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/*
* Copyright 1994-2012 Olivier Girondel
*
* This file is part of lebiniou.
*
* lebiniou is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* lebiniou is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with lebiniou. If not, see <http://www.gnu.org/licenses/>.
*/
#include "spline.h"
Spline_t *
Spline_new(const u_char span, const u_long nb_cpoints)
{
u_char dd;
Spline_t *s = xcalloc(1, sizeof(Spline_t));
s->span = span;
s->nb_cpoints = nb_cpoints;
s->nb_spoints = (s->nb_cpoints-1) * s->span + 1;
s->dt = 1.0 / (float)s->span;
for (dd = 0; dd < 8; dd++)
s->space[dd] = xcalloc(nb_cpoints, sizeof(float));
s->cpoints = xcalloc(s->nb_cpoints, sizeof(Point3d_t));
s->spoints = xcalloc(s->nb_spoints, sizeof(Point3d_t));
return s;
}
void
Spline_delete(Spline_t *s)
{
u_char dd;
xfree(s->cpoints);
xfree(s->spoints);
for (dd = 0; dd < 8; dd++)
xfree(s->space[dd]);
xfree(s);
}
void
Spline_compute(const Spline_t *s)
{
/* C'est parti */
float *a, *b, *c, *d;
float *h0, *h1, *h2, *h3, *hi_a;
short i, i1, imax;
float t;
u_char k;
Point3d_t *v;
const short nb_cpoints = s->nb_cpoints;
if (nb_cpoints < 2)
return;
h0 = s->space[0];
h1 = s->space[1];
h2 = s->space[2];
h3 = s->space[3];
for (k = 0; k < 3; k++) {
a = s->space[4];
b = s->space[5];
c = s->space[6];
d = s->space[7];
/* Trigonal system */
for (i = 0; i < nb_cpoints; i++)
d[i] = s->cpoints[i].coords[k];
for (i = 0, imax = nb_cpoints - 2; i < imax; i++) {
h3[i] = 3 * (d[i + 2] - 2 * d[i + 1] + d[i]);
h2[i] = 1;
}
h2[nb_cpoints - 3] = 0;
/* Dissolution of the system */
a[0] = 4;
h1[0] = h3[0] / a[0];
for (i = 1, i1 = 0, imax = nb_cpoints - 2; i < imax; i++, i1++) {
h0[i1] = h2[i1] / a[i1];
a[i] = 4 - h0[i1];
h1[i] = (h3[i] - h1[i1]) / a[i];
}
b[nb_cpoints - 3] = h1[nb_cpoints - 3];
for (i = nb_cpoints - 4; i >= 0; i--)
b[i] = h1[i] - h0[i] * b[i + 1];
for (i = nb_cpoints - 2; i >= 1; i--)
b[i] = b[i - 1];
b[0] = b[nb_cpoints - 1] = 0;
hi_a = a + nb_cpoints - 1;
for ( ; a < hi_a; a++, b++, c++, d++) {
*c = *(d + 1) - *d - ( 2 * *b + *(b + 1)) / 3;
*a = (*(b + 1) - *b) / 3;
}
v = s->spoints;
a = s->space[4];
b = s->space[5];
c = s->space[6];
d = s->space[7];
#ifdef DEBUG
{
u_long lcount=0;
#endif
for ( ; a < hi_a; a++, b++, c++, d++)
for (t = 0; t < 1 - 1e-7; t += s->dt) {
/* for (t = 0; t < 1.0 - s->dt; t += s->dt) { */
(*v++).coords[k] = ((*a * t + *b) * t + *c) * t + *d;
#ifdef DEBUG
lcount++;
#endif
}
(*v++).coords[k] = *d;
#ifdef DEBUG
lcount++;
if (lcount > s->nb_spoints)
xerror("spline fatal: %d points, wanted to set %d\n", s->nb_spoints, lcount);
}
#endif
}
}
void
Spline_info(const Spline_t *s)
{
if (s == NULL)
xerror("Windows va redemarrer\n");
else {
printf("[s] Spline has span: %d\n", s->span);
printf("[s] %li control points\n", s->nb_cpoints);
printf("[s] %li spline points\n", s->nb_spoints);
}
}
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