The Rollback Reparir Mechanism For MMOG

The traditional MMOG mostly base on C/S mode, in which game states are synchronized easy, but bandwidth bottlenecks and single-point failure are inherent problems of C/S mode. As a kind of distributed computing mode, P2P can offer better scalability, reduce transmission latency and remove the problem of server bottleneck. However, nodes in this machinery cannot make centralize control of game state or fully assure state consistency between different player views. Therefore, it's very complex to maintain the consistency of game states in P2P machinery. For the network instability, synchronization algorithm can not guarantee the game state consistent absolutely. So it has to repair the temporary inconsistencies. And the efficiency of a rollback repair algorithm has an important impact on the performance of synchronization algorithms.The synchronization algorithms can be classified into two types named conservative synchronization algorithms and optimistic synchronization algorithms. Conservative synchronization algorithms cannot guarantee real-time interaction in games, so optimistic synchronization algorithms are adopted more frequently in MMOG. It needs an efficient rollback repair algorithm to fix the inconsistencies according to the features of optimistic synchronization algorithms. This dissertation analyses the synchronization schemes from home and abroad and mainly finishes the following works:(1) For detects inconsistencies, a Timewarp algorithm based on an awareness model is proposed. According to the different consistency requirements of levels which in awareness model and the effect of the object which in game environment, the algorithm analyses and filters the late events, only part of latency events trigger game state rollback. The improved algorithm not only reduce the rollback number effectively and decrease the traffic of network, but also guarantee the efficient implementation of the player nodes, and maintain the game's states consistency.(2) For repairs the inconsistent game states, this paper proposes dirty region technique to accelerate the speed of rendering, and uses the technology of animation mixed to fix the screen smoothly. So it can be guarantee the transparency of rollback process as well as the consistency of game states.(3)The algorithm which proposed in this paper is achieved. This paper makes experiments in the campus network environment. .The results show that the algorithm can decrease the number of rollback greatly, increase the interactivity and uplifts playability of the game to some extent. And the number of jumping and back-off phenomenon is decreased evidently in game session.