• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>

            天行健 君子當自強而不息

            Getting Online with Multiplayer Gaming(13)

             

            cApp::remove_player

            Just as players join the game, so do players quit, and that’s the purpose of the
            remove_player function. In the remove_player function, the server will scan the list of
            connected players for a match of a DirectPlay identification number (from the disconnecting
            player) and remove that player from the list. After the scan is complete
            and the appropriate player is removed from the list, all clients are notified of the
            disconnecting player, and the server rebuilds a list of existing players.

            void cApp::remove_player(const sMsg* msg)
            {
                
            // search for player in list
                for(long i = 0; i < MAX_PLAYERS; i++)
                {
                    
            if(m_players[i].player_id == msg->header.player_id && m_players[i].connected)
                    {
                        m_players[i].connected = 
            false;

                        
            // send remove player message to all players

                        sDestroyPlayerMsg destroy_msg;

                        destroy_msg.header.type      = MSG_DESTROY_PLAYER;
                        destroy_msg.header.size      = 
            sizeof(sDestroyPlayerMsg);
                        destroy_msg.header.player_id = msg->header.player_id;

                        send_network_msg(&destroy_msg, DPNSEND_NOLOOPBACK, ALL_CLIENT_PLAYERS);

                        m_connected_player_num--;
                        list_players();

                        
            break;
                    }
                }
            }
             

            cApp::send_player_info

            Unfortunately, in network gaming, game messages sometimes get lost along the
            way. What if one of those lost messages intended to inform the client application
            that a player had joined the game? Furthermore, what if the client started receiving
            messages related to a player that the client didn’t know existed (because of a lost
            message)?

            In cases where the client has no knowledge of a player and is receiving messages
            related to that player, the client will request the appropriate player’s data from the
            server in order to continue. The server, in turn, will send the requested player’s
            information to the client using the send_player_info function:

            bool cApp::send_player_info(const sMsg* msg, DPNID to)
            {
                sRequestPlayerInfoMsg* request_msg = (sRequestPlayerInfoMsg*) msg;

                
            for(long i = 0; i < MAX_PLAYERS; i++)
                {
                    
            // only send if found in list
                    if(m_players[i].player_id == request_msg->request_player_id && m_players[i].connected)
                    {
                        
            // send player infomation to requesting player

                        sCreatePlayerMsg create_msg;

                        create_msg.header.type      = MSG_SEND_PLAYER_INFO;
                        create_msg.header.size      = 
            sizeof(sCreatePlayerMsg);
                        create_msg.header.player_id = request_msg->request_player_id;
                        create_msg.x_pos            = m_players[i].x_pos;
                        create_msg.y_pos            = m_players[i].y_pos;
                        create_msg.z_pos            = m_players[i].z_pos;
                        create_msg.direction        = m_players[i].direction;

                        send_network_msg(&create_msg, DPNSEND_NOLOOPBACK, to);

                        
            break;
                    }
                }

                
            return true;
            }
             

            cApp::player_state_change

            The major message-processing function in the server must be player_state_change,
            which takes incoming actions from the clients and updates the internal player data.

            bool cApp::player_state_change(const sMsg* msg)
            {
                
            // get player index in list
                long player_index = -1;
                
                
            for(long i = 0; i < MAX_PLAYERS; i++)
                {
                    
            if(m_players[i].player_id == msg->header.player_id && m_players[i].connected)
                    {
                        player_index = i;
                        
            break;
                    }
                }

                
            if(player_index == -1)
                    
            return false;

                sPlayer* player = &m_players[player_index];

                
            bool allow_change = true;
                
                
            // refuse to update player if swinging sword or hurt
                if(player->last_state == STATE_SWING || player->last_state == STATE_HURT)
                    allow_change = 
            false;    

                
            // only change state if allowed
                if(! allow_change)
                    
            return false;

                sStateChangeMsg* change_msg = (sStateChangeMsg*) msg;

                
            // update selected player
                player->last_update_time = timeGetTime();
                player->last_state       = change_msg->state;
                player->direction        = change_msg->direction;

                
            // adjust action time based on latency
                player->last_update_time -= player->latency;

                sStateChangeMsg state_msg;

                
            // send player data to all clients
                state_msg.header.type      = MSG_STATE_CHANGE;
                state_msg.header.size      = 
            sizeof(sStateChangeMsg);
                state_msg.header.player_id = change_msg->header.player_id;
                state_msg.state            = player->last_state;
                state_msg.x_pos            = player->x_pos;
                state_msg.y_pos            = player->y_pos;
                state_msg.z_pos            = player->z_pos;
                state_msg.direction        = player->direction;
                state_msg.speed            = player->speed;

                send_network_msg(&state_msg, DPNSEND_NOLOOPBACK, ALL_CLIENT_PLAYERS);

                
            if(change_msg->state != STATE_SWING)
                    
            return true;

                
            // If swinging sword, determing who is hurt, check all players.
                for(long i = 0; i < MAX_PLAYERS; i++)
                {
                    
            // only check against other players that are connected
                    if(i == player_index || !m_players[i].connected)
                        
            continue;

                    
            // get distance to player
                    float x_diff = fabs(player->x_pos - m_players[i].x_pos);
                    
            float z_diff = fabs(player->z_pos - m_players[i].z_pos);
                    
            float dist   = x_diff * x_diff + z_diff * z_diff;

                    
            // continue if distance between players acceptable
                    if(dist >= 10000.0f)
                        
            continue;

                    
            // get angle between players
                    float angle = -atan2(m_players[i].z_pos - player->z_pos, m_players[i].x_pos - player->x_pos) + 1.570796f;

                    angle -= player->direction;     
            // adjust for attacker's direction
                    angle += 0.785f;                // adjust for FOV

                    // bounds angle value
                    if(angle < 0.0f)        angle += 6.28f;
                    
            if(angle >= 6.28f)      angle -= 6.28f;

                    
            // player hit if in front of attacker (90 FOV)
                    if(angle >= 0.0f && angle <= 1.570796f && m_players[i].last_state != STATE_HURT)
                    {
                        m_players[i].last_state = STATE_HURT;
                        m_players[i].last_update_time = timeGetTime();

                        
            // send network message
                        state_msg.header.type      = MSG_STATE_CHANGE;
                        state_msg.header.size      = 
            sizeof(sStateChangeMsg);
                        state_msg.header.player_id = m_players[i].player_id;
                        state_msg.state            = m_players[i].last_state;
                        state_msg.x_pos            = m_players[i].x_pos;
                        state_msg.y_pos            = m_players[i].y_pos;
                        state_msg.z_pos            = m_players[i].z_pos;
                        state_msg.direction        = m_players[i].direction;
                        state_msg.speed            = m_players[i].speed;

                        send_network_msg(&state_msg, DPNSEND_NOLOOPBACK, ALL_CLIENT_PLAYERS);
                    }
                }

                
            return true;
            }

            Up to this point, the server has looked for the player that uses the state-change
            message. If a message is coming from a player who is not connected, the message
            is ignored. From now on, the game’s logic takes over.

            Players are allowed to walk, stand still, or swing their weapons. Players whose states
            are already set as swinging their weapons or being hurt are not allowed to update
            their states (until those states are cleared).

            Now the player’s state is updated (if allowed) and sent out to all other connected
            players. Next, if the player has swung his weapon, all players are scanned to see
            whether the attacker hit them. If so, the states of those hurt are changed to HURT.

            Also, notice that I offset the state’s time variable (sPlayer::last_update_time) by the player’s
            latency value (sPlayer::latency). This adjusts for network transmission delays and
            improves synchronization. If you remove the latency offset, you’ll see a jumping
            effect when players are moving around the level.

            Note that players who are swinging their swords have a chance to hit the players in
            front of them. To check whether another player was hit during an attack, you first
            perform a distance calculation, and if any characters are considered close enough,
            the angles between the players are checked. If the players being attacked are within
            a 90-degree field of view in front of the attackers (as illustrated in Figure 19.14),
            they are considered hit, at which point, those victims’ states are changed to HURT.

            And that’s it for dealing with the game messages and state changes in players.
            Although the player_state_change function is responsible for parsing the queued game
            messages, it’s really up to another function to move players and clear their swinging
            or hurt states, as you see in the following section.

            posted on 2007-12-18 22:39 lovedday 閱讀(237) 評論(0)  編輯 收藏 引用

            公告

            導航

            統計

            常用鏈接

            隨筆分類(178)

            3D游戲編程相關鏈接

            搜索

            最新評論

            久久亚洲国产精品成人AV秋霞| 国产精品无码久久久久| 久久笫一福利免费导航| 国产A级毛片久久久精品毛片| 久久性生大片免费观看性| 久久人人爽人人爽人人爽| 亚洲国产精品成人久久| 一本久久久久久久| 久久人妻少妇嫩草AV蜜桃| 久久香蕉国产线看观看乱码| 亚洲欧洲精品成人久久曰影片 | 天天躁日日躁狠狠久久| Xx性欧美肥妇精品久久久久久| 久久久久亚洲精品日久生情| 日韩精品久久久久久| 色狠狠久久AV五月综合| 无码精品久久一区二区三区 | 亚洲成人精品久久| 久久九九兔免费精品6| 94久久国产乱子伦精品免费| 久久人人爽人人爽人人片AV东京热| 伊人久久大香线焦综合四虎| 久久成人国产精品免费软件| 亚洲国产日韩欧美久久| 久久毛片免费看一区二区三区| 久久青青草原精品国产| 婷婷久久久亚洲欧洲日产国码AV| 亚洲欧美日韩精品久久亚洲区| 久久精品中文字幕第23页| 亚洲国产天堂久久综合网站| 久久99精品国产99久久6男男| 久久久久久毛片免费播放| 亚洲国产精品高清久久久| 久久精品国产亚洲av麻豆图片| 香蕉久久夜色精品国产2020| 久久久久亚洲AV无码去区首| 久久久久国产亚洲AV麻豆| 久久综合亚洲色HEZYO国产| 一本一道久久a久久精品综合| 亚洲国产成人久久精品99 | 国内精品久久久久久中文字幕 |