feat(gameplay): implement entity update packets

Add S2CEntityUpdate to sync entity positions from server to client, including update handling in the client entity manager and server-side AI updates.

include/Cubed/gameplay/client_entity_manager.hpp

@@ -10,14 +10,15 @@ namespace Cubed {
 class ClientWorld;
 class ClientEntityManager {
 public:
-    enum class Command { CREATE, DESTORY };
+    enum class Command { CREATE, DESTORY, UPDATE };
 
     ClientEntityManager(ClientWorld& world);
     void update();
     void init();
 
-    void receive_entity_create(S2CEntityCreate& s2c);
+    void receive_entity_create(S2CEntityCreate& msg);
     void receive_entity_destory(EntityID id);
+    void receive_entity_update(S2CEntityUpdate& msg);
 
     void destory(EntityID id);
     void create(std::string_view name, const glm::vec3& pos);
@@ -30,11 +31,17 @@ private:
         std::string name;
         glm::vec3 pos;
     };
+
+    struct UpdateInfo {
+        EntityID id;
+        glm::vec3 pos;
+    };
+
     using EntityMap = tbb::concurrent_hash_map<EntityID, entt::entity>;
     using acc = EntityMap::accessor;
     using cacc = EntityMap::const_accessor;
     using CreateFunc = std::function<void(EntityID id)>;
-    using TaskElement = std::variant<EntityCreateElement, EntityID>;
+    using TaskElement = std::variant<EntityCreateElement, EntityID, UpdateInfo>;
     using TaskPair = std::pair<Command, TaskElement>;
 
     ClientWorld& m_world;
@@ -48,6 +55,7 @@ private:
     // not thread safe
     void handle_entity_create(EntityID id, std::string_view name,
                               const glm::vec3& pos);
+    void handle_entity_update(UpdateInfo& info);
     template <typename... Args>
     void create_entity_in_registry(EntityID id, Args&&... args) {
         {

include/Cubed/gameplay/packet.hpp

@@ -51,10 +51,12 @@ enum class PacketEnum : uint16_t {
     LOGIN_RSP = 1002,
     LOGOUT_REQ = 1003,
     LOGOUT_RSP = 1004,
+
     PLAYER_INFO = 2001,
     C2S_PLAYER_INFO = 2002,
     PLAYER_INFO_RSP = 2003,
     PLAYER_WATER_SOUND = 2004,
+
     CHUNK_DATA_REQ = 3001,
     CHUNK_DATA_RSP = 3002,
     BLOCK_CHANGE_REQ = 3003,
@@ -65,8 +67,11 @@ enum class PacketEnum : uint16_t {
     S2C_ENTITY_DESTORY = 3008,
     C2S_ENTITY_CREATE_REQUEST = 3009,
     C2S_ENTITY_DESTORY_REQUEST = 3010,
+    S2C_ENTITY_UPDATE = 3011,
+
     CHAT_MSG = 4001,
     VOICE_MSG = 4002,
+
     PING = 9001,
     PONG = 9002
 
@@ -145,6 +150,9 @@ template <> constexpr uint16_t get_packet_id<ChatMsg>() {
 template <> constexpr uint16_t get_packet_id<VoiceMsg>() {
     return std::to_underlying(PacketEnum::VOICE_MSG);
 }
+template <> constexpr uint16_t get_packet_id<S2CEntityUpdate>() {
+    return std::to_underlying(PacketEnum::S2C_ENTITY_UPDATE);
+}
 
 template <typename T>
     requires std::derived_from<T, google::protobuf::Message>

include/Cubed/gameplay/server_entity_manager.hpp

@@ -44,6 +44,7 @@ private:
     void handle_entity_destory(EntityID id);
     void handle_task();
     void send_all_entities(std::shared_ptr<Session>& session);
+    void update_ai();
     template <typename... Args>
     EntityID create_entity_in_factory(Args&&... args) {
         auto entity = m_registry.create();

src/gameplay/client_entity_manager.cpp

@@ -36,8 +36,23 @@ void ClientEntityManager::handle_entity_create(EntityID id,
     c->transform.position.value = pos;
 }
 
+void ClientEntityManager::handle_entity_update(UpdateInfo& info) {
+    entt::entity e;
+    {
+        cacc a;
+        if (m_entities.find(a, info.id)) {
+            e = a->second;
+        } else {
+            return;
+        }
+    }
+    auto creature = m_registry.try_get<BaseClientCreature>(e);
+    ASSERT(creature);
+    creature->transform.position.value = info.pos;
+}
+
 void ClientEntityManager::receive_entity_create(S2CEntityCreate& s2c) {
-    EntityCreateElement c;
+    EntityCreateElement c{};
     c.id = s2c.id();
     c.name = s2c.name();
     c.pos = {s2c.pos().x(), s2c.pos().y(), s2c.pos().z()};
@@ -48,6 +63,13 @@ void ClientEntityManager::receive_entity_destory(EntityID id) {
     m_tasks.emplace(Command::DESTORY, id);
 }
 
+void ClientEntityManager::receive_entity_update(S2CEntityUpdate& msg) {
+    UpdateInfo e;
+    e.id = msg.id();
+    e.pos = Tools::get_net_pos(msg.pos());
+    m_tasks.emplace(Command::UPDATE, std::move(e));
+}
+
 void ClientEntityManager::destory(EntityID id) {
     auto client = m_world.get_client();
     Arena arena;
@@ -81,6 +103,11 @@ void ClientEntityManager::handle_task() {
             ASSERT(p);
             handle_entity_destory(*p);
         } break;
+        case Command::UPDATE: {
+            auto* p = std::get_if<UpdateInfo>(&pair.second);
+            ASSERT(p);
+            handle_entity_update(*p);
+        }
         }
     }
 }

src/gameplay/network_client.cpp

@@ -156,6 +156,12 @@ asio::awaitable<void> NetworkClient::read_loop() {
                     m_world.entity_manager().receive_entity_destory(msg->id());
                 }
             } break;
+            case std::to_underlying(PacketEnum::S2C_ENTITY_UPDATE): {
+                auto* msg = Arena::Create<S2CEntityUpdate>(&arena);
+                if (decode_packet(*msg, body_data, header)) {
+                    m_world.entity_manager().receive_entity_update(*msg);
+                }
+            } break;
             }
         }
     } catch (const asio::system_error& e) {

src/gameplay/server_entity_manager.cpp

@@ -22,7 +22,10 @@ void ServerEntityManager::init() {
                                         std::move(c), PigTag{});
     });
 }
-void ServerEntityManager::update() { handle_task(); }
+void ServerEntityManager::update() {
+    handle_task();
+    update_ai();
+}
 
 void ServerEntityManager::handle_task() {
     TaskPair pair;

src/proto/world/entity.proto

@@ -21,4 +21,9 @@ message C2SEntityCreateRequest {
     string uuid = 1;
     string name = 2;
     Vec3 pos = 3;
+}
+
+message S2CEntityUpdate {
+    uint64 id = 1;
+    Vec3 pos = 2;
 }