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=== Background === | === Background === | ||
for visualizing orbital mechanics, the two most useful projections are groundtrack (for inclination, node crossing and what you should see looking out of the window) and the projection orthogonal to the orbital plane<ref>{{cite web | |||
|url = https://forum.flightgear.org/viewtopic.php?p=285896#p285896 | |||
|title = <nowiki> Re: Space Shuttle </nowiki> | |||
|author = <nowiki> Thorsten </nowiki> | |||
|date = May 20th, 2016 | |||
|added = May 20th, 2016 | |||
|script_version = 0.40 | |||
}}</ref> | |||
{{FGCquote | {{FGCquote | ||
|1= I stumbled across what is perhaps closer to the core of the issue in a flight over the North Pole. Flightplan legs are rendered as great circle segments, so long legs are drawn with a curve. Somewhere, the flightplan has to be flattened into a map view. It appears that this is easy to do over short distances in lower latitudes, but becomes increasingly difficult over long distances with a bigger component of Earth's curvature involved. The map view is not really geared for polar routes, so the leg that goes over the pole has an extreme curve drawn in it. And when that leg was in range, the frame rate dropped from 25-30 down to 8-12. Once it went out of range, frame rate was back to normal. It seems like calculating curvature may be the rate-limiting step. | |1= I stumbled across what is perhaps closer to the core of the issue in a flight over the North Pole. Flightplan legs are rendered as great circle segments, so long legs are drawn with a curve. Somewhere, the flightplan has to be flattened into a map view. It appears that this is easy to do over short distances in lower latitudes, but becomes increasingly difficult over long distances with a bigger component of Earth's curvature involved. The map view is not really geared for polar routes, so the leg that goes over the pole has an extreme curve drawn in it. And when that leg was in range, the frame rate dropped from 25-30 down to 8-12. Once it went out of range, frame rate was back to normal. It seems like calculating curvature may be the rate-limiting step. | ||