private void OneChain()
{
// Here are all unattached edges.
var edgeKvps = m_edgeMap.Where(kvp => kvp.Value.Count == 1).ToArray();
Edge[] edges = edgeKvps.Select(kvp => kvp.Key).ToArray();
Trace.WriteLine(string.Format("Chain length {0}", edges.Length));
// Find all the vertices connected to two polygons.
// This will necessarily lie on the edges above.
// These are vertices that are candidates for filling in with a polygon.
Vector3D[] vertices = m_vertexMap.Where(kvp => kvp.Value.Count > 1).Select(kvp => kvp.Key).ToArray();
HashSet <Vector3D> edgeVerts = new HashSet <Vector3D>();
foreach (Edge e in edges)
{
edgeVerts.Add(e.Start);
edgeVerts.Add(e.End);
}
//Vector3D[] vertices = edgeVerts.ToArray();
// XXX - Things that are hard.
// - How can we tell when a vertex is done?
// - How to avoid duplicating edges and vertices?
// Attempt to fill those verts.
foreach (Vector3D v in vertices)
{
Edge[] connectedEdges = m_vertexToEdgeMap[v].Intersect(edges, new H3.Cell.EdgeEqualityComparer()).ToArray();
// Is it on the chain?
if (connectedEdges.Length != 2)
{
continue;
}
Edge e1 = connectedEdges[0];
Edge e2 = connectedEdges[1];
Vector3D v1 = e1.Opp(v) - v;
Vector3D v2 = e2.Opp(v) - v;
double angle = v1.AngleTo(v2);
int nSides = PolyWithAngle(angle);
if (nSides != 0)
{
Vector3D normal = v1.Cross(v2);
Polygon poly = Polygon.CreateEuclidean(nSides, v, e1.Opp(v), normal);
// Things may have changed, so we must double check.
if (m_edgeMap[e1].Count == 1 &&
m_edgeMap[e2].Count == 1)
{
AddPoly(poly);
Trace.WriteLine(string.Format("Added {0}-gon", nSides));
}
}
}
}
/// <summary>
/// Connects two polygons by rotating them about edges of a static polygon
/// The three polygons will meet at a single vertex afterward (this vertex will be convex).
/// </summary>
private static void ConnectPolys(Polygon staticPoly, Polygon poly1, Polygon poly2)
{
// All three polygons should share one vertex.
// The edges connected to this vertex (that are in the static polyhedron)
// will be the hinges we rotate around to connect poly1 and poly2.
// These are also the edges the static poly shares with the other two.
Vector3D[] iVerts = staticPoly.Vertices.Intersect(poly1.Vertices).Intersect(poly2.Vertices).ToArray();
if (iVerts.Length != 1)
{
throw new System.ArgumentException();
}
Vector3D vertex = iVerts.First();
// Get our hinges and the two edges we want to merge.
Edge hinge1 = Hinge(staticPoly, poly1);
Edge hinge2 = Hinge(staticPoly, poly2);
Edge e1 = AdjacentEdge(poly1, hinge1, vertex);
Edge e2 = AdjacentEdge(poly2, hinge2, vertex);
// Construct circles through the edges they will rotate through when hinged.
Circle3D c1 = ConstructRotationCircle(hinge1, vertex, e1.Opp(vertex));
Circle3D c2 = ConstructRotationCircle(hinge2, vertex, e2.Opp(vertex));
// These circles both lie on the same sphere (with center = vertex and radius 1),
// and will intersect in two points. Those two points will determine the two
// locations we can hinge our polys to.
Vector3D i1, i2;
SphericalTrig.IntersectionSmart(vertex, c1, c2, out i1, out i2);
// XXX - Need to think more about how to choose among options.
double a1 = (e1.Opp(vertex) - c1.Center).AngleTo(i1 - c1.Center);
double a2 = (e2.Opp(vertex) - c2.Center).AngleTo(i1 - c2.Center);
RotatePoly(poly1, EdgeAxis(hinge1), -a1);
RotatePoly(poly2, EdgeAxis(hinge2), a2);
}