--- ray/src/cv/mgflib/context.c	1995/04/12 17:16:33	1.20
+++ ray/src/cv/mgflib/context.c	1995/05/10 17:46:09	1.22
@@ -105,6 +105,8 @@ register char	**av;
 			c_ccname = NULL;
 			return(MG_OK);
 		}
+		if (!isname(av[1]))
+			return(MG_EILL);
 		lp = lu_find(&clr_tab, av[1]);	/* lookup context */
 		if (lp == NULL)
 			return(MG_EMEM);
@@ -221,6 +223,8 @@ register char	**av;
 			c_cmname = NULL;
 			return(MG_OK);
 		}
+		if (!isname(av[1]))
+			return(MG_EILL);
 		lp = lu_find(&mat_tab, av[1]);	/* lookup context */
 		if (lp == NULL)
 			return(MG_EMEM);
@@ -259,6 +263,17 @@ register char	**av;
 		*c_cmaterial = *(C_MATERIAL *)lp->data;
 		c_cmaterial->clock = i + 1;
 		return(MG_OK);
+	case MG_E_IR:		/* set index of refraction */
+		if (ac != 3)
+			return(MG_EARGC);
+		if (!isflt(av[1]) | !isflt(av[2]))
+			return(MG_ETYPE);
+		c_cmaterial->nr = atof(av[1]);
+		c_cmaterial->ni = atof(av[2]);
+		if (c_cmaterial->nr <= FTINY)
+			return(MG_EILL);
+		c_cmaterial->clock++;
+		return(MG_OK);
 	case MG_E_RD:		/* set diffuse reflectance */
 		if (ac != 2)
 			return(MG_EARGC);
@@ -355,6 +370,8 @@ register char	**av;
 			c_cvname = NULL;
 			return(MG_OK);
 		}
+		if (!isname(av[1]))
+			return(MG_EILL);
 		lp = lu_find(&vtx_tab, av[1]);	/* lookup context */
 		if (lp == NULL)
 			return(MG_EMEM);