private void InitBound()
{
// The bounding rectangle of a loop is not necessarily the same as the
// bounding rectangle of its vertices. First, the loop may wrap entirely
// around the sphere (e.g. a loop that defines two revolutions of a
// candy-cane stripe). Second, the loop may include one or both poles.
// Note that a small clockwise loop near the equator contains both poles.
var bounder = new RectBounder();
for (var i = 0; i <= NumVertices; ++i)
{
bounder.AddPoint(Vertex(i));
}
var b = bounder.Bound;
// Note that we need to initialize bound with a temporary value since
// contains() does a bounding rectangle check before doing anything else.
_bound = S2LatLngRect.Full;
if (Contains(new S2Point(0, 0, 1)))
{
b = new S2LatLngRect(new R1Interval(b.Lat.Lo, S2.PiOver2), S1Interval.Full);
}
// If a loop contains the south pole, then either it wraps entirely
// around the sphere (full longitude range), or it also contains the
// north pole in which case b.lng().isFull() due to the test above.
if (b.Lng.IsFull && Contains(new S2Point(0, 0, -1)))
{
b = new S2LatLngRect(new R1Interval(-S2.PiOver2, b.Lat.Hi), b.Lng);
}
_bound = b;
}
private S2LatLngRect getEdgeBound(double x1,
double y1,
double z1,
double x2,
double y2,
double z2)
{
var bounder = new RectBounder();
var p1 = S2Point.Normalize(new S2Point(x1, y1, z1));
var p2 = S2Point.Normalize(new S2Point(x2, y2, z2));
bounder.AddPoint(p1);
bounder.AddPoint(p2);
return bounder.Bound;
}