--- ray/src/rt/noise3.c	1991/05/24 14:23:33	1.5
+++ ray/src/rt/noise3.c	2011/02/22 16:45:12	2.12
@@ -1,20 +1,18 @@
-/* Copyright (c) 1988 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: noise3.c,v 2.12 2011/02/22 16:45:12 greg Exp $";
 #endif
-
 /*
  *  noise3.c - noise functions for random textures.
  *
  *     Credit for the smooth algorithm goes to Ken Perlin.
  *     (ref. SIGGRAPH Vol 19, No 3, pp 287-96)
- *
- *     4/15/86
- *     5/19/88	Added fractal noise function
  */
 
+#include "copyright.h"
 
+#include  "ray.h"
+#include  "func.h"
+
 #define  A		0
 #define  B		1
 #define  C		2
@@ -25,28 +23,39 @@ 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
 
-static char  *noise_name[4] = {"noise3a", "noise3b", "noise3c", "noise3"};
+#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] = {"noise3x", "noise3y", "noise3z", "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];
 
-#define  EPSILON	.0001		/* error allowed in fractal */
+#define  EPSILON	.001		/* error allowed in fractal */
 
 #define  frand3(x,y,z)	frand(17*(x)+23*(y)+29*(z))
 
+static double l_noise3(char  *nam);
+static double l_hermite(char *nm);
+static double * noise3(double  xnew[3]);
+static void interpolate(double  f[4], int  i, int  n);
+static double frand(long  s);
+static double fnoise3(double  p[3]);
 
+
 static double
-l_noise3(nam)			/* compute a noise function */
-register char  *nam;
+l_noise3(			/* compute a noise function */
+	register char  *nam
+)
 {
 	register int  i;
 	double  x[3];
@@ -61,13 +70,15 @@ register char  *nam;
 	while (i--)
 		if (nam == noise_name[i])
 			return(noise3(x)[i]);
-	eputs("Bad call to l_noise3()!\n");
+	eputs(nam);
+	eputs(": called l_noise3!\n");
 	quit(1);
+	return 1; /* pro forma return */
 }
 
 
-double
-l_hermite()			/* library call for hermite interpolation */
+static double
+l_hermite(char *nm)		/* library call for hermite interpolation */
 {
 	double  t;
 	
@@ -77,7 +88,8 @@ l_hermite()			/* library call for hermite interpolatio
 }
 
 
-setnoisefuncs()			/* add noise functions to library */
+extern void
+setnoisefuncs(void)			/* add noise functions to library */
 {
 	register int  i;
 
@@ -89,11 +101,11 @@ setnoisefuncs()			/* add noise functions to library */
 }
 
 
-double *
-noise3(xnew)			/* compute the noise function */
-register double  xnew[3];
+static double *
+noise3(			/* 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];
 
@@ -111,12 +123,14 @@ register double  xnew[3];
 }
 
 
-static
-interpolate(f, i, n)
-double  f[4];
-register int  i, n;
+static void
+interpolate(
+	double  f[4],
+	register int  i,
+	register int  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]);
@@ -127,28 +141,31 @@ 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]);
 	}
 }
 
 
-double
-frand(s)			/* get random number from seed */
-register long  s;
+static double
+frand(			/* get random number from seed */
+	register long  s
+)
 {
 	s = s<<13 ^ s;
 	return(1.0-((s*(s*s*15731+789221)+1376312589)&0x7fffffff)/1073741824.0);
 }
 
 
-double
-fnoise3(p)			/* compute fractal noise function */
-double  p[3];
+static double
+fnoise3(			/* compute fractal noise function */
+	double  p[3]
+)
 {
-	double  floor();
 	long  t[3], v[3], beg[3];
 	double  fval[8], fc;
 	int  branch;
@@ -199,12 +216,12 @@ double  p[3];
 			v[i] = beg[i] + s;
 		}
 		for (i = 0; i < 3; i++) {	/* do edges */
-			j = (i+1)%3;
+			if ((j = i+1) == 3) j = 0;
 			if (branch & 1<<j)
 				v[j] += s;
 			else
 				v[j] -= s;
-			j = (i+2)%3;
+			if (++j == 3) j = 0;
 			if (branch & 1<<j)
 				v[j] += s;
 			else
@@ -213,9 +230,9 @@ double  p[3];
 			fc += fval[branch | 1<<i];
 			fc = 0.5*fc + s*EPSILON*frand3(v[0],v[1],v[2]);
 			fval[branch^1<<i] = fc;
-			j = (i+1)%3;
+			if ((j = i+1) == 3) j = 0;
 			v[j] = beg[j] + s;
-			j = (i+2)%3;
+			if (++j == 3) j = 0;
 			v[j] = beg[j] + s;
 		}
 		for (i = 0; i < 3; i++)		/* new cube */