--- ray/src/gen/gensurf.c	1990/03/02 17:24:02	1.6
+++ ray/src/gen/gensurf.c	1990/03/07 11:14:36	1.7
@@ -1,9 +1,9 @@
-/* Copyright (c) 1989 Regents of the University of California */
-
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
 #endif
 
+/* Copyright (c) 1989 Regents of the University of California */
+
 /*
  *  gensurf.c - program to generate functional surfaces
  *
@@ -34,7 +34,7 @@ int  smooth = 0;		/* apply smoothing? */
 
 char  *modname, *surfname;
 
-double  funvalue(), l_hermite(), l_bezier(), argument();
+double  funvalue(), l_hermite(), l_bezier(), l_bspline(), argument();
 
 typedef struct {
 	FVECT  p;	/* vertex position */
@@ -53,6 +53,7 @@ char  *argv[];
 	varset("PI", PI);
 	funset("hermite", 5, l_hermite);
 	funset("bezier", 5, l_bezier);
+	funset("bspline", 5, l_bspline);
 
 	if (argc < 8)
 		goto userror;
@@ -429,4 +430,17 @@ l_bezier()
 		argument(2) * 3.*t*(1.+t*(-2.+t)) +
 		argument(3) * 3.*t*t*(1.-t) +
 		argument(4) * t*t*t );
+}
+
+
+double
+l_bspline()
+{
+	double  t;
+
+	t = argument(5);
+	return(	argument(1) * (1./6.+t*(-1./2.+t*(1./2.-1./6.*t))) +
+		argument(2) * (2./3.+t*t*(-1.+1./2.*t)) +
+		argument(3) * (1./6.+t*(1./2.+t*(1./2.-1./2.*t))) +
+		argument(4) * (1./6.*t*t*t) );
 }