Earthview: Difference between revisions

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Earthview (view source)

Revision as of 08:13, 21 March 2016

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→‎Customization
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== Customization ==
== Customization ==


{{FGCquote
Getting your own hires version of textures requires a few simple steps:
|1= If you're interested in spaceflight, I think we really have that covered nicely and fast with EarthView these days - especially if you use the hires textures provided by NASA
|2= {{cite web
  | url    = http://forum.flightgear.org/viewtopic.php?p=228058#p228058
  | title  = <nowiki>Re: Initial FlightGear / OsgEarth integration</nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Dec 25th, 2014
  | added  = Dec 25th, 2014
  | script_version = 0.23
  }}
}}


{{FGCquote
* obtain a texture set
|1= EarthView uses a sphere with 8 separate texture sheets (and I think even a similar naming convention to the NASA files...). The site you're looking for is [http://visibleearth.nasa.gov/ Visible Earth], especially the Blue Marble section.
Go to [http://visibleearth.nasa.gov/ Visible Earth], look into the Blue Marble section and download a texture set of your choice (there's different seasons available for instance).
|2= {{cite web
  | url    = http://forum.flightgear.org/viewtopic.php?p=219587#p219587
  | title  = <nowiki>Re: </nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Sep 30th, 2014
  | added  = Sep 30th, 2014
  | script_version = 0.23
  }}
}}


{{FGCquote
NASA typically delivers the hires textures with naming conventions N1 - N4 (northern hemisphere) and S1 - S4 (southern hemisphere) and Earthview follows that convention.
|1= EarthView resides in /Models/Astro - the file that's loaded is specified in earth.xml - if you do your own textures, you attach them to earyh_unitscale_rawuv.ac and reference that in earth.xml , or if you create margins, you can simply replace pale_blue_aug_*.png (the naming convention has N1 to N4 and S1 to S4 which is close to what NASA uses).
If you alter the texture names, you edit the *.ac file by search/replace or with your favourite model editor. Okay, I'm expecting here that if I say 're-texture that sphere' its not going to be an unsurmountable problem... that's sort of basic modelling done a few hundred times per day in the forum...


* convert the texture set


|2= {{cite web
Graphics cards prefer powers of two in texture sizes, so you probably want to resize the sheets to either 8192x8192 or 16384x16384. At the same time, you might want to save them in pre-compressed and mip-mapped dds format (this may require a gimp plugin) for better loading times. Do this on a machine with plenty of memory, as the graphics program may need a lot in intermediate stages.
  | url    = http://forum.flightgear.org/viewtopic.php?p=219606#p219606
  | title  = <nowiki>Re: </nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Sep 30th, 2014
  | added  = Sep 30th, 2014
  | script_version = 0.23
  }}
}}


{{FGCquote
* assign the texture sheets
|1= Because graphics cards like powers of 2, we're actually using 16384x16384 rather than full resolution (which would choke even my high-end GPU), and here we see the virtue of precompressed dds, so if I remember one of the precompressed and mipmapped files is 172 MB.
Unless you have 8+ GB of memory, using half the resolution is probably a very good idea.
Once you are at it, notice that also the cloudsphere is available at higher resolution... makes a hell of difference.
|2= {{cite web
  | url    = http://forum.flightgear.org/viewtopic.php?p=219606#p219606
  | title  = <nowiki>Re: </nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Sep 30th, 2014
  | added  = Sep 30th, 2014
  | script_version = 0.23
  }}
}}


{{FGCquote
Look into $FGData/Models/Astro  - this is where Earthview resides. The current texture sheets are pale_blue_aug_??.png and clouds_??.png where ?? stands for the NASA position reference.
|1= If you download the full resolution earth and cloud textures from NASA Visible Earth and re-texture the sphere, then you can have this


The simple way is to assign your texture to earth_unitscale_rawuv.ac (then they can be used 'as is'). It's easiest to open the file with the text editor, look for the lines like
<b>texture "pale_blue_aug_N1.png"</b>
and replace them with your own N1 texture. Then open earth.xml and point to your just edited 3d model via <path>earth_unitscale_rawuv.ac</path>. Do the same for cloudsphere.xml (it's entirely possible to do all this in a 3d modeling application like blender, but chances are it will get rather slow and unwieldy for such huge texture sheets).


|2= {{cite web
Assigning textures as they are to the rawuv sphere creates visible seams where the texture sheets end. The solution is to add margins (like done for the texture set provided). If you edit your textures to add such margins, you don't need to use <b>earth_unitscale_rawuv.ac</b> and can assign your textures to <b>earth_unitscale_hires.ac</b>
  | url    = http://forum.flightgear.org/viewtopic.php?p=234082#p234082
  | title  = <nowiki>Re: </nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Mar 5th, 2015
  | added  = Mar 5th, 2015
  | script_version = 0.23
  }}
}}


{{FGCquote
For comparison, a 16384x16384 texture sheet in pre-compressed and mip-mapped dds format should come to 172 MB. Unless you have a substantial amount of memory, consider using less than full resolution.
|1= I reasoned that if 'texture the sphere' doesn't mean anything to a user, he probably can't do it anyway. Besides, at 16384 x 16384 texture resolution, you may run into memory and architecture limits of your machine, so there's really no one sie fits all path at the upper end - I ended up using dds textures to reduce loading time.
The models in question are Models/Astro/earth_unitscale_hires.ac,  earth_unitscale_rawuv.ac and clouds_unitscale_hires.ac. The unitscale_hires are smart uv-mapped and need textures with a characteristic border to avoid seams, the rawuv has a simple mapping to which you can apply texture sheets as is.
Open with the model editor of your choice, map with the textures of your choice, done.
|2= {{cite web
  | url    = http://forum.flightgear.org/viewtopic.php?p=234112#p234112
  | title  = <nowiki>Re: </nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Mar 5th, 2015
  | added  = Mar 5th, 2015
  | script_version = 0.23
  }}
}}
 
{{FGCquote
|1= the simple, slightly seamy way is you download a file, resie it to a 2^n size to make life easy for the GPU, save it as png (or if you want it fancy dds) and... done.
The hard way without any seams involves creating a suitable margin like in the existing textures.
|2= {{cite web
  | url    = http://forum.flightgear.org/viewtopic.php?p=219587#p219587
  | title  = <nowiki>Re: </nowiki>
  | author = <nowiki>Thorsten</nowiki>
  | date  = Sep 30th, 2014
  | added  = Sep 30th, 2014
  | script_version = 0.23
  }}
}}


== Implementation ==
== Implementation ==
Thorsten
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