src/rt/source.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 *  source.c - routines dealing with illumination sources.
 *
 *  External symbols declared in source.h
 */

/* ====================================================================
 * 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  "otypes.h"

#include  "source.h"

#include  "random.h"

extern double  ssampdist;               /* scatter sampling distance */

#ifndef MAXSSAMP
#define MAXSSAMP        16              /* maximum samples per ray */
#endif

/*
 * Structures used by direct()
 */

typedef struct {
        int  sno;               /* source number */
        FVECT  dir;             /* source direction */
        COLOR  coef;            /* material coefficient */
        COLOR  val;             /* contribution */
}  CONTRIB;             /* direct contribution */

typedef struct {
        int  sndx;              /* source index (to CONTRIB array) */
        float  brt;             /* brightness (for comparison) */
}  CNTPTR;              /* contribution pointer */

static CONTRIB  *srccnt;                /* source contributions in direct() */
static CNTPTR  *cntord;                 /* source ordering in direct() */
static int  maxcntr = 0;                /* size of contribution arrays */


void
marksources()                   /* find and mark source objects */
{
        int  foundsource = 0;
        int  i;
        register OBJREC  *o, *m;
        register int  ns;
                                        /* initialize dispatch table */
        initstypes();
                                        /* find direct sources */
        for (i = 0; i < nobjects; i++) {
        
                o = objptr(i);

                if (!issurface(o->otype) || o->omod == OVOID)
                        continue;

                m = objptr(o->omod);

                if (!islight(m->otype))
                        continue;
        
                if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
                                m->otype == MAT_SPOT ? 7 : 3))
                        objerror(m, USER, "bad # arguments");

                if (m->otype == MAT_GLOW &&
                                o->otype != OBJ_SOURCE &&
                                m->oargs.farg[3] <= FTINY)
                        continue;                       /* don't bother */
                if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
                                m->oargs.farg[2] <= FTINY)
                        continue;                       /* don't bother */

                if (sfun[o->otype].of == NULL ||
                                sfun[o->otype].of->setsrc == NULL)
                        objerror(o, USER, "illegal material");

                if ((ns = newsource()) < 0)
                        goto memerr;

                setsource(&source[ns], o);

                if (m->otype == MAT_GLOW) {
                        source[ns].sflags |= SPROX;
                        source[ns].sl.prox = m->oargs.farg[3];
                        if (source[ns].sflags & SDISTANT)
                                source[ns].sflags |= SSKIP;
                } else if (m->otype == MAT_SPOT) {
                        source[ns].sflags |= SSPOT;
                        if ((source[ns].sl.s = makespot(m)) == NULL)
                                goto memerr;
                        if (source[ns].sflags & SFLAT &&
                                !checkspot(source[ns].sl.s,source[ns].snorm)) {
                                objerror(o, WARNING,
                                        "invalid spotlight direction");
                                source[ns].sflags |= SSKIP;
                        }
                }
                if (!(source[ns].sflags & SSKIP))
                        foundsource++;
        }
        if (!foundsource) {
                error(WARNING, "no light sources found");
                return;
        }
        markvirtuals();                 /* find and add virtual sources */
                                /* allocate our contribution arrays */
        maxcntr = nsources + MAXSPART;  /* start with this many */
        srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
        cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
        if (srccnt == NULL | cntord == NULL)
                goto memerr;
        return;
memerr:
        error(SYSTEM, "out of memory in marksources");
}


void
freesources()                   /* free all source structures */
{
        if (nsources > 0) {
                free((void *)source);
                source = NULL;
                nsources = 0;
        }
        if (maxcntr <= 0)
                return;
        free((void *)srccnt);
        srccnt = NULL;
        free((void *)cntord);
        cntord = NULL;
        maxcntr = 0;
}


int
srcray(sr, r, si)               /* send a ray to a source, return domega */
register RAY  *sr;              /* returned source ray */
RAY  *r;                        /* ray which hit object */
SRCINDEX  *si;                  /* source sample index */
{
    double  d;                          /* distance to source */
    register SRCREC  *srcp;

    rayorigin(sr, r, SHADOW, 1.0);              /* ignore limits */

    while ((d = nextssamp(sr, si)) != 0.0) {
        sr->rsrc = si->sn;                      /* remember source */
        srcp = source + si->sn;
        if (srcp->sflags & SDISTANT) {
                if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
                        continue;
                return(1);              /* sample OK */
        }
                                /* local source */
                                                /* check proximity */
        if (srcp->sflags & SPROX && d > srcp->sl.prox)
                continue;
                                                /* check angle */
        if (srcp->sflags & SSPOT) {
                if (spotout(sr, srcp->sl.s))
                        continue;
                                        /* adjust solid angle */
                si->dom *= d*d;
                d += srcp->sl.s->flen;
                si->dom /= d*d;
        }
        return(1);                      /* sample OK */
    }
    return(0);                  /* no more samples */
}


void
srcvalue(r)                     /* punch ray to source and compute value */
register RAY  *r;
{
        register SRCREC  *sp;

        sp = &source[r->rsrc];
        if (sp->sflags & SVIRTUAL) {    /* virtual source */
                                        /* check intersection */
                if (!(*ofun[sp->so->otype].funp)(sp->so, r))
                        return;
                if (!rayshade(r, r->ro->omod))  /* compute contribution */
                        goto nomat;
                rayparticipate(r);
                return;
        }
                                        /* compute intersection */
        if (sp->sflags & SDISTANT ? sourcehit(r) :
                        (*ofun[sp->so->otype].funp)(sp->so, r)) {
                if (sp->sa.success >= 0)
                        sp->sa.success++;
                if (!rayshade(r, r->ro->omod))  /* compute contribution */
                        goto nomat;
                rayparticipate(r);
                return;
        }
                                        /* we missed our mark! */
        if (sp->sa.success < 0)
                return;                 /* bitched already */
        sp->sa.success -= AIMREQT;
        if (sp->sa.success >= 0)
                return;                 /* leniency */
        sprintf(errmsg, "aiming failure for light source \"%s\"",
                        sp->so->oname);
        error(WARNING, errmsg);         /* issue warning */
        return;
nomat:
        objerror(r->ro, USER, "material not found");
}


int
sourcehit(r)                    /* check to see if ray hit distant source */
register RAY  *r;
{
        int  first, last;
        register int  i;

        if (r->rsrc >= 0) {             /* check only one if aimed */
                first = last = r->rsrc;
        } else {                        /* otherwise check all */
                first = 0; last = nsources-1;
        }
        for (i = first; i <= last; i++)
                if ((source[i].sflags & (SDISTANT|SVIRTUAL)) == SDISTANT)
                        /*
                         * Check to see if ray is within
                         * solid angle of source.
                         */
                        if (2.0*PI * (1.0 - DOT(source[i].sloc,r->rdir))
                                        <= source[i].ss2) {
                                r->ro = source[i].so;
                                if (!(source[i].sflags & SSKIP))
                                        break;
                        }

        if (r->ro != NULL) {
                r->robj = objndx(r->ro);
                for (i = 0; i < 3; i++)
                        r->ron[i] = -r->rdir[i];
                r->rod = 1.0;
                r->rox = NULL;
                return(1);
        }
        return(0);
}


static int
cntcmp(sc1, sc2)                        /* contribution compare (descending) */
register CNTPTR  *sc1, *sc2;
{
        if (sc1->brt > sc2->brt)
                return(-1);
        if (sc1->brt < sc2->brt)
                return(1);
        return(0);
}


void
direct(r, f, p)                         /* add direct component */
RAY  *r;                        /* ray that hit surface */
void  (*f)();                   /* direct component coefficient function */
char  *p;                       /* data for f */
{
        extern void  (*trace)();
        register int  sn;
        register CONTRIB  *scp;
        SRCINDEX  si;
        int  nshadcheck, ncnts;
        int  nhits;
        double  prob, ourthresh, hwt;
        RAY  sr;
                        /* NOTE: srccnt and cntord global so no recursion */
        if (nsources <= 0)
                return;         /* no sources?! */
                                                /* potential contributions */
        initsrcindex(&si);
        for (sn = 0; srcray(&sr, r, &si); sn++) {
                if (sn >= maxcntr) {
                        maxcntr = sn + MAXSPART;
                        srccnt = (CONTRIB *)realloc((char *)srccnt,
                                        maxcntr*sizeof(CONTRIB));
                        cntord = (CNTPTR *)realloc((char *)cntord,
                                        maxcntr*sizeof(CNTPTR));
                        if (srccnt == NULL | cntord == NULL)
                                error(SYSTEM, "out of memory in direct");
                }
                cntord[sn].sndx = sn;
                scp = srccnt + sn;
                scp->sno = sr.rsrc;
                                                /* compute coefficient */
                (*f)(scp->coef, p, sr.rdir, si.dom);
                cntord[sn].brt = bright(scp->coef);
                if (cntord[sn].brt <= 0.0)
                        continue;
                VCOPY(scp->dir, sr.rdir);
                                                /* compute potential */
                sr.revf = srcvalue;
                rayvalue(&sr);
                copycolor(scp->val, sr.rcol);
                multcolor(scp->val, scp->coef);
                cntord[sn].brt = bright(scp->val);
        }
                                                /* sort contributions */
        qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
        {                                       /* find last */
                register int  l, m;

                ncnts = l = sn;
                sn = 0;
                while ((m = (sn + ncnts) >> 1) != l) {
                        if (cntord[m].brt > 0.0)
                                sn = m;
                        else
                                ncnts = m;
                        l = m;
                }
        }
        if (ncnts == 0)
                return;         /* no contributions! */
                                                /* accumulate tail */
        for (sn = ncnts-1; sn > 0; sn--)
                cntord[sn-1].brt += cntord[sn].brt;
                                                /* compute number to check */
        nshadcheck = pow((double)ncnts, shadcert) + .5;
                                                /* modify threshold */
        ourthresh = shadthresh / r->rweight;
                                                /* test for shadows */
        for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
                        hwt += (double)source[scp->sno].nhits /
                                (double)source[scp->sno].ntests,
                        sn++) {
                                                /* check threshold */
                if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
                                cntord[sn].brt-cntord[sn+nshadcheck].brt)
                                < ourthresh*bright(r->rcol))
                        break;
                scp = srccnt + cntord[sn].sndx;
                                                /* test for hit */
                rayorigin(&sr, r, SHADOW, 1.0);
                VCOPY(sr.rdir, scp->dir);
                sr.rsrc = scp->sno;
                source[scp->sno].ntests++;      /* keep statistics */
                if (localhit(&sr, &thescene) &&
                                ( sr.ro != source[scp->sno].so ||
                                source[scp->sno].sflags & SFOLLOW )) {
                                                /* follow entire path */
                        raycont(&sr);
                        rayparticipate(&sr);
                        if (trace != NULL)
                                (*trace)(&sr);  /* trace execution */
                        if (bright(sr.rcol) <= FTINY)
                                continue;       /* missed! */
                        copycolor(scp->val, sr.rcol);
                        multcolor(scp->val, scp->coef);
                }
                                                /* add contribution if hit */
                addcolor(r->rcol, scp->val);
                nhits++;
                source[scp->sno].nhits++;
        }
                                        /* source hit rate */
        if (hwt > FTINY)
                hwt = (double)nhits / hwt;
        else
                hwt = 0.5;
#ifdef DEBUG
        sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
                        sn, ncnts-sn, hwt);
        eputs(errmsg);
#endif
                                        /* add in untested sources */
        for ( ; sn < ncnts; sn++) {
                scp = srccnt + cntord[sn].sndx;
                prob = hwt * (double)source[scp->sno].nhits /
                                (double)source[scp->sno].ntests;
                if (prob > 1.0)
                        prob = 1.0;
                scalecolor(scp->val, prob);
                addcolor(r->rcol, scp->val);
        }
}


void
srcscatter(r)                   /* compute source scattering into ray */
register RAY  *r;
{
        int  oldsampndx;
        int  nsamps;
        RAY  sr;
        SRCINDEX  si;
        double  t, d;
        double  re, ge, be;
        COLOR  cvext;
        int  i, j;

        if (r->slights == NULL || r->slights[0] == 0
                        || r->gecc >= 1.-FTINY || r->rot >= FHUGE)
                return;
        if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1)
                nsamps = 1;
#if MAXSSAMP
        else if (nsamps > MAXSSAMP)
                nsamps = MAXSSAMP;
#endif
        oldsampndx = samplendx;
        samplendx = random()&0x7fff;            /* randomize */
        for (i = r->slights[0]; i > 0; i--) {   /* for each source */
                for (j = 0; j < nsamps; j++) {  /* for each sample position */
                        samplendx++;
                        t = r->rot * (j+frandom())/nsamps;
                                                        /* extinction */
                        re = t*colval(r->cext,RED);
                        ge = t*colval(r->cext,GRN);
                        be = t*colval(r->cext,BLU);
                        setcolor(cvext, re > 92. ? 0. : exp(-re),
                                        ge > 92. ? 0. : exp(-ge),
                                        be > 92. ? 0. : exp(-be));
                        if (intens(cvext) <= FTINY)
                                break;                  /* too far away */
                        sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
                        sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
                        sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
                        sr.rmax = 0.;
                        initsrcindex(&si);      /* sample ray to this source */
                        si.sn = r->slights[i];
                        nopart(&si, &sr);
                        if (!srcray(&sr, NULL, &si) ||
                                        sr.rsrc != r->slights[i])
                                continue;               /* no path */
                        copycolor(sr.cext, r->cext);
                        copycolor(sr.albedo, r->albedo);
                        sr.gecc = r->gecc;
                        sr.slights = r->slights;
                        rayvalue(&sr);                  /* eval. source ray */
                        if (bright(sr.rcol) <= FTINY)
                                continue;
                        if (r->gecc <= FTINY)           /* compute P(theta) */
                                d = 1.;
                        else {
                                d = DOT(r->rdir, sr.rdir);
                                d = 1. + r->gecc*r->gecc - 2.*r->gecc*d;
                                d = (1. - r->gecc*r->gecc) / (d*sqrt(d));
                        }
                                                        /* other factors */
                        d *= si.dom * r->rot / (4.*PI*nsamps);
                        multcolor(sr.rcol, r->cext);
                        multcolor(sr.rcol, r->albedo);
                        scalecolor(sr.rcol, d);
                        multcolor(sr.rcol, cvext);
                        addcolor(r->rcol, sr.rcol);     /* add it in */
                }
        }
        samplendx = oldsampndx;
}


/****************************************************************
 * The following macros were separated from the m_light() routine
 * because they are very nasty and difficult to understand.
 */

/* illumblock *
 *
 * We cannot allow an illum to pass to another illum, because that
 * would almost certainly constitute overcounting.
 * However, we do allow an illum to pass to another illum
 * that is actually going to relay to a virtual light source.
 * We also prevent an illum from passing to a glow; this provides a
 * convenient mechanism for defining detailed light source
 * geometry behind (or inside) an effective radiator.
 */

static int weaksrcmod(obj) int obj;     /* efficiency booster function */
{register OBJREC *o = objptr(obj);
return(o->otype==MAT_ILLUM|o->otype==MAT_GLOW);}

#define  illumblock(m, r)       (!(source[r->rsrc].sflags&SVIRTUAL) && \
                                r->rod > 0.0 && \
                                weaksrcmod(source[r->rsrc].so->omod))

/* wrongsource *
 *
 * This source is the wrong source (ie. overcounted) if we are
 * aimed to a different source than the one we hit and the one
 * we hit is not an illum that should be passed.
 */

#define  wrongsource(m, r)      (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
                                (m->otype!=MAT_ILLUM || illumblock(m,r)))

/* distglow *
 *
 * A distant glow is an object that sometimes acts as a light source,
 * but is too far away from the test point to be one in this case.
 * (Glows with negative radii should NEVER participate in illumination.)
 */

#define  distglow(m, r, d)      (m->otype==MAT_GLOW && \
                                m->oargs.farg[3] >= -FTINY && \
                                d > m->oargs.farg[3])

/* badcomponent *
 *
 * We must avoid counting light sources in the ambient calculation,
 * since the direct component is handled separately.  Therefore, any
 * ambient ray which hits an active light source must be discarded.
 * The same is true for stray specular samples, since the specular
 * contribution from light sources is calculated separately.
 */

#define  badcomponent(m, r)     (r->crtype&(AMBIENT|SPECULAR) && \
                                !(r->crtype&SHADOW || r->rod < 0.0 || \
                /* not 100% correct */  distglow(m, r, r->rot)))

/* passillum *
 *
 * An illum passes to another material type when we didn't hit it
 * on purpose (as part of a direct calculation), or it is relaying
 * a virtual light source.
 */

#define  passillum(m, r)        (m->otype==MAT_ILLUM && \
                                (r->rsrc<0 || source[r->rsrc].so!=r->ro || \
                                source[r->rsrc].sflags&SVIRTUAL))

/* srcignore *
 *
 * The -dv flag is normally on for sources to be visible.
 */

#define  srcignore(m, r)        !(directvis || r->crtype&SHADOW || \
                                distglow(m, r, raydist(r,PRIMARY)))


int
m_light(m, r)                   /* ray hit a light source */
register OBJREC  *m;
register RAY  *r;
{
                                                /* check for over-counting */
        if (badcomponent(m, r))
                return(1);
        if (wrongsource(m, r))
                return(1);
                                                /* check for passed illum */
        if (passillum(m, r)) {
                if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
                        return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
                raytrans(r);
                return(1);
        }
                                        /* otherwise treat as source */
                                                /* check for behind */
        if (r->rod < 0.0)
                return(1);
                                                /* check for invisibility */
        if (srcignore(m, r))
                return(1);
                                                /* check for outside spot */
        if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
                return(1);
                                                /* get distribution pattern */
        raytexture(r, m->omod);
                                                /* get source color */
        setcolor(r->rcol, m->oargs.farg[0],
                          m->oargs.farg[1],
                          m->oargs.farg[2]);
                                                /* modify value */
        multcolor(r->rcol, r->pcol);
        return(1);
}
Revision:	2.29
Committed:	Sat Feb 22 02:07:29 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.28:	+86 -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	1.1	#ifndef lint
2	greg	2.29	static const char RCSid[] = "$Id$";
3	greg	1.1	#endif
4			/*
5			* source.c - routines dealing with illumination sources.
6			*
7	greg	2.29	* External symbols declared in source.h
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	greg	1.1	*/
66
67			#include "ray.h"
68
69			#include "otypes.h"
70
71	greg	1.35	#include "source.h"
72	greg	1.1
73	greg	2.19	#include "random.h"
74
75			extern double ssampdist; /* scatter sampling distance */
76
77	greg	2.22	#ifndef MAXSSAMP
78			#define MAXSSAMP 16 /* maximum samples per ray */
79			#endif
80
81	greg	1.35	/*
82			* Structures used by direct()
83			*/
84	greg	1.1
85	greg	1.35	typedef struct {
86	greg	1.45	int sno; /* source number */
87	greg	1.35	FVECT dir; /* source direction */
88			COLOR coef; /* material coefficient */
89			COLOR val; /* contribution */
90			} CONTRIB; /* direct contribution */
91	greg	1.1
92	greg	1.35	typedef struct {
93	greg	1.45	int sndx; /* source index (to CONTRIB array) */
94	greg	1.35	float brt; /* brightness (for comparison) */
95			} CNTPTR; /* contribution pointer */
96	greg	1.1
97	greg	1.25	static CONTRIB srccnt; / source contributions in direct() */
98			static CNTPTR cntord; / source ordering in direct() */
99	greg	1.45	static int maxcntr = 0; /* size of contribution arrays */
100	greg	1.1
101	greg	1.25
102	greg	2.29	void
103	greg	1.1	marksources() /* find and mark source objects */
104			{
105	greg	2.3	int foundsource = 0;
106	greg	1.33	int i;
107	greg	1.1	register OBJREC o, m;
108	greg	1.36	register int ns;
109	greg	1.35	/* initialize dispatch table */
110			initstypes();
111			/* find direct sources */
112	greg	1.1	for (i = 0; i < nobjects; i++) {
113
114			o = objptr(i);
115
116	greg	1.35	if (!issurface(o->otype) \|\| o->omod == OVOID)
117	greg	1.1	continue;
118
119			m = objptr(o->omod);
120
121	greg	1.24	if (!islight(m->otype))
122	greg	1.1	continue;
123
124	greg	1.6	if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
125			m->otype == MAT_SPOT ? 7 : 3))
126	greg	1.1	objerror(m, USER, "bad # arguments");
127
128	greg	1.6	if (m->otype == MAT_GLOW &&
129			o->otype != OBJ_SOURCE &&
130			m->oargs.farg[3] <= FTINY)
131	greg	1.1	continue; /* don't bother */
132	greg	2.16	if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
133			m->oargs.farg[2] <= FTINY)
134			continue; /* don't bother */
135	greg	1.1
136	greg	1.35	if (sfun[o->otype].of == NULL \|\|
137			sfun[o->otype].of->setsrc == NULL)
138			objerror(o, USER, "illegal material");
139
140	greg	1.36	if ((ns = newsource()) < 0)
141	greg	1.25	goto memerr;
142	greg	1.1
143	greg	1.37	setsource(&source[ns], o);
144	greg	1.1
145	greg	1.6	if (m->otype == MAT_GLOW) {
146	greg	1.36	source[ns].sflags \|= SPROX;
147			source[ns].sl.prox = m->oargs.farg[3];
148	greg	2.8	if (source[ns].sflags & SDISTANT)
149	greg	1.36	source[ns].sflags \|= SSKIP;
150	greg	1.6	} else if (m->otype == MAT_SPOT) {
151	greg	1.36	source[ns].sflags \|= SSPOT;
152			if ((source[ns].sl.s = makespot(m)) == NULL)
153	greg	1.33	goto memerr;
154	greg	1.38	if (source[ns].sflags & SFLAT &&
155			!checkspot(source[ns].sl.s,source[ns].snorm)) {
156			objerror(o, WARNING,
157			"invalid spotlight direction");
158			source[ns].sflags \|= SSKIP;
159			}
160	greg	1.6	}
161	greg	2.3	if (!(source[ns].sflags & SSKIP))
162			foundsource++;
163	greg	1.1	}
164	greg	2.3	if (!foundsource) {
165	greg	1.25	error(WARNING, "no light sources found");
166			return;
167			}
168	greg	1.33	markvirtuals(); /* find and add virtual sources */
169	greg	1.45	/* allocate our contribution arrays */
170	greg	1.48	maxcntr = nsources + MAXSPART; /* start with this many */
171	greg	1.45	srccnt = (CONTRIB )malloc(maxcntrsizeof(CONTRIB));
172			cntord = (CNTPTR )malloc(maxcntrsizeof(CNTPTR));
173	greg	1.48	if (srccnt == NULL \| cntord == NULL)
174	greg	1.33	goto memerr;
175			return;
176	greg	1.25	memerr:
177			error(SYSTEM, "out of memory in marksources");
178	greg	1.1	}
179
180
181	greg	2.29	void
182			freesources() /* free all source structures */
183			{
184			if (nsources > 0) {
185			free((void *)source);
186			source = NULL;
187			nsources = 0;
188			}
189			if (maxcntr <= 0)
190			return;
191			free((void *)srccnt);
192			srccnt = NULL;
193			free((void *)cntord);
194			cntord = NULL;
195			maxcntr = 0;
196			}
197
198
199			int
200	greg	1.45	srcray(sr, r, si) /* send a ray to a source, return domega */
201	greg	1.1	register RAY sr; / returned source ray */
202			RAY r; / ray which hit object */
203	greg	1.45	SRCINDEX si; / source sample index */
204	greg	1.1	{
205	greg	1.45	double d; /* distance to source */
206			register SRCREC *srcp;
207	greg	1.1
208	greg	1.45	rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
209	greg	1.1
210	greg	1.47	while ((d = nextssamp(sr, si)) != 0.0) {
211	greg	1.45	sr->rsrc = si->sn; /* remember source */
212			srcp = source + si->sn;
213			if (srcp->sflags & SDISTANT) {
214	greg	2.18	if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
215	greg	2.4	continue;
216	greg	1.45	return(1); /* sample OK */
217	greg	1.40	}
218	greg	1.45	/* local source */
219	greg	1.6	/* check proximity */
220	greg	1.45	if (srcp->sflags & SPROX && d > srcp->sl.prox)
221			continue;
222	greg	1.6	/* check angle */
223	greg	1.45	if (srcp->sflags & SSPOT) {
224	greg	2.18	if (spotout(sr, srcp->sl.s))
225	greg	1.45	continue;
226			/* adjust solid angle */
227			si->dom = dd;
228			d += srcp->sl.s->flen;
229			si->dom /= d*d;
230	greg	1.1	}
231	greg	1.45	return(1); /* sample OK */
232			}
233			return(0); /* no more samples */
234	greg	1.1	}
235
236
237	greg	2.29	void
238	greg	1.35	srcvalue(r) /* punch ray to source and compute value */
239	greg	2.15	register RAY *r;
240	greg	1.1	{
241	greg	1.35	register SRCREC *sp;
242	greg	1.1
243	greg	1.35	sp = &source[r->rsrc];
244			if (sp->sflags & SVIRTUAL) { /* virtual source */
245			/* check intersection */
246			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
247			return;
248	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
249			goto nomat;
250	greg	2.19	rayparticipate(r);
251	greg	1.35	return;
252	greg	1.1	}
253	greg	1.35	/* compute intersection */
254			if (sp->sflags & SDISTANT ? sourcehit(r) :
255			(*ofun[sp->so->otype].funp)(sp->so, r)) {
256			if (sp->sa.success >= 0)
257			sp->sa.success++;
258	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
259			goto nomat;
260	greg	2.19	rayparticipate(r);
261	greg	1.35	return;
262	greg	1.1	}
263	greg	2.15	/* we missed our mark! */
264	greg	1.35	if (sp->sa.success < 0)
265			return; /* bitched already */
266			sp->sa.success -= AIMREQT;
267			if (sp->sa.success >= 0)
268			return; /* leniency */
269			sprintf(errmsg, "aiming failure for light source \"%s\"",
270			sp->so->oname);
271			error(WARNING, errmsg); /* issue warning */
272	greg	2.15	return;
273			nomat:
274			objerror(r->ro, USER, "material not found");
275	greg	1.1	}
276
277
278	greg	2.29	int
279	greg	2.5	sourcehit(r) /* check to see if ray hit distant source */
280			register RAY *r;
281			{
282			int first, last;
283			register int i;
284
285			if (r->rsrc >= 0) { /* check only one if aimed */
286			first = last = r->rsrc;
287			} else { /* otherwise check all */
288			first = 0; last = nsources-1;
289			}
290			for (i = first; i <= last; i++)
291			if ((source[i].sflags & (SDISTANT\|SVIRTUAL)) == SDISTANT)
292			/*
293			* Check to see if ray is within
294			* solid angle of source.
295			*/
296			if (2.0PI (1.0 - DOT(source[i].sloc,r->rdir))
297			<= source[i].ss2) {
298			r->ro = source[i].so;
299			if (!(source[i].sflags & SSKIP))
300			break;
301			}
302
303			if (r->ro != NULL) {
304	gregl	2.27	r->robj = objndx(r->ro);
305	greg	2.5	for (i = 0; i < 3; i++)
306			r->ron[i] = -r->rdir[i];
307			r->rod = 1.0;
308			r->rox = NULL;
309			return(1);
310			}
311			return(0);
312			}
313
314
315	greg	1.4	static int
316			cntcmp(sc1, sc2) /* contribution compare (descending) */
317	greg	1.9	register CNTPTR sc1, sc2;
318	greg	1.4	{
319			if (sc1->brt > sc2->brt)
320			return(-1);
321			if (sc1->brt < sc2->brt)
322			return(1);
323			return(0);
324			}
325
326
327	greg	2.29	void
328	greg	1.4	direct(r, f, p) /* add direct component */
329			RAY r; / ray that hit surface */
330	greg	2.29	void (f)(); / direct component coefficient function */
331	greg	1.4	char p; / data for f */
332			{
333	greg	2.29	extern void (*trace)();
334	greg	1.4	register int sn;
335	greg	2.7	register CONTRIB *scp;
336	greg	1.45	SRCINDEX si;
337	greg	1.12	int nshadcheck, ncnts;
338	greg	1.29	int nhits;
339	greg	1.45	double prob, ourthresh, hwt;
340	greg	1.4	RAY sr;
341	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
342	greg	1.22	if (nsources <= 0)
343	greg	1.25	return; /* no sources?! */
344	greg	1.4	/* potential contributions */
345	greg	1.45	initsrcindex(&si);
346			for (sn = 0; srcray(&sr, r, &si); sn++) {
347			if (sn >= maxcntr) {
348			maxcntr = sn + MAXSPART;
349			srccnt = (CONTRIB )realloc((char )srccnt,
350			maxcntr*sizeof(CONTRIB));
351			cntord = (CNTPTR )realloc((char )cntord,
352			maxcntr*sizeof(CNTPTR));
353	greg	1.48	if (srccnt == NULL \| cntord == NULL)
354	greg	1.45	error(SYSTEM, "out of memory in direct");
355			}
356			cntord[sn].sndx = sn;
357	greg	2.7	scp = srccnt + sn;
358			scp->sno = sr.rsrc;
359	greg	1.4	/* compute coefficient */
360	greg	2.7	(*f)(scp->coef, p, sr.rdir, si.dom);
361			cntord[sn].brt = bright(scp->coef);
362	greg	1.15	if (cntord[sn].brt <= 0.0)
363	greg	1.4	continue;
364	greg	2.7	VCOPY(scp->dir, sr.rdir);
365	greg	1.35	/* compute potential */
366			sr.revf = srcvalue;
367			rayvalue(&sr);
368	greg	2.7	copycolor(scp->val, sr.rcol);
369			multcolor(scp->val, scp->coef);
370			cntord[sn].brt = bright(scp->val);
371	greg	1.4	}
372			/* sort contributions */
373	greg	1.45	qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
374	greg	1.13	{ /* find last */
375			register int l, m;
376
377	greg	1.45	ncnts = l = sn;
378			sn = 0;
379	greg	1.13	while ((m = (sn + ncnts) >> 1) != l) {
380			if (cntord[m].brt > 0.0)
381			sn = m;
382			else
383			ncnts = m;
384			l = m;
385			}
386			}
387	greg	2.2	if (ncnts == 0)
388			return; /* no contributions! */
389	greg	1.12	/* accumulate tail */
390			for (sn = ncnts-1; sn > 0; sn--)
391			cntord[sn-1].brt += cntord[sn].brt;
392	greg	1.45	/* compute number to check */
393			nshadcheck = pow((double)ncnts, shadcert) + .5;
394			/* modify threshold */
395			ourthresh = shadthresh / r->rweight;
396	greg	1.10	/* test for shadows */
397	greg	2.13	for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
398			hwt += (double)source[scp->sno].nhits /
399			(double)source[scp->sno].ntests,
400			sn++) {
401	greg	1.10	/* check threshold */
402	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
403	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
404			< ourthresh*bright(r->rcol))
405	greg	1.4	break;
406	greg	2.7	scp = srccnt + cntord[sn].sndx;
407	greg	1.4	/* test for hit */
408			rayorigin(&sr, r, SHADOW, 1.0);
409	greg	2.7	VCOPY(sr.rdir, scp->dir);
410			sr.rsrc = scp->sno;
411			source[scp->sno].ntests++; /* keep statistics */
412	greg	1.4	if (localhit(&sr, &thescene) &&
413	greg	2.7	( sr.ro != source[scp->sno].so \|\|
414			source[scp->sno].sflags & SFOLLOW )) {
415	greg	1.33	/* follow entire path */
416	greg	2.23	raycont(&sr);
417	greg	2.19	rayparticipate(&sr);
418	greg	1.42	if (trace != NULL)
419			(trace)(&sr); / trace execution */
420	greg	1.5	if (bright(sr.rcol) <= FTINY)
421	greg	1.4	continue; /* missed! */
422	greg	2.7	copycolor(scp->val, sr.rcol);
423			multcolor(scp->val, scp->coef);
424	greg	1.4	}
425			/* add contribution if hit */
426	greg	2.7	addcolor(r->rcol, scp->val);
427	greg	1.29	nhits++;
428	greg	2.7	source[scp->sno].nhits++;
429	greg	1.4	}
430	greg	2.13	/* source hit rate */
431			if (hwt > FTINY)
432			hwt = (double)nhits / hwt;
433	greg	1.29	else
434			hwt = 0.5;
435	greg	1.20	#ifdef DEBUG
436	greg	2.13	sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
437	greg	1.12	sn, ncnts-sn, hwt);
438			eputs(errmsg);
439	greg	1.4	#endif
440			/* add in untested sources */
441	greg	1.12	for ( ; sn < ncnts; sn++) {
442	greg	2.7	scp = srccnt + cntord[sn].sndx;
443			prob = hwt * (double)source[scp->sno].nhits /
444			(double)source[scp->sno].ntests;
445	greg	2.13	if (prob > 1.0)
446			prob = 1.0;
447	greg	2.7	scalecolor(scp->val, prob);
448			addcolor(r->rcol, scp->val);
449	greg	2.19	}
450			}
451
452
453	greg	2.29	void
454	greg	2.19	srcscatter(r) /* compute source scattering into ray */
455			register RAY *r;
456			{
457	greg	2.20	int oldsampndx;
458	greg	2.19	int nsamps;
459			RAY sr;
460			SRCINDEX si;
461	greg	2.25	double t, d;
462			double re, ge, be;
463			COLOR cvext;
464	greg	2.19	int i, j;
465
466	greg	2.22	if (r->slights == NULL \|\| r->slights[0] == 0
467			\|\| r->gecc >= 1.-FTINY \|\| r->rot >= FHUGE)
468	greg	2.19	return;
469			if (ssampdist <= FTINY \|\| (nsamps = r->rot/ssampdist + .5) < 1)
470			nsamps = 1;
471	greg	2.22	#if MAXSSAMP
472			else if (nsamps > MAXSSAMP)
473			nsamps = MAXSSAMP;
474			#endif
475	greg	2.20	oldsampndx = samplendx;
476			samplendx = random()&0x7fff; /* randomize */
477	greg	2.19	for (i = r->slights[0]; i > 0; i--) { /* for each source */
478	greg	2.25	for (j = 0; j < nsamps; j++) { /* for each sample position */
479	greg	2.19	samplendx++;
480			t = r->rot * (j+frandom())/nsamps;
481	greg	2.25	/* extinction */
482			re = t*colval(r->cext,RED);
483			ge = t*colval(r->cext,GRN);
484			be = t*colval(r->cext,BLU);
485			setcolor(cvext, re > 92. ? 0. : exp(-re),
486			ge > 92. ? 0. : exp(-ge),
487			be > 92. ? 0. : exp(-be));
488			if (intens(cvext) <= FTINY)
489			break; /* too far away */
490	greg	2.19	sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
491			sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
492			sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
493			sr.rmax = 0.;
494	greg	2.21	initsrcindex(&si); /* sample ray to this source */
495			si.sn = r->slights[i];
496			nopart(&si, &sr);
497			if (!srcray(&sr, NULL, &si) \|\|
498			sr.rsrc != r->slights[i])
499			continue; /* no path */
500	greg	2.19	copycolor(sr.cext, r->cext);
501	greg	2.24	copycolor(sr.albedo, r->albedo);
502	greg	2.19	sr.gecc = r->gecc;
503	gregl	2.26	sr.slights = r->slights;
504	greg	2.19	rayvalue(&sr); /* eval. source ray */
505			if (bright(sr.rcol) <= FTINY)
506			continue;
507			if (r->gecc <= FTINY) /* compute P(theta) */
508			d = 1.;
509			else {
510			d = DOT(r->rdir, sr.rdir);
511	greg	2.25	d = 1. + r->geccr->gecc - 2.r->gecc*d;
512			d = (1. - r->geccr->gecc) / (dsqrt(d));
513	greg	2.19	}
514			/* other factors */
515	greg	2.24	d = si.dom r->rot / (4.PInsamps);
516	greg	2.19	multcolor(sr.rcol, r->cext);
517	greg	2.24	multcolor(sr.rcol, r->albedo);
518	greg	2.19	scalecolor(sr.rcol, d);
519	greg	2.25	multcolor(sr.rcol, cvext);
520			addcolor(r->rcol, sr.rcol); /* add it in */
521	greg	2.19	}
522	greg	1.1	}
523	greg	2.20	samplendx = oldsampndx;
524	greg	2.4	}
525
526
527			/****************************************************************
528			* The following macros were separated from the m_light() routine
529			* because they are very nasty and difficult to understand.
530			*/
531
532	greg	2.11	/* illumblock *
533	greg	2.4	*
534			* We cannot allow an illum to pass to another illum, because that
535			* would almost certainly constitute overcounting.
536			* However, we do allow an illum to pass to another illum
537			* that is actually going to relay to a virtual light source.
538	greg	2.11	* We also prevent an illum from passing to a glow; this provides a
539			* convenient mechanism for defining detailed light source
540			* geometry behind (or inside) an effective radiator.
541	greg	2.4	*/
542
543	greg	2.11	static int weaksrcmod(obj) int obj; /* efficiency booster function */
544			{register OBJREC *o = objptr(obj);
545			return(o->otype==MAT_ILLUM\|o->otype==MAT_GLOW);}
546	greg	2.4
547	greg	2.11	#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
548	greg	2.12	r->rod > 0.0 && \
549	greg	2.11	weaksrcmod(source[r->rsrc].so->omod))
550
551	greg	2.4	/* wrongsource *
552			*
553			* This source is the wrong source (ie. overcounted) if we are
554			* aimed to a different source than the one we hit and the one
555	greg	2.11	* we hit is not an illum that should be passed.
556	greg	2.4	*/
557
558			#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
559	greg	2.11	(m->otype!=MAT_ILLUM \|\| illumblock(m,r)))
560	greg	2.4
561			/* distglow *
562			*
563			* A distant glow is an object that sometimes acts as a light source,
564			* but is too far away from the test point to be one in this case.
565	greg	2.11	* (Glows with negative radii should NEVER participate in illumination.)
566	greg	2.4	*/
567
568	greg	2.17	#define distglow(m, r, d) (m->otype==MAT_GLOW && \
569	greg	2.10	m->oargs.farg[3] >= -FTINY && \
570	greg	2.17	d > m->oargs.farg[3])
571	greg	2.4
572			/* badcomponent *
573			*
574			* We must avoid counting light sources in the ambient calculation,
575			* since the direct component is handled separately. Therefore, any
576			* ambient ray which hits an active light source must be discarded.
577			* The same is true for stray specular samples, since the specular
578			* contribution from light sources is calculated separately.
579			*/
580
581			#define badcomponent(m, r) (r->crtype&(AMBIENT\|SPECULAR) && \
582			!(r->crtype&SHADOW \|\| r->rod < 0.0 \|\| \
583	greg	2.17	/* not 100% correct */ distglow(m, r, r->rot)))
584	greg	2.4
585			/* passillum *
586			*
587			* An illum passes to another material type when we didn't hit it
588			* on purpose (as part of a direct calculation), or it is relaying
589			* a virtual light source.
590			*/
591
592			#define passillum(m, r) (m->otype==MAT_ILLUM && \
593			(r->rsrc<0 \|\| source[r->rsrc].so!=r->ro \|\| \
594			source[r->rsrc].sflags&SVIRTUAL))
595
596			/* srcignore *
597			*
598	greg	2.10	* The -dv flag is normally on for sources to be visible.
599	greg	2.4	*/
600
601	greg	2.17	#define srcignore(m, r) !(directvis \|\| r->crtype&SHADOW \|\| \
602			distglow(m, r, raydist(r,PRIMARY)))
603	greg	2.4
604
605	greg	2.29	int
606	greg	2.4	m_light(m, r) /* ray hit a light source */
607			register OBJREC *m;
608			register RAY *r;
609			{
610			/* check for over-counting */
611	greg	2.12	if (badcomponent(m, r))
612	greg	2.14	return(1);
613	greg	2.17	if (wrongsource(m, r))
614	greg	2.14	return(1);
615	greg	2.4	/* check for passed illum */
616			if (passillum(m, r)) {
617	greg	2.14	if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
618	gwlarson	2.28	return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
619	greg	2.14	raytrans(r);
620			return(1);
621	greg	2.4	}
622			/* otherwise treat as source */
623			/* check for behind */
624			if (r->rod < 0.0)
625	greg	2.14	return(1);
626	greg	2.4	/* check for invisibility */
627			if (srcignore(m, r))
628	greg	2.14	return(1);
629	greg	2.4	/* check for outside spot */
630	greg	2.18	if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
631	greg	2.14	return(1);
632	greg	2.4	/* get distribution pattern */
633			raytexture(r, m->omod);
634			/* get source color */
635			setcolor(r->rcol, m->oargs.farg[0],
636			m->oargs.farg[1],
637			m->oargs.farg[2]);
638			/* modify value */
639			multcolor(r->rcol, r->pcol);
640	greg	2.14	return(1);
641	greg	1.1	}