C++ ON_3dVector::MaximumCoordinateIndex方法代码示例

ON_3dVector ON_Light::PerpindicularDirection() const
{
  // returns a consistent vector perpendicular to the
  // light's direction.  This vector is useful for
  // user interface display.
  ON_3dVector dir = m_direction;
  if ( !dir.IsValid() || !dir.Unitize() )
    return ON_UNSET_VECTOR;

  ON_3dVector xdir;
  if ( IsLinearLight() || IsRectangularLight() )
  {
    xdir = m_length;
    if ( xdir.IsValid() && xdir.Unitize() && fabs(xdir*dir) <= ON_SQRT_EPSILON )
      return xdir;
  }

  if( dir.IsParallelTo( ON_zaxis, ON_DEGREES_TO_RADIANS * 3.0))
    xdir = ON_CrossProduct( dir, ON_xaxis);
  else
    xdir = ON_CrossProduct( dir, ON_zaxis);
  xdir.Unitize();
  ON_3dVector ydir = ON_CrossProduct(dir,xdir);
  ydir.Unitize();
  ON_3dVector right;

  switch(dir.MaximumCoordinateIndex())
  {
  case 0:
    right = (fabs(xdir.y) > fabs(ydir.y)) ? xdir : ydir;
    if ( right.y < 0.0 )
      right.Reverse();
    break;
  case 1:
  case 2:
    right = (fabs(xdir.x) > fabs(ydir.x)) ? xdir : ydir;
    if ( right.x < 0.0 )
      right.Reverse();
    break;
  default:
    right = xdir;
    break;
  }

  if ( right[right.MaximumCoordinateIndex()] < 0.0 )
    right.Reverse();

  return right;  
}

bool ON_Intersect( const ON_BoundingBox& bbox, 
                   const ON_Line& line, 
                   double tol,
                   ON_Interval* line_parameters)
{
  double a,b,d,mn,mx,s0,s1, t0, t1;
  const double M = 1.0e308;

  // i,j,k are indices of coordinates to trim.
  // trim the direction with the biggest line deltas first
  ON_3dVector v = line.Direction();
  const int i = v.MaximumCoordinateIndex();

  // gaurd against ON_UNSET_VALUE as input
  if ( !(tol >= 0.0) )
    tol = 0.0;

  // clip i-th coordinate
  a = line.from[i];
  b = line.to[i];
  mn = bbox.m_min[i];
  mx = bbox.m_max[i];
  if ( !(mn <= mx) )
    return false;
  mn -= (tol+a);
  mx += (tol-a);
  if ( !(mn <= mx) )
    return false;
  d = b-a;
  if ( 0.0 == d )
  {
    // happens when line.from == line.to
    if ( 0.0 < mn || 0.0 > mx )
    {
      // point is in box
      if ( line_parameters )
      {
        // setting parameters makes no sense - just use 0.0
        // so it's clear we have a point
        line_parameters->Set(0.0,0.0);
      }
      return true;
    }
    return false; // point is outside box
  }
  if ( fabs(d) < 1.0 && (fabs(mn) >= fabs(d)*M || fabs(mx) >= fabs(d)*M) )
  {
    // the value of mn/d or mx/d is too large for a realistic answer to be computed
    return false;
  }
  d = 1.0/d;
  t0 = mn*d;
  t1 = mx*d;

  // set "chord" = line segment that begins and ends on the
  // i-th coordinate box side planes.
  ON_Line chord(line.PointAt(t0),line.PointAt(t1));

  // test j-th coordinate direction
  const int j = (i + (fabs(v[(i+1)%3])>fabs(v[(i+2)%3])?1:2) ) % 3;
  a = chord.from[j];
  b = chord.to[j];
  mn = bbox.m_min[j];
  mx = bbox.m_max[j];
  if ( !(mn <= mx) )
    return false;
  mn -= (tol+a);
  mx += (tol-a);
  if ( !(mn <= mx) )
    return false;
  d = b-a;
  if ( (0.0 < mn && d < mn) || (0.0 > mx && d > mx) )
  {
    // chord lies outside the box
    return false;
  }

  while ( fabs(d) >= 1.0 || (fabs(mn) <= fabs(d)*M && fabs(mx) <= fabs(d)*M) )
  {
    // The chord is not (nearly) parallel to the j-th sides.
    // See if the chord needs to be trimmed by the j-th sides.
    d = 1.0/d;
    s0 = mn*d;
    s1 = mx*d;
    if ( s0 > 1.0 )
    {
      if ( s1 > 1.0 )
      {
        // unstable calculation happens when
        // fabs(d) is very tiny and chord is
        // on the j-th side.
        break;
      }
      s0 = 1.0;
    }
    else if ( s0 < 0.0 )
    {
      if (s1 < 0.0)
      {
        // unstable calculation happens when
//.........这里部分代码省略.........