(C) 2012 Gabor Berenyi. I forked the original Linux project for an iOS demo, inspired by the default wallpaper of OS X: http://www.tomsguide.com/us/mac-os-x-lion-wallpaper-andromeda,news-12164.html. The code is covered by the BSD-License cited below.

It's also a cross-platform app development test, using tools Google positively recommended: 
"SDL together with OpenGL(ES) and C++ provide an excellent basis for making great cross platform games". 
(from http://google.github.io/pienoon/pie_noon_guide_engine.html) 

For a possible improvement (adding black holes) see this: http://www.gamedev.net/topic/588330-black-hole-distortion/?p=4736190

And here is a link to another similar project: https://github.com/hannorein/OpenGLMilkyWay (and its variations by hannorein). 
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 /  _____/_____  |  | _____  ___  ______.__.
/   \  ___\__  \ |  | \__  \ \  \/  <   |  |
\    \_\  \/ __ \|  |__/ __ \_>    < \___  |
 \______  (____  /____(____  /__/\_ \/ ____|
        \/     \/          \/      \/\/       
   a 2D Galaxy Renderer based on the density wave theory
   (C) 2012 Ingo Berg

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This Project provides source code to render a 2D Galaxy with the SDL/OpenGL. The code
will compile into a small application allowing you to create 2D galaxies by modifying
a set of geometrical parameters. There is only a minimalistic user interface 
as main purpose of the code was to render animations for the wikipedia article on dark 
matter:

http://de.wikipedia.org/wiki/Datei:Galaxy_rotation_under_the_influence_of_dark_matter.ogv

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Disclaimer and Credits:

  The renderer is in part based on code written by John Walker (specrend.c). 
  specrend.c was published as public domain and can be obtained from the 
  authors web site: 

		http://www.fourmilab.ch/documents/specrend/specrend.c

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  The Code is published under the BSD-License:

  Permission is hereby granted, free of charge, to any person obtaining a copy of
  this software and associated documentation files (the "Software"), to deal in 
  the Software without restriction, including without limitation the rights to 
  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
  of the Software, and to permit persons to whom the Software is furnished to do 
  so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all 
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 
  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR 
  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 
  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
  OR OTHER DEALINGS IN THE SOFTWARE.