UF_VEC3_affine_comb函数的数学原理

double* Point1=(double *)malloc(3*sizeof(double));
 double dir_r=sqrt(Dir[0]*Dir[0]+Dir[1]*Dir[1]+Dir[2]*Dir[2]);
 double h=80/dir_r;
 UF_VEC3_affine_comb(Point ,h,Dir,Point1);