/// <summary>
/// Split all the encroached subsegments.
/// </summary>
/// <param name="triflaws">A flag that specifies whether one should take
/// note of new bad triangles that result from inserting vertices to repair
/// encroached subsegments.</param>
/// <remarks>
/// Each encroached subsegment is repaired by splitting it - inserting a
/// vertex at or near its midpoint. Newly inserted vertices may encroach
/// upon other subsegments; these are also repaired.
/// </remarks>
private void SplitEncSegs(bool triflaws)
{
Otri enctri = default(Otri);
Otri testtri = default(Otri);
Osub testsh = default(Osub);
Osub currentenc = default(Osub);
BadSubseg seg;
Vertex eorg, edest, eapex;
Vertex newvertex;
InsertVertexResult success;
float segmentlength, nearestpoweroftwo;
float split;
float multiplier, divisor;
bool acuteorg, acuteorg2, acutedest, acutedest2;
// Note that steinerleft == -1 if an unlimited number
// of Steiner points is allowed.
while (badsubsegs.Count > 0)
{
if (mesh.steinerleft == 0)
{
break;
}
seg = badsubsegs.Dequeue();
currentenc = seg.encsubseg;
eorg = currentenc.Org();
edest = currentenc.Dest();
// Make sure that this segment is still the same segment it was
// when it was determined to be encroached. If the segment was
// enqueued multiple times (because several newly inserted
// vertices encroached it), it may have already been split.
if (!Osub.IsDead(currentenc.seg) && (eorg == seg.subsegorg) && (edest == seg.subsegdest))
{
// To decide where to split a segment, we need to know if the
// segment shares an endpoint with an adjacent segment.
// The concern is that, if we simply split every encroached
// segment in its center, two adjacent segments with a small
// angle between them might lead to an infinite loop; each
// vertex added to split one segment will encroach upon the
// other segment, which must then be split with a vertex that
// will encroach upon the first segment, and so on forever.
// To avoid this, imagine a set of concentric circles, whose
// radii are powers of two, about each segment endpoint.
// These concentric circles determine where the segment is
// split. (If both endpoints are shared with adjacent
// segments, split the segment in the middle, and apply the
// concentric circles for later splittings.)
// Is the origin shared with another segment?
currentenc.TriPivot(ref enctri);
enctri.Lnext(ref testtri);
testtri.SegPivot(ref testsh);
acuteorg = testsh.seg != Mesh.dummysub;
// Is the destination shared with another segment?
testtri.LnextSelf();
testtri.SegPivot(ref testsh);
acutedest = testsh.seg != Mesh.dummysub;
// If we're using Chew's algorithm (rather than Ruppert's)
// to define encroachment, delete free vertices from the
// subsegment's diametral circle.
if (!behavior.ConformingDelaunay && !acuteorg && !acutedest)
{
eapex = enctri.Apex();
while ((eapex.type == VertexType.FreeVertex) &&
((eorg.x - eapex.x) * (edest.x - eapex.x) +
(eorg.y - eapex.y) * (edest.y - eapex.y) < 0.0))
{
mesh.DeleteVertex(ref testtri);
currentenc.TriPivot(ref enctri);
eapex = enctri.Apex();
enctri.Lprev(ref testtri);
}
}
// Now, check the other side of the segment, if there's a triangle there.
enctri.Sym(ref testtri);
if (testtri.triangle != Mesh.dummytri)
{
// Is the destination shared with another segment?
testtri.LnextSelf();
testtri.SegPivot(ref testsh);
acutedest2 = testsh.seg != Mesh.dummysub;
acutedest = acutedest || acutedest2;
// Is the origin shared with another segment?
testtri.LnextSelf();
testtri.SegPivot(ref testsh);
acuteorg2 = testsh.seg != Mesh.dummysub;
acuteorg = acuteorg || acuteorg2;
// Delete free vertices from the subsegment's diametral circle.
if (!behavior.ConformingDelaunay && !acuteorg2 && !acutedest2)
{
eapex = testtri.Org();
while ((eapex.type == VertexType.FreeVertex) &&
((eorg.x - eapex.x) * (edest.x - eapex.x) +
(eorg.y - eapex.y) * (edest.y - eapex.y) < 0.0))
{
mesh.DeleteVertex(ref testtri);
enctri.Sym(ref testtri);
eapex = testtri.Apex();
testtri.LprevSelf();
}
}
}
// Use the concentric circles if exactly one endpoint is shared
// with another adjacent segment.
if (acuteorg || acutedest)
{
segmentlength = UnityEngine.Mathf.Sqrt((edest.x - eorg.x) * (edest.x - eorg.x) +
(edest.y - eorg.y) * (edest.y - eorg.y));
// Find the power of two that most evenly splits the segment.
// The worst case is a 2:1 ratio between subsegment lengths.
nearestpoweroftwo = 1.0f;
while (segmentlength > 3.0f * nearestpoweroftwo)
{
nearestpoweroftwo *= 2.0f;
}
while (segmentlength < 1.5f * nearestpoweroftwo)
{
nearestpoweroftwo *= 0.5f;
}
// Where do we split the segment?
split = nearestpoweroftwo / segmentlength;
if (acutedest)
{
split = 1.0f - split;
}
}
else
{
// If we're not worried about adjacent segments, split
// this segment in the middle.
split = 0.5f;
}
// Create the new vertex (interpolate coordinates).
newvertex = new Vertex(
eorg.x + split * (edest.x - eorg.x),
eorg.y + split * (edest.y - eorg.y),
currentenc.Mark(),
mesh.nextras);
newvertex.type = VertexType.SegmentVertex;
newvertex.hash = mesh.hash_vtx++;
newvertex.id = newvertex.hash;
mesh.vertices.Add(newvertex.hash, newvertex);
// Interpolate attributes.
for (int i = 0; i < mesh.nextras; i++)
{
newvertex.attributes[i] = eorg.attributes[i]
+ split * (edest.attributes[i] - eorg.attributes[i]);
}
if (!Behavior.NoExact)
{
// Roundoff in the above calculation may yield a 'newvertex'
// that is not precisely collinear with 'eorg' and 'edest'.
// Improve collinearity by one step of iterative refinement.
multiplier = Primitives.CounterClockwise(eorg, edest, newvertex);
divisor = ((eorg.x - edest.x) * (eorg.x - edest.x) +
(eorg.y - edest.y) * (eorg.y - edest.y));
if ((multiplier != 0.0) && (divisor != 0.0))
{
multiplier = multiplier / divisor;
// Watch out for NANs.
if (!float.IsNaN(multiplier))
{
newvertex.x += multiplier * (edest.y - eorg.y);
newvertex.y += multiplier * (eorg.x - edest.x);
}
}
}
// Check whether the new vertex lies on an endpoint.
if (((newvertex.x == eorg.x) && (newvertex.y == eorg.y)) ||
((newvertex.x == edest.x) && (newvertex.y == edest.y)))
{
logger.Error("Ran out of precision: I attempted to split a"
+ " segment to a smaller size than can be accommodated by"
+ " the finite precision of floating point arithmetic.",
"Quality.SplitEncSegs()");
throw new Exception("Ran out of precision");
}
// Insert the splitting vertex. This should always succeed.
success = mesh.InsertVertex(newvertex, ref enctri, ref currentenc, true, triflaws);
if ((success != InsertVertexResult.Successful) && (success != InsertVertexResult.Encroaching))
{
logger.Error("Failure to split a segment.", "Quality.SplitEncSegs()");
throw new Exception("Failure to split a segment.");
}
if (mesh.steinerleft > 0)
{
mesh.steinerleft--;
}
// Check the two new subsegments to see if they're encroached.
CheckSeg4Encroach(ref currentenc);
currentenc.NextSelf();
CheckSeg4Encroach(ref currentenc);
}
// Set subsegment's origin to NULL. This makes it possible to detect dead
// badsubsegs when traversing the list of all badsubsegs.
seg.subsegorg = null;
}
}
private void SplitEncSegs(bool triflaws)
{
Vertex vertex;
double num;
Otri otri = new Otri();
Otri otri1 = new Otri();
Osub osub = new Osub();
Osub osub1 = new Osub();
while (this.badsubsegs.Count > 0 && this.mesh.steinerleft != 0)
{
BadSubseg badSubseg = this.badsubsegs.Dequeue();
osub1 = badSubseg.encsubseg;
Vertex vertex1 = osub1.Org();
Vertex vertex2 = osub1.Dest();
if (!Osub.IsDead(osub1.seg) && vertex1 == badSubseg.subsegorg && vertex2 == badSubseg.subsegdest)
{
osub1.TriPivot(ref otri);
otri.Lnext(ref otri1);
otri1.SegPivot(ref osub);
bool flag = osub.seg != Mesh.dummysub;
otri1.LnextSelf();
otri1.SegPivot(ref osub);
bool flag1 = osub.seg != Mesh.dummysub;
if (!this.behavior.ConformingDelaunay && !flag && !flag1)
{
vertex = otri.Apex();
while (vertex.type == VertexType.FreeVertex && (vertex1.x - vertex.x) * (vertex2.x - vertex.x) + (vertex1.y - vertex.y) * (vertex2.y - vertex.y) < 0)
{
this.mesh.DeleteVertex(ref otri1);
osub1.TriPivot(ref otri);
vertex = otri.Apex();
otri.Lprev(ref otri1);
}
}
otri.Sym(ref otri1);
if (otri1.triangle != Mesh.dummytri)
{
otri1.LnextSelf();
otri1.SegPivot(ref osub);
bool flag2 = osub.seg != Mesh.dummysub;
flag1 = flag1 | flag2;
otri1.LnextSelf();
otri1.SegPivot(ref osub);
bool flag3 = osub.seg != Mesh.dummysub;
flag = flag | flag3;
if (!this.behavior.ConformingDelaunay && !flag3 && !flag2)
{
vertex = otri1.Org();
while (vertex.type == VertexType.FreeVertex && (vertex1.x - vertex.x) * (vertex2.x - vertex.x) + (vertex1.y - vertex.y) * (vertex2.y - vertex.y) < 0)
{
this.mesh.DeleteVertex(ref otri1);
otri.Sym(ref otri1);
vertex = otri1.Apex();
otri1.LprevSelf();
}
}
}
if (!(flag | flag1))
{
num = 0.5;
}
else
{
double num1 = Math.Sqrt((vertex2.x - vertex1.x) * (vertex2.x - vertex1.x) + (vertex2.y - vertex1.y) * (vertex2.y - vertex1.y));
double num2 = 1;
while (num1 > 3 * num2)
{
num2 = num2 * 2;
}
while (num1 < 1.5 * num2)
{
num2 = num2 * 0.5;
}
num = num2 / num1;
if (flag1)
{
num = 1 - num;
}
}
Vertex vertex3 = new Vertex(vertex1.x + num * (vertex2.x - vertex1.x), vertex1.y + num * (vertex2.y - vertex1.y), osub1.Mark(), this.mesh.nextras)
{
type = VertexType.SegmentVertex
};
Mesh mesh = this.mesh;
int hashVtx = mesh.hash_vtx;
mesh.hash_vtx = hashVtx + 1;
vertex3.hash = hashVtx;
vertex3.id = vertex3.hash;
this.mesh.vertices.Add(vertex3.hash, vertex3);
for (int i = 0; i < this.mesh.nextras; i++)
{
vertex3.attributes[i] = vertex1.attributes[i] + num * (vertex2.attributes[i] - vertex1.attributes[i]);
}
if (!Behavior.NoExact)
{
double num3 = Primitives.CounterClockwise(vertex1, vertex2, vertex3);
double num4 = (vertex1.x - vertex2.x) * (vertex1.x - vertex2.x) + (vertex1.y - vertex2.y) * (vertex1.y - vertex2.y);
if (num3 != 0 && num4 != 0)
{
num3 = num3 / num4;
if (!double.IsNaN(num3))
{
Vertex vertex4 = vertex3;
vertex4.x = vertex4.x + num3 * (vertex2.y - vertex1.y);
Vertex vertex5 = vertex3;
vertex5.y = vertex5.y + num3 * (vertex1.x - vertex2.x);
}
}
}
if (vertex3.x == vertex1.x && vertex3.y == vertex1.y || vertex3.x == vertex2.x && vertex3.y == vertex2.y)
{
this.logger.Error("Ran out of precision: I attempted to split a segment to a smaller size than can be accommodated by the finite precision of floating point arithmetic.", "Quality.SplitEncSegs()");
throw new Exception("Ran out of precision");
}
InsertVertexResult insertVertexResult = this.mesh.InsertVertex(vertex3, ref otri, ref osub1, true, triflaws);
if (insertVertexResult != InsertVertexResult.Successful && insertVertexResult != InsertVertexResult.Encroaching)
{
this.logger.Error("Failure to split a segment.", "Quality.SplitEncSegs()");
throw new Exception("Failure to split a segment.");
}
if (this.mesh.steinerleft > 0)
{
Mesh mesh1 = this.mesh;
mesh1.steinerleft = mesh1.steinerleft - 1;
}
this.CheckSeg4Encroach(ref osub1);
osub1.NextSelf();
this.CheckSeg4Encroach(ref osub1);
}
badSubseg.subsegorg = null;
}
}
