> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > Derek Evan Mart > Sent: 21 November 2005 15:36 > To: [email protected] > Subject: [hlds_linux] facts about demos > > I apologize that this is not having to do with the > development of hlds_l or really anything that has been > discussed on this list up to this point. I need factual > information about how the client receives game packets from > the server, how the client records them into a demo, and then > how lag might affect a demo, giving the appearance of cheating.
I will see what I can do. > Someone posted a demo on my forums of someone that might have > been cheating. The question has come up that lag may have > caused the demo to look like it did. What has happened is > that while aiming at one player, a shot was fired, bullet > sound made, the player next to the one being targeted is > killed, then the shooter's crosshair moves to the player that > just died (with a delay) and back again. It is more obvious > when using the slow play feature of viewdemo to spot it and > then again in regular time. Set cl_interpolate 0, cl_interp 0.01, cl_smooth 0, cl_smoothtime 0.01 and view again. It is entirely possible that you are seeing a screw up with the prediction system, along with a slight oddity of the netcode. The other possibility is that the bullet did not fire in a straight line - they don't always in Source. > Here is how I think it works; I would like confirmation on > this. Demo's aren't actually real time video recordings of > what the client sees. No, they are recordings of what the server sends the client, but they are played in the same way the client would play it normally, i.e. with interpolation, prediction and so on, AFAIK. (tests did seem to verify this too, although that was a while ago). > They are in fact a recording of event > information that is used by the client to reconstruct the > events as they unfold. My evidence is that one can't view a > demo that has maps and models that aren't already on the > client's machine. This is indeed true, although the content is addressed by name, so it _can_ be added to another client. > Therefore, there is no video recording > going on at all, Correct. > and due to the nature of TCP sending data to > the application layer in the order they were intended to be > received, I conclude that packet loss does not affect a demo > recording. Actually, it's UDP, and yes, packet loss can affect a client recorded demo. Source has it's own handler for dealing with UDP datagrams, their reliability and ordering, based on "ticks". > Is this correct? Will the server send this event > information out of order? It can, but it should be re-ordered by the client. Certain effects are client side, and certain effects are server side. Some effects are also rendered irrespective of your cl_interp settings (e.g. scores and death messages). > Am I way off base here? No, not way off, I'd suggest reading this: http://developer.valvesoftware.com/wiki/Source_Multiplayer_Networking > I really need closure on this because this player has been a > regular for a long time. Irregularities in timing are unlikely to be cheats, most of the Source cheats out there at the moment are aimbots, not lagbots. > Again, I know this isn't an anti-cheating discussion group. I > don't want to know if they player is cheating. I want to know > if lag can affect the demo in this manner. It is my belief that it is possible yes. > I can provide the demo for reference per request. Please, just for interests sake. > > Best, > -Marticus > > -- > "An investment in knowledge always pays the best interest" > - Benjamin Franklin > (1706-1790) Derek Evan Mart Systems Administrator U of L - > Electrical & Computer Engineering The Marticus Project - > http://www.marticus.org/ > 1514 3659 D057 D10C 6BE6 3E68 15BE B181 2F1F 510B AA C4 72 > 14 97 6F 14 14 B3 9C BB 6E D8 71 9A 67 > > _______________________________________________ > To unsubscribe, edit your list preferences, or view the list > archives, please visit: > http://list.valvesoftware.com/mailman/listinfo/hlds_linux _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: http://list.valvesoftware.com/mailman/listinfo/hlds_linux
