extern "C" void
rt_nmg_brep(ON_Brep **b, const struct rt_db_internal *ip, const struct bn_tol *tol)
{
struct model *m;
struct nmgregion *r;
struct shell *s;
struct faceuse *fu;
struct loopuse *lu;
struct edgeuse *eu;
int edge_index;
long* brepi;
RT_CK_DB_INTERNAL(ip);
m = (struct model *)ip->idb_ptr;
NMG_CK_MODEL(m);
brepi = static_cast<long*>(bu_malloc(m->maxindex * sizeof(long), "rt_nmg_brep: brepi[]"));
for (int i = 0; i < m->maxindex; i++) brepi[i] = -INT_MAX;
for (BU_LIST_FOR(r, nmgregion, &m->r_hd)) {
for (BU_LIST_FOR(s, shell, &r->s_hd)) {
for (BU_LIST_FOR(fu, faceuse, &s->fu_hd)) {
NMG_CK_FACEUSE(fu);
if (fu->orientation != OT_SAME) continue;
// Need to create ON_NurbsSurface based on plane of
// face in order to have UV space in which to define
// trimming loops. Bounding points are NOT on the
// face plane, so another approach must be used.
//
// General approach: For all loops in the faceuse,
// collect all the vertices. Find the center point of
// all the vertices, and search for the point with the
// greatest distance from that center point. Once
// found, cross the vector between the center point
// and furthest point with the normal of the face and
// scale the resulting vector to have the same length
// as the vector to the furthest point. Add the two
// resulting vectors to find the first corner point.
// Mirror the first corner point across the center to
// find the second corner point. Cross the two
// vectors created by the first two corner points with
// the face normal to get the vectors of the other two
// corners, and scale the resulting vectors to the
// same magnitude as the first two. These four points
// bound all vertices on the plane and form a suitable
// staring point for a UV space, since all points on
// all the edges are equal to or further than the
// distance between the furthest vertex and the center
// point.
// ............. .............
// . .* . .
// . . . . .
// . . . . .
// . . . * .
// . . . . .
// . . . . .
// . . . . .
// . * * . .
// . . . .
// . . . .
// . . . .
// . *. . .
// . ... ...* .
// . .... .... .
// . * .
// ...........................
//
const struct face_g_plane *fg = fu->f_p->g.plane_p;
struct bu_ptbl vert_table;
nmg_tabulate_face_g_verts(&vert_table, fg);
point_t tmppt, center, max_pt;
struct vertex **pt;
VSET(tmppt, 0, 0, 0);
VSET(max_pt, 0, 0, 0);
int ptcnt = 0;
for (BU_PTBL_FOR(pt, (struct vertex **), &vert_table)) {
tmppt[0] += (*pt)->vg_p->coord[0];
tmppt[1] += (*pt)->vg_p->coord[1];
tmppt[2] += (*pt)->vg_p->coord[2];
ptcnt++;
if (brepi[(*pt)->vg_p->index] == -INT_MAX) {
ON_BrepVertex& vert = (*b)->NewVertex((*pt)->vg_p->coord, SMALL_FASTF);
brepi[(*pt)->vg_p->index] = vert.m_vertex_index;
}
}
VSET(center, tmppt[0]/ptcnt, tmppt[1]/ptcnt, tmppt[2]/ptcnt);
fastf_t max_dist = 0.0;
fastf_t curr_dist;
for (BU_PTBL_FOR(pt, (struct vertex **), &vert_table)) {
tmppt[0] = (*pt)->vg_p->coord[0];
tmppt[1] = (*pt)->vg_p->coord[1];
tmppt[2] = (*pt)->vg_p->coord[2];
curr_dist = DIST_PT_PT(center, tmppt);
if (curr_dist > max_dist) {
max_dist = curr_dist;
VMOVE(max_pt, tmppt);
}
}
bu_ptbl_free(&vert_table);
int ccw = 0;
vect_t vtmp, uv1, uv2, uv3, uv4, vnormal;
// If an outer loop is found in the nmg with a cw
// orientation, use a flipped normal to form the NURBS
// surface
for (BU_LIST_FOR(lu, loopuse, &fu->lu_hd)) {
if (lu->orientation == OT_SAME && nmg_loop_is_ccw(lu, fg->N, tol) == -1) ccw = -1;
}
if (ccw != -1) {
VSET(vnormal, fg->N[0], fg->N[1], fg->N[2]);
} else {
VSET(vnormal, -fg->N[0], -fg->N[1], -fg->N[2]);
}
VSUB2(uv1, max_pt, center);
VCROSS(vtmp, uv1, vnormal);
VADD2(uv1, uv1, vtmp);
VCROSS(uv2, uv1, vnormal);
VREVERSE(uv3, uv1);
VCROSS(uv4, uv3, vnormal);
VADD2(uv1, uv1, center);
VADD2(uv2, uv2, center);
VADD2(uv3, uv3, center);
VADD2(uv4, uv4, center);
ON_3dPoint p1 = ON_3dPoint(uv1);
ON_3dPoint p2 = ON_3dPoint(uv2);
ON_3dPoint p3 = ON_3dPoint(uv3);
ON_3dPoint p4 = ON_3dPoint(uv4);
(*b)->m_S.Append(sideSurface(p1, p4, p3, p2));
ON_Surface *surf = (*(*b)->m_S.Last());
int surfindex = (*b)->m_S.Count();
// Now that we have the surface, define the face
ON_BrepFace& face = (*b)->NewFace(surfindex - 1);
// With the surface and the face defined, make
// trimming loops and create faces. To generate UV
// coordinates for each from and to for the
// edgecurves, the UV origin is defined to be v1,
// v1->v2 is defined as the U domain, and v1->v4 is
// defined as the V domain.
vect_t u_axis, v_axis;
VSUB2(u_axis, uv2, uv1);
VSUB2(v_axis, uv4, uv1);
fastf_t u_axis_dist = MAGNITUDE(u_axis);
fastf_t v_axis_dist = MAGNITUDE(v_axis);
// Now that the surface context is set up, add the loops.
for (BU_LIST_FOR(lu, loopuse, &fu->lu_hd)) {
int edges=0;
if (BU_LIST_FIRST_MAGIC(&lu->down_hd) != NMG_EDGEUSE_MAGIC) continue; // loop is a single vertex
ON_BrepLoop::TYPE looptype;
// Check if this is an inner or outer loop
if (lu->orientation == OT_SAME) {
looptype = ON_BrepLoop::outer;
} else {
looptype = ON_BrepLoop::inner;
}
ON_BrepLoop& loop = (*b)->NewLoop(looptype, face);
for (BU_LIST_FOR(eu, edgeuse, &lu->down_hd)) {
++edges;
vect_t ev1, ev2;
struct vertex_g *vg1, *vg2;
vg1 = eu->vu_p->v_p->vg_p;
NMG_CK_VERTEX_G(vg1);
int vert1 = brepi[vg1->index];
VMOVE(ev1, vg1->coord);
vg2 = eu->eumate_p->vu_p->v_p->vg_p;
NMG_CK_VERTEX_G(vg2);
int vert2 = brepi[vg2->index];
VMOVE(ev2, vg2->coord);
// Add edge if not already added
if (brepi[eu->e_p->index] == -INT_MAX) {
/* always add edges with the small vertex index as from */
if (vg1->index > vg2->index) {
int tmpvert = vert1;
vert1 = vert2;
vert2 = tmpvert;
}
// Create and add 3D curve
ON_Curve* c3d = new ON_LineCurve((*b)->m_V[vert1].Point(), (*b)->m_V[vert2].Point());
c3d->SetDomain(0.0, 1.0);
(*b)->m_C3.Append(c3d);
// Create and add 3D edge
ON_BrepEdge& e = (*b)->NewEdge((*b)->m_V[vert1], (*b)->m_V[vert2] , (*b)->m_C3.Count() - 1);
e.m_tolerance = 0.0;
brepi[eu->e_p->index] = e.m_edge_index;
}
// Regardless of whether the edge existed as
// an object, it needs to be added to the
// trimming loop
vect_t u_component, v_component;
ON_3dPoint vg1pt(vg1->coord);
int orientation = 0;
edge_index = brepi[eu->e_p->index];
if (vg1pt != (*b)->m_V[(*b)->m_E[edge_index].m_vi[0]].Point()) {
orientation = 1;
}
// Now, make 2d trimming curves
vect_t vect1, vect2;
VSUB2(vect1, ev1, uv1);
VSUB2(vect2, ev2, uv1);
ON_2dPoint from_uv, to_uv;
double u0, u1, v0, v1;
surf->GetDomain(0, &u0, &u1);
surf->GetDomain(1, &v0, &v1);
VPROJECT(vect1, u_axis, u_component, v_component);
from_uv.y = u0 + MAGNITUDE(u_component)/u_axis_dist*(u1-u0);
from_uv.x = v0 + MAGNITUDE(v_component)/v_axis_dist*(v1-v0);
VPROJECT(vect2, u_axis, u_component, v_component);
to_uv.y = u0 + MAGNITUDE(u_component)/u_axis_dist*(u1-u0);
to_uv.x = v0 + MAGNITUDE(v_component)/v_axis_dist*(v1-v0);
ON_3dPoint S1, S2;
ON_3dVector Su, Sv;
surf->Ev1Der(from_uv.x, from_uv.y, S1, Su, Sv);
surf->Ev1Der(to_uv.x, to_uv.y, S2, Su, Sv);
ON_Curve* c2d = new ON_LineCurve(from_uv, to_uv);
c2d->SetDomain(0.0, 1.0);
int c2i = (*b)->m_C2.Count();
(*b)->m_C2.Append(c2d);
edge_index = brepi[eu->e_p->index];
ON_BrepTrim& trim = (*b)->NewTrim((*b)->m_E[edge_index], orientation, loop, c2i);
trim.m_type = ON_BrepTrim::mated;
trim.m_tolerance[0] = 0.0;
trim.m_tolerance[1] = 0.0;
}
}
}
(*b)->SetTrimIsoFlags();
}
}
bu_free(brepi, "rt_nmg_brep: brepi[]");
}
