private bool JoinPoints(JoinRec j, out OutPt p1, out OutPt p2)
{
Contract.Requires(j != null);
Contract.Requires(j.Poly1Idx >= 0 && j.Poly1Idx < _polyOuts.Count);
Contract.Requires(j.Poly2Idx >= 0 && j.Poly2Idx < _polyOuts.Count);
p1 = null;
p2 = null;
var outRec1 = _polyOuts[j.Poly1Idx];
var outRec2 = _polyOuts[j.Poly2Idx];
if (outRec1 == null || outRec2 == null)
return false;
var pp1A = outRec1.Pts;
var pp2A = outRec2.Pts;
IntPoint pt1 = j.Pt2A, pt2 = j.Pt2B;
IntPoint pt3 = j.Pt1A, pt4 = j.Pt1B;
if (!FindSegment(ref pp1A, ref pt1, ref pt2))
return false;
if (outRec1 == outRec2)
{
//we're searching the same polygon for overlapping segments so
//segment 2 mustn't be the same as segment 1 ...
pp2A = pp1A.Next;
if (!FindSegment(ref pp2A, ref pt3, ref pt4) || (pp2A == pp1A))
return false;
}
else if (!FindSegment(ref pp2A, ref pt3, ref pt4))
return false;
if (!GetOverlapSegment(pt1, pt2, pt3, pt4, out pt1, out pt2))
return false;
OutPt p3, p4, prev = pp1A.Prev;
//get p1 & p2 polypts - the overlap start & endpoints on poly1
if (pp1A.Pt.Equals(pt1))
p1 = pp1A;
else if (prev.Pt.Equals(pt1))
p1 = prev;
else
p1 = InsertPolyPtBetween(pp1A, prev, pt1);
if (pp1A.Pt.Equals(pt2))
p2 = pp1A;
else if (prev.Pt.Equals(pt2))
p2 = prev;
else if ((p1 == pp1A) || (p1 == prev))
p2 = InsertPolyPtBetween(pp1A, prev, pt2);
else if (Pt3IsBetweenPt1AndPt2(pp1A.Pt, p1.Pt, pt2))
p2 = InsertPolyPtBetween(pp1A, p1, pt2);
else
p2 = InsertPolyPtBetween(p1, prev, pt2);
//get p3 & p4 polypts - the overlap start & endpoints on poly2
prev = pp2A.Prev;
if (pp2A.Pt.Equals(pt1))
p3 = pp2A;
else if (prev.Pt.Equals(pt1))
p3 = prev;
else
p3 = InsertPolyPtBetween(pp2A, prev, pt1);
if (pp2A.Pt.Equals(pt2))
p4 = pp2A;
else if (prev.Pt.Equals(pt2))
p4 = prev;
else if ((p3 == pp2A) || (p3 == prev))
p4 = InsertPolyPtBetween(pp2A, prev, pt2);
else if (Pt3IsBetweenPt1AndPt2(pp2A.Pt, p3.Pt, pt2))
p4 = InsertPolyPtBetween(pp2A, p3, pt2);
else
p4 = InsertPolyPtBetween(p3, prev, pt2);
//p1.pt == p3.pt and p2.pt == p4.pt so join p1 to p3 and p2 to p4 ...
if (p1.Next == p2 && p3.Prev == p4)
{
p1.Next = p3;
p3.Prev = p1;
p2.Prev = p4;
p4.Next = p2;
return true;
}
else if (p1.Prev == p2 && p3.Next == p4)
{
p1.Prev = p3;
p3.Next = p1;
p2.Next = p4;
p4.Prev = p2;
return true;
}
else
return false; //an orientation is probably wrong
}
private void AddJoin(TEdge e1, TEdge e2, int e1OutIdx, int e2OutIdx)
{
Contract.Requires(e1 != null);
Contract.Requires(e2 != null);
var jr = new JoinRec {
Poly1Idx = e1OutIdx >= 0 ? e1OutIdx : e1.OutIdx,
Pt1A = new IntPoint(e1.XCurr, e1.YCurr),
Pt1B = new IntPoint(e1.XTop, e1.YTop),
Poly2Idx = e2OutIdx >= 0 ? e2OutIdx : e2.OutIdx,
Pt2A = new IntPoint(e2.XCurr, e2.YCurr),
Pt2B = new IntPoint(e2.XTop, e2.YTop)
};
_joins.Add(jr);
}
private void FixupJoinRecs(JoinRec j, OutPt pt, int startIdx)
{
for (var k = startIdx; k < _joins.Count; k++)
{
var j2 = _joins[k];
if (j2.Poly1Idx == j.Poly1Idx && InternalHelpers.PointIsVertex(j2.Pt1A, pt))
j2.Poly1Idx = j.Poly2Idx;
if (j2.Poly2Idx == j.Poly1Idx && InternalHelpers.PointIsVertex(j2.Pt2A, pt))
j2.Poly2Idx = j.Poly2Idx;
}
}
