private void PreparePolygons(IEnumerable <Poly2Tri.DelaunayTriangle> triangles)
{
this.PolygonEdges.Clear();
this.Polygons.Clear();
// For building edges we need a mapping of the original triangles to polygons
Dictionary <Poly2Tri.DelaunayTriangle, Poly2Tri.Point2DList> triangleToPolygon = new Dictionary <Poly2Tri.DelaunayTriangle, Poly2Tri.Point2DList>();
Dictionary <Poly2Tri.Point2DList, Poly2Tri.DelaunayTriangle> polygonToTriangle = new Dictionary <Poly2Tri.Point2DList, Poly2Tri.DelaunayTriangle>();
// Initially, our polygons are simply the triangles in polygon form
foreach (var triangle in triangles)
{
var polygonPoints = triangle.Points.Select(p => new Poly2Tri.Point2D(p.X, p.Y)).ToList();
Poly2Tri.Point2DList polygon = new Poly2Tri.Point2DList(polygonPoints);
triangleToPolygon[triangle] = polygon;
polygonToTriangle[polygon] = triangle;
this.Polygons.Add(polygon);
}
// Build up the edge list
foreach (var polygon in this.Polygons)
{
// Does this polygon have any neighbors? If so, that's how we make our edges.
var triangle = polygonToTriangle[polygon];
// We can have up to 3 neighbors on each triangle
for (int n = 0; n < 3; ++n)
{
var neighborTriangle = triangle.Neighbors[n];
if (neighborTriangle == null)
{
continue;
}
if (!triangleToPolygon.ContainsKey(neighborTriangle))
{
continue;
}
var neighborPolygon = triangleToPolygon[neighborTriangle];
// If the neighbor polygon still has a triangle associated with it then we haven't added its edges yet
// Otherwise, we have added her edges and we don't want to do so again
if (!polygonToTriangle.ContainsKey(neighborPolygon))
{
continue;
}
// Gather the points needed for the edge
Poly2Tri.TriangulationPoint triPoint1 = triangle.Points[(n + 1) % 3];
Poly2Tri.TriangulationPoint triPoint2 = triangle.Points[(n + 2) % 3];
// Create an polygon edge
SharedPolygonEdge edge = new SharedPolygonEdge();
edge.PolygonA = polygon;
edge.PolygonB = neighborPolygon;
edge.EdgePoint1 = new Poly2Tri.PolygonPoint(triPoint1.X, triPoint1.Y);
edge.EdgePoint2 = new Poly2Tri.PolygonPoint(triPoint2.X, triPoint2.Y);
this.PolygonEdges.Add(edge);
}
// Remove the polygon from the triangle mapping. We are done with it.
polygonToTriangle.Remove(polygon);
}
}
private void PreparePolygons(IEnumerable<Poly2Tri.DelaunayTriangle> triangles)
{
this.PolygonEdges.Clear();
this.Polygons.Clear();
// For building edges we need a mapping of the original triangles to polygons
Dictionary<Poly2Tri.DelaunayTriangle, Poly2Tri.Point2DList> triangleToPolygon = new Dictionary<Poly2Tri.DelaunayTriangle, Poly2Tri.Point2DList>();
Dictionary<Poly2Tri.Point2DList, Poly2Tri.DelaunayTriangle> polygonToTriangle = new Dictionary<Poly2Tri.Point2DList, Poly2Tri.DelaunayTriangle>();
// Initially, our polygons are simply the triangles in polygon form
foreach (var triangle in triangles)
{
var polygonPoints = triangle.Points.Select(p => new Poly2Tri.Point2D(p.X, p.Y)).ToList();
Poly2Tri.Point2DList polygon = new Poly2Tri.Point2DList(polygonPoints);
triangleToPolygon[triangle] = polygon;
polygonToTriangle[polygon] = triangle;
this.Polygons.Add(polygon);
}
// Build up the edge list
foreach (var polygon in this.Polygons)
{
// Does this polygon have any neighbors? If so, that's how we make our edges.
var triangle = polygonToTriangle[polygon];
// We can have up to 3 neighbors on each triangle
for (int n = 0; n < 3; ++n)
{
var neighborTriangle = triangle.Neighbors[n];
if (neighborTriangle == null)
continue;
if (!triangleToPolygon.ContainsKey(neighborTriangle))
continue;
var neighborPolygon = triangleToPolygon[neighborTriangle];
// If the neighbor polygon still has a triangle associated with it then we haven't added its edges yet
// Otherwise, we have added her edges and we don't want to do so again
if (!polygonToTriangle.ContainsKey(neighborPolygon))
continue;
// Gather the points needed for the edge
Poly2Tri.TriangulationPoint triPoint1 = triangle.Points[(n + 1) % 3];
Poly2Tri.TriangulationPoint triPoint2 = triangle.Points[(n + 2) % 3];
// Create an polygon edge
SharedPolygonEdge edge = new SharedPolygonEdge();
edge.PolygonA = polygon;
edge.PolygonB = neighborPolygon;
edge.EdgePoint1 = new Poly2Tri.PolygonPoint(triPoint1.X, triPoint1.Y);
edge.EdgePoint2 = new Poly2Tri.PolygonPoint(triPoint2.X, triPoint2.Y);
this.PolygonEdges.Add(edge);
}
// Remove the polygon from the triangle mapping. We are done with it.
polygonToTriangle.Remove(polygon);
}
}
private void CombinePolygonsAlongEdge(int index)
{
// We are going to combine all the points from polygon B into polygon A
var edge = this.PolygonEdges[index];
// Gather a list of all the points from polygon B to be added
// This is all the points from polygon B except for the shared edge
List <Poly2Tri.Point2D> pointsToAdd = new List <Poly2Tri.Point2D>();
{
int edgeStartOnBIndex = edge.PolygonB.IndexOf(edge.EdgePoint1);
int edgeStopOnBIndex = edge.PolygonB.IndexOf(edge.EdgePoint2);
int indexToAdd = edge.PolygonB.NextIndex(edgeStartOnBIndex);
while (indexToAdd != edgeStopOnBIndex)
{
Poly2Tri.Point2D point = edge.PolygonB[indexToAdd];
pointsToAdd.Add(point);
indexToAdd = edge.PolygonB.NextIndex(indexToAdd);
}
}
// Insert the points to add between the edge points on polygon A
List <Poly2Tri.Point2D> newPolygonAPoints = edge.PolygonA.ToList();
{
int edgeStartOnAIndex = edge.PolygonA.IndexOf(edge.EdgePoint1);
int nextIndexA = edge.PolygonA.NextIndex(edgeStartOnAIndex);
newPolygonAPoints.InsertRange(nextIndexA, pointsToAdd);
}
// Create a new polygon A
Poly2Tri.Point2DList newPolygonA = new Poly2Tri.Point2DList(newPolygonAPoints);
this.Polygons.Add(newPolygonA);
// Any furter edges that had PolygonA or PolygonB in it must be updated
for (int i = index + 1; i < this.PolygonEdges.Count; ++i)
{
var furtherEdge = this.PolygonEdges[i];
if (furtherEdge.PolygonA == edge.PolygonA)
{
furtherEdge.PolygonA = newPolygonA;
}
else if (furtherEdge.PolygonA == edge.PolygonB)
{
furtherEdge.PolygonA = newPolygonA;
}
if (furtherEdge.PolygonB == edge.PolygonA)
{
furtherEdge.PolygonB = newPolygonA;
}
else if (furtherEdge.PolygonB == edge.PolygonB)
{
furtherEdge.PolygonB = newPolygonA;
}
}
// Old PolygonA and PolygonB are removed from the list of polygons
this.Polygons.Remove(edge.PolygonA);
this.Polygons.Remove(edge.PolygonB);
}
private void CombinePolygonsAlongEdge(int index)
{
// We are going to combine all the points from polygon B into polygon A
var edge = this.PolygonEdges[index];
// Gather a list of all the points from polygon B to be added
// This is all the points from polygon B except for the shared edge
List<Poly2Tri.Point2D> pointsToAdd = new List<Poly2Tri.Point2D>();
{
int edgeStartOnBIndex = edge.PolygonB.IndexOf(edge.EdgePoint1);
int edgeStopOnBIndex = edge.PolygonB.IndexOf(edge.EdgePoint2);
int indexToAdd = edge.PolygonB.NextIndex(edgeStartOnBIndex);
while (indexToAdd != edgeStopOnBIndex)
{
Poly2Tri.Point2D point = edge.PolygonB[indexToAdd];
pointsToAdd.Add(point);
indexToAdd = edge.PolygonB.NextIndex(indexToAdd);
}
}
// Insert the points to add between the edge points on polygon A
List<Poly2Tri.Point2D> newPolygonAPoints = edge.PolygonA.ToList();
{
int edgeStartOnAIndex = edge.PolygonA.IndexOf(edge.EdgePoint1);
int nextIndexA = edge.PolygonA.NextIndex(edgeStartOnAIndex);
newPolygonAPoints.InsertRange(nextIndexA, pointsToAdd);
}
// Create a new polygon A
Poly2Tri.Point2DList newPolygonA = new Poly2Tri.Point2DList(newPolygonAPoints);
this.Polygons.Add(newPolygonA);
// Any furter edges that had PolygonA or PolygonB in it must be updated
for (int i = index + 1; i < this.PolygonEdges.Count; ++i)
{
var furtherEdge = this.PolygonEdges[i];
if (furtherEdge.PolygonA == edge.PolygonA)
{
furtherEdge.PolygonA = newPolygonA;
}
else if (furtherEdge.PolygonA == edge.PolygonB)
{
furtherEdge.PolygonA = newPolygonA;
}
if (furtherEdge.PolygonB == edge.PolygonA)
{
furtherEdge.PolygonB = newPolygonA;
}
else if (furtherEdge.PolygonB == edge.PolygonB)
{
furtherEdge.PolygonB = newPolygonA;
}
}
// Old PolygonA and PolygonB are removed from the list of polygons
this.Polygons.Remove(edge.PolygonA);
this.Polygons.Remove(edge.PolygonB);
}
