Solved

Network Interpolation

Posted on 1998-12-21
13
363 Views
Last Modified: 2013-11-20
How can I achieve a good network interpolation for realtime games. I want to write code that does the same that is done in Quake. If you have packet loss or if packets arrive in a wrong order the game should still behave approximately as it usually behaves (as in Quake). Please help.
0
Comment
Question by:MarcoHelmers
  • 7
  • 4
  • 2
13 Comments
 
LVL 4

Expert Comment

by:nil_dib
ID: 1326504
Why dont you use stream sockets?
Are you sure that games like quake works with datagram sockets?
0
 
LVL 86

Expert Comment

by:jkr
ID: 1326505
My usual answer to this kind of problem is taking a look at RPC, which makes life easier concerning all the different network transports (TCP, IPX, NetBios etc.)... You might want to take a look at the 'Hello' sample that comes with VC++ ('\DEVSTUDIO\VC\SAMPLES\SDK\RPC\HELLO') before we continue...
0
 
LVL 86

Expert Comment

by:jkr
ID: 1326506
nil_dib - sockets are usually OK, but what to do if there's no TCP/IP installed...?
0
 
LVL 4

Expert Comment

by:nil_dib
ID: 1326507
mhh but in MFC I have socket support for DECNet, TCP/IP, IPX/SPX, NetBui ...
I think its also a problem to decide on which layer to put on ..4,5,6 ...
0
 

Author Comment

by:MarcoHelmers
ID: 1326508
I think you did not understand my problem. I have no problem sending packets or so (I use DirectPlay) ... I only want to know how to interpolate movement in a realtime (3D) game like Quake when you have situations where packets arrive very late (e.g. internet) ! In Quake the server in some way interpolates the movement of the clients so that the game seems to run smooth (even if no packets arrive for a while !!). Can you tell me a good way how to do it ?
0
 
LVL 86

Expert Comment

by:jkr
ID: 1326509
I'd recommend keeping track of the recent packets and 'extrapolate' the movement sequence from the behaviour in the near past (liear or nonlinear, depends on what applies better...)
0
Maximize Your Threat Intelligence Reporting

Reporting is one of the most important and least talked about aspects of a world-class threat intelligence program. Here’s how to do it right.

 

Author Comment

by:MarcoHelmers
ID: 1326510
Does that really help ? What if a person ran directly towards a wall and shortly before he can turn around no packets arrive any longer ? Shall he run against the wall for a few seconds ?
0
 
LVL 86

Expert Comment

by:jkr
ID: 1326511
Nope ;-)
But the player has to remain there, as you hardly can make an assumption on what could be done...
0
 

Author Comment

by:MarcoHelmers
ID: 1326512
Ok ... perhaps I did not completely understand you proposal ... could you explain it more precisely or perhaps even give some pseudo-coude to illustrate it ?
0
 
LVL 86

Expert Comment

by:jkr
ID: 1326513
OK ;-)
Think of the following:
- you maintain a list of the last (let's say 2 for explanation purposes...) movement notifications

if there's a packet, all's well, add it to the list & remove the last

if there's no packet, calculate the (vectorial) difference of the last 2 moves and add the difference to the last move to create a new one and use it as if it was the arrived packet (this e.g. helps to maintain a circular movement - ok, it _could_ turn out to give a rediculus result)

if you decide to use more moving states, it might come in handy to treat them as a vectorial signal and use signal processing algorithms to extrapolate it (you see, i usually don't write games, but have done quite a lot signal processing... ;-)
0
 
LVL 86

Expert Comment

by:jkr
ID: 1326514
Hmm, what's gonna happen with this Q? ;-)
0
 

Author Comment

by:MarcoHelmers
ID: 1326515
Ok ... it would have been great if there would have been other ideas and suggestions but as this is not the case:
jkr: Please lock the question so that I can give you the points.
0
 
LVL 86

Accepted Solution

by:
jkr earned 150 total points
ID: 1326516
Thanx ;-)

BTW/PS: 'MarcoHelmers' sounds quite 'german', so: 'Gruß aus Schwaben' ;-)
0

Featured Post

6 Surprising Benefits of Threat Intelligence

All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

Join & Write a Comment

Suggested Solutions

Here is how to use MFC's automatic Radio Button handling in your dialog boxes and forms.  Beginner programmers usually start with a OnClick handler for each radio button and that's just not the right way to go.  MFC has a very cool system for handli…
This is to be the first in a series of articles demonstrating the development of a complete windows based application using the MFC classes.  I’ll try to keep each article focused on one (or a couple) of the tasks that one may meet.   Introductio…
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Excel styles will make formatting consistent and let you apply and change formatting faster. In this tutorial, you'll learn how to use Excel's built-in styles, how to modify styles, and how to create your own. You'll also learn how to use your custo…

758 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now