public void Test_UVWFace()
{
// Check that GetUVWFace is consistent with GetUVWAxis.
for (int face = 0; face < 6; ++face)
{
for (int axis = 0; axis < 3; ++axis)
{
Assert.Equal(S2.GetFace(-S2.GetUVWAxis(face, axis)),
S2.GetUVWFace(face, axis, 0));
Assert.Equal(S2.GetFace(S2.GetUVWAxis(face, axis)),
S2.GetUVWFace(face, axis, 1));
}
}
}
public void Test_VisitCells_QueryEdgeOnFaceBoundary()
{
int kIters = 100;
for (int iter = 0; iter < kIters; ++iter)
{
_logger.WriteLine("Iteration " + iter);
// Choose an edge AB such that B is nearly on the edge between two S2 cube
// faces, and such that the result of clipping AB to the face that nominally
// contains B (according to S2.GetFace) is empty when no padding is used.
int a_face, b_face;
S2Point a, b;
R2Point a_uv, b_uv;
do
{
a_face = S2Testing.Random.Uniform(6);
a = S2.FaceUVtoXYZ(a_face, S2Testing.Random.UniformDouble(-1, 1),
S2Testing.Random.UniformDouble(-1, 1)).Normalize();
b_face = S2.GetUVWFace(a_face, 0, 1); // Towards positive u-axis
var uTmp = 1 - S2Testing.Random.Uniform(2) * 0.5 * S2.DoubleEpsilon;
b = S2.FaceUVtoXYZ(b_face, uTmp, S2Testing.Random.UniformDouble(-1, 1)).Normalize();
} while (S2.GetFace(b) != b_face ||
S2EdgeClipping.ClipToFace(a, b, b_face, out a_uv, out b_uv));
// Verify that the clipping result is non-empty when a padding of
// S2EdgeClipping.kFaceClipErrorUVCoord is used instead.
Assert.True(S2EdgeClipping.ClipToPaddedFace(a, b, b_face, S2EdgeClipping.kFaceClipErrorUVCoord,
out a_uv, out b_uv));
// Create an S2ShapeIndex containing a single edge BC, where C is on the
// same S2 cube face as B (which is different than the face containing A).
S2Point c = S2.FaceUVtoXYZ(b_face, S2Testing.Random.UniformDouble(-1, 1),
S2Testing.Random.UniformDouble(-1, 1)).Normalize();
MutableS2ShapeIndex index = new();
index.Add(new S2Polyline.OwningShape(
new S2Polyline(new S2Point[] { b, c })));
// Check that the intersection between AB and BC is detected when the face
// containing BC is specified as a root cell. (Note that VisitCells()
// returns false only if the CellVisitor returns false, and otherwise
// returns true.)
S2CrossingEdgeQuery query = new(index);
S2PaddedCell root = new(S2CellId.FromFace(b_face), 0);
Assert.False(query.VisitCells(a, b, root, (S2ShapeIndexCell x) => false));
}
}
