Ray-triangle intersection test. Based on https://github.com/pmjoniak/GeometricTools/blob/master/GTEngine/Include/Mathematics/GteIntrRay3Triangle3.h
output object to store result (hit boolean, fraction, frontFacing)
ray origin
ray direction
ray length
first vertex of triangle
second vertex of triangle
third vertex of triangle
if true, backfaces will not be considered hits
Ray-triangle intersection test. Based on https://github.com/pmjoniak/GeometricTools/blob/master/GTEngine/Include/Mathematics/GteIntrRay3Triangle3.h