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root/radiance/ray/src/rt/noise3.c
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Comparing ray/src/rt/noise3.c (file contents):
Revision 2.5 by greg, Thu Oct 31 10:58:36 1996 UTC vs.
Revision 2.11 by greg, Fri Sep 3 21:16:50 2010 UTC

# Line 1 | Line 1
1 /* Copyright (c) 1988 Regents of the University of California */
2
1   #ifndef lint
2 < static char SCCSid[] = "$SunId$ LBL";
2 > static const char       RCSid[] = "$Id$";
3   #endif
6
4   /*
5   *  noise3.c - noise functions for random textures.
6   *
7   *     Credit for the smooth algorithm goes to Ken Perlin.
8   *     (ref. SIGGRAPH Vol 19, No 3, pp 287-96)
12 *
13 *     4/15/86
14 *     5/19/88  Added fractal noise function
9   */
10  
11 + #include "copyright.h"
12 +
13   #include  <math.h>
14  
15 + #include  "calcomp.h"
16 + #include  "func.h"
17 +
18   #define  A              0
19   #define  B              1
20   #define  C              2
# Line 40 | Line 39 | static char  noise_name[4][8] = {"noise3x", "noise3y",
39   static char  fnoise_name[] = "fnoise3";
40   static char  hermite_name[] = "hermite";
41  
43 double  *noise3(), fnoise3(), argument(), frand();
44 static  interpolate();
45
42   static long  xlim[3][2];
43   static double  xarg[3];
44  
# Line 50 | Line 46 | static double  xarg[3];
46  
47   #define  frand3(x,y,z)  frand(17*(x)+23*(y)+29*(z))
48  
49 + static double l_noise3(char  *nam);
50 + static double l_hermite(char *nm);
51 + static double * noise3(double  xnew[3]);
52 + static void interpolate(double  f[4], int  i, int  n);
53 + static double frand(long  s);
54 + static double fnoise3(double  p[3]);
55  
56 +
57   static double
58 < l_noise3(nam)                   /* compute a noise function */
59 < register char  *nam;
58 > l_noise3(                       /* compute a noise function */
59 >        register char  *nam
60 > )
61   {
62          register int  i;
63          double  x[3];
# Line 71 | Line 75 | register char  *nam;
75          eputs(nam);
76          eputs(": called l_noise3!\n");
77          quit(1);
78 +        return 1; /* pro forma return */
79   }
80  
81  
82 < double
83 < l_hermite()                     /* library call for hermite interpolation */
82 > static double
83 > l_hermite(char *nm)             /* library call for hermite interpolation */
84   {
85          double  t;
86          
# Line 85 | Line 90 | l_hermite()                    /* library call for hermite interpolatio
90   }
91  
92  
93 < setnoisefuncs()                 /* add noise functions to library */
93 > extern void
94 > setnoisefuncs(void)                     /* add noise functions to library */
95   {
96          register int  i;
97  
# Line 97 | Line 103 | setnoisefuncs()                        /* add noise functions to library */
103   }
104  
105  
106 < double *
107 < noise3(xnew)                    /* compute the noise function */
108 < register double  xnew[3];
106 > static double *
107 > noise3(                 /* compute the noise function */
108 >        register double  xnew[3]
109 > )
110   {
111          static double  x[3] = {-100000.0, -100000.0, -100000.0};
112          static double  f[4];
# Line 118 | Line 125 | register double  xnew[3];
125   }
126  
127  
128 < static
129 < interpolate(f, i, n)
130 < double  f[4];
131 < register int  i, n;
128 > static void
129 > interpolate(
130 >        double  f[4],
131 >        register int  i,
132 >        register int  n
133 > )
134   {
135          double  f0[4], f1[4], hp1, hp2;
136  
# Line 144 | Line 153 | register int  i, n;
153   }
154  
155  
156 < double
157 < frand(s)                        /* get random number from seed */
158 < register long  s;
156 > static double
157 > frand(                  /* get random number from seed */
158 >        register long  s
159 > )
160   {
161          s = s<<13 ^ s;
162          return(1.0-((s*(s*s*15731+789221)+1376312589)&0x7fffffff)/1073741824.0);
163   }
164  
165  
166 < double
167 < fnoise3(p)                      /* compute fractal noise function */
168 < double  p[3];
166 > static double
167 > fnoise3(                        /* compute fractal noise function */
168 >        double  p[3]
169 > )
170   {
171          long  t[3], v[3], beg[3];
172          double  fval[8], fc;
# Line 207 | Line 218 | double  p[3];
218                          v[i] = beg[i] + s;
219                  }
220                  for (i = 0; i < 3; i++) {       /* do edges */
221 <                        j = (i+1)%3;
221 >                        if ((j = i+1) == 3) j = 0;
222                          if (branch & 1<<j)
223                                  v[j] += s;
224                          else
225                                  v[j] -= s;
226 <                        j = (i+2)%3;
226 >                        if (++j == 3) j = 0;
227                          if (branch & 1<<j)
228                                  v[j] += s;
229                          else
# Line 221 | Line 232 | double  p[3];
232                          fc += fval[branch | 1<<i];
233                          fc = 0.5*fc + s*EPSILON*frand3(v[0],v[1],v[2]);
234                          fval[branch^1<<i] = fc;
235 <                        j = (i+1)%3;
235 >                        if ((j = i+1) == 3) j = 0;
236                          v[j] = beg[j] + s;
237 <                        j = (i+2)%3;
237 >                        if (++j == 3) j = 0;
238                          v[j] = beg[j] + s;
239                  }
240                  for (i = 0; i < 3; i++)         /* new cube */

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