//-----------------------------------------------------------------------------
// Assemble curves in sbl into a single loop. The curves may appear in any
// direction (start to finish, or finish to start), and will be reversed if
// necessary. The curves in the returned loop are removed from sbl, even if
// the loop cannot be closed.
//-----------------------------------------------------------------------------
SBezierLoop SBezierLoop::FromCurves(SBezierList *sbl,
bool *allClosed, SEdge *errorAt)
{
SBezierLoop loop;
ZERO(&loop);
if(sbl->l.n < 1) return loop;
sbl->l.ClearTags();
SBezier *first = &(sbl->l.elem[0]);
first->tag = 1;
loop.l.Add(first);
Vector start = first->Start();
Vector hanging = first->Finish();
int auxA = first->auxA;
sbl->l.RemoveTagged();
while(sbl->l.n > 0 && !hanging.Equals(start)) {
int i;
bool foundNext = false;
for(i = 0; i < sbl->l.n; i++) {
SBezier *test = &(sbl->l.elem[i]);
if((test->Finish()).Equals(hanging) && test->auxA == auxA) {
test->Reverse();
// and let the next test catch it
}
if((test->Start()).Equals(hanging) && test->auxA == auxA) {
test->tag = 1;
loop.l.Add(test);
hanging = test->Finish();
sbl->l.RemoveTagged();
foundNext = true;
break;
}
}
if(!foundNext) {
// The loop completed without finding the hanging edge, so
// it's an open loop
errorAt->a = hanging;
errorAt->b = start;
*allClosed = false;
return loop;
}
}
if(hanging.Equals(start)) {
*allClosed = true;
} else {
// We ran out of edges without forming a closed loop.
errorAt->a = hanging;
errorAt->b = start;
*allClosed = false;
}
return loop;
}
void SBezierLoop::Reverse(void) {
l.Reverse();
SBezier *sb;
for(sb = l.First(); sb; sb = l.NextAfter(sb)) {
// If we didn't reverse each curve, then the next curve in list would
// share your start, not your finish.
sb->Reverse();
}
}
void SSurface::AddExactIntersectionCurve(SBezier *sb, SSurface *srfB,
SShell *agnstA, SShell *agnstB, SShell *into)
{
SCurve sc = {};
// Important to keep the order of (surfA, surfB) consistent; when we later
// rewrite the identifiers, we rewrite surfA from A and surfB from B.
sc.surfA = h;
sc.surfB = srfB->h;
sc.exact = *sb;
sc.isExact = true;
// Now we have to piecewise linearize the curve. If there's already an
// identical curve in the shell, then follow that pwl exactly, otherwise
// calculate from scratch.
SCurve split, *existing = NULL, *se;
SBezier sbrev = *sb;
sbrev.Reverse();
bool backwards = false;
for(se = into->curve.First(); se; se = into->curve.NextAfter(se)) {
if(se->isExact) {
if(sb->Equals(&(se->exact))) {
existing = se;
break;
}
if(sbrev.Equals(&(se->exact))) {
existing = se;
backwards = true;
break;
}
}
}
if(existing) {
SCurvePt *v;
for(v = existing->pts.First(); v; v = existing->pts.NextAfter(v)) {
sc.pts.Add(v);
}
if(backwards) sc.pts.Reverse();
split = sc;
sc = {};
} else {
sb->MakePwlInto(&(sc.pts));
// and split the line where it intersects our existing surfaces
split = sc.MakeCopySplitAgainst(agnstA, agnstB, this, srfB);
sc.Clear();
}
// Test if the curve lies entirely outside one of the
SCurvePt *scpt;
bool withinA = false, withinB = false;
for(scpt = split.pts.First(); scpt; scpt = split.pts.NextAfter(scpt)) {
double tol = 0.01;
Point2d puv;
ClosestPointTo(scpt->p, &puv);
if(puv.x > -tol && puv.x < 1 + tol &&
puv.y > -tol && puv.y < 1 + tol)
{
withinA = true;
}
srfB->ClosestPointTo(scpt->p, &puv);
if(puv.x > -tol && puv.x < 1 + tol &&
puv.y > -tol && puv.y < 1 + tol)
{
withinB = true;
}
// Break out early, no sense wasting time if we already have the answer.
if(withinA && withinB) break;
}
if(!(withinA && withinB)) {
// Intersection curve lies entirely outside one of the surfaces, so
// it's fake.
split.Clear();
return;
}
#if 0
if(sb->deg == 2) {
dbp(" ");
SCurvePt *prev = NULL, *v;
dbp("split.pts.n = %d", split.pts.n);
for(v = split.pts.First(); v; v = split.pts.NextAfter(v)) {
if(prev) {
Vector e = (prev->p).Minus(v->p).WithMagnitude(0);
SS.nakedEdges.AddEdge((prev->p).Plus(e), (v->p).Minus(e));
}
prev = v;
}
}
#endif // 0
ssassert(!(sb->Start()).Equals(sb->Finish()),
"Unexpected zero-length edge");
split.source = SCurve::Source::INTERSECTION;
into->curve.AddAndAssignId(&split);
}
