--- ray/src/common/fvect.c	1991/10/23 13:43:15	1.7
+++ ray/src/common/fvect.c	1993/12/10 09:53:30	2.3
@@ -10,6 +10,7 @@ static char SCCSid[] = "$SunId$ LBL";
  *     8/14/85
  */
 
+#include  <math.h>
 #include  "fvect.h"
 
 
@@ -102,16 +103,15 @@ register FVECT  v;
 	if (len <= 0.0)
 		return(0.0);
 	
-	/****** problematic
-	if (len >= (1.0-FTINY)*(1.0-FTINY) &&
-			len <= (1.0+FTINY)*(1.0+FTINY))
-		return(1.0);
-	******/
+	if (len <= 1.0+FTINY && len >= 1.0-FTINY)
+		len = 0.5 + 0.5*len;	/* first order approximation */
+	else
+		len = sqrt(len);
 
-	len = sqrt(len);
 	v[0] /= len;
 	v[1] /= len;
 	v[2] /= len;
+
 	return(len);
 }
 
@@ -120,7 +120,6 @@ spinvector(vres, vorig, vnorm, theta)	/* rotate vector
 FVECT  vres, vorig, vnorm;
 double  theta;
 {
-	extern double  cos(), sin();
 	double  sint, cost, normprod;
 	FVECT  vperp;
 	register int  i;