Revert "fixing broken shading on edges of low polygon models"
Revert "fixing broken shading on edges of low polygon models"

This reverts commit 44a544f25861b520062c36b9a37be1e3d1416541.

wilsonCernWq/ospray,MengjiaoH/ospray,ospray/OSPRay,MengjiaoH/ospray,MengjiaoH/ospray,wilsonCernWq/ospray,MengjiaoH/ospray,ospray/OSPRay,wilsonCernWq/ospray,ospray/OSPRay,MengjiaoH/ospray,ospray/OSPRay