private static void MakeEnterExitList(CircularLinkedList <Vector2> subject,
CircularLinkedList <Vector2> clip,
Dictionary <Vector2, Pair <Vector2> > intersections,
CircularLinkedList <Vector2> entering,
CircularLinkedList <Vector2> exiting,
Polygon ClipP,
Polygon SbujectP)
{
LinkedListNode <Vector2> curr = subject.First;
do
{
if (intersections.ContainsKey(curr.Value))
{
bool isEntering = Vector2Cross(subject.NextOrFirst(curr).Value.X - subject.PreviousOrLast(curr).Value.X,
subject.NextOrFirst(curr).Value.Y - subject.PreviousOrLast(curr).Value.Y,
intersections[curr.Value].Second.X - intersections[curr.Value].First.X,
intersections[curr.Value].Second.Y - intersections[curr.Value].First.Y) < 0;
if (isEntering)
{
entering.AddLast(curr.Value);
}
else
{
exiting.AddLast(curr.Value);
}
}
curr = subject.NextOrFirst(curr);
} while (curr != subject.First);
}
public CircularLinkedList <T> Reverse()
{
CircularLinkedList <T> temp = new CircularLinkedList <T>();
foreach (var current in this)
{
temp.AddFirst(current);
}
return(temp);
}
public static List <Polygon> GetClippedPolygons(Polygon Clip, Polygon Subject)
{
List <Polygon> output = new List <Polygon>();
CircularLinkedList <Vector2> SubjectL = new CircularLinkedList <Vector2>();
CircularLinkedList <Vector2> ClipL = new CircularLinkedList <Vector2>();
//todo check if subject inside clip
bool AllPointsInside = true;
for (int i = 0; i < Subject.points.Count; i++)
{
if (!Clip.IsInside(Subject.points[i]))
{
AllPointsInside = false;
break;
}
}
if (AllPointsInside)
{
output.Add(Subject);
return(output);
}
for (int i = 0; i < Clip.points.Count; i++)
{
ClipL.AddLast(new Vector2(Clip.points[i].X, Clip.points[i].Y));
}
for (int i = 0; i < Subject.points.Count; i++)
{
SubjectL.AddLast(new Vector2(Subject.points[i].X, Subject.points[i].Y));
}
List <CircularLinkedList <Vector2> > result = (List <CircularLinkedList <Vector2> >)WeilerAtherton.Process(SubjectL, ClipL, Operation.Intersect, Clip, Subject);
for (int i = 0; i < result.Count; i++)
{
output.Add(new Polygon()
{
Completed = true
});
List <Vector2> temp = result[i].ToList <Vector2>();
for (int j = 0; j < temp.Count; j++)
{
output[output.Count - 1].Add(new Point((int)temp[j].X, (int)temp[j].Y));
}
}
return(output);
}
private static void Traverse(CircularLinkedList <Vector2> subject,
CircularLinkedList <Vector2> clip,
CircularLinkedList <Vector2> entering,
CircularLinkedList <Vector2> exiting,
List <CircularLinkedList <Vector2> > polygons,
Operation operation)
{
while (entering.Count > 0)
{
CircularLinkedList <Vector2> polygon = new CircularLinkedList <Vector2>();
Vector2 start = entering.First.Value;
LinkedListNode <Vector2> curNode = subject.Find(start);
polygon.AddLast(curNode.Value);
curNode = subject.NextOrFirst(curNode);
bool IsSubjectNode = true;
while (curNode.Value != start)
{
polygon.AddLast(curNode.Value);
if (entering.Contains(curNode.Value))
{
entering.Remove(curNode.Value);
IsSubjectNode = true;
curNode = subject.Find(curNode.Value);
}
if (exiting.Contains(curNode.Value))
{
exiting.Remove(curNode.Value);
IsSubjectNode = false;
curNode = clip.Find(curNode.Value);
}
if (IsSubjectNode)
{
curNode = subject.NextOrFirst(curNode);
}
else
{
curNode = clip.NextOrFirst(curNode);
}
}
entering.Remove(curNode.Value);
polygons.Add(polygon);
}
}
private static LinkedListNode <Vector2> TraverseList(CircularLinkedList <Vector2> contour,
CircularLinkedList <Vector2> entering,
CircularLinkedList <Vector2> exiting,
CircularLinkedList <Vector2> polygon,
LinkedListNode <Vector2> currentNode,
Vector2 startNode,
CircularLinkedList <Vector2> contour2)
{
LinkedListNode <Vector2> contourNode = contour.Find(currentNode.Value);
if (contourNode == null)
{
return(null);
}
entering.Remove(currentNode.Value);
while (contourNode != null
&&
!entering.Contains(contourNode.Value)
&&
!exiting.Contains(contourNode.Value)
)
{
polygon.AddLast(contourNode.Value);
contourNode = contour.NextOrFirst(contourNode);
if (contourNode.Value == startNode)
{
return(null);
}
}
entering.Remove(contourNode.Value);
polygon.AddLast(contourNode.Value);
return(contour2.NextOrFirst(contour2.Find(contourNode.Value)));
}
/// <summary>
///
/// </summary>
/// <param name="subject">Первый контур.</param>
/// <param name="clip">Второй контур.</param>
/// <param name="operation">Операция, проводимая над контурами.</param>
/// <returns></returns>
public static ICollection <CircularLinkedList <Vector2> > Process(CircularLinkedList <Vector2> subject,
CircularLinkedList <Vector2> clip,
Operation operation,
Polygon ClipP,
Polygon SubjectP)
{
LinkedListNode <Vector2> curSubject = subject.First;
Dictionary <Vector2, Pair <Vector2> > intersections = new Dictionary <Vector2, Pair <Vector2> >();
List <CircularLinkedList <Vector2> > polygons = new List <CircularLinkedList <Vector2> >();
if (AreEqual <Vector2>(subject, clip))
{
switch (operation)
{
case Operation.Union:
polygons.Add(subject);
return(polygons);
case Operation.Intersect:
polygons.Add(subject);
return(polygons);
case Operation.Difference:
// нужно как-то разграничивать внешние и внутренние полигоны
return(polygons);
default:
break;
}
}
do
{
LinkedListNode <Vector2> curClip = clip.First;
do
{
Vector2 intersectionPoint;
if (IntersectSegment(curSubject.Value,
subject.NextOrFirst(curSubject).Value,
curClip.Value,
clip.NextOrFirst(curClip).Value,
out intersectionPoint))
{
if (!intersections.ContainsKey(intersectionPoint))
{
subject.AddAfter(curSubject, intersectionPoint);
clip.AddAfter(curClip, intersectionPoint);
intersections.Add(intersectionPoint, new Pair <Vector2>(curClip.Value, clip.NextOrFirst(curClip).Value));
}
}
curClip = clip.NextOrFirst(curClip);
}while (curClip != clip.First);
curSubject = subject.NextOrFirst(curSubject);
}while (curSubject != subject.First);
CircularLinkedList <Vector2> entering = new CircularLinkedList <Vector2>();
CircularLinkedList <Vector2> exiting = new CircularLinkedList <Vector2>();
MakeEnterExitList(subject, clip, intersections, entering, exiting, ClipP, SubjectP);
Traverse(subject, clip, entering, exiting, polygons, operation);
return(polygons);
}