sdf font相关资料

http://www.opengl.org/discussion_boards/showthread.php/180197-Signed-Distance-Field-for-drawing-text

https://forum.libcinder.org/topic/signed-distance-field-font-rendering

https://github.com/paulhoux/Cinder-Samples/tree/master/TextRendering

http://www.gamedev.net/topic/491938-signed-distance-bitmap-font-tool/

http://www.valvesoftware.com/publications/2007/SIGGRAPH2007_AlphaTestedMagnification.pdf

http://www.codersnotes.com/notes/signed-distance-fields

http://cs.brown.edu/~pff/dt/ 

http://www.codersnotes.com/notes/signed-distance-fields

http://bytewrangler.blogspot.gr/2011/10/signed-distance-fields.html