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 SRCREC  *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()) == NULL)
                        goto memerr;

                (*sfun[o->otype].of->setsrc)(ns, o);

                if (m->otype == MAT_GLOW) {
                        ns->sflags |= SPROX;
                        ns->sl.prox = m->oargs.farg[3];
                        if (o->otype == OBJ_SOURCE)
                                ns->sflags |= SSKIP;
                } else if (m->otype == MAT_SPOT) {
                        ns->sflags |= SSPOT;
                        if ((ns->sl.s = makespot(m)) == NULL)
                                goto memerr;
                }
        }
        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) {
                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(source[sn].sloc,vd);
                        d = DOT(vd,vd) - d*d;
                        if (PI*d > source[sn].sl.s->siz)
                                return(0.0);
                }
                                                /* 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(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];

        } else if (source[sn].sflags & SDISTANT)
                                                /* already normalized */
                return(source[sn].ss2);

        if ((d = normalize(sr->rdir)) == 0.0)
                                                /* at source! */
                return(0.0);
        
        if (source[sn].sflags & SDISTANT)
                                                /* domega constant */
                return(source[sn].ss2);

                                                /* 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:	1.35
Committed:	Thu Jun 20 13:43:29 1991 UTC (32 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.34:	+50 -222 lines
Log Message:	major reorganization using dispatch table for source types
#	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	1.33	register SRCREC *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	1.33	if ((ns = newsource()) == NULL)
76	greg	1.25	goto memerr;
77	greg	1.1
78	greg	1.35	(*sfun[o->otype].of->setsrc)(ns, o);
79	greg	1.1
80	greg	1.6	if (m->otype == MAT_GLOW) {
81	greg	1.33	ns->sflags \|= SPROX;
82			ns->sl.prox = m->oargs.farg[3];
83	greg	1.6	if (o->otype == OBJ_SOURCE)
84	greg	1.33	ns->sflags \|= SSKIP;
85	greg	1.6	} else if (m->otype == MAT_SPOT) {
86	greg	1.33	ns->sflags \|= SSPOT;
87			if ((ns->sl.s = makespot(m)) == NULL)
88			goto memerr;
89	greg	1.6	}
90	greg	1.1	}
91	greg	1.25	if (nsources <= 0) {
92			error(WARNING, "no light sources found");
93			return;
94			}
95	greg	1.33	markvirtuals(); /* find and add virtual sources */
96	greg	1.25	srccnt = (CONTRIB )malloc(nsourcessizeof(CONTRIB));
97			cntord = (CNTPTR )malloc(nsourcessizeof(CNTPTR));
98			if (srccnt != NULL && cntord != NULL)
99	greg	1.33	goto memerr;
100			return;
101	greg	1.25	memerr:
102			error(SYSTEM, "out of memory in marksources");
103	greg	1.1	}
104
105
106			double
107			srcray(sr, r, sn) /* send a ray to a source, return domega */
108			register RAY sr; / returned source ray */
109			RAY r; / ray which hit object */
110			register int sn; /* source number */
111			{
112			double ddot; /* (distance times) cosine */
113			FVECT vd;
114			double d;
115			register int i;
116
117	greg	1.4	if (source[sn].sflags & SSKIP)
118	greg	1.1	return(0.0); /* skip this source */
119
120			rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
121
122			sr->rsrc = sn; /* remember source */
123			/* get source direction */
124	greg	1.33	if (source[sn].sflags & SDISTANT) {
125			if (source[sn].sflags & SSPOT) { /* check location */
126			for (i = 0; i < 3; i++)
127			vd[i] = sr->rorg[i] - source[sn].sl.s->aim[i];
128			d = DOT(source[sn].sloc,vd);
129			d = DOT(vd,vd) - d*d;
130			if (PI*d > source[sn].sl.s->siz)
131			return(0.0);
132			}
133	greg	1.1	/* constant direction */
134	greg	1.4	VCOPY(sr->rdir, source[sn].sloc);
135	greg	1.33	} else { /* compute direction */
136	greg	1.1	for (i = 0; i < 3; i++)
137	greg	1.4	sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];
138	greg	1.1
139	greg	1.33	if (source[sn].sflags & SFLAT &&
140			(ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
141	greg	1.1	return(0.0); /* behind surface! */
142			}
143			if (dstrsrc > FTINY) {
144			/* distribute source direction */
145	greg	1.31	dimlist[ndims++] = sn;
146			for (i = 0; i < 3; i++) {
147			dimlist[ndims] = i + 8831;
148			vd[i] = dstrsrc * source[sn].ss *
149			(1.0 - 2.0*urand(ilhash(dimlist,ndims+1)+samplendx));
150			}
151			ndims--;
152	greg	1.33	if (source[sn].sflags & SFLAT) { /* project offset */
153			d = DOT(vd, source[sn].snorm);
154	greg	1.1	for (i = 0; i < 3; i++)
155	greg	1.33	vd[i] -= d * source[sn].snorm[i];
156	greg	1.1	}
157			for (i = 0; i < 3; i++) /* offset source direction */
158			sr->rdir[i] += vd[i];
159
160	greg	1.4	} else if (source[sn].sflags & SDISTANT)
161	greg	1.1	/* already normalized */
162	greg	1.4	return(source[sn].ss2);
163	greg	1.1
164			if ((d = normalize(sr->rdir)) == 0.0)
165			/* at source! */
166			return(0.0);
167
168	greg	1.4	if (source[sn].sflags & SDISTANT)
169	greg	1.1	/* domega constant */
170	greg	1.4	return(source[sn].ss2);
171	greg	1.1
172	greg	1.6	/* check proximity */
173	greg	1.27	if (source[sn].sflags & SPROX &&
174			d > source[sn].sl.prox)
175			return(0.0);
176			/* compute dot product */
177	greg	1.33	if (source[sn].sflags & SFLAT)
178	greg	1.27	ddot /= d;
179			else
180			ddot = 1.0;
181	greg	1.6	/* check angle */
182	greg	1.27	if (source[sn].sflags & SSPOT) {
183			if (source[sn].sl.s->siz < 2.0PI
184	greg	1.6	(1.0 + DOT(source[sn].sl.s->aim,sr->rdir)))
185	greg	1.27	return(0.0);
186			d += source[sn].sl.s->flen; /* adjust length */
187	greg	1.1	}
188	greg	1.27	/* compute domega */
189			return(ddotsource[sn].ss2/(dd));
190	greg	1.1	}
191
192
193	greg	1.35	srcvalue(r) /* punch ray to source and compute value */
194			RAY *r;
195	greg	1.1	{
196	greg	1.35	register SRCREC *sp;
197	greg	1.1
198	greg	1.35	sp = &source[r->rsrc];
199			if (sp->sflags & SVIRTUAL) { /* virtual source */
200			/* check intersection */
201			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
202			return;
203			raycont(r); /* compute contribution */
204			return;
205	greg	1.1	}
206	greg	1.35	/* compute intersection */
207			if (sp->sflags & SDISTANT ? sourcehit(r) :
208			(*ofun[sp->so->otype].funp)(sp->so, r)) {
209			if (sp->sa.success >= 0)
210			sp->sa.success++;
211			raycont(r); /* compute contribution */
212			return;
213	greg	1.1	}
214	greg	1.35	if (sp->sa.success < 0)
215			return; /* bitched already */
216			sp->sa.success -= AIMREQT;
217			if (sp->sa.success >= 0)
218			return; /* leniency */
219			sprintf(errmsg, "aiming failure for light source \"%s\"",
220			sp->so->oname);
221			error(WARNING, errmsg); /* issue warning */
222	greg	1.1	}
223
224
225	greg	1.4	static int
226			cntcmp(sc1, sc2) /* contribution compare (descending) */
227	greg	1.9	register CNTPTR sc1, sc2;
228	greg	1.4	{
229			if (sc1->brt > sc2->brt)
230			return(-1);
231			if (sc1->brt < sc2->brt)
232			return(1);
233			return(0);
234			}
235
236
237			direct(r, f, p) /* add direct component */
238			RAY r; / ray that hit surface */
239			int (f)(); / direct component coefficient function */
240			char p; / data for f */
241			{
242	greg	1.12	extern double pow();
243	greg	1.4	register int sn;
244	greg	1.12	int nshadcheck, ncnts;
245	greg	1.29	int nhits;
246	greg	1.34	double dom, prob, ourthresh, hwt;
247	greg	1.4	RAY sr;
248	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
249	greg	1.22	if (nsources <= 0)
250	greg	1.25	return; /* no sources?! */
251	greg	1.12	/* compute number to check */
252			nshadcheck = pow((double)nsources, shadcert) + .5;
253	greg	1.8	/* modify threshold */
254			ourthresh = shadthresh / r->rweight;
255	greg	1.4	/* potential contributions */
256			for (sn = 0; sn < nsources; sn++) {
257	greg	1.9	cntord[sn].sno = sn;
258			cntord[sn].brt = 0.0;
259	greg	1.4	/* get source ray */
260	greg	1.34	if ((dom = srcray(&sr, r, sn)) == 0.0)
261	greg	1.4	continue;
262			VCOPY(srccnt[sn].dir, sr.rdir);
263			/* compute coefficient */
264	greg	1.34	(*f)(srccnt[sn].coef, p, srccnt[sn].dir, dom);
265			cntord[sn].brt = bright(srccnt[sn].coef);
266	greg	1.15	if (cntord[sn].brt <= 0.0)
267	greg	1.4	continue;
268	greg	1.35	/* compute potential */
269			sr.revf = srcvalue;
270			rayvalue(&sr);
271	greg	1.34	copycolor(srccnt[sn].val, sr.rcol);
272			multcolor(srccnt[sn].val, srccnt[sn].coef);
273	greg	1.9	cntord[sn].brt = bright(srccnt[sn].val);
274	greg	1.4	}
275			/* sort contributions */
276	greg	1.9	qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
277	greg	1.13	{ /* find last */
278			register int l, m;
279
280			sn = 0; ncnts = l = nsources;
281			while ((m = (sn + ncnts) >> 1) != l) {
282			if (cntord[m].brt > 0.0)
283			sn = m;
284			else
285			ncnts = m;
286			l = m;
287			}
288			}
289	greg	1.12	/* accumulate tail */
290			for (sn = ncnts-1; sn > 0; sn--)
291			cntord[sn-1].brt += cntord[sn].brt;
292	greg	1.10	/* test for shadows */
293	greg	1.29	nhits = 0;
294	greg	1.12	for (sn = 0; sn < ncnts; sn++) {
295	greg	1.10	/* check threshold */
296	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
297	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
298			< ourthresh*bright(r->rcol))
299	greg	1.4	break;
300			/* get statistics */
301	greg	1.9	source[cntord[sn].sno].ntests++;
302	greg	1.4	/* test for hit */
303			rayorigin(&sr, r, SHADOW, 1.0);
304	greg	1.9	VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
305	greg	1.19	sr.rsrc = cntord[sn].sno;
306	greg	1.4	if (localhit(&sr, &thescene) &&
307	greg	1.33	( sr.ro != source[cntord[sn].sno].so \|\|
308			source[cntord[sn].sno].sflags & SFOLLOW )) {
309			/* follow entire path */
310	greg	1.19	raycont(&sr);
311	greg	1.5	if (bright(sr.rcol) <= FTINY)
312	greg	1.4	continue; /* missed! */
313	greg	1.34	copycolor(srccnt[cntord[sn].sno].val, sr.rcol);
314			multcolor(srccnt[cntord[sn].sno].val,
315			srccnt[cntord[sn].sno].coef);
316	greg	1.4	}
317			/* add contribution if hit */
318	greg	1.9	addcolor(r->rcol, srccnt[cntord[sn].sno].val);
319	greg	1.29	nhits++;
320	greg	1.9	source[cntord[sn].sno].nhits++;
321	greg	1.4	}
322	greg	1.29	/* surface hit rate */
323			if (sn > 0)
324			hwt = (double)nhits / (double)sn;
325			else
326			hwt = 0.5;
327	greg	1.20	#ifdef DEBUG
328	greg	1.12	sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
329			sn, ncnts-sn, hwt);
330			eputs(errmsg);
331	greg	1.4	#endif
332			/* add in untested sources */
333	greg	1.12	for ( ; sn < ncnts; sn++) {
334	greg	1.9	prob = hwt * (double)source[cntord[sn].sno].nhits /
335			(double)source[cntord[sn].sno].ntests;
336			scalecolor(srccnt[cntord[sn].sno].val, prob);
337			addcolor(r->rcol, srccnt[cntord[sn].sno].val);
338	greg	1.1	}
339			}