private Face connectHalfEdges(
HalfEdge hedgePrev, HalfEdge hedge)
{
Face discardedFace = null;
if (hedgePrev.oppositeFace() == hedge.oppositeFace())
{ // then there is a redundant edge that we can get rid off
Face oppFace = hedge.oppositeFace();
HalfEdge hedgeOpp;
if (hedgePrev == he0)
{
he0 = hedge;
}
if (oppFace.numVertices() == 3)
{ // then we can get rid of the opposite face altogether
hedgeOpp = hedge.getOpposite().prev.getOpposite();
oppFace.mark = DELETED;
discardedFace = oppFace;
}
else
{
hedgeOpp = hedge.getOpposite().next;
if (oppFace.he0 == hedgeOpp.prev)
{
oppFace.he0 = hedgeOpp;
}
hedgeOpp.prev = hedgeOpp.prev.prev;
hedgeOpp.prev.next = hedgeOpp;
}
hedge.prev = hedgePrev.prev;
hedge.prev.next = hedge;
hedge.opposite = hedgeOpp;
hedgeOpp.opposite = hedge;
// oppFace was modified, so need to recompute
oppFace.computeNormalAndCentroid();
}
else
{
hedgePrev.next = hedge;
hedge.prev = hedgePrev;
}
return(discardedFace);
}
public int mergeAdjacentFace(HalfEdge hedgeAdj,
Face[] discarded)
{
Face oppFace = hedgeAdj.oppositeFace();
int numDiscarded = 0;
discarded[numDiscarded++] = oppFace;
oppFace.mark = DELETED;
HalfEdge hedgeOpp = hedgeAdj.getOpposite();
HalfEdge hedgeAdjPrev = hedgeAdj.prev;
HalfEdge hedgeAdjNext = hedgeAdj.next;
HalfEdge hedgeOppPrev = hedgeOpp.prev;
HalfEdge hedgeOppNext = hedgeOpp.next;
while (hedgeAdjPrev.oppositeFace() == oppFace)
{
hedgeAdjPrev = hedgeAdjPrev.prev;
hedgeOppNext = hedgeOppNext.next;
}
while (hedgeAdjNext.oppositeFace() == oppFace)
{
hedgeOppPrev = hedgeOppPrev.prev;
hedgeAdjNext = hedgeAdjNext.next;
}
HalfEdge hedge;
for (hedge = hedgeOppNext; hedge != hedgeOppPrev.next; hedge = hedge.next)
{
hedge.face = this;
}
if (hedgeAdj == he0)
{
he0 = hedgeAdjNext;
}
// handle the half edges at the head
Face discardedFace;
discardedFace = connectHalfEdges(hedgeOppPrev, hedgeAdjNext);
if (discardedFace != null)
{
discarded[numDiscarded++] = discardedFace;
}
// handle the half edges at the tail
discardedFace = connectHalfEdges(hedgeAdjPrev, hedgeOppNext);
if (discardedFace != null)
{
discarded[numDiscarded++] = discardedFace;
}
computeNormalAndCentroid();
checkConsistency();
return(numDiscarded);
}
private bool doAdjacentMerge(Face face, int mergeType)
{
HalfEdge hedge = face.he0;
bool convex = true;
do
{
Face oppFace = hedge.oppositeFace();
bool merge = false;
double dist1;
if (mergeType == NONCONVEX)
{ // then merge faces if they are definitively non-convex
if (oppFaceDistance(hedge) > -tolerance ||
oppFaceDistance(hedge.opposite) > -tolerance)
{
merge = true;
}
}
else // mergeType == NONCONVEX_WRT_LARGER_FACE
{ // merge faces if they are parallel or non-convex
// wrt to the larger face; otherwise, just mark
// the face non-convex for the second pass.
if (face.area > oppFace.area)
{
if ((dist1 = oppFaceDistance(hedge)) > -tolerance)
{
merge = true;
}
else if (oppFaceDistance(hedge.opposite) > -tolerance)
{
convex = false;
}
}
else
{
if (oppFaceDistance(hedge.opposite) > -tolerance)
{
merge = true;
}
else if (oppFaceDistance(hedge) > -tolerance)
{
convex = false;
}
}
}
if (merge)
{
if (debug)
{
Print(
" merging " + face.getVertexString() + " and " +
oppFace.getVertexString());
}
int numd = face.mergeAdjacentFace(hedge, discardedFaces);
for (int i = 0; i < numd; i++)
{
deleteFacePoints(discardedFaces[i], face);
}
if (debug)
{
Print(
" result: " + face.getVertexString());
}
return(true);
}
hedge = hedge.next;
}while (hedge != face.he0);
if (!convex)
{
face.mark = Face.NON_CONVEX;
}
return(false);
}
