--- ray/src/rt/source.c	1989/06/08 09:35:43	1.9
+++ ray/src/rt/source.c	1989/09/29 10:04:01	1.17
@@ -27,6 +27,7 @@ static char SCCSid[] = "$SunId$ LBL";
 
 extern double  dstrsrc;			/* source distribution amount */
 extern double  shadthresh;		/* relative shadow threshold */
+extern double  shadcert;		/* shadow testing certainty */
 
 SRCREC  *source = NULL;			/* our list of sources */
 int  nsources = 0;			/* the number of sources */
@@ -301,17 +302,20 @@ RAY  *r;			/* ray that hit surface */
 int  (*f)();			/* direct component coefficient function */
 char  *p;			/* data for f */
 {
+	extern double  pow();
 	register int  sn;
 	register CONTRIB  *srccnt;
 	register CNTPTR  *cntord;
-	int  ncnts;
-	double  ourthresh, prob, hwt, test2, hit2;
+	int  nshadcheck, ncnts;
+	double  prob, ourthresh, hwt, test2, hit2;
 	RAY  sr;
 
 	srccnt = (CONTRIB *)malloc(nsources*sizeof(CONTRIB));
 	cntord = (CNTPTR *)malloc(nsources*sizeof(CNTPTR));
 	if (srccnt == NULL || cntord == NULL)
 		error(SYSTEM, "out of memory in direct");
+						/* compute number to check */
+	nshadcheck = pow((double)nsources, shadcert) + .5;
 						/* modify threshold */
 	ourthresh = shadthresh / r->rweight;
 						/* potential contributions */
@@ -325,7 +329,7 @@ char  *p;			/* data for f */
 						/* compute coefficient */
 		(*f)(srccnt[sn].val, p, srccnt[sn].dir, srccnt[sn].dom);
 		cntord[sn].brt = bright(srccnt[sn].val);
-		if (cntord[sn].brt <= FTINY)
+		if (cntord[sn].brt <= 0.0)
 			continue;
 						/* compute intersection */
 		if (!( source[sn].sflags & SDISTANT ?
@@ -340,24 +344,29 @@ char  *p;			/* data for f */
 	}
 						/* sort contributions */
 	qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
-	hit2 = 0.0; test2 = FTINY;
-						/* find last */
-	sn = 0; ncnts = nsources;
-	while (sn < ncnts-1) {
-		register int  m;
-		m = (sn + ncnts) >> 1;
-		if (cntord[m].brt > 0.0)
-			sn = m;
-		else
-			ncnts = m;
+	{					/* 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;
-						/* shadow testing */
+                                                /* accumulate tail */
+        for (sn = ncnts-1; sn > 0; sn--)
+                cntord[sn-1].brt += cntord[sn].brt;
+						/* start with prob=.5 */
+	hit2 = 0.5; test2 = 1.0;
+						/* test for shadows */
 	for (sn = 0; sn < ncnts; sn++) {
-						/* tail below threshold? */
-		if (cntord[sn].brt < ourthresh*bright(r->rcol))
+						/* check threshold */
+		if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
+				cntord[sn].brt-cntord[sn+nshadcheck].brt) <
+				ourthresh*bright(r->rcol))
 			break;
 						/* get statistics */
 		hwt = (double)source[cntord[sn].sno].nhits /
@@ -370,10 +379,7 @@ char  *p;			/* data for f */
 		if (localhit(&sr, &thescene) &&
 				sr.ro != source[cntord[sn].sno].so) {
 						/* check for transmission */
-			if (sr.clipset != NULL && inset(sr.clipset,sr.ro->omod))
-				raytrans(&sr);		/* object is clipped */
-			else
-				rayshade(&sr, sr.ro->omod);
+			rayshade(&sr, sr.ro->omod);
 			if (bright(sr.rcol) <= FTINY)
 				continue;	/* missed! */
 			(*f)(srccnt[cntord[sn].sno].val, p,
@@ -388,9 +394,10 @@ char  *p;			/* data for f */
 	}
 					/* weighted hit rate */
 	hwt = hit2 / test2;
-#ifdef DEBUG
-	fprintf(stderr, "%d tested, %d untested, %f hit rate\n",
+#ifdef notdef
+	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++) {
@@ -399,6 +406,7 @@ char  *p;			/* data for f */
 		scalecolor(srccnt[cntord[sn].sno].val, prob);
 		addcolor(r->rcol, srccnt[cntord[sn].sno].val);
 	}
+		
 	free(srccnt);
 	free(cntord);
 }
@@ -420,9 +428,6 @@ m_light(m, r)			/* ray hit a light source */
 register OBJREC  *m;
 register RAY  *r;
 {
-						/* check for behind */
-	if (r->rod < 0.0)
-		return;
 						/* check for over-counting */
 	if (wrongsource(m, r) || badambient(m, r))
 		return;
@@ -436,6 +441,9 @@ register RAY  *r;
 
 						/* otherwise treat as source */
 	} else {
+						/* check for behind */
+		if (r->rod < 0.0)
+			return;
 						/* get distribution pattern */
 		raytexture(r, m->omod);
 						/* get source color */