public void testContinuity()
{
Trace.WriteLine("TestContinuity");
// Make sure that sequentially increasing cell ids form a continuous
// path over the surface of the sphere, i.e. there are no
// discontinuous jumps from one region to another.
var maxDist = S2Projections.MaxEdge.GetValue(MAX_WALK_LEVEL);
var end = S2CellId.End(MAX_WALK_LEVEL);
var id = S2CellId.Begin(MAX_WALK_LEVEL);
for (; !id.Equals(end); id = id.Next)
{
Assert.True(id.ToPointRaw().Angle(id.NextWithWrap.ToPointRaw()) <= maxDist);
// Check that the ToPointRaw() returns the center of each cell
// in (s,t) coordinates.
var p = id.ToPointRaw();
var face = S2Projections.XyzToFace(p);
var uv = S2Projections.ValidFaceXyzToUv(face, p);
assertDoubleNear(Math.IEEERemainder(
S2Projections.UvToSt(uv.X), 1.0 / (1 << MAX_WALK_LEVEL)), 0);
assertDoubleNear(Math.IEEERemainder(
S2Projections.UvToSt(uv.Y), 1.0 / (1 << MAX_WALK_LEVEL)), 0);
}
}
public void testSTUV()
{
// Check boundary conditions.
for (double x = -1; x <= 1; ++x)
{
assertEquals(S2Projections.StToUv(x), x);
assertEquals(S2Projections.UvToSt(x), x);
}
// Check that UVtoST and STtoUV are inverses.
for (double x = -1; x <= 1; x += 0.0001)
{
assertDoubleNear(S2Projections.UvToSt(S2Projections.StToUv(x)), x);
assertDoubleNear(S2Projections.StToUv(S2Projections.UvToSt(x)), x);
}
}