public Intersecter(bool selfIntersection, BuildLog buildLog = null)
{
this.selfIntersection = selfIntersection;
this.buildLog = buildLog;
}
public static SegmentList xor(SegmentList segments, BuildLog buildLog)
{
return(select(segments, xor_select_table, buildLog));
}
public static SegmentList differenceRev(SegmentList segments, BuildLog buildLog)
{
return(select(segments, differenceRev_select_table, buildLog));
}
public static SegmentList intersect(SegmentList segments, BuildLog buildLog)
{
return(select(segments, intersect_select_table, buildLog));
}
public static SegmentList union(SegmentList segments, BuildLog buildLog)
{
return(select(segments, union_select_table, buildLog));
}
public List <PointList> chain(SegmentList segments, BuildLog buildLog = null)
{
this.buildLog = buildLog;
this.chains = new List <PointList>();
this.regions = new List <PointList>();
foreach (var seg in segments)
{
var pt1 = seg.start;
var pt2 = seg.end;
if (Epsilon.pointsSame(pt1, pt2))
{
Console.WriteLine("PolyBool: Warning: Zero-length segment detected; your epsilon is probably too small or too large");
continue;
}
if (buildLog != null)
{
buildLog.chainStart(seg);
}
first_match = new Match()
{
index = 0,
matches_head = false,
matches_pt1 = false
};
second_match = new Match()
{
index = 0,
matches_head = false,
matches_pt1 = false
};
next_match = first_match;
for (var i = 0; i < chains.Count; i++)
{
var chain = chains[i];
var head = chain[0];
var head2 = chain[1];
var tail = chain[chain.Count - 1];
var tail2 = chain[chain.Count - 2];
if (Epsilon.pointsSame(head, pt1))
{
if (setMatch(i, true, true))
{
break;
}
}
else if (Epsilon.pointsSame(head, pt2))
{
if (setMatch(i, true, false))
{
break;
}
}
else if (Epsilon.pointsSame(tail, pt1))
{
if (setMatch(i, false, true))
{
break;
}
}
else if (Epsilon.pointsSame(tail, pt2))
{
if (setMatch(i, false, false))
{
break;
}
}
}
if (next_match == first_match)
{
// we didn't match anything, so create a new chain
chains.Add(new PointList()
{
pt1, pt2
});
if (buildLog != null)
{
buildLog.chainNew(pt1, pt2);
}
continue;
}
if (next_match == second_match)
{
// we matched a single chain
if (buildLog != null)
{
buildLog.chainMatch(first_match.index);
}
// add the other point to the apporpriate end, and check to see if we've closed the
// chain into a loop
var index = first_match.index;
var pt = first_match.matches_pt1 ? pt2 : pt1; // if we matched pt1, then we add pt2, etc
var addToHead = first_match.matches_head; // if we matched at head, then add to the head
var chain = chains[index];
var grow = addToHead ? chain[0] : chain[chain.Count - 1];
var grow2 = addToHead ? chain[1] : chain[chain.Count - 2];
var oppo = addToHead ? chain[chain.Count - 1] : chain[0];
var oppo2 = addToHead ? chain[chain.Count - 2] : chain[1];
if (Epsilon.pointsCollinear(grow2, grow, pt))
{
// grow isn't needed because it's directly between grow2 and pt:
// grow2 ---grow---> pt
if (addToHead)
{
if (buildLog != null)
{
buildLog.chainRemoveHead(first_match.index, pt);
}
chain.RemoveAt(0);
}
else
{
if (buildLog != null)
{
buildLog.chainRemoveTail(first_match.index, pt);
}
chain.RemoveAt(chain.Count - 1);
}
grow = grow2; // old grow is gone... new grow is what grow2 was
}
if (Epsilon.pointsSame(oppo, pt))
{
// we're closing the loop, so remove chain from chains
chains.RemoveAt(index);
if (Epsilon.pointsCollinear(oppo2, oppo, grow))
{
// oppo isn't needed because it's directly between oppo2 and grow:
// oppo2 ---oppo--->grow
if (addToHead)
{
if (buildLog != null)
{
buildLog.chainRemoveTail(first_match.index, grow);
}
chain.RemoveAt(chain.Count - 1);
}
else
{
if (buildLog != null)
{
buildLog.chainRemoveHead(first_match.index, grow);
}
chain.RemoveAt(0);
}
}
if (buildLog != null)
{
buildLog.chainClose(first_match.index);
}
// we have a closed chain!
regions.Add(chain);
continue;
}
// not closing a loop, so just add it to the apporpriate side
if (addToHead)
{
if (buildLog != null)
{
buildLog.chainAddHead(first_match.index, pt);
}
chain.Insert(0, pt);
}
else
{
if (buildLog != null)
{
buildLog.chainAddTail(first_match.index, pt);
}
chain.Add(pt);
}
continue;
}
// otherwise, we matched two chains, so we need to combine those chains together
var F = first_match.index;
var S = second_match.index;
if (buildLog != null)
{
buildLog.chainConnect(F, S);
}
var reverseF = chains[F].Count < chains[S].Count; // reverse the shorter chain, if needed
if (first_match.matches_head)
{
if (second_match.matches_head)
{
if (reverseF)
{
// <<<< F <<<< --- >>>> S >>>>
reverseChain(F);
// >>>> F >>>> --- >>>> S >>>>
appendChain(F, S);
}
else
{
// <<<< F <<<< --- >>>> S >>>>
reverseChain(S);
// <<<< F <<<< --- <<<< S <<<< logically same as:
// >>>> S >>>> --- >>>> F >>>>
appendChain(S, F);
}
}
else
{
// <<<< F <<<< --- <<<< S <<<< logically same as:
// >>>> S >>>> --- >>>> F >>>>
appendChain(S, F);
}
}
else
{
if (second_match.matches_head)
{
// >>>> F >>>> --- >>>> S >>>>
appendChain(F, S);
}
else
{
if (reverseF)
{
// >>>> F >>>> --- <<<< S <<<<
reverseChain(F);
// <<<< F <<<< --- <<<< S <<<< logically same as:
// >>>> S >>>> --- >>>> F >>>>
appendChain(S, F);
}
else
{
// >>>> F >>>> --- <<<< S <<<<
reverseChain(S);
// >>>> F >>>> --- >>>> S >>>>
appendChain(F, S);
}
}
}
}
return(regions);
}
