// Verifies that EncodedS2LaxPolygonShape behaves identically to
// S2LaxPolygonShape. Also supports testing that the encoded form is identical
// to the re-encoded form.
private static void TestEncodedS2LaxPolygonShape(S2LaxPolygonShape original)
{
Encoder encoder = new();
original.Encode(encoder, CodingHint.COMPACT);
var decoder = encoder.Decoder();
var(success, encoded) = EncodedS2LaxPolygonShape.Init(decoder);
Assert.True(success);
Assert.Equal(encoded.NumLoops, original.NumLoops);
Assert.Equal(encoded.NumVertices, original.NumVertices);
Assert.Equal(encoded.NumEdges(), original.NumEdges());
Assert.Equal(encoded.NumChains(), original.NumChains());
Assert.Equal(encoded.Dimension(), original.Dimension());
Assert.Equal(encoded.IsEmpty(), original.IsEmpty());
Assert.Equal(encoded.IsFull(), original.IsFull());
Assert.Equal(encoded.GetReferencePoint(), original.GetReferencePoint());
for (int i = 0; i < original.NumLoops; ++i)
{
Assert.Equal(encoded.NumLoopVertices(i), original.NumLoopVertices(i));
Assert.Equal(encoded.GetChain(i), original.GetChain(i));
for (int j = 0; j < original.NumLoopVertices(i); ++j)
{
Assert.Equal(encoded.LoopVertex(i, j), original.LoopVertex(i, j));
Assert.Equal(encoded.ChainEdge(i, j), original.ChainEdge(i, j));
}
}
// Now test all the edges in a random order in order to exercise the cases
// involving prev_loop_.
var count = original.NumEdges();
List <int> edge_ids = new(count);
LinqUtils.Iota(edge_ids, 0, count);
var mt = new PseudoRandom.MersenneTwister();
edge_ids = edge_ids.Shuffle(mt.genrand_N).ToList();
foreach (var e in edge_ids)
{
Assert.Equal(encoded.GetChainPosition(e), original.GetChainPosition(e));
Assert.Equal(encoded.GetEdge(e), original.GetEdge(e));
}
// Let's also test that the encoded form can be encoded, yielding the same
// bytes as the originally encoded form.
Encoder reencoder = new();
encoded.Encode(reencoder, CodingHint.COMPACT);
Assert.True(encoder == reencoder);
}
public void Test_S2LaxPolygonShape_ManyLoopPolygon()
{
// Test a polygon with enough loops so that binary search is used to find
// the loop containing a given edge.
var loops = new List <List <S2Point> >();
for (int i = 0; i < 100; ++i)
{
var center = S2LatLng.FromDegrees(0, i).ToPoint();
var loop = S2Testing.MakeRegularPoints(
center, S1Angle.FromDegrees(0.1),
S2Testing.Random.Uniform(3));
loops.Add(loop.ToList());
}
var shape = new S2LaxPolygonShape(loops);
Assert.Equal(loops.Count, shape.NumLoops);
int num_vertices = 0;
Assert.Equal(loops.Count, shape.NumChains());
for (int i = 0; i < loops.Count; ++i)
{
Assert.Equal(loops[i].Count, shape.NumLoopVertices(i));
Assert.Equal(num_vertices, shape.GetChain(i).Start);
Assert.Equal(loops[i].Count, shape.GetChain(i).Length);
for (int j = 0; j < loops[i].Count; ++j)
{
Assert.Equal(loops[i][j], shape.LoopVertex(i, j));
int e = num_vertices + j;
Assert.Equal(shape.GetChainPosition(e), new S2Shape.ChainPosition(i, j));
Assert.Equal(loops[i][j], shape.GetEdge(e).V0);
Assert.Equal(loops[i][(j + 1) % loops[i].Count], shape.GetEdge(e).V1);
}
num_vertices += loops[i].Count;
}
Assert.Equal(num_vertices, shape.NumVertices);
Assert.Equal(num_vertices, shape.NumEdges());
// Now test all the edges in a random order in order to exercise the cases
// involving prev_loop_.
List <(int, int, int)> edges = new();
for (int i = 0, e = 0; i < loops.Count; ++i)
{
for (int j = 0; j < loops[i].Count; ++j, ++e)
{
edges.Add((e, i, j));
}
}
var mt = new PseudoRandom.MersenneTwister();
edges = edges.Shuffle(mt.genrand_N).ToList();
foreach (var(e, i, j) in edges)
{
Assert.Equal(shape.GetChainPosition(e), new S2Shape.ChainPosition(i, j));
var v0 = loops[i][j];
var v1 = loops[i][(j + 1) % loops[i].Count];
Assert.Equal(shape.GetEdge(e), new S2Shape.Edge(v0, v1));
}
TestEncodedS2LaxPolygonShape(shape);
}