--- ray/src/rt/otspecial.h	2018/11/08 00:54:07	2.9
+++ ray/src/rt/otspecial.h	2019/04/18 22:37:36	2.10
@@ -1,4 +1,4 @@
-/* RCSid $Id: otspecial.h,v 2.9 2018/11/08 00:54:07 greg Exp $ */
+/* RCSid $Id: otspecial.h,v 2.10 2019/04/18 22:37:36 greg Exp $ */
 /*
  * Special type flags for objects used in rendering.
  * Depends on definitions in otypes.h
@@ -20,7 +20,7 @@ extern "C" {
 #define  isopaque(t)    (ofun[t].flags & T_OPAQUE)
 
 		/* test if we have a BSDF proxy surface */
-#define isBSDFproxy(m)	((m)->otype == MAT_BSDF && (m)->oargs.nsargs && \
+#define isBSDFproxy(m)	(((m)->otype == MAT_BSDF) & ((m)->oargs.nsargs > 0) &&\
 				strcmp((m)->oargs.sarg[0], "0"))
 
 		/* defined in initotypes.c */
@@ -30,4 +30,3 @@ extern OBJREC   *findmaterial(OBJREC *o);
 }
 #endif
 #endif /* _RAD_OTSPECIAL_H_ */
-