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FlightGear Newsletter April 2014: Difference between revisions
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→FlightGear/Oculus Rift Experiments: http://sourceforge.net/p/flightgear/mailman/message/32262904/
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===Orbital Rendering:Earthview === | |||
{{Conversational}} | |||
<pre> | |||
I have just pushed a first version of the Earthview orbital rendering engine. The textures for the planet are based on the NASA Visible Earth collection | |||
http://visibleearth.nasa.gov | |||
As far as I understand the terms of use which allow re-use, re-distribution and commercial use, this should be fine with GPL. | |||
To see the blue planet from high up, start FG using the ufo at a high altitude (around 10 million ft is quite good with the texture resolution provided), open the (currently minimalistic) GUI from the View menu, push start, wait for the textures to load and admire the view. | |||
Space is grey up there because this is outside of the skydome, and the overall background color is defined fog-grey. As far as I understand, this is legacy code coming from a time when FG unloaded the skydome in poor visibility to get a few percent more performance out. We don't actually have to do this these days and if you want space black, there is a way. To quote Lauri who figured this out: | |||
If you want to try to change the clear color to black, you must edit | |||
flightgear/src/Main/renderer.cxx around line 700. There are two | |||
instances of following: | |||
camera->setClearColor(toOsg(clearColor)); | |||
which should be changed to | |||
camera->setClearColor(osg::Vec4(0.0, 0.0, 0.0, 0.0)); | |||
Without this, only a rim around Earth is rendered in proper colors. | |||
Earthview responds to the weather visibility setting and typically 80-140 km visibility work best (won't affect any scenery loading because we're too far from the planet). Also, rendering in ALS manually tweaking Rayleigh and Mie constants gives a nice atmosphere effect. | |||
NASA provides textures in /much/ higher resolution - in my highest resolution texture set I have the planet covered in 32768x16384 and the cloud layer in half of that. For such large textures, loading time is an issue (Earthview isn't excatly *cough* elegant) and pre-mipmapped compressed DDS is pretty much the only sane option - then that's 8 texture chunks a 176 MB each. It'd be nice to make higher resolution versions available for download, but I realize that's quite a bandwidth hog - if there's sufficient interest and someone knows a server... the textures are there. | |||
Provided you have the texture memory, performance should actually be pretty high - there's just two textured spheres in the scene, and even on my old computer I get a solid 60 fps. | |||
Enjoy! | |||
* Thorsten | |||
</pre> | |||
=== FlightGear/Oculus Rift Experiments === | === FlightGear/Oculus Rift Experiments === | ||