private static void ChooseEdgeNearCell(S2Cell cell, out S2Point a, out S2Point b)
{
S2Cap cap = cell.GetCapBound();
if (S2Testing.Random.OneIn(5))
{
// Choose a point anywhere on the sphere.
a = S2Testing.RandomPoint();
}
else
{
// Choose a point inside or somewhere near the cell.
a = S2Testing.SamplePoint(new S2Cap(cap.Center, 1.5 * cap.RadiusAngle()));
}
// Now choose a maximum edge length ranging from very short to very long
// relative to the cell size, and choose the other endpoint.
double max_length = Math.Min(100 * Math.Pow(1e-4, S2Testing.Random.RandDouble()) *
cap.Radius.Radians(), S2.M_PI_2);
b = S2Testing.SamplePoint(new S2Cap(a, S1Angle.FromRadians(max_length)));
if (S2Testing.Random.OneIn(20))
{
// Occasionally replace edge with antipodal edge.
a = -a;
b = -b;
}
}
public void Test_S2ConvexHullQuery_PointsInsideHull()
{
// Repeatedly build the convex hull of a set of points, then add more points
// inside that loop and build the convex hull again. The result should
// always be the same.
int kIters = 1000;
for (int iter = 0; iter < kIters; ++iter)
{
S2Testing.Random.Reset(iter + 1); // Easier to reproduce a specific case.
// Choose points from within a cap of random size, up to but not including
// an entire hemisphere.
S2Cap cap = S2Testing.GetRandomCap(S2.DoubleError, 1.999 * Math.PI);
S2ConvexHullQuery query = new();
int num_points1 = S2Testing.Random.Uniform(100) + 3;
for (int i = 0; i < num_points1; ++i)
{
query.AddPoint(S2Testing.SamplePoint(cap));
}
var hull = query.GetConvexHull();
// When the convex hull is nearly a hemisphere, the algorithm sometimes
// returns a full cap instead. This is because it first computes a
// bounding rectangle for all the input points/edges and then converts it
// to a bounding cap, which sometimes yields a non-convex cap (radius
// larger than 90 degrees). This should not be a problem in practice
// (since most convex hulls are not hemispheres), but in order make this
// test pass reliably it means that we need to reject convex hulls whose
// bounding cap (when computed from a bounding rectangle) is not convex.
//
// TODO(b/203702905): This test can still fail (about 1 iteration in
// 500,000) because the S2LatLngRect::GetCapBound implementation does not
// guarantee that A.Contains(B) implies
// A.GetCapBound().Contains(B.GetCapBound()).
if (hull.GetCapBound().Height() >= 1)
{
continue;
}
// Otherwise, add more points inside the convex hull.
int num_points2 = 1000;
for (int i = 0; i < num_points2; ++i)
{
S2Point p = S2Testing.SamplePoint(cap);
if (hull.Contains(p))
{
query.AddPoint(p);
}
}
// Finally, build a new convex hull and check that it hasn't changed.
var hull2 = (query.GetConvexHull());
_logger.WriteLine("Iteration: " + iter);
Assert.True(hull2.BoundaryEquals(hull));
}
}
public void AddEdges(S2Cap index_cap, int num_edges, MutableS2ShapeIndex index)
{
var points = new List <S2Point>();
for (int i = 0; i < num_edges; ++i)
{
points.Add(S2Testing.SamplePoint(index_cap));
}
index.Add(new S2PointVectorShape(points.ToArray()));
}
public void Test_S2_ProjectError()
{
for (int iter = 0; iter < 1000; ++iter)
{
S2Testing.Random.Reset(iter + 1); // Easier to reproduce a specific case.
S2Point a = ChoosePoint();
S2Point b = ChoosePoint();
S2Point n = S2.RobustCrossProd(a, b).Normalize();
S2Point x = S2Testing.SamplePoint(new S2Cap(n, S1Angle.FromRadians(1e-15)));
S2Point p = S2.Project(x, a, b);
Assert.True(S2Pred.CompareEdgeDistance(
p, a, b, new S1ChordAngle(S2.kProjectPerpendicularErrorS1Angle)) < 0);
}
}
private static void CompareS2LoopToShape(S2Loop loop, S2Shape shape)
{
MutableS2ShapeIndex index = new();
index.Add(shape);
S2Cap cap = loop.GetCapBound();
var query = index.MakeS2ContainsPointQuery();
for (int iter = 0; iter < 100; ++iter)
{
S2Point point = S2Testing.SamplePoint(cap);
Assert.Equal(loop.Contains(point),
query.ShapeContains(index.Shape(0), point));
}
}
public void Test_S2Cell_ConsistentWithS2CellIdFromPoint()
{
// Construct many points that are nearly on an S2Cell edge, and verify that
// S2Cell(S2CellId(p)).Contains(p) is always true.
for (int iter = 0; iter < 1000; ++iter)
{
S2Cell cell = new(S2Testing.GetRandomCellId());
int i = S2Testing.Random.Uniform(4);
S2Point v1 = cell.Vertex(i);
S2Point v2 = S2Testing.SamplePoint(
new S2Cap(cell.Vertex(i + 1), S1Angle.FromRadians(1e-15)));
S2Point p = S2.Interpolate(S2Testing.Random.RandDouble(), v1, v2);
Assert.True(new S2Cell(new S2CellId(p)).Contains(p));
}
}
public void Test_VisitIntersectingShapes_Polygons()
{
MutableS2ShapeIndex index = new();
S2Cap center_cap = new(new(1, 0, 0), S1Angle.FromRadians(0.5));
S2Testing.Fractal fractal = new();
for (int i = 0; i < 10; ++i)
{
fractal.SetLevelForApproxMaxEdges(3 * 64);
S2Point center = S2Testing.SamplePoint(center_cap);
index.Add(new S2Loop.Shape(
fractal.MakeLoop(S2Testing.GetRandomFrameAt(center),
S1Angle.FromRadians(S2Testing.Random.RandDouble()))));
}
// Also add a big polygon containing most of the polygons above to ensure
// that we test containment of cells that are ancestors of index cells.
index.Add(NewPaddedCell(S2CellId.FromFace(0), 0));
new VisitIntersectingShapesTest(index).Run();
}
public void Test_S2Cell_RectBoundIsLargeEnough()
{
// Construct many points that are nearly on an S2Cell edge, and verify that
// whenever the cell contains a point P then its bound contains S2LatLng(P).
for (int iter = 0; iter < 1000; /* advanced in loop below */)
{
S2Cell cell = new(S2Testing.GetRandomCellId());
int i = S2Testing.Random.Uniform(4);
S2Point v1 = cell.Vertex(i);
S2Point v2 = S2Testing.SamplePoint(
new S2Cap(cell.Vertex(i + 1), S1Angle.FromRadians(1e-15)));
S2Point p = S2.Interpolate(S2Testing.Random.RandDouble(), v1, v2);
if (new S2Loop(cell).Contains(p))
{
Assert.True(cell.GetRectBound().Contains(new S2LatLng(p)));
++iter;
}
}
}
public void Test_S2ContainsPointQuery_GetContainingShapes()
{
// Also tests ShapeContains().
int kNumVerticesPerLoop = 10;
S1Angle kMaxLoopRadius = S2Testing.KmToAngle(10);
S2Cap center_cap = new(S2Testing.RandomPoint(), kMaxLoopRadius);
MutableS2ShapeIndex index = new();
for (int i = 0; i < 100; ++i)
{
var loop = S2Loop.MakeRegularLoop(
S2Testing.SamplePoint(center_cap),
S2Testing.Random.RandDouble() * kMaxLoopRadius, kNumVerticesPerLoop);
index.Add(new S2Loop.Shape(loop));
}
var query = index.MakeS2ContainsPointQuery();
for (int i = 0; i < 100; ++i)
{
S2Point p = S2Testing.SamplePoint(center_cap);
List <S2Shape> expected = new();
foreach (var shape in index)
{
var loop = ((S2Loop.Shape)shape).Loop;
if (loop.Contains(p))
{
Assert.True(query.ShapeContains(shape, p));
expected.Add(shape);
}
else
{
Assert.False(query.ShapeContains(shape, p));
}
}
var actual = query.GetContainingShapes(p);
Assert.Equal(expected, actual);
}
}
public void Test_VisitIntersectingShapes_Polylines()
{
MutableS2ShapeIndex index = new();
S2Cap center_cap = new(new S2Point(1, 0, 0), S1Angle.FromRadians(0.5));
for (int i = 0; i < 50; ++i)
{
S2Point center = S2Testing.SamplePoint(center_cap);
S2Point[] vertices;
if (S2Testing.Random.OneIn(10))
{
vertices = new[] { center, center }; // Try a few degenerate polylines.
}
else
{
vertices = S2Testing.MakeRegularPoints(
center, S1Angle.FromRadians(S2Testing.Random.RandDouble()),
S2Testing.Random.Uniform(20) + 3);
}
index.Add(new S2LaxPolylineShape(vertices));
}
new VisitIntersectingShapesTest(index).Run();
}
// The running time of this test is proportional to
// (num_indexes + num_queries) * num_edges.
// (Note that every query is checked using the brute force algorithm.)
private static void TestWithIndexFactory(IShapeIndexFactory factory,
int num_indexes, int num_edges,
int num_queries)
{
// Build a set of MutableS2ShapeIndexes containing the desired geometry.
List <S2Cap> index_caps = new();
List <MutableS2ShapeIndex> indexes = new();
for (int i = 0; i < num_indexes; ++i)
{
S2Testing.Random.Reset(S2Testing.Random.RandomSeed + i);
index_caps.Add(new S2Cap(S2Testing.RandomPoint(), kTestCapRadius));
indexes.Add(new MutableS2ShapeIndex());
factory.AddEdges(index_caps.Last(), num_edges, indexes.Last());
}
for (int i = 0; i < num_queries; ++i)
{
S2Testing.Random.Reset(S2Testing.Random.RandomSeed + i);
int i_index = S2Testing.Random.Uniform(num_indexes);
var index_cap = index_caps[i_index];
// Choose query points from an area approximately 4x larger than the
// geometry being tested.
var query_radius = 2 * index_cap.RadiusAngle();
S2Cap query_cap = new(index_cap.Center, query_radius);
S2ClosestEdgeQuery query = new(indexes[i_index]);
// Occasionally we don't set any limit on the number of result edges.
// (This may return all edges if we also don't set a distance limit.)
if (!S2Testing.Random.OneIn(5))
{
query.Options_.MaxResults = (1 + S2Testing.Random.Uniform(10));
}
// We set a distance limit 2/3 of the time.
if (!S2Testing.Random.OneIn(3))
{
query.Options_.MaxDistance = new(S2Testing.Random.RandDouble() * query_radius);
}
if (S2Testing.Random.OneIn(2))
{
// Choose a maximum error whose logarithm is uniformly distributed over
// a reasonable range, except that it is sometimes zero.
query.Options_.MaxError = new(S1Angle.FromRadians(
Math.Pow(1e-4, S2Testing.Random.RandDouble()) * query_radius.Radians));
}
query.Options_.IncludeInteriors = (S2Testing.Random.OneIn(2));
int target_type = S2Testing.Random.Uniform(4);
if (target_type == 0)
{
// Find the edges closest to a given point.
S2Point point = S2Testing.SamplePoint(query_cap);
S2ClosestEdgeQuery.PointTarget target = new(point);
var closest = TestFindClosestEdges(target, query);
if (!closest.Distance.IsInfinity())
{
// Also test the Project method.
Assert2.Near(
closest.Distance.ToAngle().Radians,
new S1Angle(point, query.Project(point, closest)).Radians,
kTestChordAngleError);
}
}
else if (target_type == 1)
{
// Find the edges closest to a given edge.
S2Point a = S2Testing.SamplePoint(query_cap);
S2Point b = S2Testing.SamplePoint(
new S2Cap(a, Math.Pow(1e-4, S2Testing.Random.RandDouble()) * query_radius));
S2ClosestEdgeQuery.EdgeTarget target = new(a, b);
TestFindClosestEdges(target, query);
}
else if (target_type == 2)
{
// Find the edges closest to a given cell.
int min_level = S2.kMaxDiag.GetLevelForMaxValue(query_radius.Radians);
int level = min_level + S2Testing.Random.Uniform(
S2.kMaxCellLevel - min_level + 1);
S2Point a = S2Testing.SamplePoint(query_cap);
S2Cell cell = new(new S2CellId(a).Parent(level));
S2ClosestEdgeQuery.CellTarget target = new(cell);
TestFindClosestEdges(target, query);
}
else
{
Assert.Equal(3, target_type);
// Use another one of the pre-built indexes as the target.
int j_index = S2Testing.Random.Uniform(num_indexes);
S2ClosestEdgeQuery.ShapeIndexTarget target = new(indexes[j_index]);
target.IncludeInteriors = (S2Testing.Random.OneIn(2));
TestFindClosestEdges(target, query);
}
}
}
