/** Erases all edges of the given loop and marks them as unused. */
private void RejectLoop(S2Loop v, int n, System.Collections.Generic.IList <S2Edge> unusedEdges)
{
for (int i = n - 1, j = 0; j < n; i = j++)
{
unusedEdges.Add(new S2Edge(v.Vertex(i), v.Vertex(j)));
}
}
private void EraseLoop(S2Loop v, int n)
{
for (int i = n - 1, j = 0; j < n; i = j++)
{
EraseEdge(v.Vertex(i), v.Vertex(j));
}
}
/**
* Copy constructor.
*/
public S2Polygon(S2Loop loop)
{
_loops = new List <S2Loop>();
_bound = loop.RectBound;
_hasHoles = false;
_numVertices = loop.NumVertices;
_loops.Add(loop);
}
private static void InsertLoop(S2Loop newLoop, S2Loop parent, System.Collections.Generic.IDictionary <NullObject <S2Loop>, List <S2Loop> > loopMap)
{
List <S2Loop> children = null;
if (loopMap.ContainsKey(parent))
{
children = loopMap[parent];
}
if (children == null)
{
children = new List <S2Loop>();
loopMap[parent] = children;
}
foreach (var child in children)
{
if (child.ContainsNested(newLoop))
{
InsertLoop(newLoop, child, loopMap);
return;
}
}
// No loop may contain the complement of another loop. (Handling this case
// is significantly more complicated.)
// assert (parent == null || !newLoop.containsNested(parent));
// Some of the children of the parent loop may now be children of
// the new loop.
List <S2Loop> newChildren = null;
if (loopMap.ContainsKey(newLoop))
{
newChildren = loopMap[newLoop];
}
for (var i = 0; i < children.Count;)
{
var child = children[i];
if (newLoop.ContainsNested(child))
{
if (newChildren == null)
{
newChildren = new List <S2Loop>();
loopMap[newLoop] = newChildren;
}
newChildren.Add(child);
children.RemoveAt(i);
}
else
{
++i;
}
}
children.Add(newLoop);
}
/**
* Add all edges in the given loop. If the sign() of the loop is negative
* (i.e. this loop represents a hole), the reverse edges are added instead.
* This implies that "shells" are CCW and "holes" are CW, as required for the
* directed edges convention described above.
*
* This method does not take ownership of the loop.
*/
public void AddLoop(S2Loop loop)
{
var sign = loop.Sign;
for (var i = loop.NumVertices; i > 0; --i)
{
// Vertex indices need to be in the range [0, 2*num_vertices()-1].
AddEdge(loop.Vertex(i), loop.Vertex(i + sign));
}
}
/** Return true if any loop contains the given loop. */
private bool AnyLoopContains(S2Loop b)
{
for (var i = 0; i < NumLoops; ++i)
{
if (Loop(i).Contains(b))
{
return(true);
}
}
return(false);
}
/**
* If this method returns false, the region does not intersect the given cell.
* Otherwise, either region intersects the cell, or the intersection
* relationship could not be determined.
*/
public bool MayIntersect(S2Cell cell)
{
if (NumLoops == 1)
{
return(Loop(0).MayIntersect(cell));
}
var cellBound = cell.RectBound;
if (!_bound.Intersects(cellBound))
{
return(false);
}
var cellLoop = new S2Loop(cell, cellBound);
var cellPoly = new S2Polygon(cellLoop);
return(Intersects(cellPoly));
}
/**
* If this method returns true, the region completely contains the given cell.
* Otherwise, either the region does not contain the cell or the containment
* relationship could not be determined.
*/
public bool Contains(S2Cell cell)
{
if (NumLoops == 1)
{
return(Loop(0).Contains(cell));
}
var cellBound = cell.RectBound;
if (!_bound.Contains(cellBound))
{
return(false);
}
var cellLoop = new S2Loop(cell, cellBound);
var cellPoly = new S2Polygon(cellLoop);
return(Contains(cellPoly));
}
private int ContainsOrCrosses(S2Loop b)
{
var inside = false;
for (var i = 0; i < NumLoops; ++i)
{
var result = Loop(i).ContainsOrCrosses(b);
if (result < 0)
{
return(-1); // The loop boundaries intersect.
}
if (result > 0)
{
inside ^= true;
}
}
return(inside ? 1 : 0); // True if loop B is contained by the polygon.
}
private void InitLoop(S2Loop loop, int depth, System.Collections.Generic.IDictionary <NullObject <S2Loop>, List <S2Loop> > loopMap)
{
if (loop != null)
{
loop.Depth = depth;
_loops.Add(loop);
}
List <S2Loop> children = null;
if (loopMap.ContainsKey(loop))
{
children = loopMap[loop];
}
if (children != null)
{
foreach (var child in children)
{
InitLoop(child, depth + 1, loopMap);
}
}
}
public AnonS2EdgeIndex(S2Loop This)
{
_this = This;
}
/**
* We start at the given edge and assemble a loop taking left turns whenever
* possible. We stop the loop as soon as we encounter any vertex that we have
* seen before *except* for the first vertex (v0). This ensures that only CCW
* loops are constructed when possible.
*/
private S2Loop AssembleLoop(S2Point v0, S2Point v1, System.Collections.Generic.IList <S2Edge> unusedEdges)
{
// The path so far.
var path = new List <S2Point>();
// Maps a vertex to its index in "path".
var index = new Dictionary <S2Point, int>();
path.Add(v0);
path.Add(v1);
index.Add(v1, 1);
while (path.Count >= 2)
{
// Note that "v0" and "v1" become invalid if "path" is modified.
v0 = path[path.Count - 2];
v1 = path[path.Count - 1];
var v2 = default(S2Point);
var v2Found = false;
HashBag <S2Point> vset;
_edges.TryGetValue(v1, out vset);
if (vset != null)
{
foreach (var v in vset)
{
// We prefer the leftmost outgoing edge, ignoring any reverse edges.
if (v.Equals(v0))
{
continue;
}
if (!v2Found || S2.OrderedCcw(v0, v2, v, v1))
{
v2 = v;
}
v2Found = true;
}
}
if (!v2Found)
{
// We've hit a dead end. Remove this edge and backtrack.
unusedEdges.Add(new S2Edge(v0, v1));
EraseEdge(v0, v1);
index.Remove(v1);
path.RemoveAt(path.Count - 1);
}
else if (!index.ContainsKey(v2))
{
// This is the first time we've visited this vertex.
index.Add(v2, path.Count);
path.Add(v2);
}
else
{
// We've completed a loop. Throw away any initial vertices that
// are not part of the loop.
var start = index[v2];
path = path.GetRange(start, path.Count - start);
if (_options.Validate && !S2Loop.IsValidLoop(path))
{
// We've constructed a loop that crosses itself, which can only happen
// if there is bad input data. Throw away the whole loop.
RejectLoop(path, path.Count, unusedEdges);
EraseLoop(path, path.Count);
return(null);
}
return(new S2Loop(path));
}
}
return(null);
}
