private int eventCompare(bool p1_isStart, ref Vector2 p1_1, ref Vector2 p1_2, bool p2_isStart, ref Vector2 p2_1, ref Vector2 p2_2)
{
// compare the selected points first
var comp = Epsilon.pointsCompare(p1_1, p2_1);
if (comp != 0)
{
return(comp);
}
// the selected points are the same
if (Epsilon.pointsSame(p1_2, p2_2)) // if the non-selected points are the same too...
{
return(0); // then the segments are equal
}
if (p1_isStart != p2_isStart) // if one is a start and the other isn't...
{
return(p1_isStart ? 1 : -1); // favor the one that isn't the start
}
// otherwise, we'll have to calculate which one is below the other manually
return(Epsilon.pointAboveOrOnLine(
p1_2,
p2_isStart ? p2_1 : p2_2, // order matters
p2_isStart ? p2_2 : p2_1
) ? 1 : -1);
}
private int statusCompare(EventNode ev1, EventNode ev2)
{
var a1 = ev1.seg.start;
var a2 = ev1.seg.end;
var b1 = ev2.seg.start;
var b2 = ev2.seg.end;
if (Epsilon.pointsCollinear(a1, b1, b2))
{
if (Epsilon.pointsCollinear(a2, b1, b2))
{
return(1); //eventCompare(true, a1, a2, true, b1, b2);
}
return(Epsilon.pointAboveOrOnLine(a2, b1, b2) ? 1 : -1);
}
return(Epsilon.pointAboveOrOnLine(a1, b1, b2) ? 1 : -1);
}
private void appendChain(int index1, int index2)
{
// index1 gets index2 appended to it, and index2 is removed
var chain1 = chains[index1];
var chain2 = chains[index2];
var tail = chain1[chain1.Count - 1];
var tail2 = chain1[chain1.Count - 2];
var head = chain2[0];
var head2 = chain2[1];
if (Epsilon.pointsCollinear(tail2, tail, head))
{
// tail isn't needed because it's directly between tail2 and head
// tail2 ---tail---> head
if (buildLog != null)
{
buildLog.chainRemoveTail(index1, tail);
}
chain1.RemoveAt(chain1.Count - 1);
tail = tail2; // old tail is gone... new tail is what tail2 was
}
if (Epsilon.pointsCollinear(tail, head, head2))
{
// head isn't needed because it's directly between tail and head2
// tail ---head---> head2
if (buildLog != null)
{
buildLog.chainRemoveHead(index2, head);
}
chain2.RemoveAt(0);
}
if (buildLog != null)
{
buildLog.chainJoin(index1, index2);
}
chain1.AddRange(chain2);
chains.RemoveAt(index2);
}
public void addRegion(PointList region)
{
if (!selfIntersection)
{
throw new Exception("The addRegion() function is only intended for use when selfIntersection = false");
}
// Ensure that the polygon is fully closed (the start point and end point are exactly the same)
if (!Epsilon.pointsSame(region[region.Count - 1], region[0]))
{
region.Add(region[0]);
}
// regions are a list of points:
// [ [0, 0], [100, 0], [50, 100] ]
// you can add multiple regions before running calculate
var pt1 = new Point();
var pt2 = region[region.Count - 1];
for (var i = 0; i < region.Count; i++)
{
pt1 = pt2;
pt2 = region[i];
var forward = Epsilon.pointsCompare(pt1, pt2);
if (forward == 0) // points are equal, so we have a zero-length segment
{
continue; // just skip it
}
eventAddSegment(
segmentNew(
forward < 0 ? pt1 : pt2,
forward < 0 ? pt2 : pt1
),
true
);
}
}
public List <List <Vector2> > chain(SegmentList segments, BuildLog buildLog = null)
{
this.buildLog = buildLog;
this.chains = new List <List <Vector2> >();
this.regions = new List <List <Vector2> >();
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 List <Vector2>()
{
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);
}
private EventNode checkIntersection(EventNode ev1, EventNode ev2)
{
// returns the segment equal to ev1, or false if nothing equal
var seg1 = ev1.seg;
var seg2 = ev2.seg;
var a1 = seg1.start;
var a2 = seg1.end;
var b1 = seg2.start;
var b2 = seg2.end;
if (buildLog != null)
{
buildLog.checkIntersection(seg1, seg2);
}
Intersection intersect;
if (!Epsilon.linesIntersect(a1, a2, b1, b2, out intersect))
{
// segments are parallel or coincident
// if points aren't collinear, then the segments are parallel, so no intersections
if (!Epsilon.pointsCollinear(a1, a2, b1))
{
return(null);
}
// otherwise, segments are on top of each other somehow (aka coincident)
if (Epsilon.pointsSame(a1, b2) || Epsilon.pointsSame(a2, b1))
{
return(null); // segments touch at endpoints... no intersection
}
var a1_equ_b1 = Epsilon.pointsSame(a1, b1);
var a2_equ_b2 = Epsilon.pointsSame(a2, b2);
if (a1_equ_b1 && a2_equ_b2)
{
return(ev2); // segments are exactly equal
}
var a1_between = !a1_equ_b1 && Epsilon.pointBetween(a1, b1, b2);
var a2_between = !a2_equ_b2 && Epsilon.pointBetween(a2, b1, b2);
// handy for debugging:
// buildLog.log({
// a1_equ_b1: a1_equ_b1,
// a2_equ_b2: a2_equ_b2,
// a1_between: a1_between,
// a2_between: a2_between
// });
if (a1_equ_b1)
{
if (a2_between)
{
// (a1)---(a2)
// (b1)----------(b2)
eventDivide(ev2, a2);
}
else
{
// (a1)----------(a2)
// (b1)---(b2)
eventDivide(ev1, b2);
}
return(ev2);
}
else if (a1_between)
{
if (!a2_equ_b2)
{
// make a2 equal to b2
if (a2_between)
{
// (a1)---(a2)
// (b1)-----------------(b2)
eventDivide(ev2, a2);
}
else
{
// (a1)----------(a2)
// (b1)----------(b2)
eventDivide(ev1, b2);
}
}
// (a1)---(a2)
// (b1)----------(b2)
eventDivide(ev2, a1);
}
}
else
{
// otherwise, lines intersect at i.pt, which may or may not be between the endpoints
// is A divided between its endpoints? (exclusive)
if (intersect.alongA == 0)
{
if (intersect.alongB == -1) // yes, at exactly b1
{
eventDivide(ev1, b1);
}
else if (intersect.alongB == 0) // yes, somewhere between B's endpoints
{
eventDivide(ev1, intersect.pt);
}
else if (intersect.alongB == 1) // yes, at exactly b2
{
eventDivide(ev1, b2);
}
}
// is B divided between its endpoints? (exclusive)
if (intersect.alongB == 0)
{
if (intersect.alongA == -1) // yes, at exactly a1
{
eventDivide(ev2, a1);
}
else if (intersect.alongA == 0) // yes, somewhere between A's endpoints (exclusive)
{
eventDivide(ev2, intersect.pt);
}
else if (intersect.alongA == 1) // yes, at exactly a2
{
eventDivide(ev2, a2);
}
}
}
return(null);
}
