Fix online mode creature spawning and packet parsing

- Fix encryption desync by tracking decrypted header bytes in world socket
- Fix UPDATE_OBJECT movement block parsing to handle 3.3.5a update flags
- Fix UNIT_FIELD_DISPLAYID index (67, not 71)
- Add creature spawn/despawn callbacks with DBC-based model loading
- Add SMSG_COMPRESSED_UPDATE_OBJECT opcode support

include/core/application.hpp

@@ -6,6 +6,7 @@
 #include <memory>
 #include <string>
 #include <vector>
+#include <unordered_map>
 
 namespace wowee {
 
@@ -81,6 +82,10 @@ private:
     std::string getPlayerModelPath() const;
     static const char* mapIdToName(uint32_t mapId);
     void loadOnlineWorldTerrain(uint32_t mapId, float x, float y, float z);
+    void spawnOnlineCreature(uint64_t guid, uint32_t displayId, float x, float y, float z, float orientation);
+    void despawnOnlineCreature(uint64_t guid);
+    void buildCreatureDisplayLookups();
+    std::string getModelPathForDisplayId(uint32_t displayId) const;
 
     static Application* instance;
 
@@ -118,6 +123,14 @@ private:
     std::vector<std::string> underwearPaths_;
     uint32_t skinTextureSlotIndex_ = 0;
     uint32_t cloakTextureSlotIndex_ = 0;
+
+    // Online creature model spawning
+    std::unordered_map<uint32_t, uint32_t> displayToModelId_;   // displayId → modelId (from CreatureDisplayInfo.dbc)
+    std::unordered_map<uint32_t, std::string> modelIdToPath_;   // modelId → M2 path (from CreatureModelData.dbc)
+    std::unordered_map<uint64_t, uint32_t> creatureInstances_;  // guid → render instanceId
+    std::unordered_map<uint64_t, uint32_t> creatureModelIds_;   // guid → loaded modelId
+    uint32_t nextCreatureModelId_ = 5000;  // Model IDs for online creatures
+    bool creatureLookupsBuilt_ = false;
 };
 
 } // namespace core

include/game/entity.hpp

@@ -147,6 +147,10 @@ public:
     uint32_t getEntry() const { return entry; }
     void setEntry(uint32_t e) { entry = e; }
 
+    // Display ID (model display)
+    uint32_t getDisplayId() const { return displayId; }
+    void setDisplayId(uint32_t id) { displayId = id; }
+
 protected:
     std::string name;
     uint32_t health = 0;
@@ -156,6 +160,7 @@ protected:
     uint8_t powerType = 0;   // 0=mana, 1=rage, 2=focus, 3=energy
     uint32_t level = 1;
     uint32_t entry = 0;
+    uint32_t displayId = 0;
 };
 
 /**

include/game/game_handler.hpp

@@ -276,6 +276,15 @@ public:
     using WorldEntryCallback = std::function<void(uint32_t mapId, float x, float y, float z)>;
     void setWorldEntryCallback(WorldEntryCallback cb) { worldEntryCallback_ = std::move(cb); }
 
+    // Creature spawn callback (online mode - triggered when creature enters view)
+    // Parameters: guid, displayId, x, y, z (canonical), orientation
+    using CreatureSpawnCallback = std::function<void(uint64_t guid, uint32_t displayId, float x, float y, float z, float orientation)>;
+    void setCreatureSpawnCallback(CreatureSpawnCallback cb) { creatureSpawnCallback_ = std::move(cb); }
+
+    // Creature despawn callback (online mode - triggered when creature leaves view)
+    using CreatureDespawnCallback = std::function<void(uint64_t guid)>;
+    void setCreatureDespawnCallback(CreatureDespawnCallback cb) { creatureDespawnCallback_ = std::move(cb); }
+
     // Cooldowns
     float getSpellCooldown(uint32_t spellId) const;
 
@@ -383,6 +392,11 @@ private:
      */
     void handleUpdateObject(network::Packet& packet);
 
+    /**
+     * Handle SMSG_COMPRESSED_UPDATE_OBJECT from server
+     */
+    void handleCompressedUpdateObject(network::Packet& packet);
+
     /**
      * Handle SMSG_DESTROY_OBJECT from server
      */
@@ -529,6 +543,8 @@ private:
     // ---- Phase 3: Spells ----
     HearthstoneCallback hearthstoneCallback;
     WorldEntryCallback worldEntryCallback_;
+    CreatureSpawnCallback creatureSpawnCallback_;
+    CreatureDespawnCallback creatureDespawnCallback_;
     std::vector<uint32_t> knownSpells;
     std::unordered_map<uint32_t, float> spellCooldowns;    // spellId -> remaining seconds
     uint8_t castCount = 0;

include/game/opcodes.hpp

@@ -46,6 +46,7 @@ enum class Opcode : uint16_t {
 
     // ---- Entity/Object updates ----
     SMSG_UPDATE_OBJECT               = 0x0A9,
+    SMSG_COMPRESSED_UPDATE_OBJECT    = 0x1F6,
     SMSG_DESTROY_OBJECT              = 0x0AA,
 
     // ---- Chat ----

include/network/world_socket.hpp

@@ -85,6 +85,10 @@ private:
     // Receive buffer
     std::vector<uint8_t> receiveBuffer;
 
+    // Track how many header bytes have been decrypted (0-4)
+    // This prevents re-decrypting the same header when waiting for more data
+    size_t headerBytesDecrypted = 0;
+
     // Packet callback
     std::function<void(const Packet&)> packetCallback;
 };