KR20050068360A - Method for synchronization in network game and computer readable medium storing game program in which the synchronization method is implemented - Google Patents

Abstract

The present invention relates to a method for synchronizing a game environment provided by a plurality of game clients constituting an online game, and to a computer readable recording medium recording a game program on which the method is implemented. Synchronization method of each game client comprising the steps of setting a packet buffer consisting of its own packet buffer and an external packet buffer; Receiving a game start signal from the game server, when the game is played, the self-generated frames are sequentially stored in its own packet buffer and transmitted to the other game client, and the externally generated frames received from the other game client are sequentially stored in the external packet buffer. ; And after the first packet is stored in its own packet buffer, after a frame time corresponding to a predetermined number of frames (Ts) has elapsed, the corresponding packets are extracted from the own packet buffer and the external packet buffer according to the basic frame rate, and processed. It is configured to include the steps to proceed.

According to the present invention, while maintaining the basic frame rate at 60 frames per second, it is possible to eliminate most packet delays due to deterioration of the network environment, and to achieve game synchronization that provides the same environment to multiple game clients.

Description

Method for synchronization in network game and computer readable medium storing game program in which the synchronization method is implemented

The present invention relates to an online game using a network, and more particularly, to a method for synchronizing a game environment provided by a plurality of game clients constituting an online game, and to a computer readable recording medium recording a game program on which the method is implemented. It is about.

A game is a competition in which players have a common goal and compete according to certain rules. And, computer games are those in which one or more players compete in a computer-generated chapter, following a computer-generated rule for a common goal presented by the computer. Early computer games were played by one or two players in the same space by game programs running on game machines or personal computers. However, with the development of networks including the Internet, online network games have emerged as a new type of game involving multiple players located in different spaces in one game. In the case of such a network game, the game is played in an integrated field through the network, but since a plurality of players (or game clients) who play the game are actually located in different spaces, the action of one player is different from the other player. The problem of synchronization arises so that they can be recognized at the same time.

Among the online games, in the case of RPG (Role Playing Game) or strategy simulation game, all game clients access and operate the game server, and each game client exchanges packets only with the game server and displays the screen displayed by each game client. Does not match each other. In the case of such games, the game server and the game clients perform a game in a one-to-many synchronization. The action that occurs in a specific game client due to a time delay caused by network transmission is caused by the game server and all game clients. However, in the case of the above games, such a time difference does not significantly affect the overall game progression, and therefore, synchronization for accurately compensating for a time difference of several hundred ms or less is not considered.

On the other hand, in a game in which one-to-one or multiple players are divided into two sides to compete, it is very important to provide the same game environment on both sides for fair progress of the game. In particular, in games where very fast continuous motions are required, such as 3D competitive games, the motions between players located at remote locations need to be matched by a unit of time of several ms or less. Therefore, in the case of such games, the server intervenes only in the preparation process of the game, and during the actual game, the server exchanges only necessary packets between game clients without the server's intervention.

In the case of a network game such as a competitive game, each game client manages video and IO shared packet data consisting of 60 frames per second. Each frame is assigned a serial number of a time concept. In this case, it is necessary to keep the frames that are generated and processed by themselves and the frames transmitted and processed from other game clients to have the same serial number for synchronization of the game. However, because the transmission speed and signal quality of the network are not always constant, it is not easy to process frames transmitted from other game clients by matching their generated frames and serial numbers while maintaining 60 frames per second.

Conventional schemes for solving this synchronization problem are as follows.

The first is to reduce the frame rate of 60 frames per second to 20 frames per second. This method is very simple and can be synchronized clearly, but the quality of the game is reduced because the video playback rate is reduced.

Second, the frame skip rate is controlled in consideration of the network speed to send and receive packets. This method is not only complicated to implement, but also changes the frame skip rate if the network is not uniform and variable, resulting in packet delays (where packet delays arrive at packets of the corresponding serial number transmitted over the network at the point where they need to be handled). It means that the processing is delayed.) Moreover, this is not a fundamental solution to improving the quality of the game like the first.

The present invention has been made to solve the above problems, and a plurality of game clients who play network games can synchronize the game while maintaining a maximum frame rate of 60 frames per second for video and IO shared packets and minimizing packet delay. It is an object of the present invention to provide a method for synchronizing in a network game and a computer-readable recording medium for recording a game program on which the method is implemented.

In order to achieve the above objects, a synchronization method in a network game consisting of a game server and a plurality of game clients according to the present invention comprises: (a) each game client sets a packet buffer consisting of its own packet buffer and an external packet buffer; step; (b) Upon receiving a game start signal from the game server, the game server transmits its own frames to the other game client while sequentially storing them in its own packet buffer, and sequentially sends the externally generated frames received from the other game client to the external packet buffer. Storing; And (c) after the first packet is stored in the own packet buffer and a frame time corresponding to a predetermined number of frames Ts elapses, corresponding packets are fetched from the own packet buffer and the outer packet buffer according to the basic frame rate. And progressing the game by processing.

In step (c) of the synchronization method in the network game, if there is no packet corresponding to an external packet buffer, packets corresponding to a predetermined number of frames Ts in its own packet buffer are returned to another game client at a basic frame rate. Characterized in that the transmission.

Further, in the synchronization method in the network game, the predetermined number of frames Ts is

Determined by

Hereinafter, a preferred embodiment of a synchronization method in a network game according to the present invention will be described in detail with reference to the accompanying drawings.

First, according to FIG. 1, a network game in which a synchronization method according to the present invention is implemented is composed of a game server 10 and a plurality of game clients 30a and 30b connected by a network 20. In FIG. 1, two game clients are illustrated, but the present invention is not limited thereto, and three or more game clients may play the game together.

The game server 10 registers a game player who wants to play a game and provides a list of games to download a game selected by the game player to the game player's computer, allow the game player to select a game opponent, and manage game play. And so on. However, since the functions and actions of the game server 10 are outside the scope of the present invention, the functions of the game server 10 described above do not limit the scope of the present invention. However, the game server 10 according to the present invention provides an environment in which the first game client 30a and the second game client 30b can play a mutual game. The role of relay is no longer played.

The first game client 30a and the second game client 30b are computer systems of game players located remotely from each other, and programs necessary for running the same game are installed. Programs necessary for the progress of the game may be downloaded from the game server 10 via the network 20, or may be installed through a compact disc provided via offline. The game clients 30a and 30b proceed with the game while processing video and IO shared packet data consisting of 60 frames per second (base frame rate). Each frame created after the game starts is assigned a serial number.

In order to implement a synchronization method in a network game according to the present invention, a game program installed in the game clients 30a and 30b sets and manages a packet buffer including its own packet buffer and an external packet buffer in a memory. The own packet buffer is for sequentially storing frames generated by the game client itself, and the outer packet buffer is for sequentially storing external generated frames received from other game clients. The external packet buffer is separately set and managed by the number of other game clients.

In this case, the size of the buffer is preferably determined according to the transmission speed of the network 20 in units of frames. That is, the number Ts of frames stored in each buffer is determined by the following equation.

In Equation 1, the response time with other game clients is the total time of sending and receiving messages between the game client and other game clients using the ping command, and the frame time is the inverse of the basic frame rate (1/60). Seconds, and α is an extra value, suitable for about 2 frame times.

Since the size of each buffer in the above description is for managing valid frames, the size of the buffer in the actual implementation may vary depending on the implementation manner. That is, it is possible to set and manage pointers (e.g., input frame pointers and output frame pointers) that display Ts as many valid frames as a larger size buffer or manage them as buffers in the form of circular queues. .

Each game client 30a, 30b responds from its own packet buffer and an external packet buffer according to the base frame rate after a frame time corresponding to a predetermined number of frames Ts after the first packet is stored in its own packet buffer. The game proceeds by withdrawing and processing packets. Therefore, unless there is a fatal problem of not receiving externally generated frames at all during the Ts time, even if there is a small change in the network, the packet delay is eliminated through the buffer function of the packet buffer. That is, at the time of processing the packet according to the basic frame rate, all packets are already prepared in the packet buffer.

In addition, when there is no packet corresponding to the external packet buffer when a packet stored in the packet buffer is to be processed, packets corresponding to a predetermined number of frames (Ts) in the own packet buffer are repeatedly transmitted to other game clients at a basic frame rate. By transmitting, the fatal problem is eliminated and the game client is automatically synchronized when the game is played again.

Hereinafter, an operation process of a synchronization method in a network game according to the present invention will be described. Here, it is assumed that the network game is played by the game server 10 and the two game clients 30a and 30b as shown in Fig. 1, and Ts is determined to be five.

2 illustrates a packet buffer of the first game client 30a and a packet buffer of the second game client 30b immediately after the game is started when the first game client 30a and the second game client 30b simultaneously play the game. Is a timing diagram showing a time point at which a frame is stored. 2, frames 1, 2, 3, 4, 5, and 6 are generated by the first game client 30a, and frames 1 ', 2', 3 ', 4', 5 ', and 6' are second. It is generated by the game client 30b. In addition, frames 1,2,3,4,5,6 are transmitted from the first game client 30a to the second game client 30b, and the frames 1 ', 2', 3 ', 4', 5 ', 6 'is transmitted from the second game client 30b to the first game client 30a. The packet buffer of each game client at T ₀ of FIG. 2 is empty as shown in FIG. 2A. Further, the same as Figure 2 in _{T 1, T 3, T 5} , the state of the packet buffer for each of the game client from T ₆ is Figure 2b, Figure 2c, respectively, Fig. 2d and Fig 2e. In T3, the first game client 30a has not yet arrived at the frame 3 ', and according to the conventional method, a packet delay of d is generated according to the conventional method. However, in the present invention, the buffer function of the packet buffer is not a problem at all. The first game client 30a and the second game client 30b both play the game by extracting and processing frames 1 and 1 'from the packet buffer at T ₅ , and processing and processing frames 2 and 2' from T _6. By playing the game.

3 illustrates a packet buffer of the first game client 30a and the second game client 30b immediately after the game is started when the first game client 30a and the second game client 30b play a game at different time points. It is a timing chart which shows the time point at which a frame is stored in a packet buffer. According to FIG. 3, frame 1 'is stored in the packet buffer until frame 4 is stored in the packet buffer in the first game client 30a. Even in such a case, in T ₅ of FIG. 3, as shown in FIG. 3A, a game is played by drawing frames 1 and 1 ′ from the packet buffer having the same condition.

FIG. 4 is a timing diagram illustrating a state in which the second game client 30b cannot play a game even after the first game client 30a stores all the frames 1,2,3,4,5 in the packet buffer. Since the first game client 30a does not have a packet to be processed in the external packet buffer at T ₅ of FIG. 4 (see FIG. 4A), instead of processing the packet to proceed with the game, packets 1, 2, 3, 4, and 5 are again processed. It transmits to the 2nd game client 30b according to a basic frame rate. This transmission process is repeated until the first game client 30a draws all the frames 1 and 1 'from its packet buffer.

FIG. 5 is a timing diagram illustrating a state in which the second game client 30b, which is playing the game simultaneously with the first game client 30a, generates only the frame 120 'and cannot proceed any further. The state of the packet buffer of each game client in T ₁₂₀ of FIG. 5 is the same as that of FIG. 5A, but the state of the packet buffer of each game client in T ₁₂₅ of FIG. 5 is the same as that of FIG. 5B. Since there is no packet to be processed in the external packet buffer in T ₁₂₅ of FIG. 5, the first game client transmits packets 121, 122, 123, 124, and 125 to the second game client 30b again according to the basic frame rate instead of processing the packet. This transmission process is repeated until the first game client 30a draws all the frames 121 and 121 'from its packet buffer.

Meanwhile, the embodiments of the present invention described above may be recorded in a medium used in a general purpose computer including a personal computer. The medium may be a magnetic recording medium (e.g., ROM, floppy disk, hard disk, etc.), an optical reading medium (e.g., CD-ROM, DVD, etc.), an electrical recording medium (e.g., flash memory, memory stick, etc.) And record carriers such as carrier waves (eg, transmission over the Internet).

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

According to the present invention, while maintaining the basic frame rate at 60 frames per second, it is possible to eliminate most packet delays due to deterioration of the network environment, and to achieve game synchronization that provides the same environment to multiple game clients.

1 illustrates a system environment in which a network game in which a synchronization method according to the present invention is implemented is performed.

FIG. 2 is a timing diagram illustrating when frames are stored in the packet buffer of the first game client and the packet buffer of the second game client immediately after the game starts when the first game client and the second game client simultaneously play the game.

2A to 2E show the state of the packet buffer of each game client at T ₀ , T ₁ , T ₃ , T ₅ , and T ₆ of FIG. 2, respectively.

FIG. 3 is a timing diagram illustrating a time point at which frames are stored in a packet buffer of a first game client and a packet buffer of a second game client immediately after a game is started when the first game client and the second game client play a game at different times. to be.

FIG. 3A shows the state of the packet buffer of each game client at T ₅ of FIG. 3.

FIG. 4 is a timing diagram illustrating a state in which a second game client cannot play a game even after the first game client stores all the frames 1,2,3,4,5 in the packet buffer.

4A shows the state of the packet buffer of each game client at T ₅ of FIG. 4.

FIG. 5 is a timing diagram illustrating a state in which the second game client, which is playing the game simultaneously with the first game client, generates only up to frame 120 'and cannot proceed any further.

5A and 5B show the state of the packet buffer of each game client at T ₁₂₀ and T ₁₂₅ of FIG. 5, respectively.

Claims (4)

In the synchronization method in a network game consisting of a game server and a plurality of game clients, (a) each game client setting a packet buffer consisting of its own packet buffer and an external packet buffer; (b) Upon receiving a game start signal from the game server, the game server transmits its own frames to the other game client while sequentially storing them in its own packet buffer, and sequentially sends the externally generated frames received from the other game client to the external packet buffer. Storing; And (c) After the first packet is stored in the own packet buffer and a frame time corresponding to a predetermined number of frames (Ts) has elapsed, corresponding packets are extracted from the own packet buffer and the outer packet buffer according to the basic frame rate. And synchronizing the game by processing the network game. The method of claim 1, wherein in step (c) If there is no packet corresponding to the external packet buffer, a packet corresponding to a predetermined number of frames Ts in its own packet buffer is transmitted to another game client at a basic frame rate. The method according to claim 1 or 2, wherein the predetermined number of frames Ts is A method of synchronizing in a network game, characterized by. A computer-readable recording medium recording a game program in which the method of claim 1 is implemented.