--- ray/src/rt/noise3.c	1991/05/22 08:56:21	1.4
+++ ray/src/rt/noise3.c	1992/10/02 16:18:50	2.2
@@ -14,6 +14,7 @@ static char SCCSid[] = "$SunId$ LBL";
  *     5/19/88	Added fractal noise function
  */
 
+#include  <math.h>
 
 #define  A		0
 #define  B		1
@@ -25,13 +26,22 @@ static char SCCSid[] = "$SunId$ LBL";
 #define  rand3c(x,y,z)	frand(89*(x)+97*(y)+101*(z))
 #define  rand3d(x,y,z)	frand(103*(x)+107*(y)+109*(z))
 
-#define  hermite(p0,p1,r0,r1,t)  (	p0*((2.0*t-3.0)*t*t+1.0) + \
-					p1*(-2.0*t+3.0)*t*t + \
-					r0*((t-2.0)*t+1.0)*t + \
-					r1*(t-1.0)*t*t )
+#define  hpoly1(t)	((2.0*t-3.0)*t*t+1.0)
+#define  hpoly2(t)	(-2.0*t+3.0)*t*t
+#define  hpoly3(t)	((t-2.0)*t+1.0)*t
+#define  hpoly4(t)	(t-1.0)*t*t
 
-double  *noise3(), noise3coef(), argument(), frand();
+#define  hermite(p0,p1,r0,r1,t)  (	p0*hpoly1(t) + \
+					p1*hpoly2(t) + \
+					r0*hpoly3(t) + \
+					r1*hpoly4(t) )
 
+static char  noise_name[4][8] = {"noise3a", "noise3b", "noise3c", "noise3"};
+static char  fnoise_name[] = "fnoise3";
+static char  hermite_name[] = "hermite";
+
+double  *noise3(), fnoise3(), argument(), frand();
+
 static long  xlim[3][2];
 static double  xarg[3];
 
@@ -39,69 +49,57 @@ static double  xarg[3];
 
 #define  frand3(x,y,z)	frand(17*(x)+23*(y)+29*(z))
 
-double  fnoise3();
 
-
-double
-l_noise3()			/* compute 3-dimensional noise function */
+static double
+l_noise3(nam)			/* compute a noise function */
+register char  *nam;
 {
-	return(noise3coef(D));
+	register int  i;
+	double  x[3];
+					/* get point */
+	x[0] = argument(1);
+	x[1] = argument(2);
+	x[2] = argument(3);
+					/* make appropriate call */
+	if (nam == fnoise_name)
+		return(fnoise3(x));
+	i = 4;
+	while (i--)
+		if (nam == noise_name[i])
+			return(noise3(x)[i]);
+	eputs(nam);
+	eputs(": called l_noise3!\n");
+	quit(1);
 }
 
 
 double
-l_noise3a()			/* compute x slope of noise function */
+l_hermite()			/* library call for hermite interpolation */
 {
-	return(noise3coef(A));
+	double  t;
+	
+	t = argument(5);
+	return( hermite(argument(1), argument(2),
+			argument(3), argument(4), t) );
 }
 
 
-double
-l_noise3b()			/* compute y slope of noise function */
+setnoisefuncs()			/* add noise functions to library */
 {
-	return(noise3coef(B));
-}
+	register int  i;
 
-
-double
-l_noise3c()			/* compute z slope of noise function */
-{
-	return(noise3coef(C));
+	funset(hermite_name, 5, ':', l_hermite);
+	funset(fnoise_name, 3, ':', l_noise3);
+	i = 4;
+	while (i--)
+		funset(noise_name[i], 3, ':', l_noise3);
 }
 
 
-double
-l_fnoise3()			/* compute fractal noise function */
-{
-	double  x[3];
-
-	x[0] = argument(1);
-	x[1] = argument(2);
-	x[2] = argument(3);
-
-	return(fnoise3(x));
-}
-
-
-static double
-noise3coef(coef)		/* return coefficient of noise function */
-int  coef;
-{
-	double  x[3];
-
-	x[0] = argument(1);
-	x[1] = argument(2);
-	x[2] = argument(3);
-
-	return(noise3(x)[coef]);
-}
-
-
 double *
 noise3(xnew)			/* compute the noise function */
 register double  xnew[3];
 {
-	extern double  floor();
 	static double  x[3] = {-100000.0, -100000.0, -100000.0};
 	static double  f[4];
 
@@ -124,7 +122,7 @@ interpolate(f, i, n)
 double  f[4];
 register int  i, n;
 {
-	double  f0[4], f1[4];
+	double  f0[4], f1[4], hp1, hp2;
 
 	if (n == 0) {
 		f[A] = rand3a(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
@@ -135,10 +133,12 @@ register int  i, n;
 		n--;
 		interpolate(f0, i, n);
 		interpolate(f1, i | 1<<n, n);
-		f[A] = (1.0-xarg[n])*f0[A] + xarg[n]*f1[A];
-		f[B] = (1.0-xarg[n])*f0[B] + xarg[n]*f1[B];
-		f[C] = (1.0-xarg[n])*f0[C] + xarg[n]*f1[C];
-		f[D] = hermite(f0[D], f1[D], f0[n], f1[n], xarg[n]);
+		hp1 = hpoly1(xarg[n]); hp2 = hpoly2(xarg[n]);
+		f[A] = f0[A]*hp1 + f1[A]*hp2;
+		f[B] = f0[B]*hp1 + f1[B]*hp2;
+		f[C] = f0[C]*hp1 + f1[C]*hp2;
+		f[D] = f0[D]*hp1 + f1[D]*hp2 +
+				f0[n]*hpoly3(xarg[n]) + f1[n]*hpoly4(xarg[n]);
 	}
 }
 
@@ -153,21 +153,9 @@ register long  s;
 
 
 double
-l_hermite()			/* library call for hermite interpolation */
-{
-	double  t;
-	
-	t = argument(5);
-	return( hermite(argument(1), argument(2),
-			argument(3), argument(4), t) );
-}
-
-
-double
 fnoise3(p)			/* compute fractal noise function */
 double  p[3];
 {
-	double  floor();
 	long  t[3], v[3], beg[3];
 	double  fval[8], fc;
 	int  branch;