For a real flight playback, if attitude accuracy is not so important, only GPS position data (one shot every second) is enought for a smooth FG playback (if no acrobatics have been perform...).
I think this playback function could be a nice for the debriefing of Flight Intructors who let their students for their first solo country flight. Spy on board... ----- Original Message ----- From: "Roberto Manca" <[EMAIL PROTECTED]> To: "FlightGear developers discussions" <[EMAIL PROTECTED]> Sent: Tuesday, August 24, 2004 3:11 PM Subject: Re: [Flightgear-devel] Re: Bypass FG Physics and Draw > While the idea is correct in principle, what you said > it is not so straightforward. > > I've realised a flight recorder and a flight player > for Flightgear for my thesis so I played around with > few ideas. Basically I developed a virtual cockpit in > a distributed environment that uses Flightgear to have > some 'meaningful' flight data. I had to test different > configurations so I needed to use always the same data > that is to fly always the same flight. > > My experience is that it's very difficult to > synchronise Flightgear with an > initial-position-and-flight-command approach since the > only cross-platform means of communication available > is the socket. You always end up with a time shifting > of the packets that produces a space shifting of the > flight. Therefore sometimes you try to manouevre into > a mountain while you did't in the original flight. > Now what i've done is to record, through a socket, all > the flight at an accettable frame rate onto a file by > using the native-fdm data structure. (this is the > recorder). Then I wrote a player that reads the file > and sends the data over to Flightgear (previously set > up with the external-fdm option). It works quite well > apart from some adjustment in the speed of replay you > need to experiment with. > > Roberto > > --- Harald JOHNSEN <[EMAIL PROTECTED]> ha scritto: > > [EMAIL PROTECTED] wrote: > > > > > Does this mean that we would have the ability to > > save and load flight > > > data so as to reproduce, say, a taxi, take off, > > pattern and landing at > > > KSFO or another airport automatically (i.e., as a > > demo or as a > > > training exercise). Perhaps a short flight around > > the SF area also > > > showing off the new scenery? > > > > > > Could we ship such flights around scenic areas > > (Mount Ranier, Crater > > > Lake, the Grand Canyon) for new users in the base > > package or as > > > downloadables off of flightgear.org? > > > > > > How big would such files be? How much data needs > > to be kept, how much > > > can be calculated on the fly? Do weather > > conditions need to be saved > > > also? > > > > > > Would flights around scenic areas be done better > > as flight plans with > > > waypoints or tied into this new playback method > > somehow? > > > > > > Can this playback tool be used as a training > > method for new simulator > > > pilots? > > > > > > If we are not saving a real recorded flight, > > perhaps we can use a > > > similar method to extract either entire flights or > > the last XX number > > > of seconds of a flight to save to disk for later > > replay? > > > > > > MS FlightSimulator has an extensive tutorial that > > involves pre-saved > > > flights which the users can break into at certain > > points in the > > > flights. How difficult would it be to add > > something similar to FG and > > > where would one begin (if no one is already > > working on something like > > > this). > > > > > > Thanks! > > > > > > Ima > > > > > > > > > _______________________________________________ > > > Flightgear-devel mailing list > > > [EMAIL PROTECTED] > > > > > > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > > > 2f585eeea02e2c79d7b1d8c4963bae2d > > > > > I think that the ability to "play" a flight recorded > > by an external > > source is different from the ability to save/load a > > flight from FG. > > In other words, I don't think we should save any > > state variable - ie > > parts of totality of the property tree. > > We have an initial state when FG is launched with a > > specific set of > > parameters. Now how do you fly ? You use your > > joystick, mouse, > > keyboard et al to interact with the simulator. So a > > recorded fligth > > could be defined as a list of user interactions > > paired with a time stamp, > > and to be more accurate a very limited set of > > properties could be added > > lets say every 10 or 20 seconds (position, heading, > > etc). > > The advantage would be : > > - short record file size > > - accurate property tree because the simultor > > would run exactly with > > the same imputs > > - easy to implement because it is not tied to > > the internals of the > > simulator (like fdm). > > > > Harald. > > > > > > _______________________________________________ > > Flightgear-devel mailing list > > [EMAIL PROTECTED] > > > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > > 2f585eeea02e2c79d7b1d8c4963bae2d > > > > > > ___________________________________ > Yahoo! Mail: gratis 100 MB per i messaggi e allegati da 10 MB > http://mail.yahoo.it > > _______________________________________________ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > 2f585eeea02e2c79d7b1d8c4963bae2d > _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d