https://en.wikipedia.org/wiki/Texture_mapping
http://www.gamers.org/dEngine/quake/papers/checker_texmap.html
https://www.cs.uic.edu/~jbell/CourseNotes/ComputerGraphics/TextureMapping.html
http://www.decew.net/OSS/References/chapter_2_texture_mapping.pdf

# example affine texture mapping
http://archive.gamedev.net/archive/reference/articles/article852.html


http://www.lysator.liu.se/~mikaelk/doc/perspectivetexture/

# Shader... This also describes z-Buffer... :)
https://people.ece.cornell.edu/land/OldStudentProjects/cs490-95to96/GUO/report.html
https://software.intel.com/en-us/articles/the-basics-of-the-art-of-lighting-part-3-lighting-and-shaders/
https://docs.unity3d.com/Manual/Lighting.html