private List <T4_occupant> get_nearest_occupants(double x, double y)
{
double max_squared_dist = _rect.H * _rect.H + _rect.W * _rect.W;
List <T4_occupant> occupants = get_internal_occupants(x, y, ref max_squared_dist);
// shouldn't happen for non-empty regions and pickpoint inside
if (occupants.Count == 0)
{
return(occupants);
}
// purge outdated candidates (collected before dist refinement)
// find nearest occupant. all chances nearest occupant would be the last added
// because it trims the max dist most
// remove all occupants starting after the end of the nearest
T4_occupant nearest = occupants[occupants.Count - 1];
double nearest_end = nearest.Rect.Max_squared_distance_to_pt(x, y);
for (int i = occupants.Count - 2; i >= 0; i--)
{
if (occupants[i].Rect.Min_squared_outside_distance_to_pt(x, y) > nearest_end)
{
occupants.RemoveAt(i);
}
}
return(occupants);
}
private void add(T4_occupant occupant)
{
if (_rooms != null)
{
int idx = choose_room(occupant); // choosed a room for occupant successfully
if (idx != -1)
{
_rooms[idx].add(occupant);
return;
}
}
_occupants.Add(occupant);
if (_occupants.Count > MAX_OCCUPANTS)
{
relocate();
}
}
private void relocate()
{
if (_rooms == null)
{
split();
}
// try to relocate occupants to the smaller rooms
for (int i = _occupants.Count - 1; i >= 0; i--)
{
T4_occupant occupant = _occupants[i];
int idx = choose_room(occupant);
if (idx < 0)
{
continue; // occupant is too large
}
_occupants.RemoveAt(i);
_rooms[idx].add(occupant);
}
}
private int choose_room(T4_occupant occupant)
{
bool is_bottom_quads = occupant.Rect.Ymin > _rect.Ymin && occupant.Rect.Ymax < _rect.Yc;
bool is_top_quads = occupant.Rect.Ymin > _rect.Yc && occupant.Rect.Ymax < _rect.Ymax;
bool is_left_quads = occupant.Rect.Xmin > _rect.Xmin && occupant.Rect.Xmax < _rect.Xc;
bool is_right_quads = occupant.Rect.Xmin > _rect.Xc && occupant.Rect.Xmax < _rect.Xmax;
if (!(is_top_quads ^ is_bottom_quads))
{
return(-1);
}
if (!(is_left_quads ^ is_right_quads))
{
return(-1);
}
if (is_bottom_quads)
{
return(is_left_quads ? 0 : 1);
}
return(is_right_quads ? 2 : 3);
}