Function faceforward

tutorials/common/tutorial/tutorial_device.h:75–77

face forward for shading normals */

/* face forward for shading normals */
inline Vec3fa faceforward( const Vec3fa& N, const Vec3fa& I, const Vec3fa& Ng ) {
  Vec3fa NN = N; return dot(I, Ng) < 0 ? NN : neg(NN);
}

/* GLFW keys codes */
#if !defined(GLFW_KEY_F1)