src/rt/m_mist.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 * Mist volumetric material.
 */

/* ====================================================================
 * 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  "ray.h"

#include  "source.h"

/*
 *  A mist volume is used to specify a region in the scene where a certain
 *  light source (or sources) is going to contribute to scattering.  The
 *  material can add to the existing global medium, and override any ray
 *  settings for scattering albedo and eccentricity.  Overlapping mist
 *  regions should agree w.r.t. albedo and eccentricity, and
 *  should have disjoint source lists.
 *
 *  A pattern, if used, should compute the line integral of extinction,
 *  and will modify the first three arguments directly.  This will tend
 *  to invalidate results when there are other objects intersected within
 *  the mist region.
 *
 *  The string arguments for MAT_MIST are the identifiers for the important
 *  light sources, which will be looked up in the source array.  The last
 *  source found matching a name is the one used.  A relayed light source
 *  may be indicated by the relay surface name, followed by a '>' character,
 *  followed by the relayed source name (which may be another relay).
 *
 *  Up to five real arguments may be given for MAT_MIST:
 *
 *      [ext_r  ext_g  ext_b  [albedo_r albedo_g albedo_b [gecc]]]
 *
 *  The primaries indicate medium extinction per unit length (absorption
 *  plus scattering), which is added to the global extinction coefficient, set
 *  by the -me option.  The albedo is the ratio of scattering to extinction,
 *  and is set globally by the -ma option (salbedo) and overridden here.
 *  The Heyney-Greenstein eccentricity parameter (-mg seccg) indicates how much
 *  scattering favors the forward direction.  A value of 0 means isotropic
 *  scattering.  A value approaching 1 indicates strong forward scattering.
 */

#ifndef  MAXSLIST
#define  MAXSLIST       32      /* maximum sources to check */
#endif

#define RELAYDELIM      '>'             /* relay delimiter character */


static int
inslist(sl, n)          /* return index of source n if it's in list sl */
register int  *sl;
register int  n;
{
        register int  i;

        for (i = sl[0]; i > 0; i--)
                if (sl[i] == n)
                        return(i);
        return(0);
}


static int
srcmatch(sp, id)        /* check for an id match on a light source */
register SRCREC  *sp;
register char  *id;
{
        extern char  *index();
        register char  *cp;
                                                /* check for relay sources */
        while ((cp = index(id, RELAYDELIM)) != NULL) {
                if (!(sp->sflags & SVIRTUAL) || sp->so == NULL)
                        return(0);
                if (strncmp(id, sp->so->oname, cp-id) || sp->so->oname[cp-id])
                        return(0);
                id = cp + 1;                            /* relay to next */
                sp = source + sp->sa.sv.sn;
        }
        if (sp->sflags & SVIRTUAL || sp->so == NULL)
                return(0);
        return(!strcmp(id, sp->so->oname));
}


static void
add2slist(r, sl)        /* add source list to ray's */
register RAY  *r;
register int  *sl;
{
        static int  slspare[MAXSLIST+1];        /* in case of emergence */
        register int  i;

        if (sl == NULL || sl[0] == 0)           /* nothing to add */
                return;
        if (r->slights == NULL)
                (r->slights = slspare)[0] = 0;  /* just once per ray path */
        for (i = sl[0]; i > 0; i--)
                if (!inslist(r->slights, sl[i])) {
                        if (r->slights[0] >= MAXSLIST)
                                error(INTERNAL,
                                        "scattering source list overflow");
                        r->slights[++r->slights[0]] = sl[i];
                }
}


int
m_mist(m, r)            /* process a ray entering or leaving some mist */
OBJREC  *m;
register RAY  *r;
{
        RAY  p;
        int  *myslist = NULL;
        int  newslist[MAXSLIST+1];
        COLOR  mext;
        double  re, ge, be;
        register int  i, j;
                                        /* check arguments */
        if (m->oargs.nfargs > 7)
                objerror(m, USER, "bad arguments");
                                        /* get source indices */
        if (m->oargs.nsargs > 0 && (myslist = (int *)m->os) == NULL) {
                if (m->oargs.nsargs > MAXSLIST)
                        objerror(m, INTERNAL, "too many sources in list");
                myslist = (int *)malloc((m->oargs.nsargs+1)*sizeof(int));
                if (myslist == NULL)
                        goto memerr;
                myslist[0] = 0;                 /* size is first in list */
                for (j = 0; j < m->oargs.nsargs; j++) {
                        i = nsources;           /* look up each source id */
                        while (i--)
                                if (srcmatch(source+i, m->oargs.sarg[j]))
                                        break;
                        if (i < 0) {
                                sprintf(errmsg, "unknown source \"%s\"",
                                                m->oargs.sarg[j]);
                                objerror(m, WARNING, errmsg);
                        } else if (inslist(myslist, i)) {
                                sprintf(errmsg, "duplicate source \"%s\"",
                                                m->oargs.sarg[j]);
                                objerror(m, WARNING, errmsg);
                        } else
                                myslist[++myslist[0]] = i;
                }
                m->os = (char *)myslist;
        }
        if (m->oargs.nfargs > 2) {              /* compute extinction */
                setcolor(mext, m->oargs.farg[0], m->oargs.farg[1],
                                m->oargs.farg[2]);
                raytexture(r, m->omod);                 /* get modifiers */
                multcolor(mext, r->pcol);
        } else
                setcolor(mext, 0., 0., 0.);
                                                /* start transmitted ray */
        if (rayorigin(&p, r, TRANS, 1.) < 0)
                return(1);
        VCOPY(p.rdir, r->rdir);
        p.slights = newslist;
        if (r->slights != NULL)                 /* copy old list if one */
                for (j = r->slights[0]; j >= 0; j--)
                        p.slights[j] = r->slights[j];
        else
                p.slights[0] = 0;
        if (r->rod > 0.) {                      /* entering ray */
                addcolor(p.cext, mext);
                if (m->oargs.nfargs > 5)
                        setcolor(p.albedo, m->oargs.farg[3],
                                        m->oargs.farg[4], m->oargs.farg[5]);
                if (m->oargs.nfargs > 6)
                        p.gecc = m->oargs.farg[6];
                add2slist(&p, myslist);                 /* add to list */
        } else {                                /* leaving ray */
                if (myslist != NULL) {                  /* delete from list */
                        for (j = myslist[0]; j > 0; j--)
                                if (i = inslist(p.slights, myslist[j]))
                                        p.slights[i] = -1;
                        for (i = 0, j = 1; j <= p.slights[0]; j++)
                                if (p.slights[j] != -1)
                                        p.slights[++i] = p.slights[j];
                        if (p.slights[0] - i < myslist[0]) {    /* fix old */
                                addcolor(r->cext, mext);
                                if (m->oargs.nfargs > 5)
                                        setcolor(r->albedo, m->oargs.farg[3],
                                        m->oargs.farg[4], m->oargs.farg[5]);
                                if (m->oargs.nfargs > 6)
                                        r->gecc = m->oargs.farg[6];
                                add2slist(r, myslist);
                        }
                        p.slights[0] = i;
                }
                if ((re = colval(r->cext,RED) - colval(mext,RED)) <
                                colval(cextinction,RED))
                        re = colval(cextinction,RED);
                if ((ge = colval(r->cext,GRN) - colval(mext,GRN)) <
                                colval(cextinction,GRN))
                        ge = colval(cextinction,GRN);
                if ((be = colval(r->cext,BLU) - colval(mext,BLU)) <
                                colval(cextinction,BLU))
                        be = colval(cextinction,BLU);
                setcolor(p.cext, re, ge, be);
                if (m->oargs.nfargs > 5)
                        copycolor(p.albedo, salbedo);
                if (m->oargs.nfargs > 6)
                        p.gecc = seccg;
        }
        rayvalue(&p);                           /* calls rayparticipate() */
        copycolor(r->rcol, p.rcol);             /* return value */
        r->rt = r->rot + p.rt;
        return(1);
memerr:
        error(SYSTEM, "out of memory in m_mist");
}
Revision:	2.10
Committed:	Sat Feb 22 02:07:28 2003 UTC (22 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.9:	+60 -9 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
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.10	static const char RCSid[] = "$Id$";
3	greg	2.1	#endif
4			/*
5			* Mist volumetric material.
6			*/
7
8	greg	2.10	/* ====================================================================
9			* The Radiance Software License, Version 1.0
10			*
11			* Copyright (c) 1990 - 2002 The Regents of the University of California,
12			* through Lawrence Berkeley National Laboratory. All rights reserved.
13			*
14			* Redistribution and use in source and binary forms, with or without
15			* modification, are permitted provided that the following conditions
16			* are met:
17			*
18			* 1. Redistributions of source code must retain the above copyright
19			* notice, this list of conditions and the following disclaimer.
20			*
21			* 2. Redistributions in binary form must reproduce the above copyright
22			* notice, this list of conditions and the following disclaimer in
23			* the documentation and/or other materials provided with the
24			* distribution.
25			*
26			* 3. The end-user documentation included with the redistribution,
27			* if any, must include the following acknowledgment:
28			* "This product includes Radiance software
29			* (http://radsite.lbl.gov/)
30			* developed by the Lawrence Berkeley National Laboratory
31			* (http://www.lbl.gov/)."
32			* Alternately, this acknowledgment may appear in the software itself,
33			* if and wherever such third-party acknowledgments normally appear.
34			*
35			* 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
36			* and "The Regents of the University of California" must
37			* not be used to endorse or promote products derived from this
38			* software without prior written permission. For written
39			* permission, please contact [email protected].
40			*
41			* 5. Products derived from this software may not be called "Radiance",
42			* nor may "Radiance" appear in their name, without prior written
43			* permission of Lawrence Berkeley National Laboratory.
44			*
45			* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
46			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
47			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
48			* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
49			* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
51			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
52			* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
53			* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
54			* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
55			* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
56			* SUCH DAMAGE.
57			* ====================================================================
58			*
59			* This software consists of voluntary contributions made by many
60			* individuals on behalf of Lawrence Berkeley National Laboratory. For more
61			* information on Lawrence Berkeley National Laboratory, please see
62			* <http://www.lbl.gov/>.
63			*/
64
65	greg	2.1	#include "ray.h"
66
67			#include "source.h"
68
69			/*
70			* A mist volume is used to specify a region in the scene where a certain
71			* light source (or sources) is going to contribute to scattering. The
72			* material can add to the existing global medium, and override any ray
73			* settings for scattering albedo and eccentricity. Overlapping mist
74			* regions should agree w.r.t. albedo and eccentricity, and
75			* should have disjoint source lists.
76			*
77			* A pattern, if used, should compute the line integral of extinction,
78			* and will modify the first three arguments directly. This will tend
79			* to invalidate results when there are other objects intersected within
80			* the mist region.
81			*
82			* The string arguments for MAT_MIST are the identifiers for the important
83			* light sources, which will be looked up in the source array. The last
84			* source found matching a name is the one used. A relayed light source
85			* may be indicated by the relay surface name, followed by a '>' character,
86			* followed by the relayed source name (which may be another relay).
87			*
88			* Up to five real arguments may be given for MAT_MIST:
89			*
90	greg	2.6	* [ext_r ext_g ext_b [albedo_r albedo_g albedo_b [gecc]]]
91	greg	2.1	*
92			* The primaries indicate medium extinction per unit length (absorption
93	greg	2.5	* plus scattering), which is added to the global extinction coefficient, set
94			* by the -me option. The albedo is the ratio of scattering to extinction,
95	greg	2.1	* and is set globally by the -ma option (salbedo) and overridden here.
96			* The Heyney-Greenstein eccentricity parameter (-mg seccg) indicates how much
97			* scattering favors the forward direction. A value of 0 means isotropic
98			* scattering. A value approaching 1 indicates strong forward scattering.
99			*/
100
101	greg	2.7	#ifndef MAXSLIST
102			#define MAXSLIST 32 /* maximum sources to check */
103			#endif
104
105	greg	2.1	#define RELAYDELIM '>' /* relay delimiter character */
106
107
108			static int
109			inslist(sl, n) /* return index of source n if it's in list sl */
110			register int *sl;
111			register int n;
112			{
113			register int i;
114
115			for (i = sl[0]; i > 0; i--)
116			if (sl[i] == n)
117			return(i);
118			return(0);
119			}
120
121
122			static int
123	greg	2.2	srcmatch(sp, id) /* check for an id match on a light source */
124			register SRCREC *sp;
125			register char *id;
126	greg	2.1	{
127			extern char *index();
128			register char *cp;
129	greg	2.2	/* check for relay sources */
130			while ((cp = index(id, RELAYDELIM)) != NULL) {
131			if (!(sp->sflags & SVIRTUAL) \|\| sp->so == NULL)
132	greg	2.1	return(0);
133	greg	2.2	if (strncmp(id, sp->so->oname, cp-id) \|\| sp->so->oname[cp-id])
134	greg	2.1	return(0);
135	greg	2.2	id = cp + 1; /* relay to next */
136			sp = source + sp->sa.sv.sn;
137	greg	2.1	}
138	greg	2.2	if (sp->sflags & SVIRTUAL \|\| sp->so == NULL)
139	greg	2.1	return(0);
140	greg	2.2	return(!strcmp(id, sp->so->oname));
141	greg	2.1	}
142
143
144	greg	2.10	static void
145	greg	2.2	add2slist(r, sl) /* add source list to ray's */
146			register RAY *r;
147			register int *sl;
148			{
149			static int slspare[MAXSLIST+1]; /* in case of emergence */
150			register int i;
151
152			if (sl == NULL \|\| sl[0] == 0) /* nothing to add */
153			return;
154			if (r->slights == NULL)
155			(r->slights = slspare)[0] = 0; /* just once per ray path */
156			for (i = sl[0]; i > 0; i--)
157			if (!inslist(r->slights, sl[i])) {
158			if (r->slights[0] >= MAXSLIST)
159	gregl	2.9	error(INTERNAL,
160			"scattering source list overflow");
161	greg	2.2	r->slights[++r->slights[0]] = sl[i];
162			}
163			}
164
165
166	greg	2.10	int
167	greg	2.1	m_mist(m, r) /* process a ray entering or leaving some mist */
168			OBJREC *m;
169			register RAY *r;
170			{
171			RAY p;
172			int *myslist = NULL;
173			int newslist[MAXSLIST+1];
174			COLOR mext;
175			double re, ge, be;
176			register int i, j;
177			/* check arguments */
178	greg	2.8	if (m->oargs.nfargs > 7)
179	greg	2.1	objerror(m, USER, "bad arguments");
180			/* get source indices */
181	greg	2.4	if (m->oargs.nsargs > 0 && (myslist = (int *)m->os) == NULL) {
182	greg	2.2	if (m->oargs.nsargs > MAXSLIST)
183	gregl	2.9	objerror(m, INTERNAL, "too many sources in list");
184	greg	2.1	myslist = (int )malloc((m->oargs.nsargs+1)sizeof(int));
185			if (myslist == NULL)
186			goto memerr;
187	greg	2.2	myslist[0] = 0; /* size is first in list */
188			for (j = 0; j < m->oargs.nsargs; j++) {
189	greg	2.1	i = nsources; /* look up each source id */
190			while (i--)
191	greg	2.2	if (srcmatch(source+i, m->oargs.sarg[j]))
192	greg	2.1	break;
193			if (i < 0) {
194			sprintf(errmsg, "unknown source \"%s\"",
195	greg	2.2	m->oargs.sarg[j]);
196	greg	2.1	objerror(m, WARNING, errmsg);
197	greg	2.2	} else if (inslist(myslist, i)) {
198			sprintf(errmsg, "duplicate source \"%s\"",
199			m->oargs.sarg[j]);
200			objerror(m, WARNING, errmsg);
201	greg	2.1	} else
202	greg	2.2	myslist[++myslist[0]] = i;
203	greg	2.1	}
204			m->os = (char *)myslist;
205			}
206			if (m->oargs.nfargs > 2) { /* compute extinction */
207			setcolor(mext, m->oargs.farg[0], m->oargs.farg[1],
208			m->oargs.farg[2]);
209			raytexture(r, m->omod); /* get modifiers */
210			multcolor(mext, r->pcol);
211			} else
212			setcolor(mext, 0., 0., 0.);
213			/* start transmitted ray */
214			if (rayorigin(&p, r, TRANS, 1.) < 0)
215			return(1);
216			VCOPY(p.rdir, r->rdir);
217			p.slights = newslist;
218	greg	2.2	if (r->slights != NULL) /* copy old list if one */
219	greg	2.1	for (j = r->slights[0]; j >= 0; j--)
220			p.slights[j] = r->slights[j];
221			else
222			p.slights[0] = 0;
223			if (r->rod > 0.) { /* entering ray */
224			addcolor(p.cext, mext);
225	greg	2.6	if (m->oargs.nfargs > 5)
226			setcolor(p.albedo, m->oargs.farg[3],
227			m->oargs.farg[4], m->oargs.farg[5]);
228			if (m->oargs.nfargs > 6)
229			p.gecc = m->oargs.farg[6];
230	greg	2.2	add2slist(&p, myslist); /* add to list */
231			} else { /* leaving ray */
232			if (myslist != NULL) { /* delete from list */
233	greg	2.1	for (j = myslist[0]; j > 0; j--)
234	greg	2.2	if (i = inslist(p.slights, myslist[j]))
235			p.slights[i] = -1;
236			for (i = 0, j = 1; j <= p.slights[0]; j++)
237			if (p.slights[j] != -1)
238			p.slights[++i] = p.slights[j];
239			if (p.slights[0] - i < myslist[0]) { /* fix old */
240			addcolor(r->cext, mext);
241	greg	2.6	if (m->oargs.nfargs > 5)
242			setcolor(r->albedo, m->oargs.farg[3],
243			m->oargs.farg[4], m->oargs.farg[5]);
244			if (m->oargs.nfargs > 6)
245			r->gecc = m->oargs.farg[6];
246	greg	2.2	add2slist(r, myslist);
247			}
248			p.slights[0] = i;
249			}
250	greg	2.5	if ((re = colval(r->cext,RED) - colval(mext,RED)) <
251			colval(cextinction,RED))
252			re = colval(cextinction,RED);
253			if ((ge = colval(r->cext,GRN) - colval(mext,GRN)) <
254			colval(cextinction,GRN))
255			ge = colval(cextinction,GRN);
256			if ((be = colval(r->cext,BLU) - colval(mext,BLU)) <
257			colval(cextinction,BLU))
258			be = colval(cextinction,BLU);
259			setcolor(p.cext, re, ge, be);
260	greg	2.6	if (m->oargs.nfargs > 5)
261			copycolor(p.albedo, salbedo);
262			if (m->oargs.nfargs > 6)
263	greg	2.1	p.gecc = seccg;
264			}
265			rayvalue(&p); /* calls rayparticipate() */
266			copycolor(r->rcol, p.rcol); /* return value */
267			r->rt = r->rot + p.rt;
268			return(1);
269			memerr:
270			error(SYSTEM, "out of memory in m_mist");
271			}