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Logging Flight Properties

Controlling your aircraft, using the autopilot etc.

Logging Flight Properties

Postby Kaosiia » Sun Feb 14, 2021 7:57 pm

Hello,

I am wondering what is the smallest time interval that flightgear can log at?

I tried logging properties every 6ms, and in the csv file, it doesn't log the properties at 6ms, and it also double, triple, multiple counts. For example it will log 0.25 seconds multiple times.

Thanks!
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Re: Logging Flight Properties

Postby wkitty42 » Sun Feb 14, 2021 8:10 pm

i think this depends on the specific properties you are trying to record... this because some things run at frame rate while the FDM runs at 120Hz...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Logging Flight Properties

Postby Hooray » Sun Feb 14, 2021 8:23 pm

I think that's accurate, the logger used to run inside the main loop last I checked - for it to run decoupled, it would have to run in a dedicated logger thread (which probably isn't such a bad idea and also not that complicated, and indeed there are presumably already other I/O protocols already running in a worker thread, think the mongoose stuff?)
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Re: Logging Flight Properties

Postby Kaosiia » Sun Feb 14, 2021 9:44 pm

@wkitty42 i dont quite understand what u mean by some things run at frame rate and FDM runs at 120Hz....

do you mind explaining a bit more? Thanks
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Re: Logging Flight Properties

Postby wkitty42 » Sun Feb 14, 2021 10:02 pm

the FDM runs at a fixed rate of 120 cycles per second all the time...

(most?) everything else runs at the frame rate (FPS) of the system... in other words, if your GPU can churn 60FPS, then everything else is running at 60 cycles per second... if the frame rate drops to (eg) 20FPS in a heavy area of the scenery (like around Paris, France, for example) then their processing rate will drop to 20 cycles per second... leave that heavy area and the FPS goes back up and the processing will also go back up...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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wkitty42
 
Posts: 9146
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Location: central NC, USA
Callsign: wk42
Version: git next
OS: Kubuntu 20.04


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