src/common/multisamp.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 * Binary space partitioning curve for multidimensional sampling.
 *
 *      Written by Christophe Schlick
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

#include "random.h"

void
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] + frandom());
}
Revision:	2.3
Committed:	Sat Feb 22 02:07:22 2003 UTC (22 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.2:	+61 -6 lines
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	Content
1	#ifndef lint
2	static const char RCSid[] = "$Id$";
3	#endif
4	/*
5	* Binary space partitioning curve for multidimensional sampling.
6	*
7	* Written by Christophe Schlick
8	*/
9
10	/* ====================================================================
11	* The Radiance Software License, Version 1.0
12	*
13	* Copyright (c) 1990 - 2002 The Regents of the University of California,
14	* through Lawrence Berkeley National Laboratory. All rights reserved.
15	*
16	* Redistribution and use in source and binary forms, with or without
17	* modification, are permitted provided that the following conditions
18	* are met:
19	*
20	* 1. Redistributions of source code must retain the above copyright
21	* notice, this list of conditions and the following disclaimer.
22	*
23	* 2. Redistributions in binary form must reproduce the above copyright
24	* notice, this list of conditions and the following disclaimer in
25	* the documentation and/or other materials provided with the
26	* distribution.
27	*
28	* 3. The end-user documentation included with the redistribution,
29	* if any, must include the following acknowledgment:
30	* "This product includes Radiance software
31	* (http://radsite.lbl.gov/)
32	* developed by the Lawrence Berkeley National Laboratory
33	* (http://www.lbl.gov/)."
34	* Alternately, this acknowledgment may appear in the software itself,
35	* if and wherever such third-party acknowledgments normally appear.
36	*
37	* 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
38	* and "The Regents of the University of California" must
39	* not be used to endorse or promote products derived from this
40	* software without prior written permission. For written
41	* permission, please contact [email protected].
42	*
43	* 5. Products derived from this software may not be called "Radiance",
44	* nor may "Radiance" appear in their name, without prior written
45	* permission of Lawrence Berkeley National Laboratory.
46	*
47	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
48	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
49	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
50	* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
51	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
53	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
54	* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
55	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
56	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
57	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58	* SUCH DAMAGE.
59	* ====================================================================
60	*
61	* This software consists of voluntary contributions made by many
62	* individuals on behalf of Lawrence Berkeley National Laboratory. For more
63	* information on Lawrence Berkeley National Laboratory, please see
64	* <http://www.lbl.gov/>.
65	*/
66
67	#include "random.h"
68
69	void
70	multisamp(t, n, r) /* convert 1-dimensional sample to N dimensions */
71	double t[]; /* returned N-dimensional vector */
72	register int n; /* number of dimensions */
73	double r; /* 1-dimensional sample [0,1) */
74	{
75	int j;
76	register int i, k;
77	int ti[8];
78	double s;
79
80	i = n;
81	while (i-- > 0)
82	ti[i] = 0;
83	j = 8;
84	while (j--) {
85	k = s = r*(1<<n);
86	r = s - k;
87	i = n;
88	while (i-- > 0)
89	ti[i] += ti[i] + ((k>>i) & 1);
90	}
91	i = n;
92	while (i-- > 0)
93	t[i] = 1./256. * (ti[i] + frandom());
94	}