src/rt/source.c

#ifndef lint
static const char RCSid[] = "$Id: source.c,v 2.48 2005/04/14 17:43:43 greg Exp $";
#endif
/*
 *  source.c - routines dealing with illumination sources.
 *
 *  External symbols declared in source.h
 */

#include  "ray.h"
#include  "otypes.h"
#include  "rtotypes.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 */

static int cntcmp(const void *p1, const void *p2);


extern OBJREC *                 /* find an object's actual material */
findmaterial(register OBJREC *o)
{
        while (!ismaterial(o->otype)) {
                if (o->otype == MOD_ALIAS && o->oargs.nsargs) {
                        OBJECT  aobj;
                        OBJREC  *ao;
                        aobj = lastmod(objndx(o), o->oargs.sarg[0]);
                        if (aobj < 0)
                                objerror(o, USER, "bad reference");
                        ao = objptr(aobj);
                        if (ismaterial(ao->otype))
                                return(ao);
                }
                if (o->omod == OVOID)
                        return(NULL);
                o = objptr(o->omod);
        }
        return(o);              /* mixtures will return NULL */
}


extern void
marksources(void)                       /* 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 < nsceneobjs; i++) {
        
                o = objptr(i);

                if (!issurface(o->otype) || o->omod == OVOID)
                        continue;
                                        /* find material */
                m = findmaterial(objptr(o->omod));
                if (m == NULL || !islight(m->otype))
                        continue;       /* not source modifier */
        
                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  SHADCACHE
                initobscache(ns);
#endif
                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");
}


extern void
freesources(void)                       /* free all source structures */
{
        if (nsources > 0) {
#if SHADCACHE
                while (nsources--)
                        freeobscache(&source[nsources]);
#endif
                free((void *)source);
                source = NULL;
                nsources = 0;
        }
        if (maxcntr <= 0)
                return;
        free((void *)srccnt);
        srccnt = NULL;
        free((void *)cntord);
        cntord = NULL;
        maxcntr = 0;
}


extern int
srcray(                         /* 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 */
}


extern void
srcvalue(                       /* 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");
}


static int
transillum(                     /* check if material is transparent illum */
        OBJECT  obj
)
{
        OBJREC *m = findmaterial(objptr(obj));
        
        if (m == NULL)
                return(1);
        if (m->otype != MAT_ILLUM)
                return(0);
        return(!m->oargs.nsargs || !strcmp(m->oargs.sarg[0], VOIDID));
}


extern int
sourcehit(                      /* check to see if ray hit distant source */
        register RAY  *r
)
{
        int  glowsrc = -1;
        int  transrc = -1;
        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)
                        continue;
                /*
                 * Check to see if ray is within
                 * solid angle of source.
                 */
                if (2.*PI*(1. - DOT(source[i].sloc,r->rdir)) > source[i].ss2)
                        continue;
                                        /* is it the only possibility? */
                if (first == last) {
                        r->ro = source[i].so;
                        break;
                }
                /*
                 * If it's a glow or transparent illum, just remember it.
                 */
                if (source[i].sflags & SSKIP) {
                        glowsrc = i;
                        continue;
                }
                if (transillum(source[i].so->omod)) {
                        transrc = i;
                        continue;
                }
                r->ro = source[i].so;   /* otherwise, use first hit */
                break;
        }
        /*
         * Do we need fallback?
         */
        if (r->ro == NULL) {
                if (transrc >= 0 && r->crtype & (AMBIENT|SPECULAR))
                        return(0);      /* avoid overcounting */
                if (glowsrc >= 0)
                        r->ro = source[glowsrc].so;
                else
                        return(0);      /* nothing usable */
        }
        /*
         * Make assignments.
         */
        r->robj = objndx(r->ro);
        for (i = 0; i < 3; i++)
                r->ron[i] = -r->rdir[i];
        r->rod = 1.0;
        r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
        r->uv[0] = r->uv[1] = 0.0;
        r->rox = NULL;
        return(1);
}


static int
cntcmp(                         /* contribution compare (descending) */
        const void *p1,
        const void *p2
)
{
        register const CNTPTR  *sc1 = (const CNTPTR *)p1;
        register const CNTPTR  *sc2 = (const CNTPTR *)p2;

        if (sc1->brt > sc2->brt)
                return(-1);
        if (sc1->brt < sc2->brt)
                return(1);
        return(0);
}


extern void
direct(                                 /* add direct component */
        RAY  *r,                        /* ray that hit surface */
        srcdirf_t *f,                   /* direct component coefficient function */
        void  *p                        /* data for f */
)
{
        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((void *)srccnt,
                                        maxcntr*sizeof(CONTRIB));
                        cntord = (CNTPTR *)realloc((void *)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;
#if SHADCACHE
                                                /* check shadow cache */
                if (si.np == 1 && srcblocked(&sr)) {
                        cntord[sn].brt = 0.0;
                        continue;
                }
#endif
                VCOPY(scp->dir, sr.rdir);
                                                /* compute potential */
                srcvalue(&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;
                                                /* keep statistics */
                if (source[scp->sno].ntests++ > 0xfffffff0) {
                        source[scp->sno].ntests >>= 1;
                        source[scp->sno].nhits >>= 1;
                }
                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) {
#if SHADCACHE
                                if ((scp <= srccnt || scp[-1].sno != scp->sno)
                                                && (scp >= srccnt+ncnts-1 ||
                                                    scp[1].sno != scp->sno))
                                        srcblocker(&sr);
#endif
                                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);
        }
}


extern void
srcscatter(                     /* 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 */
#if SHADCACHE
                        if (srcblocked(&sr))            /* check shadow cache */
                                continue;
#endif
                        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) {
#if SHADCACHE
                                srcblocker(&sr);        /* add blocker to cache */
#endif
                                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
weaksrcmat(OBJECT obj)          /* identify material */
{
        OBJREC *m = findmaterial(objptr(obj));
        
        if (m == NULL) return(0);
        return((m->otype==MAT_ILLUM) | (m->otype==MAT_GLOW));
}

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


extern int
m_light(                                /* 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:	2.49
Committed:	Fri Apr 15 04:44:51 2005 UTC (19 years, 7 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.48:	+2 -3 lines
Log Message:	Eliminated revf member from RAY struct, as it was never really needed
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.49	static const char RCSid[] = "$Id: source.c,v 2.48 2005/04/14 17:43:43 greg Exp $";
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	greg	1.1	#include "ray.h"
11			#include "otypes.h"
12	schorsch	2.44	#include "rtotypes.h"
13	greg	1.35	#include "source.h"
14	greg	2.19	#include "random.h"
15
16			extern double ssampdist; /* scatter sampling distance */
17
18	greg	2.22	#ifndef MAXSSAMP
19			#define MAXSSAMP 16 /* maximum samples per ray */
20			#endif
21
22	greg	1.35	/*
23			* Structures used by direct()
24			*/
25	greg	1.1
26	greg	1.35	typedef struct {
27	greg	1.45	int sno; /* source number */
28	greg	1.35	FVECT dir; /* source direction */
29			COLOR coef; /* material coefficient */
30			COLOR val; /* contribution */
31			} CONTRIB; /* direct contribution */
32	greg	1.1
33	greg	1.35	typedef struct {
34	greg	1.45	int sndx; /* source index (to CONTRIB array) */
35	greg	1.35	float brt; /* brightness (for comparison) */
36			} CNTPTR; /* contribution pointer */
37	greg	1.1
38	greg	1.25	static CONTRIB srccnt; / source contributions in direct() */
39			static CNTPTR cntord; / source ordering in direct() */
40	greg	1.45	static int maxcntr = 0; /* size of contribution arrays */
41	greg	1.1
42	schorsch	2.44	static int cntcmp(const void p1, const void p2);
43
44	greg	1.25
45	schorsch	2.44	extern OBJREC * /* find an object's actual material */
46	greg	2.38	findmaterial(register OBJREC *o)
47			{
48			while (!ismaterial(o->otype)) {
49			if (o->otype == MOD_ALIAS && o->oargs.nsargs) {
50			OBJECT aobj;
51			OBJREC *ao;
52			aobj = lastmod(objndx(o), o->oargs.sarg[0]);
53			if (aobj < 0)
54			objerror(o, USER, "bad reference");
55			ao = objptr(aobj);
56			if (ismaterial(ao->otype))
57			return(ao);
58			}
59			if (o->omod == OVOID)
60			return(NULL);
61			o = objptr(o->omod);
62			}
63	greg	2.48	return(o); /* mixtures will return NULL */
64	greg	2.38	}
65
66
67	schorsch	2.44	extern void
68			marksources(void) /* find and mark source objects */
69	greg	1.1	{
70	greg	2.3	int foundsource = 0;
71	greg	1.33	int i;
72	greg	1.1	register OBJREC o, m;
73	greg	1.36	register int ns;
74	greg	1.35	/* initialize dispatch table */
75			initstypes();
76			/* find direct sources */
77	greg	2.33	for (i = 0; i < nsceneobjs; i++) {
78	greg	1.1
79			o = objptr(i);
80
81	greg	1.35	if (!issurface(o->otype) \|\| o->omod == OVOID)
82	greg	1.1	continue;
83	greg	2.36	/* find material */
84	greg	2.43	m = findmaterial(objptr(o->omod));
85	greg	2.36	if (m == NULL \|\| !islight(m->otype))
86			continue; /* not source modifier */
87	greg	1.1
88	greg	1.6	if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
89			m->otype == MAT_SPOT ? 7 : 3))
90	greg	1.1	objerror(m, USER, "bad # arguments");
91
92	greg	1.6	if (m->otype == MAT_GLOW &&
93			o->otype != OBJ_SOURCE &&
94			m->oargs.farg[3] <= FTINY)
95	greg	1.1	continue; /* don't bother */
96	greg	2.16	if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
97			m->oargs.farg[2] <= FTINY)
98			continue; /* don't bother */
99	greg	1.1
100	greg	1.35	if (sfun[o->otype].of == NULL \|\|
101			sfun[o->otype].of->setsrc == NULL)
102			objerror(o, USER, "illegal material");
103
104	greg	1.36	if ((ns = newsource()) < 0)
105	greg	1.25	goto memerr;
106	greg	1.1
107	greg	1.37	setsource(&source[ns], o);
108	greg	1.1
109	greg	1.6	if (m->otype == MAT_GLOW) {
110	greg	1.36	source[ns].sflags \|= SPROX;
111			source[ns].sl.prox = m->oargs.farg[3];
112	greg	2.8	if (source[ns].sflags & SDISTANT)
113	greg	1.36	source[ns].sflags \|= SSKIP;
114	greg	1.6	} else if (m->otype == MAT_SPOT) {
115	greg	1.36	source[ns].sflags \|= SSPOT;
116			if ((source[ns].sl.s = makespot(m)) == NULL)
117	greg	1.33	goto memerr;
118	greg	1.38	if (source[ns].sflags & SFLAT &&
119			!checkspot(source[ns].sl.s,source[ns].snorm)) {
120			objerror(o, WARNING,
121			"invalid spotlight direction");
122			source[ns].sflags \|= SSKIP;
123			}
124	greg	1.6	}
125	greg	2.38	#if SHADCACHE
126	greg	2.46	initobscache(ns);
127	greg	2.38	#endif
128	greg	2.3	if (!(source[ns].sflags & SSKIP))
129			foundsource++;
130	greg	1.1	}
131	greg	2.3	if (!foundsource) {
132	greg	1.25	error(WARNING, "no light sources found");
133			return;
134			}
135	greg	1.33	markvirtuals(); /* find and add virtual sources */
136	greg	1.45	/* allocate our contribution arrays */
137	greg	1.48	maxcntr = nsources + MAXSPART; /* start with this many */
138	greg	1.45	srccnt = (CONTRIB )malloc(maxcntrsizeof(CONTRIB));
139			cntord = (CNTPTR )malloc(maxcntrsizeof(CNTPTR));
140	schorsch	2.35	if ((srccnt == NULL) \| (cntord == NULL))
141	greg	1.33	goto memerr;
142			return;
143	greg	1.25	memerr:
144			error(SYSTEM, "out of memory in marksources");
145	greg	1.1	}
146
147
148	schorsch	2.44	extern void
149			freesources(void) /* free all source structures */
150	greg	2.29	{
151			if (nsources > 0) {
152	greg	2.38	#if SHADCACHE
153			while (nsources--)
154			freeobscache(&source[nsources]);
155			#endif
156	greg	2.29	free((void *)source);
157			source = NULL;
158			nsources = 0;
159			}
160			if (maxcntr <= 0)
161			return;
162			free((void *)srccnt);
163			srccnt = NULL;
164			free((void *)cntord);
165			cntord = NULL;
166			maxcntr = 0;
167			}
168
169
170	schorsch	2.44	extern int
171	greg	2.38	srcray( /* send a ray to a source, return domega */
172	schorsch	2.44	register RAY sr, / returned source ray */
173			RAY r, / ray which hit object */
174			SRCINDEX si / source sample index */
175	greg	2.38	)
176	greg	1.1	{
177	greg	1.45	double d; /* distance to source */
178			register SRCREC *srcp;
179	greg	1.1
180	greg	1.45	rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
181	greg	1.1
182	greg	1.47	while ((d = nextssamp(sr, si)) != 0.0) {
183	greg	1.45	sr->rsrc = si->sn; /* remember source */
184			srcp = source + si->sn;
185			if (srcp->sflags & SDISTANT) {
186	greg	2.18	if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
187	greg	2.4	continue;
188	greg	1.45	return(1); /* sample OK */
189	greg	1.40	}
190	greg	1.45	/* local source */
191	greg	1.6	/* check proximity */
192	greg	1.45	if (srcp->sflags & SPROX && d > srcp->sl.prox)
193			continue;
194	greg	1.6	/* check angle */
195	greg	1.45	if (srcp->sflags & SSPOT) {
196	greg	2.18	if (spotout(sr, srcp->sl.s))
197	greg	1.45	continue;
198			/* adjust solid angle */
199			si->dom = dd;
200			d += srcp->sl.s->flen;
201			si->dom /= d*d;
202	greg	1.1	}
203	greg	1.45	return(1); /* sample OK */
204			}
205			return(0); /* no more samples */
206	greg	1.1	}
207
208
209	schorsch	2.44	extern void
210	greg	2.38	srcvalue( /* punch ray to source and compute value */
211	schorsch	2.44	register RAY *r
212	greg	2.38	)
213	greg	1.1	{
214	greg	1.35	register SRCREC *sp;
215	greg	1.1
216	greg	1.35	sp = &source[r->rsrc];
217			if (sp->sflags & SVIRTUAL) { /* virtual source */
218			/* check intersection */
219			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
220			return;
221	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
222			goto nomat;
223	greg	2.19	rayparticipate(r);
224	greg	1.35	return;
225	greg	1.1	}
226	greg	1.35	/* compute intersection */
227			if (sp->sflags & SDISTANT ? sourcehit(r) :
228			(*ofun[sp->so->otype].funp)(sp->so, r)) {
229			if (sp->sa.success >= 0)
230			sp->sa.success++;
231	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
232			goto nomat;
233	greg	2.19	rayparticipate(r);
234	greg	1.35	return;
235	greg	1.1	}
236	greg	2.15	/* we missed our mark! */
237	greg	1.35	if (sp->sa.success < 0)
238			return; /* bitched already */
239			sp->sa.success -= AIMREQT;
240			if (sp->sa.success >= 0)
241			return; /* leniency */
242			sprintf(errmsg, "aiming failure for light source \"%s\"",
243			sp->so->oname);
244			error(WARNING, errmsg); /* issue warning */
245	greg	2.15	return;
246			nomat:
247			objerror(r->ro, USER, "material not found");
248	greg	1.1	}
249
250
251	greg	2.47	static int
252			transillum( /* check if material is transparent illum */
253			OBJECT obj
254			)
255			{
256			OBJREC *m = findmaterial(objptr(obj));
257
258			if (m == NULL)
259			return(1);
260			if (m->otype != MAT_ILLUM)
261			return(0);
262			return(!m->oargs.nsargs \|\| !strcmp(m->oargs.sarg[0], VOIDID));
263			}
264
265
266	schorsch	2.44	extern int
267	greg	2.38	sourcehit( /* check to see if ray hit distant source */
268	schorsch	2.44	register RAY *r
269	greg	2.38	)
270	greg	2.5	{
271	greg	2.47	int glowsrc = -1;
272			int transrc = -1;
273	greg	2.5	int first, last;
274			register int i;
275
276			if (r->rsrc >= 0) { /* check only one if aimed */
277			first = last = r->rsrc;
278			} else { /* otherwise check all */
279			first = 0; last = nsources-1;
280			}
281	greg	2.47	for (i = first; i <= last; i++) {
282			if ((source[i].sflags & (SDISTANT\|SVIRTUAL)) != SDISTANT)
283			continue;
284			/*
285			* Check to see if ray is within
286			* solid angle of source.
287			*/
288			if (2.PI(1. - DOT(source[i].sloc,r->rdir)) > source[i].ss2)
289			continue;
290			/* is it the only possibility? */
291			if (first == last) {
292			r->ro = source[i].so;
293			break;
294			}
295			/*
296			* If it's a glow or transparent illum, just remember it.
297			*/
298			if (source[i].sflags & SSKIP) {
299			glowsrc = i;
300			continue;
301			}
302			if (transillum(source[i].so->omod)) {
303			transrc = i;
304			continue;
305			}
306			r->ro = source[i].so; /* otherwise, use first hit */
307			break;
308	greg	2.5	}
309	greg	2.47	/*
310			* Do we need fallback?
311			*/
312			if (r->ro == NULL) {
313			if (transrc >= 0 && r->crtype & (AMBIENT\|SPECULAR))
314			return(0); /* avoid overcounting */
315			if (glowsrc >= 0)
316			r->ro = source[glowsrc].so;
317			else
318			return(0); /* nothing usable */
319			}
320			/*
321			* Make assignments.
322			*/
323			r->robj = objndx(r->ro);
324			for (i = 0; i < 3; i++)
325			r->ron[i] = -r->rdir[i];
326			r->rod = 1.0;
327			r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
328			r->uv[0] = r->uv[1] = 0.0;
329			r->rox = NULL;
330			return(1);
331	greg	2.5	}
332	greg	2.38
333
334	greg	1.4	static int
335	greg	2.38	cntcmp( /* contribution compare (descending) */
336	schorsch	2.44	const void *p1,
337			const void *p2
338	greg	2.38	)
339	greg	1.4	{
340	greg	2.38	register const CNTPTR sc1 = (const CNTPTR )p1;
341			register const CNTPTR sc2 = (const CNTPTR )p2;
342
343	greg	1.4	if (sc1->brt > sc2->brt)
344			return(-1);
345			if (sc1->brt < sc2->brt)
346			return(1);
347			return(0);
348			}
349
350
351	schorsch	2.44	extern void
352	greg	2.38	direct( /* add direct component */
353	schorsch	2.44	RAY r, / ray that hit surface */
354			srcdirf_t f, / direct component coefficient function */
355			void p / data for f */
356	greg	2.38	)
357	greg	1.4	{
358			register int sn;
359	greg	2.7	register CONTRIB *scp;
360	greg	1.45	SRCINDEX si;
361	greg	1.12	int nshadcheck, ncnts;
362	greg	1.29	int nhits;
363	greg	1.45	double prob, ourthresh, hwt;
364	greg	1.4	RAY sr;
365	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
366	greg	1.22	if (nsources <= 0)
367	greg	1.25	return; /* no sources?! */
368	greg	1.4	/* potential contributions */
369	greg	1.45	initsrcindex(&si);
370			for (sn = 0; srcray(&sr, r, &si); sn++) {
371			if (sn >= maxcntr) {
372			maxcntr = sn + MAXSPART;
373	greg	2.32	srccnt = (CONTRIB )realloc((void )srccnt,
374	greg	1.45	maxcntr*sizeof(CONTRIB));
375	greg	2.32	cntord = (CNTPTR )realloc((void )cntord,
376	greg	1.45	maxcntr*sizeof(CNTPTR));
377	schorsch	2.35	if ((srccnt == NULL) \| (cntord == NULL))
378	greg	1.45	error(SYSTEM, "out of memory in direct");
379			}
380			cntord[sn].sndx = sn;
381	greg	2.7	scp = srccnt + sn;
382			scp->sno = sr.rsrc;
383	greg	1.4	/* compute coefficient */
384	greg	2.7	(*f)(scp->coef, p, sr.rdir, si.dom);
385			cntord[sn].brt = bright(scp->coef);
386	greg	1.15	if (cntord[sn].brt <= 0.0)
387	greg	1.4	continue;
388	greg	2.38	#if SHADCACHE
389			/* check shadow cache */
390			if (si.np == 1 && srcblocked(&sr)) {
391			cntord[sn].brt = 0.0;
392			continue;
393			}
394			#endif
395	greg	2.7	VCOPY(scp->dir, sr.rdir);
396	greg	1.35	/* compute potential */
397	greg	2.49	srcvalue(&sr);
398	greg	2.7	copycolor(scp->val, sr.rcol);
399			multcolor(scp->val, scp->coef);
400			cntord[sn].brt = bright(scp->val);
401	greg	1.4	}
402			/* sort contributions */
403	greg	1.45	qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
404	greg	1.13	{ /* find last */
405			register int l, m;
406
407	greg	1.45	ncnts = l = sn;
408			sn = 0;
409	greg	1.13	while ((m = (sn + ncnts) >> 1) != l) {
410			if (cntord[m].brt > 0.0)
411			sn = m;
412			else
413			ncnts = m;
414			l = m;
415			}
416			}
417	greg	2.2	if (ncnts == 0)
418			return; /* no contributions! */
419	greg	1.12	/* accumulate tail */
420			for (sn = ncnts-1; sn > 0; sn--)
421			cntord[sn-1].brt += cntord[sn].brt;
422	greg	1.45	/* compute number to check */
423			nshadcheck = pow((double)ncnts, shadcert) + .5;
424			/* modify threshold */
425			ourthresh = shadthresh / r->rweight;
426	greg	1.10	/* test for shadows */
427	greg	2.13	for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
428			hwt += (double)source[scp->sno].nhits /
429			(double)source[scp->sno].ntests,
430			sn++) {
431	greg	1.10	/* check threshold */
432	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
433	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
434			< ourthresh*bright(r->rcol))
435	greg	1.4	break;
436	greg	2.7	scp = srccnt + cntord[sn].sndx;
437	greg	1.4	/* test for hit */
438			rayorigin(&sr, r, SHADOW, 1.0);
439	greg	2.7	VCOPY(sr.rdir, scp->dir);
440			sr.rsrc = scp->sno;
441	greg	2.34	/* keep statistics */
442			if (source[scp->sno].ntests++ > 0xfffffff0) {
443			source[scp->sno].ntests >>= 1;
444			source[scp->sno].nhits >>= 1;
445			}
446	greg	1.4	if (localhit(&sr, &thescene) &&
447	greg	2.7	( sr.ro != source[scp->sno].so \|\|
448			source[scp->sno].sflags & SFOLLOW )) {
449	greg	1.33	/* follow entire path */
450	greg	2.23	raycont(&sr);
451	greg	2.19	rayparticipate(&sr);
452	greg	1.42	if (trace != NULL)
453			(trace)(&sr); / trace execution */
454	greg	2.38	if (bright(sr.rcol) <= FTINY) {
455			#if SHADCACHE
456			if ((scp <= srccnt \|\| scp[-1].sno != scp->sno)
457	greg	2.41	&& (scp >= srccnt+ncnts-1 \|\|
458	greg	2.38	scp[1].sno != scp->sno))
459			srcblocker(&sr);
460			#endif
461	greg	1.4	continue; /* missed! */
462	greg	2.38	}
463	greg	2.7	copycolor(scp->val, sr.rcol);
464			multcolor(scp->val, scp->coef);
465	greg	1.4	}
466			/* add contribution if hit */
467	greg	2.7	addcolor(r->rcol, scp->val);
468	greg	1.29	nhits++;
469	greg	2.7	source[scp->sno].nhits++;
470	greg	1.4	}
471	greg	2.13	/* source hit rate */
472			if (hwt > FTINY)
473			hwt = (double)nhits / hwt;
474	greg	1.29	else
475			hwt = 0.5;
476	greg	1.20	#ifdef DEBUG
477	greg	2.13	sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
478	greg	1.12	sn, ncnts-sn, hwt);
479			eputs(errmsg);
480	greg	1.4	#endif
481			/* add in untested sources */
482	greg	1.12	for ( ; sn < ncnts; sn++) {
483	greg	2.7	scp = srccnt + cntord[sn].sndx;
484			prob = hwt * (double)source[scp->sno].nhits /
485			(double)source[scp->sno].ntests;
486	greg	2.13	if (prob > 1.0)
487			prob = 1.0;
488	greg	2.7	scalecolor(scp->val, prob);
489			addcolor(r->rcol, scp->val);
490	greg	2.19	}
491			}
492
493
494	schorsch	2.44	extern void
495	greg	2.38	srcscatter( /* compute source scattering into ray */
496	schorsch	2.44	register RAY *r
497	greg	2.38	)
498	greg	2.19	{
499	greg	2.20	int oldsampndx;
500	greg	2.19	int nsamps;
501			RAY sr;
502			SRCINDEX si;
503	greg	2.25	double t, d;
504			double re, ge, be;
505			COLOR cvext;
506	greg	2.19	int i, j;
507
508	greg	2.22	if (r->slights == NULL \|\| r->slights[0] == 0
509			\|\| r->gecc >= 1.-FTINY \|\| r->rot >= FHUGE)
510	greg	2.19	return;
511			if (ssampdist <= FTINY \|\| (nsamps = r->rot/ssampdist + .5) < 1)
512			nsamps = 1;
513	greg	2.22	#if MAXSSAMP
514			else if (nsamps > MAXSSAMP)
515			nsamps = MAXSSAMP;
516			#endif
517	greg	2.20	oldsampndx = samplendx;
518			samplendx = random()&0x7fff; /* randomize */
519	greg	2.19	for (i = r->slights[0]; i > 0; i--) { /* for each source */
520	greg	2.25	for (j = 0; j < nsamps; j++) { /* for each sample position */
521	greg	2.19	samplendx++;
522			t = r->rot * (j+frandom())/nsamps;
523	greg	2.25	/* extinction */
524			re = t*colval(r->cext,RED);
525			ge = t*colval(r->cext,GRN);
526			be = t*colval(r->cext,BLU);
527			setcolor(cvext, re > 92. ? 0. : exp(-re),
528			ge > 92. ? 0. : exp(-ge),
529			be > 92. ? 0. : exp(-be));
530			if (intens(cvext) <= FTINY)
531			break; /* too far away */
532	greg	2.19	sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
533			sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
534			sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
535			sr.rmax = 0.;
536	greg	2.21	initsrcindex(&si); /* sample ray to this source */
537			si.sn = r->slights[i];
538			nopart(&si, &sr);
539			if (!srcray(&sr, NULL, &si) \|\|
540			sr.rsrc != r->slights[i])
541			continue; /* no path */
542	greg	2.45	#if SHADCACHE
543			if (srcblocked(&sr)) /* check shadow cache */
544			continue;
545			#endif
546	greg	2.19	copycolor(sr.cext, r->cext);
547	greg	2.24	copycolor(sr.albedo, r->albedo);
548	greg	2.19	sr.gecc = r->gecc;
549	gregl	2.26	sr.slights = r->slights;
550	greg	2.19	rayvalue(&sr); /* eval. source ray */
551	greg	2.45	if (bright(sr.rcol) <= FTINY) {
552			#if SHADCACHE
553			srcblocker(&sr); /* add blocker to cache */
554			#endif
555	greg	2.19	continue;
556	greg	2.45	}
557	greg	2.19	if (r->gecc <= FTINY) /* compute P(theta) */
558			d = 1.;
559			else {
560			d = DOT(r->rdir, sr.rdir);
561	greg	2.25	d = 1. + r->geccr->gecc - 2.r->gecc*d;
562			d = (1. - r->geccr->gecc) / (dsqrt(d));
563	greg	2.19	}
564			/* other factors */
565	greg	2.24	d = si.dom r->rot / (4.PInsamps);
566	greg	2.19	multcolor(sr.rcol, r->cext);
567	greg	2.24	multcolor(sr.rcol, r->albedo);
568	greg	2.19	scalecolor(sr.rcol, d);
569	greg	2.25	multcolor(sr.rcol, cvext);
570			addcolor(r->rcol, sr.rcol); /* add it in */
571	greg	2.19	}
572	greg	1.1	}
573	greg	2.20	samplendx = oldsampndx;
574	greg	2.4	}
575
576
577			/****************************************************************
578			* The following macros were separated from the m_light() routine
579			* because they are very nasty and difficult to understand.
580			*/
581
582	greg	2.11	/* illumblock *
583	greg	2.4	*
584			* We cannot allow an illum to pass to another illum, because that
585			* would almost certainly constitute overcounting.
586			* However, we do allow an illum to pass to another illum
587			* that is actually going to relay to a virtual light source.
588	greg	2.11	* We also prevent an illum from passing to a glow; this provides a
589			* convenient mechanism for defining detailed light source
590			* geometry behind (or inside) an effective radiator.
591	greg	2.4	*/
592
593	greg	2.37	static int
594	greg	2.42	weaksrcmat(OBJECT obj) /* identify material */
595	greg	2.37	{
596	greg	2.47	OBJREC *m = findmaterial(objptr(obj));
597	greg	2.37
598	greg	2.47	if (m == NULL) return(0);
599			return((m->otype==MAT_ILLUM) \| (m->otype==MAT_GLOW));
600	greg	2.37	}
601	greg	2.4
602	greg	2.11	#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
603	greg	2.12	r->rod > 0.0 && \
604	greg	2.37	weaksrcmat(source[r->rsrc].so->omod))
605	greg	2.11
606	greg	2.4	/* wrongsource *
607			*
608			* This source is the wrong source (ie. overcounted) if we are
609			* aimed to a different source than the one we hit and the one
610	greg	2.11	* we hit is not an illum that should be passed.
611	greg	2.4	*/
612
613			#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
614	greg	2.11	(m->otype!=MAT_ILLUM \|\| illumblock(m,r)))
615	greg	2.4
616			/* distglow *
617			*
618			* A distant glow is an object that sometimes acts as a light source,
619			* but is too far away from the test point to be one in this case.
620	greg	2.11	* (Glows with negative radii should NEVER participate in illumination.)
621	greg	2.4	*/
622
623	greg	2.17	#define distglow(m, r, d) (m->otype==MAT_GLOW && \
624	greg	2.10	m->oargs.farg[3] >= -FTINY && \
625	greg	2.17	d > m->oargs.farg[3])
626	greg	2.4
627			/* badcomponent *
628			*
629			* We must avoid counting light sources in the ambient calculation,
630			* since the direct component is handled separately. Therefore, any
631			* ambient ray which hits an active light source must be discarded.
632			* The same is true for stray specular samples, since the specular
633			* contribution from light sources is calculated separately.
634			*/
635
636			#define badcomponent(m, r) (r->crtype&(AMBIENT\|SPECULAR) && \
637			!(r->crtype&SHADOW \|\| r->rod < 0.0 \|\| \
638	greg	2.17	/* not 100% correct */ distglow(m, r, r->rot)))
639	greg	2.4
640			/* passillum *
641			*
642			* An illum passes to another material type when we didn't hit it
643			* on purpose (as part of a direct calculation), or it is relaying
644			* a virtual light source.
645			*/
646
647			#define passillum(m, r) (m->otype==MAT_ILLUM && \
648			(r->rsrc<0 \|\| source[r->rsrc].so!=r->ro \|\| \
649			source[r->rsrc].sflags&SVIRTUAL))
650
651			/* srcignore *
652			*
653	greg	2.10	* The -dv flag is normally on for sources to be visible.
654	greg	2.4	*/
655
656	greg	2.17	#define srcignore(m, r) !(directvis \|\| r->crtype&SHADOW \|\| \
657			distglow(m, r, raydist(r,PRIMARY)))
658	greg	2.4
659
660	schorsch	2.44	extern int
661	greg	2.38	m_light( /* ray hit a light source */
662	schorsch	2.44	register OBJREC *m,
663			register RAY *r
664	greg	2.38	)
665	greg	2.4	{
666			/* check for over-counting */
667	greg	2.12	if (badcomponent(m, r))
668	greg	2.14	return(1);
669	greg	2.17	if (wrongsource(m, r))
670	greg	2.14	return(1);
671	greg	2.4	/* check for passed illum */
672			if (passillum(m, r)) {
673	greg	2.14	if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
674	gwlarson	2.28	return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
675	greg	2.14	raytrans(r);
676			return(1);
677	greg	2.4	}
678			/* otherwise treat as source */
679			/* check for behind */
680			if (r->rod < 0.0)
681	greg	2.14	return(1);
682	greg	2.4	/* check for invisibility */
683			if (srcignore(m, r))
684	greg	2.14	return(1);
685	greg	2.4	/* check for outside spot */
686	greg	2.18	if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
687	greg	2.14	return(1);
688	greg	2.4	/* get distribution pattern */
689			raytexture(r, m->omod);
690			/* get source color */
691			setcolor(r->rcol, m->oargs.farg[0],
692			m->oargs.farg[1],
693			m->oargs.farg[2]);
694			/* modify value */
695			multcolor(r->rcol, r->pcol);
696	greg	2.14	return(1);
697	greg	1.1	}