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Earthview: Difference between revisions
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== Implementation == | == Implementation == | ||
{{FGCquote | |||
|1= Have you wondered why you can't see the terrain when you switch EarthView on? That would be because the EarthView sphere is neither where you think it is, nor as large as you think it is. | |||
In actual reality of rendering geometry, the sphere has a radius of ~58 km and when you are at an altitude of 30.000 ft, it is only 100 m away from you. You don't realie any of this of course since the sphere is constantly repositioned. The reason that is done is because the renderer works with floating point precision, the internal unit is meters, and if you throw a distance of 6 million meters at it, all you get back is numerical garbage. For that reason, there's a far clipping distance in FG which does not render anything beyond a default of 120 km. | |||
The fogging of the EarthSphere is likewise based on the assumption that you see a 10 km think layer of atmosphere from above, not that you're inside an atmosphere with varying aerosol density - it would never match atmosphere fog properly. | |||
There's in fact nothing wrong with the way the horizon is created as long as you don't set a visibility exceeding the LOD bare and far camera clipping range. | |||
|2= {{cite web | |||
| url = http://forum.flightgear.org/viewtopic.php?p=219172#p219172 | |||
| title = <nowiki>Re: Problem in the Atmospheric Light Scattering (ALS)</nowiki> | |||
| author = <nowiki>Thorsten</nowiki> | |||
| date = Sep 23rd, 2014 | |||
| added = Sep 23rd, 2014 | |||
| script_version = 0.23 | |||
}} | |||
}} | |||
{{FGCquote | {{FGCquote | ||
|1= Real-time 3d rendering generically is not about rendering things as they really are, but rendering something that looks on screen like it would really be there. If you look into the details of how FG builds the sky, skydome, sun and moon most definitely are not real objects, neither are clouds, and there's very good reason for that. | |1= Real-time 3d rendering generically is not about rendering things as they really are, but rendering something that looks on screen like it would really be there. If you look into the details of how FG builds the sky, skydome, sun and moon most definitely are not real objects, neither are clouds, and there's very good reason for that. | ||