--- ray/src/rt/srcsamp.c	1994/07/20 12:48:44	2.6
+++ ray/src/rt/srcsamp.c	2008/12/06 01:08:53	2.12
@@ -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 2.12 2008/12/06 01:08:53 greg Exp $";
 #endif
-
 /*
  * Source sampling routines
+ *
+ *  External symbols declared in source.h
  */
 
+#include "copyright.h"
+
 #include  "ray.h"
 
 #include  "source.h"
@@ -56,7 +57,7 @@ nextsample:
 		d = urand(ilhash(dimlist,ndims+2)+samplendx);
 		if (source[si->sn].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++)
@@ -67,6 +68,30 @@ nextsample:
 
 	for (i = 0; i < 3; i++)
 		vpos[i] += (double)cent[i]/MAXSPART;
+					/* avoid circular aiming failures */
+	if (source[si->sn].sflags & SCIR) {
+		FVECT	trim;
+		double	d;
+		if (source[si->sn].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;
+			d = 1.0/0.7236;		/* correct sphsetsrc() */
+			trim[SW] = trim[SV] = trim[SU] =
+					d*sqrt(trim[SW]/trim[SU]);
+		}
+		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] +
@@ -103,6 +128,7 @@ nextsample:
 }
 
 
+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) */
@@ -112,12 +138,13 @@ 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];
@@ -134,6 +161,7 @@ unsigned char  *pt;		/* partition array */
 }
 
 
+void
 nopart(si, r)			/* single source partition */
 register SRCINDEX  *si;
 RAY  *r;
@@ -144,6 +172,7 @@ RAY  *r;
 }
 
 
+void
 cylpart(si, r)			/* partition a cylinder */
 SRCINDEX  *si;
 register RAY  *r;
@@ -220,11 +249,12 @@ 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;
@@ -235,7 +265,7 @@ 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;
 	}
@@ -308,7 +338,7 @@ 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];