Function line_line_distance

code/geometry/primitives3d.cpp:87–96

  Q = P + n;
  return true; }
double line_line_distance(L(A, B), L(C, D), point3d &E,
                                            point3d &F) {
  point3d w = (C-A), v = (B-A), u = (D-C),
          N = v*u, N1 = v*(u*v), N2 = u*(v*u);
  if (w.isZero() || (v*w).isZero()) E = F = A;
  else if (N.isZero()) E = A,
    F = A + w - v * ((w%v)/(v%v));
  else E = A + v*((w % N2)/(v%N2)),
    F = C + u*(((-w) % N1)/(u%N1));
  return (F-E).length(); }
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