--- ray/src/rt/m_brdf.c	2003/02/25 02:47:22	2.16
+++ ray/src/rt/m_brdf.c	2003/03/05 16:16:53	2.18
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: m_brdf.c,v 2.16 2003/02/25 02:47:22 greg Exp $";
+static const char	RCSid[] = "$Id: m_brdf.c,v 2.18 2003/03/05 16:16:53 greg Exp $";
 #endif
 /*
  *  Shading for materials with arbitrary BRDF's
@@ -160,7 +160,7 @@ double  omega;			/* light source size */
 		dtmp = funvalue(sa[0], 5, vldx);
 		setcolor(ctmp, dtmp, dtmp, dtmp);
 	}
-	if (errno) {
+	if (errno == EDOM || errno == ERANGE) {
 		objerror(np->mp, WARNING, "compute error");
 		return;
 	}
@@ -224,7 +224,7 @@ register RAY  *r;
 	setcolor(nd.tdiff, m->oargs.farg[6],
 			m->oargs.farg[7],
 			m->oargs.farg[8]);
-					/* get modifiers */
+						/* get modifiers */
 	raytexture(r, m->omod);
 	nd.pdot = raynormal(nd.pnorm, r);	/* perturb normal */
 	if (r->rod < 0.0) {			/* orient perturbed values */
@@ -251,7 +251,7 @@ register RAY  *r;
 	setcolor(ctmp, evalue(mf->ep[3]),
 			evalue(mf->ep[4]),
 			evalue(mf->ep[5]));
-	if (errno)
+	if (errno == EDOM || errno == ERANGE)
 		objerror(m, WARNING, "compute error");
 	else if (rayorigin(&sr, r, TRANS, bright(ctmp)) == 0) {
 		if (!(r->crtype & SHADOW) &&
@@ -280,7 +280,7 @@ register RAY  *r;
 	setcolor(ctmp, evalue(mf->ep[0]),
 			evalue(mf->ep[1]),
 			evalue(mf->ep[2]));
-	if (errno)
+	if (errno == EDOM || errno == ERANGE)
 		objerror(m, WARNING, "compute error");
 	else if (rayorigin(&sr, r, REFLECTED, bright(ctmp)) == 0) {
 		for (i = 0; i < 3; i++)
@@ -338,6 +338,18 @@ register RAY  *r;
 	if (m->oargs.nsargs < (hasdata(m->otype)?4:2) | m->oargs.nfargs <
 			(m->otype==MAT_TFUNC|m->otype==MAT_TDATA?6:4))
 		objerror(m, USER, "bad # arguments");
+						/* check for back side */
+	if (r->rod < 0.0) {
+		if (!backvis && m->otype != MAT_TFUNC
+				&& m->otype != MAT_TDATA) {
+			raytrans(r);
+			return(1);
+		}
+		raytexture(r, m->omod);
+		flipsurface(r);			/* reorient if backvis */
+	} else
+		raytexture(r, m->omod);
+
 	nd.mp = m;
 	nd.pr = r;
 						/* get material color */
@@ -359,17 +371,6 @@ register RAY  *r;
 						/* compute reflectance */
 	dtmp = 1.0 - nd.trans - nd.rspec;
 	setcolor(nd.rdiff, dtmp, dtmp, dtmp);
-						/* check for back side */
-	if (r->rod < 0.0) {
-		if (!backvis && m->otype != MAT_TFUNC
-				&& m->otype != MAT_TDATA) {
-			raytrans(r);
-			return(1);
-		}
-		flipsurface(r);			/* reorient if backvis */
-	}
-						/* get modifiers */
-	raytexture(r, m->omod);
 	nd.pdot = raynormal(nd.pnorm, r);	/* perturb normal */
 	multcolor(nd.mcolor, r->pcol);		/* modify material color */
 	multcolor(nd.rdiff, nd.mcolor);