On Friday 18 July 2003 04:06, Curtis L. Olson wrote: > I have implimented a first stab at an instant replay system and have > just commited it to CVS. The system continuously records your flight > data and allows you to play back your flight. > > Saving flight data at full resolution can quickly burn up a lot of > RAM, so at the moment, only the most recent 60 seconds is stored at > full resolution. The next most recent 10 minutes is stored at a > resolution of one snap shot every 0.5 seconds. The most recent hour > of data is stored at a resolution of one snap shot every 5 seconds. > (We might need/want to tune these values a bit as we use the system > more.) However, this gives the most resolution to the most recent > portion of the flight, and can save up to an hour's worth of flight > data without using a huge amount of memory. > > Each snapshot is time stamped with the simulation time. During > replay, the system finds the two snapshots that straddle the replay > time and linearly interpolates between them. This way, we can record > the data as best as is possible given the current rendering speed, > even with varying frame rates with possible lost frames and aren't > forced to take extraordinary measures to get a consistent sampling > rate. Then when the data is replayed, this interpolation scheme gives > us smooth playback even if the recorded frame rate is wildly (or > slightly) different from the playback frame rate. This also gives us > smooth interpolation for older data that is recorded at a slower rate. > And we can play back the recorded flight at a rate that has a 1 to 1 > match with "real" time. > > This scheme would also allow us to smoothly fast forward the replay, > or replay in super smooth "Slo-Mo-Gear" (patent pending) :-) We could > probably also rewind as well as fast forward if we really wanted to. > > For the moment, I have bound the "r" key to the instant replay > function. This will replay whatever is in the buffer. Upon > completion, you are left in "pause" mode at the point where you > activated the instant replay. Just "unpause" and you can continue the > flight. > > This whole thing is just crying for a gui/dialog box to control it > all. Any volunteers? > > I'm guessing that all the kinks are not yet quite worked out. You'll > likely run into one or two ... The sim is put into "pause" mode while > the buffer data is replayed. This has some side effects because many > subsystems do not run when the simulator is paused. This needs to be > looked at a bit more. Specifically some of the viewer code isn't run. > You can switch views with the "v" series of keys, but you can't rotate > a particular view with shift-number pad, and the chase views don't > track quite right in replay mode. > > Also, I don't and can't and won't record "everything". This means > things like AI or multiplayer traffic, weather conditions, and other > things are beyond the scope of this system at this time. > > Regards, > > Curt. > -- > Curtis Olson IVLab / HumanFIRST Program FlightGear Project > Twin Cities curt 'at' me.umn.edu curt 'at' flightgear.org > Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org
That's a nice addition - sounds neat:) I was just about to turn in for the night, and I did an update earlier this evening, but I think I'll get this now:) Hmm... I've been using the 'r' key for reheat but that's not a problem - was a consensus reached on a scheme for allocating keys in the recent discussions? I remember some ideas being thrown around but don't recall any decision being made. LeeE _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
