Pre 10 - Flickering location labels

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Topic author
don
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Pre 10 - Flickering location labels

Post #1by don » 19.07.2004, 11:05

cel://PhaseLock/Sol:Earth/Sol/2004-07-19T10:40:16.69619?x=AMHchmpAMO3EDA&y=Pu9mDl2Mxw&z=leLUMjk+IVEO&ow=0.698247&ox=-0.254702&oy=0.545972&oz=0.386642&track=Sol:Earth&select=Sol:Earth&fov=25.925934&ts=1.000000<d=0&rf=38295&lm=132
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Harry
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Re: Pre 10 - Flickering location labels

Post #2by Harry » 19.07.2004, 12:45

The flickering disappears when I switch to "follow" mode or stop time, so I think this could be the result of slightly varying observer positionrelative to Earth and insufficient precision. Don't know if this can be fixed without keeping some state from the last frame and using some kind of hysteresis mechanism.

Harald
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Topic author
don
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Post #3by don » 19.07.2004, 13:04

On my system, it flickers in every mode. The only way to stop it is to stop (pause time) Celestia. BUT, it only happens at certain distances.
-Don G.
My Celestia Scripting Resources page

Avatar: Total Lunar Eclipse from our back yard, Oct 2004. Panasonic FZ1 digital camera (no telescope), 36X digital zoom, 8 second exposure at f6.5.
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Rassilon
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Post #4by Rassilon » 19.07.2004, 14:40

Did you guys use double precision or float to plot those labels?
I'm trying to teach the cavemen how to play scrabble, its uphill work. The only word they know is Uhh and they dont know how to spell it!
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t00fri
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Post #5by t00fri » 19.07.2004, 21:08

I have reported the flickering location labels quite some time ago already in the developers list. Noone except Chris reacted!? Chris and I agreed that this is again a manifestation of single precision and needs to be fixed in the version /after/ 1.3.2.

Bye Fridger
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Topic author
don
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Post #6by don » 20.07.2004, 05:16

Thank you Fridger. :)
-Don G.

My Celestia Scripting Resources page



Avatar: Total Lunar Eclipse from our back yard, Oct 2004. Panasonic FZ1 digital camera (no telescope), 36X digital zoom, 8 second exposure at f6.5.
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Topic author
don
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Post #7by don » 20.07.2004, 05:16

Thank you Fridger! :)
-Don G.

My Celestia Scripting Resources page



Avatar: Total Lunar Eclipse from our back yard, Oct 2004. Panasonic FZ1 digital camera (no telescope), 36X digital zoom, 8 second exposure at f6.5.
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chris
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Post #8by chris » 21.07.2004, 16:21

It was a simple matter to convert the calculation to double precision and eliminate the flickering. The fix is in CVS.

--Chris
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selden
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Post #9by selden » 22.07.2004, 03:48

fwiw, I just finished downloading a fresh copy of all of the Celestia source code and compiled it on a WinXP Pro SP1 system using MS Visual Studio .NET 2003, and the labels in Don's URL don't flicker!

System:
256MB 500MHz P3, WinXP Pro SP1
128MB GF4 Ti4200, drivers 56.72 (*)
Celestia from CVS

-----
* -- I'll try 61.76 another day...
Selden
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Topic author
don
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Post #10by don » 23.07.2004, 05:26

No more label flicker! Thank you Chris. :D
-Don G.

My Celestia Scripting Resources page



Avatar: Total Lunar Eclipse from our back yard, Oct 2004. Panasonic FZ1 digital camera (no telescope), 36X digital zoom, 8 second exposure at f6.5.
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