* geometry batching - http://www.nvidia.com/docs/IO/8228/BatchBatchBatch.pdf
 * planetary rings - http://johnwhigham.blogspot.com/2011/11/planetary-rings.html
 * icosphere - http://pastebin.com/aFdWi5eQ
 * compressed textures - http://www.opengl-tutorial.org/beginners-tutorials/tutorial-5-a-textured-cube/

== GUI ==
 * Turbo badger - https://github.com/fruxo/turbobadger

== Minecraftlike ==
 * http://dev.minetest.net/Main_Page
 * http://www.volumesoffun.com/polyvox-about/
 * http://www.sea-of-memes.com/LetsCode93/LetsCode93.html

== Light and Shadow ==
 * Irradiance Environment Maps (Olgierd's suggestion) http://www1.cs.columbia.edu/~ravir/papers/envmap/
 * indirect roguelike map shader - http://pastebin.com/pTGsx4vf

== PBRT ==

 * PBRT book - http://www.pbrt.org/
 * https://github.com/mmp/pbrt-v3/ -- PBRT book code v3
 * https://github.com/mmp/pbrt-v2/ -- PBRT book code v2

 * pbr intro http://www.codinglabs.net/article_physically_based_rendering.aspx
 * pbr-cook-torrance http://www.codinglabs.net/article_physically_based_rendering_cook_torrance.aspx