//----------------------------------------------------------------------------- // 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); }