEntityTrack(entityId, serverPosX, serverPosY, serverPosZ);
+        return pkt.getPacket();
+    }
 
     public static Hashtable<Integer, NetworkMod> networkMods = new Hashtable<Integer, NetworkMod>();
     public static Hashtable<BaseMod, IGuiHandler> guiHandlers = new Hashtable<BaseMod, IGuiHandler>();

forge/forge_common/net/minecraft/src/forge/packets/ForgePacket.java

@@ -18,6 +18,7 @@ public abstract class ForgePacket
     public static final int MODLIST     = 2;
     public static final int MOD_MISSING = 3;
     public static final int OPEN_GUI    = 5;
+    public static final int TRACK       = 6;
 
     public Packet getPacket()
     {

forge/forge_common/net/minecraft/src/forge/packets/PacketEntityTrack.java

@@ -0,0 +1,44 @@
+package net.minecraft.src.forge.packets;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public class PacketEntityTrack extends ForgePacket
+{
+    public int entityId;
+    public int serverPosX;
+    public int serverPosY;
+    public int serverPosZ;
+
+    public PacketEntityTrack(){}
+    public PacketEntityTrack(int entityId, int serverPosX, int serverPosY, int serverPosZ)
+    {
+        this.entityId = entityId;
+        this.serverPosX = serverPosX;
+        this.serverPosY = serverPosY;
+        this.serverPosZ = serverPosZ;
+    }
+
+    public void writeData(DataOutputStream data) throws IOException
+    {
+        data.writeInt(entityId);
+        data.writeInt(serverPosX);
+        data.writeInt(serverPosY);
+        data.writeInt(serverPosZ);
+    }
+
+    public void readData(DataInputStream data) throws IOException
+    {
+        entityId = data.readInt();
+        serverPosX = data.readInt();
+        serverPosY = data.readInt();
+        serverPosZ = data.readInt();
+    }
+
+    @Override
+    public int getID()
+    {
+        return ForgePacket.TRACK;
+    }
+}

forge/patches/minecraft_server/net/minecraft/src/EntityTrackerEntry.java.patch

@@ -9,7 +9,22 @@
  public class EntityTrackerEntry
  {
      /** The entity that this EntityTrackerEntry tracks. */
-@@ -286,6 +288,11 @@
+@@ -226,6 +228,14 @@
+                     this.trackedPlayers.add(par1EntityPlayerMP);
+                     par1EntityPlayerMP.playerNetServerHandler.sendPacket(this.getSpawnPacket());
+ 
++                    int posX = MathHelper.floor_double(this.trackedEntity.posX * 32.0D);
++                    int posY = MathHelper.floor_double(this.trackedEntity.posY * 32.0D);
++                    int posZ = MathHelper.floor_double(this.trackedEntity.posZ * 32.0D);
++                    if (posX != this.encodedPosX || posY != this.encodedPosY || posZ != this.encodedPosZ)
++                    {
++                        par1EntityPlayerMP.playerNetServerHandler.sendPacket(ForgeHooks.getEntityTrackPacket(this.trackedEntity.entityId, this.encodedPosX, this.encodedPosY, this.encodedPosZ));
++                    }
++
+                     if (this.shouldSendMotionUpdates)
+                     {
+                         par1EntityPlayerMP.playerNetServerHandler.sendPacket(new Packet28EntityVelocity(this.trackedEntity.entityId, this.trackedEntity.motionX, this.trackedEntity.motionY, this.trackedEntity.motionZ));
+@@ -286,6 +296,11 @@
          {
              System.out.println("Fetching addPacket for removed entity");
          }