int ON_ArcCurve::GetNurbForm( // returns 0: unable to create NURBS representation // with desired accuracy. // 1: success - returned NURBS parameterization // matches the curve's to wthe desired accuracy // 2: success - returned NURBS point locus matches // the curve's to the desired accuracy but, on // the interior of the curve's domain, the // curve's parameterization and the NURBS // parameterization may not match to the // desired accuracy. ON_NurbsCurve& c, double tolerance, const ON_Interval* subdomain // OPTIONAL subdomain of arc ) const { int rc = 0; if ( subdomain ) { ON_ArcCurve trimmed_arc(*this); if ( trimmed_arc.Trim(*subdomain) ) { rc = trimmed_arc.GetNurbForm( c, tolerance, NULL ); } } else if ( m_t.IsIncreasing() && m_arc.IsValid() ) { if ( NurbsCurveArc( m_arc, m_dim, c ) ) { rc = 2; c.SetDomain( m_t[0], m_t[1] ); } } return rc; }
int ON_CurveProxy::GetNurbForm( // returns 0: unable to create NURBS representation // with desired accuracy. // 1: success - returned NURBS parameterization // matches the curve's to wthe desired accuracy // 2: success - returned NURBS point locus matches // the curve's to the desired accuracy but, on // the interior of the curve's domain, the // curve's parameterization and the NURBS // parameterization may not match to the // desired accuracy. ON_NurbsCurve& nurbs, double tolerance, // (>=0) const ON_Interval* sub_domain // OPTIONAL subdomain of ON::ProxyCurve::Domain() ) const { ON_BOOL32 rc = false; if ( m_real_curve ) { ON_Interval scratch_domain = RealCurveInterval( sub_domain ); rc = m_real_curve->GetNurbForm(nurbs,tolerance,&scratch_domain); if ( rc ) { if ( m_bReversed ) nurbs.Reverse(); ON_Interval d = m_this_domain; if ( sub_domain ) d.Intersection( *sub_domain ); nurbs.SetDomain( d[0], d[1] ); if ( nurbs.m_dim <= 3 && nurbs.m_dim >= 1 ) { double t0 = Domain()[0]; double t1 = Domain()[1]; if ( 0 != sub_domain ) { if ( t0 < sub_domain->Min() ) t0 = sub_domain->Min(); if ( sub_domain->Max() < t1 ) t1 = sub_domain->Max(); } // set ends of NURBS curve to be exactly on ends of proxy curve ON_3dPoint P0 = PointAt(t0); ON_3dPoint P1 = PointAt(t1); ON_3dPoint N0 = nurbs.PointAtStart(); ON_3dPoint N1 = nurbs.PointAtEnd(); // 22 September 2003, GBA. The end tuning code below should only be applied // to clamped nurbs curves. In particular it should not be used on // periodic nurbs curves. Fixes TRR#11502. ON_BOOL32 clamped = nurbs.IsClamped(2); if ( clamped && (P0 != N0 || P1 != N1) ) { if ( 0==nurbs.m_is_rat ) { nurbs.SetCV(0,P0); nurbs.SetCV(nurbs.m_cv_count-1,P1); } else { ON_4dPoint H0, H1; H0 = P0; H0.w = nurbs.Weight(0); H0.x *= H0.w; H0.y *= H0.w; H0.z *= H0.w; nurbs.SetCV(0,H0); H1 = P1; H1.w = nurbs.Weight(nurbs.m_cv_count-1); H1.x *= H1.w; H1.y *= H1.w; H1.z *= H1.w; nurbs.SetCV(nurbs.m_cv_count-1,H1); } } } } } return rc; }
extern "C" void rt_hyp_brep(ON_Brep **b, const struct rt_db_internal *ip, const struct bn_tol *) { struct rt_hyp_internal *eip; RT_CK_DB_INTERNAL(ip); eip = (struct rt_hyp_internal *)ip->idb_ptr; RT_HYP_CK_MAGIC(eip); point_t p1_origin, p2_origin; ON_3dPoint plane1_origin, plane2_origin; ON_3dVector plane_x_dir, plane_y_dir; // First, find planes corresponding to the top and bottom faces - initially vect_t x_dir, y_dir; VMOVE(x_dir, eip->hyp_A); VCROSS(y_dir, eip->hyp_A, eip->hyp_Hi); VREVERSE(y_dir, y_dir); VMOVE(p1_origin, eip->hyp_Vi); plane1_origin = ON_3dPoint(p1_origin); plane_x_dir = ON_3dVector(x_dir); plane_y_dir = ON_3dVector(y_dir); const ON_Plane hyp_bottom_plane(plane1_origin, plane_x_dir, plane_y_dir); VADD2(p2_origin, eip->hyp_Vi, eip->hyp_Hi); plane2_origin = ON_3dPoint(p2_origin); const ON_Plane hyp_top_plane(plane2_origin, plane_x_dir, plane_y_dir); // Next, create ellipses in the planes corresponding to the edges of the hyp ON_Ellipse b_ell(hyp_bottom_plane, MAGNITUDE(eip->hyp_A), eip->hyp_b); ON_NurbsCurve* bcurve = ON_NurbsCurve::New(); b_ell.GetNurbForm((*bcurve)); bcurve->SetDomain(0.0, 1.0); ON_Ellipse t_ell(hyp_top_plane, MAGNITUDE(eip->hyp_A), eip->hyp_b); ON_NurbsCurve* tcurve = ON_NurbsCurve::New(); t_ell.GetNurbForm((*tcurve)); tcurve->SetDomain(0.0, 1.0); // Generate the bottom cap ON_SimpleArray<ON_Curve*> boundary; boundary.Append(ON_Curve::Cast(bcurve)); ON_PlaneSurface* bp = new ON_PlaneSurface(); bp->m_plane = hyp_bottom_plane; bp->SetDomain(0, -100.0, 100.0); bp->SetDomain(1, -100.0, 100.0); bp->SetExtents(0, bp->Domain(0)); bp->SetExtents(1, bp->Domain(1)); (*b)->m_S.Append(bp); const int bsi = (*b)->m_S.Count() - 1; ON_BrepFace& bface = (*b)->NewFace(bsi); (*b)->NewPlanarFaceLoop(bface.m_face_index, ON_BrepLoop::outer, boundary, true); const ON_BrepLoop* bloop = (*b)->m_L.Last(); bp->SetDomain(0, bloop->m_pbox.m_min.x, bloop->m_pbox.m_max.x); bp->SetDomain(1, bloop->m_pbox.m_min.y, bloop->m_pbox.m_max.y); bp->SetExtents(0, bp->Domain(0)); bp->SetExtents(1, bp->Domain(1)); (*b)->FlipFace(bface); (*b)->SetTrimIsoFlags(bface); boundary.Empty(); delete bcurve; // Generate the top cap boundary.Append(ON_Curve::Cast(tcurve)); ON_PlaneSurface* tp = new ON_PlaneSurface(); tp->m_plane = hyp_top_plane; tp->SetDomain(0, -100.0, 100.0); tp->SetDomain(1, -100.0, 100.0); tp->SetExtents(0, bp->Domain(0)); tp->SetExtents(1, bp->Domain(1)); (*b)->m_S.Append(tp); int tsi = (*b)->m_S.Count() - 1; ON_BrepFace& tface = (*b)->NewFace(tsi); (*b)->NewPlanarFaceLoop(tface.m_face_index, ON_BrepLoop::outer, boundary, true); ON_BrepLoop* tloop = (*b)->m_L.Last(); tp->SetDomain(0, tloop->m_pbox.m_min.x, tloop->m_pbox.m_max.x); tp->SetDomain(1, tloop->m_pbox.m_min.y, tloop->m_pbox.m_max.y); tp->SetExtents(0, bp->Domain(0)); tp->SetExtents(1, bp->Domain(1)); (*b)->SetTrimIsoFlags(tface); delete tcurve; // Now, the hard part. Need an elliptical hyperbolic NURBS surface. // First step is to create a nurbs curve. double MX = eip->hyp_b * eip->hyp_bnr; point_t ep1, ep2, ep3; VSET(ep1, -eip->hyp_b, 0, 0.5*MAGNITUDE(eip->hyp_Hi)); VSET(ep2, -MX*eip->hyp_bnr, 0, 0); VSET(ep3, -eip->hyp_b, 0, -0.5*MAGNITUDE(eip->hyp_Hi)); ON_3dPoint onp1 = ON_3dPoint(ep1); ON_3dPoint onp2 = ON_3dPoint(ep2); ON_3dPoint onp3 = ON_3dPoint(ep3); ON_3dPointArray cpts(3); cpts.Append(onp1); cpts.Append(onp2); cpts.Append(onp3); ON_BezierCurve *bezcurve = new ON_BezierCurve(cpts); bezcurve->MakeRational(); bezcurve->SetWeight(1, bezcurve->Weight(0)/eip->hyp_bnr); ON_NurbsCurve* tnurbscurve = ON_NurbsCurve::New(); bezcurve->GetNurbForm(*tnurbscurve); delete bezcurve; ON_3dPoint revpnt1 = ON_3dPoint(0, 0, -0.5*MAGNITUDE(eip->hyp_Hi)); ON_3dPoint revpnt2 = ON_3dPoint(0, 0, 0.5*MAGNITUDE(eip->hyp_Hi)); ON_Line revaxis = ON_Line(revpnt1, revpnt2); ON_RevSurface* hyp_surf = ON_RevSurface::New(); hyp_surf->m_curve = tnurbscurve; hyp_surf->m_axis = revaxis; hyp_surf->m_angle = ON_Interval(0, 2*ON_PI); // Get the NURBS form of the surface ON_NurbsSurface *hypcurvedsurf = ON_NurbsSurface::New(); hyp_surf->GetNurbForm(*hypcurvedsurf, 0.0); delete hyp_surf; for (int i = 0; i < hypcurvedsurf->CVCount(0); i++) { for (int j = 0; j < hypcurvedsurf->CVCount(1); j++) { point_t cvpt; ON_4dPoint ctrlpt; hypcurvedsurf->GetCV(i, j, ctrlpt); // Scale and shear vect_t proj_ah; vect_t proj_ax; fastf_t factor; VPROJECT(eip->hyp_A, eip->hyp_Hi, proj_ah, proj_ax); VSET(cvpt, ctrlpt.x * MAGNITUDE(proj_ax)/eip->hyp_b, ctrlpt.y, ctrlpt.z); factor = VDOT(eip->hyp_A, eip->hyp_Hi)>0 ? 1.0 : -1.0; cvpt[2] += factor*cvpt[0]/MAGNITUDE(proj_ax)*MAGNITUDE(proj_ah) + 0.5*MAGNITUDE(eip->hyp_Hi)*ctrlpt.w; // Rotate vect_t Au, Bu, Hu; mat_t R; point_t new_cvpt; VSCALE(Bu, y_dir, 1/MAGNITUDE(y_dir)); VSCALE(Hu, eip->hyp_Hi, 1/MAGNITUDE(eip->hyp_Hi)); VCROSS(Au, Bu, Hu); VUNITIZE(Au); MAT_IDN(R); VMOVE(&R[0], Au); VMOVE(&R[4], Bu); VMOVE(&R[8], Hu); VEC3X3MAT(new_cvpt, cvpt, R); VMOVE(cvpt, new_cvpt); // Translate vect_t scale_v; VSCALE(scale_v, eip->hyp_Vi, ctrlpt.w); VADD2(cvpt, cvpt, scale_v); ON_4dPoint newpt = ON_4dPoint(cvpt[0], cvpt[1], cvpt[2], ctrlpt.w); hypcurvedsurf->SetCV(i, j, newpt); } } (*b)->m_S.Append(hypcurvedsurf); int surfindex = (*b)->m_S.Count(); ON_BrepFace& face = (*b)->NewFace(surfindex - 1); (*b)->FlipFace(face); int faceindex = (*b)->m_F.Count(); (*b)->NewOuterLoop(faceindex-1); }