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 (33 years, 11 months 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
#	User	Rev	Content
1	greg	1.1	/* 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			}