/**
* If the order of the surface is linear either direction than
* approximate it.
*/
void
rt_nurb_s_norm(struct face_g_snurb *srf, fastf_t u, fastf_t v, fastf_t *norm)
{
struct face_g_snurb *usrf, *vsrf;
point_t uvec, vvec;
fastf_t p;
fastf_t se[4], ue[4], ve[4];
int i;
/* Case (linear, lienar) find the normal from the polygon */
if (srf->order[0] == 2 && srf->order[1] == 2) {
/* Find the correct span to get the normal */
rt_nurb_s_eval(srf, u, v, se);
p = 0.0;
for (i = 0; i < srf->u.k_size -1; i++) {
if (srf->u.knots[i] <= u
&& u < srf->u.knots[i+1]) {
p = srf->u.knots[i];
if (ZERO(u - p))
p = srf->u.knots[i+1];
if (ZERO(u - p) && i > 1)
p = srf->u.knots[i-1];
}
}
rt_nurb_s_eval(srf, p, v, ue);
p = 0.0;
for (i = 0; i < srf->v.k_size -1; i++) {
if (srf->v.knots[i] < v
&& !ZERO(srf->v.knots[i+1])) {
p = srf->v.knots[i];
if (ZERO(v - p))
p = srf->v.knots[i+1];
if (ZERO(v - p) && i > 1)
p = srf->v.knots[i-1];
}
}
rt_nurb_s_eval(srf, u, p, ve);
if (RT_NURB_IS_PT_RATIONAL(srf->pt_type)) {
ue[0] = ue[0] / ue[3];
ue[1] = ue[1] / ue[3];
ue[2] = ue[2] / ue[3];
ue[3] = ue[3] / ue[3];
ve[0] = ve[0] / ve[3];
ve[1] = ve[1] / ve[3];
ve[2] = ve[2] / ve[3];
ve[3] = ve[3] / ve[3];
}
VSUB2(uvec, se, ue);
VSUB2(vvec, se, ve);
VCROSS(norm, uvec, vvec);
VUNITIZE(norm);
return;
}
/* Case (linear, > linear) Use the linear direction to approximate
* the tangent to the surface
*/
if (srf->order[0] == 2 && srf->order[1] > 2) {
rt_nurb_s_eval(srf, u, v, se);
p = 0.0;
for (i = 0; i < srf->u.k_size -1; i++) {
if (srf->u.knots[i] <= u
&& u < srf->u.knots[i+1]) {
p = srf->u.knots[i];
if (ZERO(u - p))
p = srf->u.knots[i+1];
if (ZERO(u - p) && i > 1)
p = srf->u.knots[i-1];
}
}
rt_nurb_s_eval(srf, p, v, ue);
vsrf = (struct face_g_snurb *) rt_nurb_s_diff(srf, RT_NURB_SPLIT_COL);
rt_nurb_s_eval(vsrf, u, v, ve);
if (RT_NURB_IS_PT_RATIONAL(srf->pt_type)) {
fastf_t w, inv_w;
w = se[3];
inv_w = 1.0 / w;
ve[0] = (inv_w * ve[0]) -
ve[3] / (w * w) * se[0];
ve[1] = (inv_w * ve[1]) -
ve[3] / (w * w) * se[1];
ve[2] = (inv_w * ve[2]) -
ve[3] / (w * w) * se[2];
ue[0] = ue[0] / ue[3];
ue[1] = ue[1] / ue[3];
ue[2] = ue[2] / ue[3];
ue[3] = ue[3] / ue[3];
se[0] = se[0] / se[3];
se[1] = se[1] / se[3];
se[2] = se[2] / se[3];
se[3] = se[3] / se[3];
}
VSUB2(uvec, se, ue);
VCROSS(norm, uvec, ve);
VUNITIZE(norm);
rt_nurb_free_snurb(vsrf, (struct resource *)NULL);
return;
}
if (srf->order[1] == 2 && srf->order[0] > 2) {
rt_nurb_s_eval(srf, u, v, se);
p = 0.0;
for (i = 0; i < srf->v.k_size -1; i++) {
if (srf->v.knots[i] <= v
&& v < srf->v.knots[i+1]) {
p = srf->v.knots[i];
if (ZERO(v - p))
p = srf->v.knots[i+1];
if (ZERO(v - p) && i > 1)
p = srf->v.knots[i-1];
}
}
rt_nurb_s_eval(srf, u, p, ve);
usrf = (struct face_g_snurb *) rt_nurb_s_diff(srf, RT_NURB_SPLIT_ROW);
rt_nurb_s_eval(usrf, u, v, ue);
if (RT_NURB_IS_PT_RATIONAL(srf->pt_type)) {
fastf_t w, inv_w;
w = se[3];
inv_w = 1.0 / w;
ue[0] = (inv_w * ue[0]) -
ue[3] / (w * w) * se[0];
ue[1] = (inv_w * ue[1]) -
ue[3] / (w * w) * se[1];
ue[2] = (inv_w * ue[2]) -
ue[3] / (w * w) * se[2];
ve[0] = ve[0] / ve[3];
ve[1] = ve[1] / ve[3];
ve[2] = ve[2] / ve[3];
ve[3] = ve[3] / ve[3];
se[0] = se[0] / se[3];
se[1] = se[1] / se[3];
se[2] = se[2] / se[3];
se[3] = se[3] / se[3];
}
VSUB2(vvec, se, ve);
VCROSS(norm, ue, vvec);
VUNITIZE(norm);
rt_nurb_free_snurb(usrf, (struct resource *)NULL);
return;
}
/* Case Non Rational (order > 2, order > 2) */
if (!RT_NURB_IS_PT_RATIONAL(srf->pt_type)) {
usrf = (struct face_g_snurb *) rt_nurb_s_diff(srf, RT_NURB_SPLIT_ROW);
vsrf = (struct face_g_snurb *) rt_nurb_s_diff(srf, RT_NURB_SPLIT_COL);
rt_nurb_s_eval(usrf, u, v, ue);
rt_nurb_s_eval(vsrf, u, v, ve);
VCROSS(norm, ue, ve);
VUNITIZE(norm);
rt_nurb_free_snurb(usrf, (struct resource *)NULL);
rt_nurb_free_snurb(vsrf, (struct resource *)NULL);
return;
}
/* Case Rational (order > 2, order > 2) */
if (RT_NURB_IS_PT_RATIONAL(srf->pt_type)) {
fastf_t w, inv_w;
vect_t unorm, vnorm;
rt_nurb_s_eval(srf, u, v, se);
usrf = (struct face_g_snurb *) rt_nurb_s_diff(srf, RT_NURB_SPLIT_ROW);
vsrf = (struct face_g_snurb *) rt_nurb_s_diff(srf, RT_NURB_SPLIT_COL);
rt_nurb_s_eval(usrf, u, v, ue);
rt_nurb_s_eval(vsrf, u, v, ve);
w = se[3];
inv_w = 1.0 / w;
for (i = 0; i < 3; i++) {
unorm[i] = (inv_w * ue[i]) -
ue[3] / (w*w) * se[i];
vnorm[i] = (inv_w * ve[i]) -
ve[3] / (w*w) * se[i];
}
VCROSS(norm, unorm, vnorm);
VUNITIZE(norm);
rt_nurb_free_snurb(usrf, (struct resource *)NULL);
rt_nurb_free_snurb(vsrf, (struct resource *)NULL);
return;
}
return;
}
struct rt_nurb_uv_hit *
rt_nurb_intersect(const struct face_g_snurb *srf, fastf_t *plane1, fastf_t *plane2, double uv_tol, struct resource *res, struct bu_list *plist)
{
struct rt_nurb_uv_hit * h;
struct face_g_snurb * psrf,
* osrf;
int dir,
sub;
point_t vmin,
vmax;
fastf_t u[2],
v[2];
struct bu_list rni_plist;
NMG_CK_SNURB(srf);
h = (struct rt_nurb_uv_hit *) 0;
if (plist == NULL) {
plist = &rni_plist;
BU_LIST_INIT(plist);
}
/* project the surface to a 2 dimensional problem */
/* NOTE that this gives a single snurb back, NOT a list */
psrf = rt_nurb_project_srf(srf, plane2, plane1, res);
psrf->dir = 1;
BU_LIST_APPEND(plist, &psrf->l);
if (RT_G_DEBUG & DEBUG_SPLINE)
rt_nurb_s_print("srf", psrf);
/* This list starts out with only a single snurb, but more may be
* added on as work progresses.
*/
while (BU_LIST_WHILE(psrf, face_g_snurb, plist)) {
int flat;
BU_LIST_DEQUEUE(&psrf->l);
NMG_CK_SNURB(psrf);
sub = 0;
flat = 0;
dir = psrf->dir;
while (!flat) {
fastf_t smin = 0.0, smax = 0.0;
sub++;
dir = (dir == 0)?1:0; /* change direction */
if (RT_G_DEBUG & DEBUG_SPLINE)
rt_nurb_s_print("psrf", psrf);
rt_nurb_pbound(psrf, vmin, vmax);
/* Check for origin to be included in the bounding box */
if (!(vmin[0] <= 0.0 && vmin[1] <= 0.0 &&
vmax[0] >= 0.0 && vmax[1] >= 0.0)) {
if (RT_G_DEBUG & DEBUG_SPLINE)
bu_log("this srf doesn't include the origin\n");
flat = 1;
rt_nurb_free_snurb(psrf, res);
continue;
}
rt_nurb_clip_srf(psrf, dir, &smin, &smax);
if ((smax - smin) > .8) {
struct rt_nurb_uv_hit *hp;
/* Split surf, requeue both sub-surfs at head */
/* New surfs will have same dir as arg, here */
if (RT_G_DEBUG & DEBUG_SPLINE)
bu_log("splitting this surface\n");
rt_nurb_s_split(plist, psrf, dir, res);
rt_nurb_free_snurb(psrf, res);
hp = rt_nurb_intersect(srf, plane1, plane2, uv_tol, res, plist);
return hp;
}
if (smin > 1.0 || smax < 0.0) {
if (RT_G_DEBUG & DEBUG_SPLINE)
bu_log("eliminating this surface (smin=%g, smax=%g)\n", smin, smax);
flat = 1;
rt_nurb_free_snurb(psrf, res);
continue;
}
if (dir == RT_NURB_SPLIT_ROW) {
smin = (1.0 - smin) * psrf->u.knots[0] +
smin * psrf->u.knots[
psrf->u.k_size -1];
smax = (1.0 - smax) * psrf->u.knots[0] +
smax * psrf->u.knots[
psrf->u.k_size -1];
} else {
smin = (1.0 - smin) * psrf->v.knots[0] +
smin * psrf->v.knots[
psrf->v.k_size -1];
smax = (1.0 - smax) * psrf->v.knots[0] +
smax * psrf->v.knots[
psrf->v.k_size -1];
}
osrf = psrf;
psrf = (struct face_g_snurb *) rt_nurb_region_from_srf(
osrf, dir, smin, smax, res);
psrf->dir = dir;
rt_nurb_free_snurb(osrf, res);
if (RT_G_DEBUG & DEBUG_SPLINE) {
bu_log("After call to rt_nurb_region_from_srf() (smin=%g, smax=%g)\n", smin, smax);
rt_nurb_s_print("psrf", psrf);
}
u[0] = psrf->u.knots[0];
u[1] = psrf->u.knots[psrf->u.k_size -1];
v[0] = psrf->v.knots[0];
v[1] = psrf->v.knots[psrf->v.k_size -1];
if ((u[1] - u[0]) < uv_tol && (v[1] - v[0]) < uv_tol) {
struct rt_nurb_uv_hit * hit;
if (RT_G_DEBUG & DEBUG_SPLINE) {
fastf_t p1[4], p2[4];
int coords;
vect_t diff;
coords = RT_NURB_EXTRACT_COORDS(srf->pt_type);
rt_nurb_s_eval(srf, u[0], v[0], p1);
rt_nurb_s_eval(srf, u[1], v[1], p2);
if (RT_NURB_IS_PT_RATIONAL(srf->pt_type)) {
fastf_t inv_w;
inv_w = 1.0 / p1[coords-1];
VSCALE(p1, p1, inv_w);
inv_w = 1.0 / p2[coords-1];
VSCALE(p2, p2, inv_w);
}
VSUB2(diff, p1, p2);
bu_log("Precision of hit point = %g (%f %f %f) <-> (%f %f %f)\n",
MAGNITUDE(diff), V3ARGS(p1), V3ARGS(p2));
}
hit = (struct rt_nurb_uv_hit *) bu_malloc(
sizeof(struct rt_nurb_uv_hit), "hit");
hit->next = (struct rt_nurb_uv_hit *)0;
hit->sub = sub;
hit->u = (u[0] + u[1])/2.0;
hit->v = (v[0] + v[1])/2.0;
if (h == (struct rt_nurb_uv_hit *)0)
h = hit;
else {
hit->next = h;
h = hit;
}
flat = 1;
rt_nurb_free_snurb(psrf, res);
}
if ((u[1] - u[0]) > (v[1] - v[0]))
dir = 1;
else dir = 0;
}
}
return (struct rt_nurb_uv_hit *)h;
}
