/**
* subquads are numbered as follows:
*
* 2 | 3
* --+--
* 0 | 1
*/
#region Constructors
/// <summary>
/// Initializes a new instance of the IntervalNode class.
/// </summary>
public IntervalNode(IntervalNode parent, double min, double max)
{
_parent = parent;
_min = min;
_max = max;
_center = (min + max) / 2;
}
} // private int GetSubintervalIndex( double min, double max )
/// <summary>
/// get the subinterval for the index.
/// If it doesn't exist, create it
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
private IntervalNode GetSubinterval(int index)
{
if (_subinterval[index] == null)
{
// create a new subquad in the appropriate quadrant
double submin = 0.0;
double submax = 0.0;
switch (index)
{
case 0:
submin = _min;
submax = _center;
break;
case 1:
submin = _center;
submax = _max;
break;
}
IntervalNode interval = new IntervalNode(this, submin, submax);
_subinterval[index] = interval;
} // if ( _subinterval[index] == null )
return(_subinterval[index]);
} // private IntervalNode GetSubinterval( int index )
/**
* subquads are numbered as follows:
*
* 2 | 3
* --+--
* 0 | 1
*/
#region Constructors
/// <summary>
/// Initializes a new instance of the IntervalNode class.
/// </summary>
public IntervalNode(IntervalNode parent, double min, double max)
{
_parent = parent;
_min = min;
_max = max;
_center = (min + max) / 2;
}
} // public IntervalNode GetIntervalNode( double min, double max )
/// <summary>
/// Returns the smallest existing node containing the envelope.
/// </summary>
/// <param name="min"></param>
/// <param name="max"></param>
/// <returns></returns>
public IntervalNode Find(double min, double max)
{
int subintervalIndex = GetSubintervalIndex(min, max);
if (subintervalIndex == -1 || _subinterval[subintervalIndex] == null)
{
return(this);
}
// query lies in subnode, so search it recursively
IntervalNode node = _subinterval[subintervalIndex];
return(node.Find(min, max));
} // public IntervalNode Find( double min, double max )
} // public ArrayList AddAllItemsFromOverlapping( double min, double max, ArrayList items )
/// <summary>
/// Returns the interval containing the envelope.
/// Creates the interval if it does not already exist.
/// Note that passing a zero-size interval to this routine results in infinite recursion.
/// </summary>
/// <param name="min"></param>
/// <param name="max"></param>
/// <returns></returns>
public IntervalNode GetIntervalNode(double min, double max)
{
int subintervalIndex = GetSubintervalIndex(min, max);
if (subintervalIndex != -1)
{
// create the quad if it does not exist
IntervalNode interval = GetSubinterval(subintervalIndex);
// recursively search the found quad
return(interval.GetIntervalNode(min, max));
}
else
{
return(this);
}
} // public IntervalNode GetIntervalNode( double min, double max )
} // private int GetSubintervalIndex( double min, double max )
/// <summary>
/// get the subinterval for the index.
/// If it doesn't exist, create it
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
private IntervalNode GetSubinterval( int index )
{
if ( _subinterval[index] == null )
{
// create a new subquad in the appropriate quadrant
double submin = 0.0;
double submax = 0.0;
switch ( index )
{
case 0:
submin = _min;
submax = _center;
break;
case 1:
submin = _center;
submax = _max;
break;
}
IntervalNode interval = new IntervalNode( this, submin, submax );
_subinterval[index] = interval;
} // if ( _subinterval[index] == null )
return _subinterval[index];
} // private IntervalNode GetSubinterval( int index )
