src/rt/noise3.c

#ifndef lint
static const char       RCSid[] = "$Id: noise3.c,v 2.7 2003/02/25 02:47:22 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)
 */

#include "copyright.h"

#include  "calcomp.h"

#include  <math.h>

#define  A              0
#define  B              1
#define  C              2
#define  D              3

#define  rand3a(x,y,z)  frand(67*(x)+59*(y)+71*(z))
#define  rand3b(x,y,z)  frand(73*(x)+79*(y)+83*(z))
#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  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

#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(), frand();
static  interpolate();

static long  xlim[3][2];
static double  xarg[3];

#define  EPSILON        .001            /* error allowed in fractal */

#define  frand3(x,y,z)  frand(17*(x)+23*(y)+29*(z))


static double
l_noise3(nam)                   /* compute a noise function */
register char  *nam;
{
        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_hermite(char *nm)             /* library call for hermite interpolation */
{
        double  t;
        
        t = argument(5);
        return( hermite(argument(1), argument(2),
                        argument(3), argument(4), t) );
}


setnoisefuncs()                 /* add noise functions to library */
{
        register int  i;

        funset(hermite_name, 5, ':', l_hermite);
        funset(fnoise_name, 3, ':', l_noise3);
        i = 4;
        while (i--)
                funset(noise_name[i], 3, ':', l_noise3);
}


double *
noise3(xnew)                    /* compute the noise function */
register double  xnew[3];
{
        static double  x[3] = {-100000.0, -100000.0, -100000.0};
        static double  f[4];

        if (x[0]==xnew[0] && x[1]==xnew[1] && x[2]==xnew[2])
                return(f);
        x[0] = xnew[0]; x[1] = xnew[1]; x[2] = xnew[2];
        xlim[0][0] = floor(x[0]); xlim[0][1] = xlim[0][0] + 1;
        xlim[1][0] = floor(x[1]); xlim[1][1] = xlim[1][0] + 1;
        xlim[2][0] = floor(x[2]); xlim[2][1] = xlim[2][0] + 1;
        xarg[0] = x[0] - xlim[0][0];
        xarg[1] = x[1] - xlim[1][0];
        xarg[2] = x[2] - xlim[2][0];
        interpolate(f, 0, 3);
        return(f);
}


static
interpolate(f, i, n)
double  f[4];
register int  i, n;
{
        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]);
                f[B] = rand3b(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
                f[C] = rand3c(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
                f[D] = rand3d(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
        } else {
                n--;
                interpolate(f0, i, n);
                interpolate(f1, i | 1<<n, 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;
{
        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];
{
        long  t[3], v[3], beg[3];
        double  fval[8], fc;
        int  branch;
        register long  s;
        register int  i, j;
                                                /* get starting cube */
        s = (long)(1.0/EPSILON);
        for (i = 0; i < 3; i++) {
                t[i] = s*p[i];
                beg[i] = s*floor(p[i]);
        }
        for (j = 0; j < 8; j++) {
                for (i = 0; i < 3; i++) {
                        v[i] = beg[i];
                        if (j & 1<<i)
                                v[i] += s;
                }
                fval[j] = frand3(v[0],v[1],v[2]);
        }
                                                /* compute fractal */
        for ( ; ; ) {
                fc = 0.0;
                for (j = 0; j < 8; j++)
                        fc += fval[j];
                fc *= 0.125;
                if ((s >>= 1) == 0)
                        return(fc);             /* close enough */
                branch = 0;
                for (i = 0; i < 3; i++) {       /* do center */
                        v[i] = beg[i] + s;
                        if (t[i] > v[i]) {
                                branch |= 1<<i;
                        }
                }
                fc += s*EPSILON*frand3(v[0],v[1],v[2]);
                fval[~branch & 7] = fc;
                for (i = 0; i < 3; i++) {       /* do faces */
                        if (branch & 1<<i)
                                v[i] += s;
                        else
                                v[i] -= s;
                        fc = 0.0;
                        for (j = 0; j < 8; j++)
                                if (~(j^branch) & 1<<i)
                                        fc += fval[j];
                        fc = 0.25*fc + s*EPSILON*frand3(v[0],v[1],v[2]);
                        fval[~(branch^1<<i) & 7] = fc;
                        v[i] = beg[i] + s;
                }
                for (i = 0; i < 3; i++) {       /* do edges */
                        j = (i+1)%3;
                        if (branch & 1<<j)
                                v[j] += s;
                        else
                                v[j] -= s;
                        j = (i+2)%3;
                        if (branch & 1<<j)
                                v[j] += s;
                        else
                                v[j] -= s;
                        fc = fval[branch & ~(1<<i)];
                        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;
                        v[j] = beg[j] + s;
                        j = (i+2)%3;
                        v[j] = beg[j] + s;
                }
                for (i = 0; i < 3; i++)         /* new cube */
                        if (branch & 1<<i)
                                beg[i] += s;
        }
}
Revision:	2.8
Committed:	Mon Aug 4 22:37:53 2003 UTC (20 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.7:	+5 -3 lines
Log Message:	Added prototype for LIBR function pointer in calcomp.h
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.8	static const char RCSid[] = "$Id: noise3.c,v 2.7 2003/02/25 02:47:22 greg Exp $";
3	greg	1.1	#endif
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)
9	greg	2.6	*/
10
11	greg	2.7	#include "copyright.h"
12	greg	1.1
13	greg	2.8	#include "calcomp.h"
14
15	greg	2.2	#include <math.h>
16	greg	1.1
17			#define A 0
18			#define B 1
19			#define C 2
20			#define D 3
21
22			#define rand3a(x,y,z) frand(67(x)+59(y)+71*(z))
23			#define rand3b(x,y,z) frand(73(x)+79(y)+83*(z))
24			#define rand3c(x,y,z) frand(89(x)+97(y)+101*(z))
25			#define rand3d(x,y,z) frand(103(x)+107(y)+109*(z))
26
27	greg	1.7	#define hpoly1(t) ((2.0t-3.0)t*t+1.0)
28			#define hpoly2(t) (-2.0t+3.0)t*t
29			#define hpoly3(t) ((t-2.0)t+1.0)t
30			#define hpoly4(t) (t-1.0)tt
31	greg	1.1
32	greg	1.7	#define hermite(p0,p1,r0,r1,t) ( p0*hpoly1(t) + \
33			p1*hpoly2(t) + \
34			r0*hpoly3(t) + \
35			r1*hpoly4(t) )
36
37	greg	2.5	static char noise_name[4][8] = {"noise3x", "noise3y", "noise3z", "noise3"};
38	greg	1.5	static char fnoise_name[] = "fnoise3";
39			static char hermite_name[] = "hermite";
40	greg	1.1
41	greg	2.8	double *noise3(), fnoise3(), frand();
42	greg	2.3	static interpolate();
43	greg	1.5
44	greg	1.1	static long xlim[3][2];
45			static double xarg[3];
46
47	greg	2.4	#define EPSILON .001 /* error allowed in fractal */
48	greg	1.1
49	greg	1.3	#define frand3(x,y,z) frand(17(x)+23(y)+29*(z))
50	greg	1.1
51
52	greg	1.5	static double
53			l_noise3(nam) /* compute a noise function */
54			register char *nam;
55	greg	1.1	{
56	greg	1.5	register int i;
57			double x[3];
58			/* get point */
59			x[0] = argument(1);
60			x[1] = argument(2);
61			x[2] = argument(3);
62			/* make appropriate call */
63			if (nam == fnoise_name)
64			return(fnoise3(x));
65			i = 4;
66			while (i--)
67			if (nam == noise_name[i])
68			return(noise3(x)[i]);
69	greg	1.6	eputs(nam);
70			eputs(": called l_noise3!\n");
71	greg	1.5	quit(1);
72	greg	1.1	}
73
74
75			double
76	greg	2.8	l_hermite(char nm) / library call for hermite interpolation */
77	greg	1.1	{
78	greg	1.5	double t;
79
80			t = argument(5);
81			return( hermite(argument(1), argument(2),
82			argument(3), argument(4), t) );
83	greg	1.1	}
84
85
86	greg	1.5	setnoisefuncs() /* add noise functions to library */
87	greg	1.1	{
88	greg	1.5	register int i;
89	greg	1.1
90	greg	1.5	funset(hermite_name, 5, ':', l_hermite);
91			funset(fnoise_name, 3, ':', l_noise3);
92			i = 4;
93			while (i--)
94			funset(noise_name[i], 3, ':', l_noise3);
95	greg	1.1	}
96
97
98			double *
99			noise3(xnew) /* compute the noise function */
100			register double xnew[3];
101			{
102			static double x[3] = {-100000.0, -100000.0, -100000.0};
103			static double f[4];
104
105			if (x[0]==xnew[0] && x[1]==xnew[1] && x[2]==xnew[2])
106			return(f);
107			x[0] = xnew[0]; x[1] = xnew[1]; x[2] = xnew[2];
108			xlim[0][0] = floor(x[0]); xlim[0][1] = xlim[0][0] + 1;
109			xlim[1][0] = floor(x[1]); xlim[1][1] = xlim[1][0] + 1;
110			xlim[2][0] = floor(x[2]); xlim[2][1] = xlim[2][0] + 1;
111			xarg[0] = x[0] - xlim[0][0];
112			xarg[1] = x[1] - xlim[1][0];
113			xarg[2] = x[2] - xlim[2][0];
114			interpolate(f, 0, 3);
115			return(f);
116			}
117
118
119			static
120			interpolate(f, i, n)
121			double f[4];
122			register int i, n;
123			{
124	greg	1.7	double f0[4], f1[4], hp1, hp2;
125	greg	1.1
126			if (n == 0) {
127			f[A] = rand3a(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
128			f[B] = rand3b(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
129			f[C] = rand3c(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
130			f[D] = rand3d(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
131			} else {
132			n--;
133			interpolate(f0, i, n);
134			interpolate(f1, i \| 1<<n, n);
135	greg	1.7	hp1 = hpoly1(xarg[n]); hp2 = hpoly2(xarg[n]);
136			f[A] = f0[A]hp1 + f1[A]hp2;
137			f[B] = f0[B]hp1 + f1[B]hp2;
138			f[C] = f0[C]hp1 + f1[C]hp2;
139			f[D] = f0[D]hp1 + f1[D]hp2 +
140			f0[n]hpoly3(xarg[n]) + f1[n]hpoly4(xarg[n]);
141	greg	1.1	}
142			}
143
144
145			double
146			frand(s) /* get random number from seed */
147			register long s;
148			{
149			s = s<<13 ^ s;
150			return(1.0-((s(ss*15731+789221)+1376312589)&0x7fffffff)/1073741824.0);
151			}
152
153
154			double
155			fnoise3(p) /* compute fractal noise function */
156	greg	1.3	double p[3];
157	greg	1.1	{
158	greg	1.4	long t[3], v[3], beg[3];
159	greg	1.3	double fval[8], fc;
160			int branch;
161	greg	1.4	register long s;
162	greg	1.1	register int i, j;
163			/* get starting cube */
164	greg	1.3	s = (long)(1.0/EPSILON);
165			for (i = 0; i < 3; i++) {
166			t[i] = s*p[i];
167			beg[i] = s*floor(p[i]);
168			}
169	greg	1.1	for (j = 0; j < 8; j++) {
170			for (i = 0; i < 3; i++) {
171			v[i] = beg[i];
172			if (j & 1<<i)
173	greg	1.3	v[i] += s;
174	greg	1.1	}
175			fval[j] = frand3(v[0],v[1],v[2]);
176			}
177			/* compute fractal */
178			for ( ; ; ) {
179	greg	1.4	fc = 0.0;
180			for (j = 0; j < 8; j++)
181			fc += fval[j];
182			fc *= 0.125;
183			if ((s >>= 1) == 0)
184			return(fc); /* close enough */
185	greg	1.1	branch = 0;
186			for (i = 0; i < 3; i++) { /* do center */
187			v[i] = beg[i] + s;
188	greg	1.3	if (t[i] > v[i]) {
189	greg	1.1	branch \|= 1<<i;
190	greg	1.3	}
191	greg	1.1	}
192	greg	1.3	fc += sEPSILONfrand3(v[0],v[1],v[2]);
193	greg	1.1	fval[~branch & 7] = fc;
194			for (i = 0; i < 3; i++) { /* do faces */
195			if (branch & 1<<i)
196			v[i] += s;
197			else
198			v[i] -= s;
199			fc = 0.0;
200			for (j = 0; j < 8; j++)
201			if (~(j^branch) & 1<<i)
202			fc += fval[j];
203	greg	1.3	fc = 0.25fc + sEPSILON*frand3(v[0],v[1],v[2]);
204	greg	1.1	fval[~(branch^1<<i) & 7] = fc;
205			v[i] = beg[i] + s;
206			}
207			for (i = 0; i < 3; i++) { /* do edges */
208			j = (i+1)%3;
209			if (branch & 1<<j)
210			v[j] += s;
211			else
212			v[j] -= s;
213			j = (i+2)%3;
214			if (branch & 1<<j)
215			v[j] += s;
216			else
217			v[j] -= s;
218			fc = fval[branch & ~(1<<i)];
219			fc += fval[branch \| 1<<i];
220	greg	1.3	fc = 0.5fc + sEPSILON*frand3(v[0],v[1],v[2]);
221	greg	1.1	fval[branch^1<<i] = fc;
222			j = (i+1)%3;
223			v[j] = beg[j] + s;
224			j = (i+2)%3;
225			v[j] = beg[j] + s;
226			}
227			for (i = 0; i < 3; i++) /* new cube */
228			if (branch & 1<<i)
229			beg[i] += s;
230			}
231			}