--- ray/src/rt/srcsamp.c	1991/10/28 08:07:44	1.7
+++ ray/src/rt/srcsamp.c	2010/10/23 18:13:54	2.17
@@ -1,13 +1,14 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: srcsamp.c,v 2.17 2010/10/23 18:13:54 greg Exp $";
 #endif
-
 /*
  * Source sampling routines
+ *
+ *  External symbols declared in source.h
  */
 
+#include "copyright.h"
+
 #include  "ray.h"
 
 #include  "source.h"
@@ -15,16 +16,20 @@ static char SCCSid[] = "$SunId$ LBL";
 #include  "random.h"
 
 
+static int  cyl_partit(), flt_partit();
+
+
 double
 nextssamp(r, si)		/* compute sample for source, rtn. distance */
 register RAY  *r;		/* origin is read, direction is set */
 register SRCINDEX  *si;		/* source index (modified to current) */
 {
 	int  cent[3], size[3], parr[2];
+	SRCREC  *srcp;
 	FVECT  vpos;
 	double  d;
 	register int  i;
-
+nextsample:
 	while (++si->sp >= si->np) {	/* get next sample */
 		if (++si->sn >= nsources)
 			return(0.0);	/* no more */
@@ -47,56 +52,85 @@ register SRCINDEX  *si;		/* source index (modified to 
 	if (!skipparts(cent, size, parr, si->spt))
 		error(CONSISTENCY, "bad source partition in nextssamp");
 					/* compute sample */
+	srcp = source + si->sn;
 	if (dstrsrc > FTINY) {			/* jitter sample */
 		dimlist[ndims] = si->sn + 8831;
 		dimlist[ndims+1] = si->sp + 3109;
 		d = urand(ilhash(dimlist,ndims+2)+samplendx);
-		if (source[si->sn].sflags & SFLAT) {
+		if (srcp->sflags & SFLAT) {
 			multisamp(vpos, 2, d);
-			vpos[2] = 0.5;
+			vpos[SW] = 0.5;
 		} else
 			multisamp(vpos, 3, d);
 		for (i = 0; i < 3; i++)
 			vpos[i] = dstrsrc * (1. - 2.*vpos[i]) *
-					(double)size[i]/MAXSPART;
+					(double)size[i]*(1.0/MAXSPART);
 	} else
 		vpos[0] = vpos[1] = vpos[2] = 0.0;
 
-	for (i = 0; i < 3; i++)
-		vpos[i] += (double)cent[i]/MAXSPART;
+	VSUM(vpos, vpos, cent, 1.0/MAXSPART);
+					/* avoid circular aiming failures */
+	if ((srcp->sflags & SCIR) && (si->np > 1 || dstrsrc > 0.7)) {
+		FVECT	trim;
+		if (srcp->sflags & (SFLAT|SDISTANT)) {
+			d = 1.12837917;		/* correct setflatss() */
+			trim[SU] = d*sqrt(1.0 - 0.5*vpos[SV]*vpos[SV]);
+			trim[SV] = d*sqrt(1.0 - 0.5*vpos[SU]*vpos[SU]);
+			trim[SW] = 0.0;
+		} else {
+			trim[SW] = trim[SU] = vpos[SU]*vpos[SU];
+			d = vpos[SV]*vpos[SV];
+			if (d > trim[SW]) trim[SW] = d;
+			trim[SU] += d;
+			d = vpos[SW]*vpos[SW];
+			if (d > trim[SW]) trim[SW] = d;
+			trim[SU] += d;
+			if (trim[SU] > FTINY*FTINY) {
+				d = 1.0/0.7236;	/* correct sphsetsrc() */
+				trim[SW] = trim[SV] = trim[SU] =
+						d*sqrt(trim[SW]/trim[SU]);
+			} else
+				trim[SW] = trim[SV] = trim[SU] = 0.0;
+		}
+		for (i = 0; i < 3; i++)
+			vpos[i] *= trim[i];
+	}
 					/* compute direction */
 	for (i = 0; i < 3; i++)
-		r->rdir[i] = source[si->sn].sloc[i] +
-				vpos[SU]*source[si->sn].ss[SU][i] +
-				vpos[SV]*source[si->sn].ss[SV][i] +
-				vpos[SW]*source[si->sn].ss[SW][i];
+		r->rdir[i] = srcp->sloc[i] +
+				vpos[SU]*srcp->ss[SU][i] +
+				vpos[SV]*srcp->ss[SV][i] +
+				vpos[SW]*srcp->ss[SW][i];
 
-	if (!(source[si->sn].sflags & SDISTANT))
-		for (i = 0; i < 3; i++)
-			r->rdir[i] -= r->rorg[i];
+	if (!(srcp->sflags & SDISTANT))
+		VSUB(r->rdir, r->rdir, r->rorg);
 					/* compute distance */
 	if ((d = normalize(r->rdir)) == 0.0)
-		return(nextssamp(r, si));	/* at source! */
+		goto nextsample;		/* at source! */
 
 					/* compute sample size */
-	si->dom  = source[si->sn].ss2;
-	if (source[si->sn].sflags & SFLAT) {
-		si->dom *= sflatform(si->sn, r->rdir);
-		si->dom *= (double)(size[SU]*size[SV])/(MAXSPART*MAXSPART);
-	} else if (source[si->sn].sflags & SCYL) {
-		si->dom *= scylform(si->sn, r->rdir);
-		si->dom *= (double)size[SU]/MAXSPART;
+	if (srcp->sflags & SFLAT) {
+		si->dom = sflatform(si->sn, r->rdir);
+		si->dom *= size[SU]*size[SV]*(1.0/MAXSPART/MAXSPART);
+	} else if (srcp->sflags & SCYL) {
+		si->dom = scylform(si->sn, r->rdir);
+		si->dom *= size[SU]*(1.0/MAXSPART);
 	} else {
-		si->dom *= (double)(size[SU]*size[SV]*size[SW]) /
-				(MAXSPART*MAXSPART*MAXSPART) ;
+		si->dom = size[SU]*size[SV]*(double)size[SW] *
+				(1.0/MAXSPART/MAXSPART/MAXSPART) ;
 	}
-	if (source[si->sn].sflags & SDISTANT)
+	if (srcp->sflags & SDISTANT) {
+		si->dom *= srcp->ss2;
 		return(FHUGE);
-	si->dom /= d*d;
+	}
+	if (si->dom <= 1e-4)
+		goto nextsample;		/* behind source? */
+	si->dom *= srcp->ss2/(d*d);
 	return(d);		/* sample OK, return distance */
 }
 
 
+int
 skipparts(ct, sz, pp, pt)		/* skip to requested partition */
 int  ct[3], sz[3];		/* center and size of partition (returned) */
 register int  pp[2];		/* current index, number to skip (modified) */
@@ -106,12 +140,13 @@ unsigned char  *pt;		/* partition array */
 					/* check this partition */
 	p = spart(pt, pp[0]);
 	pp[0]++;
-	if (p == S0)			/* leaf partition */
+	if (p == S0) {			/* leaf partition */
 		if (pp[1]) {
 			pp[1]--;
 			return(0);	/* not there yet */
 		} else
 			return(1);	/* we've arrived */
+	}
 				/* else check lower */
 	sz[p] >>= 1;
 	ct[p] -= sz[p];
@@ -128,6 +163,7 @@ unsigned char  *pt;		/* partition array */
 }
 
 
+void
 nopart(si, r)			/* single source partition */
 register SRCINDEX  *si;
 RAY  *r;
@@ -138,6 +174,7 @@ RAY  *r;
 }
 
 
+void
 cylpart(si, r)			/* partition a cylinder */
 SRCINDEX  *si;
 register RAY  *r;
@@ -214,11 +251,12 @@ double  d2;
 }
 
 
+void
 flatpart(si, r)				/* partition a flat source */
 register SRCINDEX  *si;
 register RAY  *r;
 {
-	register FLOAT  *vp;
+	register RREAL  *vp;
 	FVECT  v;
 	double  du2, dv2;
 	int  pi;
@@ -229,7 +267,7 @@ register RAY  *r;
 	v[1] = r->rorg[1] - vp[1];
 	v[2] = r->rorg[2] - vp[2];
 	vp = source[si->sn].snorm;
-	if (DOT(v,vp) <= FTINY) {	/* behind source */
+	if (DOT(v,vp) <= 0.) {		/* behind source */
 		si->np = 0;
 		return;
 	}
@@ -302,7 +340,7 @@ scylform(sn, dir)		/* compute cosine for cylinder's pr
 int  sn;
 register FVECT  dir;		/* assume normalized */
 {
-	register FLOAT  *dv;
+	register RREAL  *dv;
 	double  d;
 
 	dv = source[sn].ss[SU];