public void Test_S2PaddedCell_GetEntryExitVertices()
{
int kIters = 1000;
for (int iter = 0; iter < kIters; ++iter)
{
S2CellId id = S2Testing.GetRandomCellId();
// Check that entry/exit vertices do not depend on padding.
Assert.Equal(new S2PaddedCell(id, 0).GetEntryVertex(),
new S2PaddedCell(id, 0.5).GetEntryVertex());
Assert.Equal(new S2PaddedCell(id, 0).GetExitVertex(),
new S2PaddedCell(id, 0.5).GetExitVertex());
// Check that the exit vertex of one cell is the same as the entry vertex
// of the immediately following cell. (This also tests wrapping from the
// end to the start of the S2CellId curve with high probability.)
Assert.Equal(new S2PaddedCell(id, 0).GetExitVertex(),
new S2PaddedCell(id.NextWrap(), 0).GetEntryVertex());
// Check that the entry vertex of a cell is the same as the entry vertex
// of its first child, and similarly for the exit vertex.
if (!id.IsLeaf())
{
Assert.Equal(new S2PaddedCell(id, 0).GetEntryVertex(),
new S2PaddedCell(id.Child(0), 0).GetEntryVertex());
Assert.Equal(new S2PaddedCell(id, 0).GetExitVertex(),
new S2PaddedCell(id.Child(3), 0).GetExitVertex());
}
}
}
public void Test_S2CellUnion_IsNormalized()
{
var id = new S2CellId(new S2Point(1, 0, 0)).Parent(10);
var cell_union = S2CellUnion.FromVerbatim(
new List <S2CellId> {
id.Child(0), id.Child(1), id.Child(2), id.Child(3)
});
Assert.True(cell_union.IsValid());
Assert.False(cell_union.IsNormalized());
}
public void Test_GetReferencePoint_PartiallyDegenerateLoops()
{
for (var iter = 0; iter < 100; ++iter)
{
// First we construct a long convoluted edge chain that follows the
// S2CellId Hilbert curve. At some random point along the curve, we
// insert a small triangular loop.
List <List <S2Point> > loops = new(1) { new() };
var loop = loops[0];
int num_vertices = 100;
var start = S2Testing.GetRandomCellId(S2.kMaxCellLevel - 1);
var end = start.AdvanceWrap(num_vertices);
var loop_cellid = start.AdvanceWrap(
S2Testing.Random.Uniform(num_vertices - 2) + 1);
var triangle = new List <S2Point>();
for (var cellid = start; cellid != end; cellid = cellid.NextWrap())
{
if (cellid == loop_cellid)
{
// Insert a small triangular loop. We save the loop so that we can
// test whether it contains the origin later.
triangle.Add(cellid.Child(0).ToPoint());
triangle.Add(cellid.Child(1).ToPoint());
triangle.Add(cellid.Child(2).ToPoint());
loop.AddRange(triangle);
loop.Add(cellid.Child(0).ToPoint());
}
else
{
loop.Add(cellid.ToPoint());
}
}
// Now we retrace our steps, except that we skip the three edges that form
// the triangular loop above.
for (S2CellId cellid = end; cellid != start; cellid = cellid.PrevWrap())
{
if (cellid == loop_cellid)
{
loop.Add(cellid.Child(0).ToPoint());
}
else
{
loop.Add(cellid.ToPoint());
}
}
S2LaxPolygonShape shape = new(loops);
S2Loop triangle_loop = new(triangle);
var rp = shape.GetReferencePoint();
Assert.Equal(triangle_loop.Contains(rp.Point), rp.Contained);
}
}
}
public void Test_S2CellId_MaximumTile()
{
// This method is tested more thoroughly in s2cell_union_test.cc.
for (int iter = 0; iter < 1000; ++iter)
{
S2CellId id = S2Testing.GetRandomCellId(10);
// Check that "limit" is returned for tiles at or beyond "limit".
Assert.Equal(id, id.MaximumTile(id));
Assert.Equal(id, id.Child(0).MaximumTile(id));
Assert.Equal(id, id.Child(1).MaximumTile(id));
Assert.Equal(id, id.Next().MaximumTile(id));
Assert.Equal(id.Child(0), id.MaximumTile(id.Child(0)));
// Check that the tile size is increased when possible.
Assert.Equal(id, id.Child(0).MaximumTile(id.Next()));
Assert.Equal(id, id.Child(0).MaximumTile(id.Next().Child(0)));
Assert.Equal(id, id.Child(0).MaximumTile(id.Next().Child(1).Child(0)));
Assert.Equal(id, id.Child(0).Child(0).MaximumTile(id.Next()));
Assert.Equal(id, id.Child(0).Child(0).Child(0).MaximumTile(id.Next()));
// Check that the tile size is decreased when necessary.
Assert.Equal(id.Child(0), id.MaximumTile(id.Child(0).Next()));
Assert.Equal(id.Child(0), id.MaximumTile(id.Child(0).Next().Child(0)));
Assert.Equal(id.Child(0), id.MaximumTile(id.Child(0).Next().Child(1)));
Assert.Equal(id.Child(0).Child(0),
id.MaximumTile(id.Child(0).Child(0).Next()));
Assert.Equal(id.Child(0).Child(0).Child(0),
id.MaximumTile(id.Child(0).Child(0).Child(0).Next()));
// Check that the tile size is otherwise unchanged.
Assert.Equal(id, id.MaximumTile(id.Next()));
Assert.Equal(id, id.MaximumTile(id.Next().Child(0)));
Assert.Equal(id, id.MaximumTile(id.Next().Child(1).Child(0)));
}
}
