irrlicht-code/doc/irrlicht-license.txt

Copyright (C) 2002-2012 Nikolaus Gebhardt

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  Please note that the Irrlicht Engine is based in part on the work of the
  Independent JPEG Group, the zlib, libPng and aesGladman. This means that if you use
  the Irrlicht Engine in your product, you must acknowledge somewhere in your
  documentation that you've used the IJPG code. It would also be nice to mention
  that you use the Irrlicht Engine, the zlib, libPng and aesGladman. See the 
  corresponding license files for further informations. It is also possible to disable
  usage of those additional libraries by defines in the IrrCompileConfig.h header and 
  recompiling the engine.