物理模擬之網路同步

Abstract

在這篇論文中，我們實做了幾種針對物理模擬之網路同步化的解決方法，並應用在我們所設計的射擊遊戲上。首先，我們先設計小規模物理模擬的遊戲並實做網路同步化的方法，由於我們可以記錄小規模物理模擬每個時間點的資訊，所以在按鍵發生時我們可以只傳送按鍵和按鍵所發生的時間點給其他玩家，其他玩家在收到這兩個資訊後，先把時間點退回到收到按鍵所發生的時間點，再從這個時間點開始計算收到的按鍵，一直算回到現在的時間點以解決同步化的問題。接著我們設計大規模物理模擬的遊戲並實做網路同步化的方法，由於我們不可能記錄大規模物理模擬每個時間點物體的資訊，所以我們勢必要傳送更多的資訊才可以達到同步化的要求，為了達到同步化，我們會傳送有被影響物體的資訊，如物體號碼、物體位置和物體數目等給其他玩家。在大規模的遊戲裡，由於玩家與玩家之間他們也會彼此互相影響，而我們是讓號碼小的玩家來決定玩家互相影響區域間物體的資訊，然後號碼小的玩家會傳送玩家互相影響區域間物體的正確資訊給其他玩家，結果顯示我們可以讓各個玩家間達到同步化的效果。

In this thesis, we implement some solutions about network synchronization of physical simulation. The solutions are proposed as follows. Firstly, we propose methods to achieve the game of small-scale. We send key press events and the associated time steps to the other players because we record all of the data at every time step in a small-scale game. When the other players receive the data, they will move backward to the specified time steps. Then, they will calculate the received key press and move forward to the current time step. Thus, the synchronization between the players is achieved. Secondly, we propose method to achieve the game of large-scale. We do not record all of the data at every time step in large-scale game because of the limit of the memory capacity. Therefore, we have to send lots of data to synchronize the game. We send all the data of affected objects, e.g. object ID, object position, and number of affected objects to the other players. In a large-scale game, players may interact with each other. In this situation, the player whose ID is the smallest will have the authority of the objects in the interacted region. The player whose ID is the smallest will send the correct data in the interacted region to the other players. The experiments show that we can synchronize every player in the game.