Hi, My name is Duncan McCreanor. I am employed as a Software Engineer for an Australian company where we have been looking at the possibility of using Flightgear as the basis for an Air Traffic Control visual simulator.
We are in the process of putting together a demonstration of the possibilities that Flightgear provides. As part of the demonstration a colleague and I have been working on the multiplayer aspects of Flightgear. We have produced a working multiplayer version under Linux. The multiplayer code has been created from scratch without using any of the existing multiplayer code. It was felt that the existing multiplayer code was too platform (Unix/Linux) specific and appeared to slow down the frame rate. The multiplayer code we have added uses existing Simgear and plib classes so should be platform independent, although we have not tested it on other platforms and have not allowed for endian issues. The design we have implemented allows players to interact without the need for a server. If the transmit and receive addresses are set to broadcast, it is possible to play multiplayer games on a local network. Point-to-point for two players is also possible across the internet. The ability to send text chat messages to a designated player has been allowed for but not implemented. Although we have not used a server, the design does not need to be changed for use with a server. Command line parameters have been added to set up the multiplayer code. The commands are of the form: --multiplay=in | out,Hz,destination address,destination port --callsign=a_unique_name The code has only just been completed. We plan to further test and enhance it over the next few weeks. When coding/testing is completed, how do we go about getting the changes reviewed and added to Flightgear? Below are some examples of startup commands that demonstrate the use of the multiplayer facilities. For two players on a local network or across the internet: ---------------------------------------------------------- Player1: --multiplay=out,10,192.168.0.3,5500 --multiplay=in,10,192.168.0.2,5501 --callsign=player1 Player2: --multiplay=out,10,192.168.0.2,5501 --multiplay=in,10,192.168.0.3,5500 --callsign=player2 For multiple players on a local network: ---------------------------------------- Player1: --multiplay=out,10,255.255.255.255,5500 --multiplay=in,10,255.255.255.255,5500 --callsign=player1 Playern: --multiplay=out,10,255.255.255.255,5500 --multiplay=in,10,255.255.255.255,5500 --callsign=playern Note that the callsign is used to identify each player in a multiplayer game so the callsigns must be unique. The multiplayer code ignores packets that are sent back to itself, as would occur with broadcasting when the rx and tx ports are the same. Multiple players sending to a single player: -------------------------------------------- Player1: --multiplay=out,10,192.168.0.2,5500 --callsign=player1 Player2: --multiplay=out,10,192.168.0.2,5500 --callsign=player2 Player3: --multiplay=out,10,192.168.0.2,5500 --callsign=player3 Player4 (rx only): --multiplay=in,10,192.168.0.2,5500 --callsign=player4 This demonstrates that it is possible to have multiple instances of Flightgear that send to a single instance that displays all the traffic. This is the sort of implementation that we are considering for use as a tower visual simulator. For use with a server (when one is created): -------------------------------------------- Player1: --multiplay=out,10,serveraddress,6000 --multiplay=in,10,myaddress,5500 --callsign=player1 Player2: --multiplay=out,10,serveraddress,6000 --multiplay=in,10,myaddress,5501 --callsign=player2 Playern: --multiplay=out,10,serveraddress,6000 --multiplay=in,10,myaddress,5502 --callsign=playern The server would simply act as a packet forwarding mechanism. When it receives a packet, it sends it to all other active players. Regards, Duncan. _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
