grayzer Raytracing framework with sub-light speeds and gravitational ray distortion. (1995-2004) Based on the book http://sciyouth.ru/ElBibl/Komppjuterja%20geometrija%20i%20grafika/Е.В.Шикин,%20А.В.Боресков.%20Компьютерная%20графика.%20Динамика,%20реа.pdf