src/common/multisamp.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 * Binary space partitioning curve for multidimensional sampling.
 *
 *      Written by Christophe Schlick
 */

multisamp(t, n, r)      /* convert 1-dimensional sample to N dimensions */
double  t[];                    /* returned N-dimensional vector */
register int    n;              /* number of dimensions */
double  r;                      /* 1-dimensional sample [0,1) */
{
        int     j;
        register int    i, k;
        int     ti[8];
        double  s;

        i = n;
        while (i-- > 0)
                ti[i] = 0;
        j = 8;
        while (j--) {
                k = s = r*(1<<n);
                r = s - k;
                i = n;
                while (i-- > 0)
                        ti[i] += ti[i] + ((k>>i) & 1);
        }
        i = n;
        while (i-- > 0)
                t[i] = 1./256. * ti[i];
}
Revision:	2.1
Committed:	Tue Nov 12 16:56:06 1991 UTC (34 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.1:	+0 -0 lines
Log Message:	updated revision number for release 2.0
#	Content
1	/* Copyright (c) 1991 Regents of the University of California */
2
3	#ifndef lint
4	static char SCCSid[] = "$SunId$ LBL";
5	#endif
6
7	/*
8	* Binary space partitioning curve for multidimensional sampling.
9	*
10	* Written by Christophe Schlick
11	*/
12
13	multisamp(t, n, r) /* convert 1-dimensional sample to N dimensions */
14	double t[]; /* returned N-dimensional vector */
15	register int n; /* number of dimensions */
16	double r; /* 1-dimensional sample [0,1) */
17	{
18	int j;
19	register int i, k;
20	int ti[8];
21	double s;
22
23	i = n;
24	while (i-- > 0)
25	ti[i] = 0;
26	j = 8;
27	while (j--) {
28	k = s = r*(1<<n);
29	r = s - k;
30	i = n;
31	while (i-- > 0)
32	ti[i] += ti[i] + ((k>>i) & 1);
33	}
34	i = n;
35	while (i-- > 0)
36	t[i] = 1./256. * ti[i];
37	}