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/* Copyright (c) 1988 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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static const char RCSid[] = "$Id$"; |
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#endif |
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/* |
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* noise3.c - noise functions for random textures. |
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* Credit for the smooth algorithm goes to Ken Perlin. |
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* (ref. SIGGRAPH Vol 19, No 3, pp 287-96) |
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* |
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* 4/15/86 |
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* 5/19/88 Added fractal noise function |
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*/ |
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#include <math.h> |
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#include "copyright.h" |
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#include "ray.h" |
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#include "func.h" |
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#define A 0 |
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#define B 1 |
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#define C 2 |
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r0*hpoly3(t) + \ |
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r1*hpoly4(t) ) |
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static char noise_name[4][8] = {"noise3a", "noise3b", "noise3c", "noise3"}; |
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static char noise_name[4][8] = {"noise3x", "noise3y", "noise3z", "noise3"}; |
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static char fnoise_name[] = "fnoise3"; |
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static char hermite_name[] = "hermite"; |
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double *noise3(), fnoise3(), argument(), frand(); |
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static interpolate(); |
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static long xlim[3][2]; |
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static double xarg[3]; |
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#define EPSILON .0001 /* error allowed in fractal */ |
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#define EPSILON .001 /* error allowed in fractal */ |
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#define frand3(x,y,z) frand(17*(x)+23*(y)+29*(z)) |
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static double l_noise3(char *nam); |
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static double l_hermite(char *nm); |
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static double * noise3(double xnew[3]); |
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static void interpolate(double f[4], int i, int n); |
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static double frand(long s); |
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static double fnoise3(double p[3]); |
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static double |
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l_noise3(nam) /* compute a noise function */ |
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register char *nam; |
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l_noise3( /* compute a noise function */ |
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register char *nam |
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) |
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{ |
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register int i; |
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double x[3]; |
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eputs(nam); |
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eputs(": called l_noise3!\n"); |
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quit(1); |
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return 1; /* pro forma return */ |
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} |
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double |
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l_hermite() /* library call for hermite interpolation */ |
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static double |
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l_hermite(char *nm) /* library call for hermite interpolation */ |
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{ |
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double t; |
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} |
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setnoisefuncs() /* add noise functions to library */ |
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extern void |
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setnoisefuncs(void) /* add noise functions to library */ |
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{ |
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register int i; |
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} |
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double * |
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noise3(xnew) /* compute the noise function */ |
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register double xnew[3]; |
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static double * |
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noise3( /* compute the noise function */ |
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register double xnew[3] |
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) |
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{ |
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static double x[3] = {-100000.0, -100000.0, -100000.0}; |
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static double f[4]; |
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} |
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static |
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interpolate(f, i, n) |
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double f[4]; |
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register int i, n; |
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static void |
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interpolate( |
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double f[4], |
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register int i, |
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register int n |
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) |
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{ |
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double f0[4], f1[4], hp1, hp2; |
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} |
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double |
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frand(s) /* get random number from seed */ |
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register long s; |
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static double |
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frand( /* get random number from seed */ |
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register long s |
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) |
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{ |
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s = s<<13 ^ s; |
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return(1.0-((s*(s*s*15731+789221)+1376312589)&0x7fffffff)/1073741824.0); |
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} |
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double |
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fnoise3(p) /* compute fractal noise function */ |
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double p[3]; |
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static double |
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fnoise3( /* compute fractal noise function */ |
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double p[3] |
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) |
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{ |
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long t[3], v[3], beg[3]; |
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double fval[8], fc; |
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v[i] = beg[i] + s; |
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} |
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for (i = 0; i < 3; i++) { /* do edges */ |
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j = (i+1)%3; |
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if ((j = i+1) == 3) j = 0; |
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if (branch & 1<<j) |
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v[j] += s; |
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else |
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v[j] -= s; |
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j = (i+2)%3; |
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if (++j == 3) j = 0; |
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if (branch & 1<<j) |
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v[j] += s; |
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else |
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fc += fval[branch | 1<<i]; |
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fc = 0.5*fc + s*EPSILON*frand3(v[0],v[1],v[2]); |
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fval[branch^1<<i] = fc; |
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j = (i+1)%3; |
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if ((j = i+1) == 3) j = 0; |
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v[j] = beg[j] + s; |
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j = (i+2)%3; |
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if (++j == 3) j = 0; |
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v[j] = beg[j] + s; |
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} |
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for (i = 0; i < 3; i++) /* new cube */ |