src/rt/m_mist.c

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

#include "copyright.h"

#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;
{
        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:	2.12
Committed:	Mon Mar 10 17:26:26 2003 UTC (22 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R5
Changes since 2.11:	+1 -2 lines
Log Message:	Compile fixes for Linux
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.12	static const char RCSid[] = "$Id";
3	greg	2.1	#endif
4			/*
5			* Mist volumetric material.
6			*/
7
8	greg	2.11	#include "copyright.h"
9	greg	2.10
10	greg	2.1	#include "ray.h"
11
12			#include "source.h"
13
14			/*
15			* A mist volume is used to specify a region in the scene where a certain
16			* light source (or sources) is going to contribute to scattering. The
17			* material can add to the existing global medium, and override any ray
18			* settings for scattering albedo and eccentricity. Overlapping mist
19			* regions should agree w.r.t. albedo and eccentricity, and
20			* should have disjoint source lists.
21			*
22			* A pattern, if used, should compute the line integral of extinction,
23			* and will modify the first three arguments directly. This will tend
24			* to invalidate results when there are other objects intersected within
25			* the mist region.
26			*
27			* The string arguments for MAT_MIST are the identifiers for the important
28			* light sources, which will be looked up in the source array. The last
29			* source found matching a name is the one used. A relayed light source
30			* may be indicated by the relay surface name, followed by a '>' character,
31			* followed by the relayed source name (which may be another relay).
32			*
33			* Up to five real arguments may be given for MAT_MIST:
34			*
35	greg	2.6	* [ext_r ext_g ext_b [albedo_r albedo_g albedo_b [gecc]]]
36	greg	2.1	*
37			* The primaries indicate medium extinction per unit length (absorption
38	greg	2.5	* plus scattering), which is added to the global extinction coefficient, set
39			* by the -me option. The albedo is the ratio of scattering to extinction,
40	greg	2.1	* and is set globally by the -ma option (salbedo) and overridden here.
41			* The Heyney-Greenstein eccentricity parameter (-mg seccg) indicates how much
42			* scattering favors the forward direction. A value of 0 means isotropic
43			* scattering. A value approaching 1 indicates strong forward scattering.
44			*/
45
46	greg	2.7	#ifndef MAXSLIST
47			#define MAXSLIST 32 /* maximum sources to check */
48			#endif
49
50	greg	2.1	#define RELAYDELIM '>' /* relay delimiter character */
51
52
53			static int
54			inslist(sl, n) /* return index of source n if it's in list sl */
55			register int *sl;
56			register int n;
57			{
58			register int i;
59
60			for (i = sl[0]; i > 0; i--)
61			if (sl[i] == n)
62			return(i);
63			return(0);
64			}
65
66
67			static int
68	greg	2.2	srcmatch(sp, id) /* check for an id match on a light source */
69			register SRCREC *sp;
70			register char *id;
71	greg	2.1	{
72			register char *cp;
73	greg	2.2	/* check for relay sources */
74			while ((cp = index(id, RELAYDELIM)) != NULL) {
75			if (!(sp->sflags & SVIRTUAL) \|\| sp->so == NULL)
76	greg	2.1	return(0);
77	greg	2.2	if (strncmp(id, sp->so->oname, cp-id) \|\| sp->so->oname[cp-id])
78	greg	2.1	return(0);
79	greg	2.2	id = cp + 1; /* relay to next */
80			sp = source + sp->sa.sv.sn;
81	greg	2.1	}
82	greg	2.2	if (sp->sflags & SVIRTUAL \|\| sp->so == NULL)
83	greg	2.1	return(0);
84	greg	2.2	return(!strcmp(id, sp->so->oname));
85	greg	2.1	}
86
87
88	greg	2.10	static void
89	greg	2.2	add2slist(r, sl) /* add source list to ray's */
90			register RAY *r;
91			register int *sl;
92			{
93			static int slspare[MAXSLIST+1]; /* in case of emergence */
94			register int i;
95
96			if (sl == NULL \|\| sl[0] == 0) /* nothing to add */
97			return;
98			if (r->slights == NULL)
99			(r->slights = slspare)[0] = 0; /* just once per ray path */
100			for (i = sl[0]; i > 0; i--)
101			if (!inslist(r->slights, sl[i])) {
102			if (r->slights[0] >= MAXSLIST)
103	gregl	2.9	error(INTERNAL,
104			"scattering source list overflow");
105	greg	2.2	r->slights[++r->slights[0]] = sl[i];
106			}
107			}
108
109
110	greg	2.10	int
111	greg	2.1	m_mist(m, r) /* process a ray entering or leaving some mist */
112			OBJREC *m;
113			register RAY *r;
114			{
115			RAY p;
116			int *myslist = NULL;
117			int newslist[MAXSLIST+1];
118			COLOR mext;
119			double re, ge, be;
120			register int i, j;
121			/* check arguments */
122	greg	2.8	if (m->oargs.nfargs > 7)
123	greg	2.1	objerror(m, USER, "bad arguments");
124			/* get source indices */
125	greg	2.4	if (m->oargs.nsargs > 0 && (myslist = (int *)m->os) == NULL) {
126	greg	2.2	if (m->oargs.nsargs > MAXSLIST)
127	gregl	2.9	objerror(m, INTERNAL, "too many sources in list");
128	greg	2.1	myslist = (int )malloc((m->oargs.nsargs+1)sizeof(int));
129			if (myslist == NULL)
130			goto memerr;
131	greg	2.2	myslist[0] = 0; /* size is first in list */
132			for (j = 0; j < m->oargs.nsargs; j++) {
133	greg	2.1	i = nsources; /* look up each source id */
134			while (i--)
135	greg	2.2	if (srcmatch(source+i, m->oargs.sarg[j]))
136	greg	2.1	break;
137			if (i < 0) {
138			sprintf(errmsg, "unknown source \"%s\"",
139	greg	2.2	m->oargs.sarg[j]);
140	greg	2.1	objerror(m, WARNING, errmsg);
141	greg	2.2	} else if (inslist(myslist, i)) {
142			sprintf(errmsg, "duplicate source \"%s\"",
143			m->oargs.sarg[j]);
144			objerror(m, WARNING, errmsg);
145	greg	2.1	} else
146	greg	2.2	myslist[++myslist[0]] = i;
147	greg	2.1	}
148			m->os = (char *)myslist;
149			}
150			if (m->oargs.nfargs > 2) { /* compute extinction */
151			setcolor(mext, m->oargs.farg[0], m->oargs.farg[1],
152			m->oargs.farg[2]);
153			raytexture(r, m->omod); /* get modifiers */
154			multcolor(mext, r->pcol);
155			} else
156			setcolor(mext, 0., 0., 0.);
157			/* start transmitted ray */
158			if (rayorigin(&p, r, TRANS, 1.) < 0)
159			return(1);
160			VCOPY(p.rdir, r->rdir);
161			p.slights = newslist;
162	greg	2.2	if (r->slights != NULL) /* copy old list if one */
163	greg	2.1	for (j = r->slights[0]; j >= 0; j--)
164			p.slights[j] = r->slights[j];
165			else
166			p.slights[0] = 0;
167			if (r->rod > 0.) { /* entering ray */
168			addcolor(p.cext, mext);
169	greg	2.6	if (m->oargs.nfargs > 5)
170			setcolor(p.albedo, m->oargs.farg[3],
171			m->oargs.farg[4], m->oargs.farg[5]);
172			if (m->oargs.nfargs > 6)
173			p.gecc = m->oargs.farg[6];
174	greg	2.2	add2slist(&p, myslist); /* add to list */
175			} else { /* leaving ray */
176			if (myslist != NULL) { /* delete from list */
177	greg	2.1	for (j = myslist[0]; j > 0; j--)
178	greg	2.2	if (i = inslist(p.slights, myslist[j]))
179			p.slights[i] = -1;
180			for (i = 0, j = 1; j <= p.slights[0]; j++)
181			if (p.slights[j] != -1)
182			p.slights[++i] = p.slights[j];
183			if (p.slights[0] - i < myslist[0]) { /* fix old */
184			addcolor(r->cext, mext);
185	greg	2.6	if (m->oargs.nfargs > 5)
186			setcolor(r->albedo, m->oargs.farg[3],
187			m->oargs.farg[4], m->oargs.farg[5]);
188			if (m->oargs.nfargs > 6)
189			r->gecc = m->oargs.farg[6];
190	greg	2.2	add2slist(r, myslist);
191			}
192			p.slights[0] = i;
193			}
194	greg	2.5	if ((re = colval(r->cext,RED) - colval(mext,RED)) <
195			colval(cextinction,RED))
196			re = colval(cextinction,RED);
197			if ((ge = colval(r->cext,GRN) - colval(mext,GRN)) <
198			colval(cextinction,GRN))
199			ge = colval(cextinction,GRN);
200			if ((be = colval(r->cext,BLU) - colval(mext,BLU)) <
201			colval(cextinction,BLU))
202			be = colval(cextinction,BLU);
203			setcolor(p.cext, re, ge, be);
204	greg	2.6	if (m->oargs.nfargs > 5)
205			copycolor(p.albedo, salbedo);
206			if (m->oargs.nfargs > 6)
207	greg	2.1	p.gecc = seccg;
208			}
209			rayvalue(&p); /* calls rayparticipate() */
210			copycolor(r->rcol, p.rcol); /* return value */
211			r->rt = r->rot + p.rt;
212			return(1);
213			memerr:
214			error(SYSTEM, "out of memory in m_mist");
215			}