src/rt/source.c

/* Copyright (c) 1990 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  source.c - routines dealing with illumination sources.
 *
 *     8/20/85
 */

#include  "ray.h"

#include  "octree.h"

#include  "otypes.h"

#include  "source.h"

#include  "random.h"

/*
 * Structures used by direct()
 */

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

typedef struct {
        int  sno;               /* source number */
        float  brt;             /* brightness (for comparison) */
}  CNTPTR;              /* contribution pointer */

static CONTRIB  *srccnt;                /* source contributions in direct() */
static CNTPTR  *cntord;                 /* source ordering in direct() */


marksources()                   /* find and mark source objects */
{
        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 (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 (o->otype == OBJ_SOURCE)
                                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 (nsources <= 0) {
                error(WARNING, "no light sources found");
                return;
        }
        markvirtuals();                 /* find and add virtual sources */
        srccnt = (CONTRIB *)malloc(nsources*sizeof(CONTRIB));
        cntord = (CNTPTR *)malloc(nsources*sizeof(CNTPTR));
        if (srccnt == NULL || cntord == NULL)
                goto memerr;
        return;
memerr:
        error(SYSTEM, "out of memory in marksources");
}


double
srcray(sr, r, sn)               /* send a ray to a source, return domega */
register RAY  *sr;              /* returned source ray */
RAY  *r;                        /* ray which hit object */
register int  sn;               /* source number */
{
        double  ddot;                   /* (distance times) cosine */
        FVECT  vd;
        double  d;
        register int  i;

        if (source[sn].sflags & SSKIP)
                return(0.0);                    /* skip this source */

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

        sr->rsrc = sn;                          /* remember source */
                                                /* get source direction */
        if (source[sn].sflags & SDISTANT) {
                                                /* constant direction */
                VCOPY(sr->rdir, source[sn].sloc);
        } else {                                /* compute direction */
                for (i = 0; i < 3; i++)
                        sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];

                if (source[sn].sflags & SFLAT &&
                        (ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
                        return(0.0);            /* behind surface! */
        }
        if (dstrsrc > FTINY) {
                                        /* distribute source direction */
                dimlist[ndims++] = sn;
                for (i = 0; i < 3; i++) {
                        dimlist[ndims] = i + 8831;
                        vd[i] = dstrsrc * source[sn].ss *
                (1.0 - 2.0*urand(urind(ilhash(dimlist,ndims+1),samplendx)));
                }
                ndims--;
                if (source[sn].sflags & SFLAT) {        /* project offset */
                        d = DOT(vd, source[sn].snorm);
                        for (i = 0; i < 3; i++)
                                vd[i] -= d * source[sn].snorm[i];
                }
                for (i = 0; i < 3; i++)         /* offset source direction */
                        sr->rdir[i] += vd[i];
                                                /* normalize */
                d = normalize(sr->rdir);

        } else if (!(source[sn].sflags & SDISTANT))
                                                /* normalize direction */
                d = normalize(sr->rdir);

        if (source[sn].sflags & SDISTANT) {
                if (source[sn].sflags & SSPOT) {        /* check location */
                        for (i = 0; i < 3; i++)
                                vd[i] = sr->rorg[i] - source[sn].sl.s->aim[i];
                        d = DOT(sr->rdir,vd);
                        d = DOT(vd,vd) - d*d;
                        if (PI*d > source[sn].sl.s->siz)
                                return(0.0);
                }
                return(source[sn].ss2);         /* domega constant */
        }
                                                /* check direction */
        if (d == 0.0)
                return(0.0);
                                                /* check proximity */
        if (source[sn].sflags & SPROX &&
                        d > source[sn].sl.prox)
                return(0.0);
                                                /* compute dot product */
        if (source[sn].sflags & SFLAT)
                ddot /= d;
        else
                ddot = 1.0;
                                                /* check angle */
        if (source[sn].sflags & SSPOT) {
                if (source[sn].sl.s->siz < 2.0*PI *
                                (1.0 + DOT(source[sn].sl.s->aim,sr->rdir)))
                        return(0.0);
                d += source[sn].sl.s->flen;     /* adjust length */
        }
                                                /* compute domega */
        return(ddot*source[sn].ss2/(d*d));
}


srcvalue(r)                     /* punch ray to source and compute value */
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;
                raycont(r);             /* compute contribution */
                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++;
                raycont(r);             /* compute contribution */
                return;
        }
        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 */
}


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);
}


direct(r, f, p)                         /* add direct component */
RAY  *r;                        /* ray that hit surface */
int  (*f)();                    /* direct component coefficient function */
char  *p;                       /* data for f */
{
        extern double  pow();
        register int  sn;
        int  nshadcheck, ncnts;
        int  nhits;
        double  dom, prob, ourthresh, hwt;
        RAY  sr;
                        /* NOTE: srccnt and cntord global so no recursion */
        if (nsources <= 0)
                return;         /* no sources?! */
                                                /* compute number to check */
        nshadcheck = pow((double)nsources, shadcert) + .5;
                                                /* modify threshold */
        ourthresh = shadthresh / r->rweight;
                                                /* potential contributions */
        for (sn = 0; sn < nsources; sn++) {
                cntord[sn].sno = sn;
                cntord[sn].brt = 0.0;
                                                /* get source ray */
                if ((dom = srcray(&sr, r, sn)) == 0.0)
                        continue;
                VCOPY(srccnt[sn].dir, sr.rdir);
                                                /* compute coefficient */
                (*f)(srccnt[sn].coef, p, srccnt[sn].dir, dom);
                cntord[sn].brt = bright(srccnt[sn].coef);
                if (cntord[sn].brt <= 0.0)
                        continue;
                                                /* compute potential */
                sr.revf = srcvalue;
                rayvalue(&sr);
                copycolor(srccnt[sn].val, sr.rcol);
                multcolor(srccnt[sn].val, srccnt[sn].coef);
                cntord[sn].brt = bright(srccnt[sn].val);
        }
                                                /* sort contributions */
        qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
        {                                       /* find last */
                register int  l, m;

                sn = 0; ncnts = l = nsources;
                while ((m = (sn + ncnts) >> 1) != l) {
                        if (cntord[m].brt > 0.0)
                                sn = m;
                        else
                                ncnts = m;
                        l = m;
                }
        }
                                                /* accumulate tail */
        for (sn = ncnts-1; sn > 0; sn--)
                cntord[sn-1].brt += cntord[sn].brt;
                                                /* test for shadows */
        nhits = 0;
        for (sn = 0; sn < ncnts; sn++) {
                                                /* check threshold */
                if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
                                cntord[sn].brt-cntord[sn+nshadcheck].brt)
                                < ourthresh*bright(r->rcol))
                        break;
                                                /* get statistics */
                source[cntord[sn].sno].ntests++;
                                                /* test for hit */
                rayorigin(&sr, r, SHADOW, 1.0);
                VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
                sr.rsrc = cntord[sn].sno;
                if (localhit(&sr, &thescene) &&
                                ( sr.ro != source[cntord[sn].sno].so ||
                                source[cntord[sn].sno].sflags & SFOLLOW )) {
                                                /* follow entire path */
                        raycont(&sr);
                        if (bright(sr.rcol) <= FTINY)
                                continue;       /* missed! */
                        copycolor(srccnt[cntord[sn].sno].val, sr.rcol);
                        multcolor(srccnt[cntord[sn].sno].val,
                                        srccnt[cntord[sn].sno].coef);
                }
                                                /* add contribution if hit */
                addcolor(r->rcol, srccnt[cntord[sn].sno].val);
                nhits++;
                source[cntord[sn].sno].nhits++;
        }
                                        /* surface hit rate */
        if (sn > 0)
                hwt = (double)nhits / (double)sn;
        else
                hwt = 0.5;
#ifdef DEBUG
        sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
                        sn, ncnts-sn, hwt);
        eputs(errmsg);
#endif
                                        /* add in untested sources */
        for ( ; sn < ncnts; sn++) {
                prob = hwt * (double)source[cntord[sn].sno].nhits /
                                (double)source[cntord[sn].sno].ntests;
                scalecolor(srccnt[cntord[sn].sno].val, prob);
                addcolor(r->rcol, srccnt[cntord[sn].sno].val);
        }
}
Revision:	1.40
Committed:	Tue Jul 30 18:23:41 1991 UTC (32 years, 9 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.39:	+18 -18 lines
Log Message:	fixed improper creation and testing of spots
#	User	Rev	Content
1	greg	1.25	/* Copyright (c) 1990 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* source.c - routines dealing with illumination sources.
9			*
10			* 8/20/85
11			*/
12
13			#include "ray.h"
14
15	greg	1.4	#include "octree.h"
16
17	greg	1.1	#include "otypes.h"
18
19	greg	1.35	#include "source.h"
20	greg	1.1
21			#include "random.h"
22
23	greg	1.35	/*
24			* Structures used by direct()
25			*/
26	greg	1.1
27	greg	1.35	typedef struct {
28			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			int sno; /* source number */
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	1.1
41	greg	1.25
42	greg	1.1	marksources() /* find and mark source objects */
43			{
44	greg	1.33	int i;
45	greg	1.1	register OBJREC o, m;
46	greg	1.36	register int ns;
47	greg	1.35	/* initialize dispatch table */
48			initstypes();
49			/* find direct sources */
50	greg	1.1	for (i = 0; i < nobjects; i++) {
51
52			o = objptr(i);
53
54	greg	1.35	if (!issurface(o->otype) \|\| o->omod == OVOID)
55	greg	1.1	continue;
56
57			m = objptr(o->omod);
58
59	greg	1.24	if (!islight(m->otype))
60	greg	1.1	continue;
61
62	greg	1.6	if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
63			m->otype == MAT_SPOT ? 7 : 3))
64	greg	1.1	objerror(m, USER, "bad # arguments");
65
66	greg	1.6	if (m->otype == MAT_GLOW &&
67			o->otype != OBJ_SOURCE &&
68			m->oargs.farg[3] <= FTINY)
69	greg	1.1	continue; /* don't bother */
70
71	greg	1.35	if (sfun[o->otype].of == NULL \|\|
72			sfun[o->otype].of->setsrc == NULL)
73			objerror(o, USER, "illegal material");
74
75	greg	1.36	if ((ns = newsource()) < 0)
76	greg	1.25	goto memerr;
77	greg	1.1
78	greg	1.37	setsource(&source[ns], o);
79	greg	1.1
80	greg	1.6	if (m->otype == MAT_GLOW) {
81	greg	1.36	source[ns].sflags \|= SPROX;
82			source[ns].sl.prox = m->oargs.farg[3];
83	greg	1.6	if (o->otype == OBJ_SOURCE)
84	greg	1.36	source[ns].sflags \|= SSKIP;
85	greg	1.6	} else if (m->otype == MAT_SPOT) {
86	greg	1.36	source[ns].sflags \|= SSPOT;
87			if ((source[ns].sl.s = makespot(m)) == NULL)
88	greg	1.33	goto memerr;
89	greg	1.38	if (source[ns].sflags & SFLAT &&
90			!checkspot(source[ns].sl.s,source[ns].snorm)) {
91			objerror(o, WARNING,
92			"invalid spotlight direction");
93			source[ns].sflags \|= SSKIP;
94			}
95	greg	1.6	}
96	greg	1.1	}
97	greg	1.25	if (nsources <= 0) {
98			error(WARNING, "no light sources found");
99			return;
100			}
101	greg	1.33	markvirtuals(); /* find and add virtual sources */
102	greg	1.25	srccnt = (CONTRIB )malloc(nsourcessizeof(CONTRIB));
103			cntord = (CNTPTR )malloc(nsourcessizeof(CNTPTR));
104	greg	1.36	if (srccnt == NULL \|\| cntord == NULL)
105	greg	1.33	goto memerr;
106			return;
107	greg	1.25	memerr:
108			error(SYSTEM, "out of memory in marksources");
109	greg	1.1	}
110
111
112			double
113			srcray(sr, r, sn) /* send a ray to a source, return domega */
114			register RAY sr; / returned source ray */
115			RAY r; / ray which hit object */
116			register int sn; /* source number */
117			{
118			double ddot; /* (distance times) cosine */
119			FVECT vd;
120			double d;
121			register int i;
122
123	greg	1.4	if (source[sn].sflags & SSKIP)
124	greg	1.1	return(0.0); /* skip this source */
125
126			rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
127
128			sr->rsrc = sn; /* remember source */
129			/* get source direction */
130	greg	1.33	if (source[sn].sflags & SDISTANT) {
131	greg	1.1	/* constant direction */
132	greg	1.4	VCOPY(sr->rdir, source[sn].sloc);
133	greg	1.33	} else { /* compute direction */
134	greg	1.1	for (i = 0; i < 3; i++)
135	greg	1.4	sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];
136	greg	1.1
137	greg	1.33	if (source[sn].sflags & SFLAT &&
138			(ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
139	greg	1.1	return(0.0); /* behind surface! */
140			}
141			if (dstrsrc > FTINY) {
142			/* distribute source direction */
143	greg	1.31	dimlist[ndims++] = sn;
144			for (i = 0; i < 3; i++) {
145			dimlist[ndims] = i + 8831;
146			vd[i] = dstrsrc * source[sn].ss *
147	greg	1.39	(1.0 - 2.0*urand(urind(ilhash(dimlist,ndims+1),samplendx)));
148	greg	1.31	}
149			ndims--;
150	greg	1.33	if (source[sn].sflags & SFLAT) { /* project offset */
151			d = DOT(vd, source[sn].snorm);
152	greg	1.1	for (i = 0; i < 3; i++)
153	greg	1.33	vd[i] -= d * source[sn].snorm[i];
154	greg	1.1	}
155			for (i = 0; i < 3; i++) /* offset source direction */
156			sr->rdir[i] += vd[i];
157	greg	1.40	/* normalize */
158			d = normalize(sr->rdir);
159	greg	1.1
160	greg	1.40	} else if (!(source[sn].sflags & SDISTANT))
161			/* normalize direction */
162			d = normalize(sr->rdir);
163	greg	1.1
164	greg	1.40	if (source[sn].sflags & SDISTANT) {
165			if (source[sn].sflags & SSPOT) { /* check location */
166			for (i = 0; i < 3; i++)
167			vd[i] = sr->rorg[i] - source[sn].sl.s->aim[i];
168			d = DOT(sr->rdir,vd);
169			d = DOT(vd,vd) - d*d;
170			if (PI*d > source[sn].sl.s->siz)
171			return(0.0);
172			}
173			return(source[sn].ss2); /* domega constant */
174			}
175			/* check direction */
176			if (d == 0.0)
177	greg	1.1	return(0.0);
178	greg	1.6	/* check proximity */
179	greg	1.27	if (source[sn].sflags & SPROX &&
180			d > source[sn].sl.prox)
181			return(0.0);
182			/* compute dot product */
183	greg	1.33	if (source[sn].sflags & SFLAT)
184	greg	1.27	ddot /= d;
185			else
186			ddot = 1.0;
187	greg	1.6	/* check angle */
188	greg	1.27	if (source[sn].sflags & SSPOT) {
189			if (source[sn].sl.s->siz < 2.0PI
190	greg	1.6	(1.0 + DOT(source[sn].sl.s->aim,sr->rdir)))
191	greg	1.27	return(0.0);
192			d += source[sn].sl.s->flen; /* adjust length */
193	greg	1.1	}
194	greg	1.27	/* compute domega */
195			return(ddotsource[sn].ss2/(dd));
196	greg	1.1	}
197
198
199	greg	1.35	srcvalue(r) /* punch ray to source and compute value */
200			RAY *r;
201	greg	1.1	{
202	greg	1.35	register SRCREC *sp;
203	greg	1.1
204	greg	1.35	sp = &source[r->rsrc];
205			if (sp->sflags & SVIRTUAL) { /* virtual source */
206			/* check intersection */
207			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
208			return;
209			raycont(r); /* compute contribution */
210			return;
211	greg	1.1	}
212	greg	1.35	/* compute intersection */
213			if (sp->sflags & SDISTANT ? sourcehit(r) :
214			(*ofun[sp->so->otype].funp)(sp->so, r)) {
215			if (sp->sa.success >= 0)
216			sp->sa.success++;
217			raycont(r); /* compute contribution */
218			return;
219	greg	1.1	}
220	greg	1.35	if (sp->sa.success < 0)
221			return; /* bitched already */
222			sp->sa.success -= AIMREQT;
223			if (sp->sa.success >= 0)
224			return; /* leniency */
225			sprintf(errmsg, "aiming failure for light source \"%s\"",
226			sp->so->oname);
227			error(WARNING, errmsg); /* issue warning */
228	greg	1.1	}
229
230
231	greg	1.4	static int
232			cntcmp(sc1, sc2) /* contribution compare (descending) */
233	greg	1.9	register CNTPTR sc1, sc2;
234	greg	1.4	{
235			if (sc1->brt > sc2->brt)
236			return(-1);
237			if (sc1->brt < sc2->brt)
238			return(1);
239			return(0);
240			}
241
242
243			direct(r, f, p) /* add direct component */
244			RAY r; / ray that hit surface */
245			int (f)(); / direct component coefficient function */
246			char p; / data for f */
247			{
248	greg	1.12	extern double pow();
249	greg	1.4	register int sn;
250	greg	1.12	int nshadcheck, ncnts;
251	greg	1.29	int nhits;
252	greg	1.34	double dom, prob, ourthresh, hwt;
253	greg	1.4	RAY sr;
254	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
255	greg	1.22	if (nsources <= 0)
256	greg	1.25	return; /* no sources?! */
257	greg	1.12	/* compute number to check */
258			nshadcheck = pow((double)nsources, shadcert) + .5;
259	greg	1.8	/* modify threshold */
260			ourthresh = shadthresh / r->rweight;
261	greg	1.4	/* potential contributions */
262			for (sn = 0; sn < nsources; sn++) {
263	greg	1.9	cntord[sn].sno = sn;
264			cntord[sn].brt = 0.0;
265	greg	1.4	/* get source ray */
266	greg	1.34	if ((dom = srcray(&sr, r, sn)) == 0.0)
267	greg	1.4	continue;
268			VCOPY(srccnt[sn].dir, sr.rdir);
269			/* compute coefficient */
270	greg	1.34	(*f)(srccnt[sn].coef, p, srccnt[sn].dir, dom);
271			cntord[sn].brt = bright(srccnt[sn].coef);
272	greg	1.15	if (cntord[sn].brt <= 0.0)
273	greg	1.4	continue;
274	greg	1.35	/* compute potential */
275			sr.revf = srcvalue;
276			rayvalue(&sr);
277	greg	1.34	copycolor(srccnt[sn].val, sr.rcol);
278			multcolor(srccnt[sn].val, srccnt[sn].coef);
279	greg	1.9	cntord[sn].brt = bright(srccnt[sn].val);
280	greg	1.4	}
281			/* sort contributions */
282	greg	1.9	qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
283	greg	1.13	{ /* find last */
284			register int l, m;
285
286			sn = 0; ncnts = l = nsources;
287			while ((m = (sn + ncnts) >> 1) != l) {
288			if (cntord[m].brt > 0.0)
289			sn = m;
290			else
291			ncnts = m;
292			l = m;
293			}
294			}
295	greg	1.12	/* accumulate tail */
296			for (sn = ncnts-1; sn > 0; sn--)
297			cntord[sn-1].brt += cntord[sn].brt;
298	greg	1.10	/* test for shadows */
299	greg	1.29	nhits = 0;
300	greg	1.12	for (sn = 0; sn < ncnts; sn++) {
301	greg	1.10	/* check threshold */
302	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
303	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
304			< ourthresh*bright(r->rcol))
305	greg	1.4	break;
306			/* get statistics */
307	greg	1.9	source[cntord[sn].sno].ntests++;
308	greg	1.4	/* test for hit */
309			rayorigin(&sr, r, SHADOW, 1.0);
310	greg	1.9	VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
311	greg	1.19	sr.rsrc = cntord[sn].sno;
312	greg	1.4	if (localhit(&sr, &thescene) &&
313	greg	1.33	( sr.ro != source[cntord[sn].sno].so \|\|
314			source[cntord[sn].sno].sflags & SFOLLOW )) {
315			/* follow entire path */
316	greg	1.19	raycont(&sr);
317	greg	1.5	if (bright(sr.rcol) <= FTINY)
318	greg	1.4	continue; /* missed! */
319	greg	1.34	copycolor(srccnt[cntord[sn].sno].val, sr.rcol);
320			multcolor(srccnt[cntord[sn].sno].val,
321			srccnt[cntord[sn].sno].coef);
322	greg	1.4	}
323			/* add contribution if hit */
324	greg	1.9	addcolor(r->rcol, srccnt[cntord[sn].sno].val);
325	greg	1.29	nhits++;
326	greg	1.9	source[cntord[sn].sno].nhits++;
327	greg	1.4	}
328	greg	1.29	/* surface hit rate */
329			if (sn > 0)
330			hwt = (double)nhits / (double)sn;
331			else
332			hwt = 0.5;
333	greg	1.20	#ifdef DEBUG
334	greg	1.12	sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
335			sn, ncnts-sn, hwt);
336			eputs(errmsg);
337	greg	1.4	#endif
338			/* add in untested sources */
339	greg	1.12	for ( ; sn < ncnts; sn++) {
340	greg	1.9	prob = hwt * (double)source[cntord[sn].sno].nhits /
341			(double)source[cntord[sn].sno].ntests;
342			scalecolor(srccnt[cntord[sn].sno].val, prob);
343			addcolor(r->rcol, srccnt[cntord[sn].sno].val);
344	greg	1.1	}
345			}