/**
* rt_nurb_c_xsplit()
*
* Split a NURB curve by inserting a multiple knot and return the
* result of the two curves.
*
* Algorithm:
*
* Insert a multiple knot of the curve order. A parameter is give for
* the knot value for which the curve will be split.
*/
struct edge_g_cnurb *
rt_nurb_c_xsplit(struct edge_g_cnurb *crv, fastf_t param)
{
struct knot_vector new_kv;
struct oslo_mat * oslo;
int k_index;
struct edge_g_cnurb * crv1, * crv2;
int coords;
NMG_CK_CNURB(crv);
coords = RT_NURB_EXTRACT_COORDS(crv->pt_type),
k_index = crv->order;
rt_nurb_kvmult(&new_kv, &crv->k, crv->order, param, (struct resource *)NULL);
oslo = (struct oslo_mat *)
rt_nurb_calc_oslo(crv->order, &crv->k, &new_kv, (struct resource *)NULL);
GET_CNURB(crv1);
crv1->order = crv->order;
rt_nurb_kvextract(&crv1->k, &new_kv, 0, k_index + crv->order, (struct resource *)NULL);
crv1->pt_type = crv->pt_type;
crv1->c_size = crv1->k.k_size - crv1->order;
crv1->ctl_points = (fastf_t *)
bu_malloc(sizeof(fastf_t) * crv1->c_size *
RT_NURB_EXTRACT_COORDS(crv1->pt_type),
"rt_nurb_c_xsplit: crv1 control points");
GET_CNURB(crv2);
crv2->order = crv->order;
rt_nurb_kvextract(&crv2->k, &new_kv, k_index, new_kv.k_size, (struct resource *)NULL);
crv2->pt_type = crv->pt_type;
crv2->c_size = crv2->k.k_size - crv2->order;
crv2->ctl_points = (fastf_t *)
bu_malloc(sizeof(fastf_t) * crv2->c_size *
RT_NURB_EXTRACT_COORDS(crv2->pt_type),
"rt_nurb_c_xsplit: crv2 row mesh control points");
rt_nurb_map_oslo(oslo, crv->ctl_points, crv1->ctl_points,
coords, coords, 0, k_index, crv->pt_type);
rt_nurb_map_oslo(oslo, crv->ctl_points, crv2->ctl_points,
coords, coords, k_index, new_kv.k_size - crv2->order,
crv2->pt_type);
rt_nurb_free_oslo(oslo, (struct resource *)NULL);
bu_free((char *) new_kv.knots, "rt_nurb_c_xsplit: new_kv.knots");
BU_LIST_APPEND(&crv1->l, &crv2->l);
return crv1;
}
/**
* Create a place holder for a new nurb curve.
*/
struct edge_g_cnurb *
rt_nurb_new_cnurb(int order, int n_knots, int n_pts, int pt_type)
{
register struct edge_g_cnurb * crv;
GET_CNURB(crv);
crv->order = order;
crv->k.k_size = n_knots;
crv->k.knots = (fastf_t *)
bu_malloc(n_knots * sizeof(fastf_t),
"rt_nurb_new_cnurb: knot values");
crv->c_size = n_pts;
crv->pt_type = pt_type;
crv->ctl_points = (fastf_t *)
bu_malloc(sizeof(fastf_t) * RT_NURB_EXTRACT_COORDS(pt_type) *
n_pts,
"rt_nurb_new_cnurb: mesh point values");
return crv;
}
/**
* Split a NURB curve by inserting a multiple knot and return the
* result of the two curves.
*
* Algorithm
*
* Insert a multiple knot of the curve order. If internal knot values
* exist than pick the one closest to the middle and add additional
* knots to split at that value, otherwise add multiple knots at the
* mid point of the knot vector. Use the new knot vector to pass to
* the oslo refinement process and split the curve. Separate the
* curve and return the two resulting curves.
*
* The original curve is undisturbed by this operation.
*/
void
rt_nurb_c_split(struct bu_list *split_hd, const struct edge_g_cnurb *crv)
{
struct knot_vector new_kv;
fastf_t value;
struct oslo_mat * oslo;
int i;
int k_index = 0;
struct edge_g_cnurb * crv1, * crv2;
int coords;
NMG_CK_CNURB(crv);
coords = RT_NURB_EXTRACT_COORDS(crv->pt_type),
value = crv->k.knots[(crv->k.k_size -1)/2];
for (i = 0; i < crv->k.k_size; i++)
if (ZERO(value - crv->k.knots[i])) {
k_index = i;
break;
}
if (k_index == 0) {
value = (value +
crv->k.knots[ crv->k.k_size -1])
/2.0;
k_index = crv->order;
}
rt_nurb_kvmult(&new_kv, &crv->k, crv->order, value, (struct resource *)NULL);
oslo = (struct oslo_mat *)
rt_nurb_calc_oslo(crv->order, &crv->k, &new_kv, (struct resource *)NULL);
GET_CNURB(crv1);
crv1->order = crv->order;
rt_nurb_kvextract(&crv1->k, &new_kv, 0, k_index + crv->order, (struct resource *)NULL);
crv1->pt_type = crv->pt_type;
crv1->c_size = crv1->k.k_size - crv1->order;
crv1->ctl_points = (fastf_t *)
bu_malloc(sizeof(fastf_t) * crv1->c_size *
RT_NURB_EXTRACT_COORDS(crv1->pt_type),
"rt_nurb_c_split: crv1 control points");
GET_CNURB(crv2);
crv2->order = crv->order;
rt_nurb_kvextract(&crv2->k, &new_kv, k_index, new_kv.k_size, (struct resource *)NULL);
crv2->pt_type = crv->pt_type;
crv2->c_size = crv2->k.k_size - crv2->order;
crv2->ctl_points = (fastf_t *)
bu_malloc(sizeof(fastf_t) * crv2->c_size *
RT_NURB_EXTRACT_COORDS(crv2->pt_type),
"rt_nurb_s_split: crv2 mesh control points");
rt_nurb_map_oslo(oslo, crv->ctl_points, crv1->ctl_points,
coords, coords, 0, k_index, crv->pt_type);
rt_nurb_map_oslo(oslo, crv->ctl_points, crv2->ctl_points,
coords, coords, k_index, new_kv.k_size - crv2->order,
crv2->pt_type);
rt_nurb_free_oslo(oslo, (struct resource *)NULL);
bu_free((char *) new_kv.knots, "rt_nurb_c_split; new_kv.knots");
/* Arrangement will be: head, crv1, crv2 */
BU_LIST_APPEND(split_hd, &crv2->l);
BU_LIST_APPEND(split_hd, &crv1->l);
}
