--- ray/src/rt/ambient.c	2016/11/01 20:39:39	2.103
+++ ray/src/rt/ambient.c	2019/02/16 00:09:53	2.107
@@ -1,4 +1,4 @@
-static const char	RCSid[] = "$Id: ambient.c,v 2.103 2016/11/01 20:39:39 greg Exp $";
+static const char	RCSid[] = "$Id: ambient.c,v 2.107 2019/02/16 00:09:53 greg Exp $";
 /*
  *  ambient.c - routines dealing with ambient (inter-reflected) component.
  *
@@ -12,6 +12,7 @@ static const char	RCSid[] = "$Id: ambient.c,v 2.103 20
 #include  "platform.h"
 #include  "ray.h"
 #include  "otypes.h"
+#include  "otspecial.h"
 #include  "resolu.h"
 #include  "ambient.h"
 #include  "random.h"
@@ -131,7 +132,7 @@ setambacc(				/* set ambient accuracy */
 	newa *= (newa > 0);
 	if (fabs(newa - olda) >= .05*(newa + olda)) {
 		ambacc = newa;
-		if (nambvals > 0)
+		if (ambacc > FTINY && nambvals > 0)
 			sortambvals(1);		/* rebuild tree */
 	}
 }
@@ -415,7 +416,8 @@ plugaleak(RAY *r, AMBVAL *ap, FVECT anorm, double ang)
 	VSUM(rtst.rdir, vdif, anorm, t[1]);	/* further dist. > plane */
 	rtst.rmax = normalize(rtst.rdir);	/* short ray test */
 	while (localhit(&rtst, &thescene)) {	/* check for occluder */
-		if (rtst.ro->omod != OVOID &&
+		OBJREC	*m = findmaterial(rtst.ro);
+		if (m != NULL && !istransp(m->otype) && !isBSDFproxy(m) &&
 				(rtst.clipset == NULL ||
 					!inset(rtst.clipset, rtst.ro->omod)))
 			return(1);		/* plug light leak */
@@ -1327,10 +1329,10 @@ ambsync(void)			/* synchronize ambient file */
 	if ((flen = lseek(fileno(ambfp), (off_t)0, SEEK_END)) < 0)
 		goto seekerr;
 	if ((n = flen - lastpos) > 0) {		/* file has grown */
-		if (ambinp == NULL) {		/* use duplicate filedes */
-			ambinp = fdopen(dup(fileno(ambfp)), "r");
+		if (ambinp == NULL) {		/* get new file pointer */
+			ambinp = fopen(ambfile, "rb");
 			if (ambinp == NULL)
-				error(SYSTEM, "fdopen failed in ambsync");
+				error(SYSTEM, "fopen failed in ambsync");
 		}
 		if (fseek(ambinp, lastpos, SEEK_SET) < 0)
 			goto seekerr;
@@ -1345,24 +1347,18 @@ ambsync(void)			/* synchronize ambient file */
 			avstore(&avs);
 			n -= AMBVALSIZ;
 		}
-		lastpos = flen - n;
-		/*** seek always as safety measure
-		if (n) ***/			/* alignment */
-			if (lseek(fileno(ambfp), (off_t)lastpos, SEEK_SET) < 0)
-				goto seekerr;
+		lastpos = flen - n;		/* check alignment */
+		if (n && lseek(fileno(ambfp), (off_t)lastpos, SEEK_SET) < 0)
+			goto seekerr;
 	}
 	n = fflush(ambfp);			/* calls write() at last */
-	if (n != EOF)
-		lastpos += (long)nunflshed*AMBVALSIZ;
-	else if ((lastpos = lseek(fileno(ambfp), (off_t)0, SEEK_CUR)) < 0)
-		goto seekerr;
-		
+	lastpos += (long)nunflshed*AMBVALSIZ;
 	aflock(F_UNLCK);			/* release file */
 	nunflshed = 0;
 	return(n);
 seekerr:
 	error(SYSTEM, "seek failed in ambsync");
-	return -1; /* pro forma return */
+	return(EOF);	/* pro forma return */
 }
 
 #else	/* ! F_SETLKW */