hyp = (viewx==curline->v1->x && viewy==curline->v1->y)?
    0 : R_PointToDist (curline->v1->x, curline->v1->y);

  // if wall is horizontal or vertical, finding the distance to it is trivial
  if (curline->v1->y == curline->v2->y)
    rw_distance = D_abs(viewy - curline->v1->y);
  else if (curline->v1->x == curline->v2->x)
    rw_distance = D_abs(viewx - curline->v1->x);
  else
  {
    fixed_t sineval = finecosine[offsetangle >> ANGLETOFINESHIFT];
    // use old code for short walls and for walls that arent too oblique
    if (hyp < 1024 << FRACBITS && sineval > 2000)
    {
      rw_distance = FixedMul(hyp, sineval);
    }
    else
    {
      int_64_t a, c;
      fixed_t dx, dy;
      fixed_t rwd_x_offset, rwd_y_offset;
      fixed_t recentered_v1x, recentered_v1y, recentered_v2x, recentered_v2y;
      const int bb = 11;

      recentered_v1x = (curline->v1->x - viewx) >> bb;
      recentered_v1y = (curline->v1->y - viewy) >> bb;
      recentered_v2x = (curline->v2->x - viewx) >> bb;
      recentered_v2y = (curline->v2->y - viewy) >> bb;

      dx = recentered_v2x - recentered_v1x;
      dy = recentered_v2y - recentered_v1y;

      a = (int_64_t)recentered_v1x * recentered_v2y - (int_64_t)recentered_v1y * recentered_v2x;
      c = (int_64_t)dx * dx + (int_64_t)dy * dy;
      if (!c)
        c = 1; // just in case

      rwd_x_offset = ((fixed_t)(a * (-dy) / c)) << bb;
      rwd_y_offset = ((fixed_t)(a * ( dx) / c)) << bb;

      if (!rwd_x_offset && !rwd_y_offset)
        rw_distance = 0;
      else
        rw_distance = R_PointToDist(viewx + rwd_x_offset, viewy + rwd_y_offset);
    }
  }