src/rt/noise3.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#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  <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(), argument(), 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()                     /* 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:	2.7
Committed:	Tue Feb 25 02:47:22 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R5
Changes since 2.6:	+1 -56 lines
Log Message:	Replaced inline copyright notice with #include "copyright.h"
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.6	static const char RCSid[] = "$Id$";
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	2.2	#include <math.h>
14	greg	1.1
15			#define A 0
16			#define B 1
17			#define C 2
18			#define D 3
19
20			#define rand3a(x,y,z) frand(67(x)+59(y)+71*(z))
21			#define rand3b(x,y,z) frand(73(x)+79(y)+83*(z))
22			#define rand3c(x,y,z) frand(89(x)+97(y)+101*(z))
23			#define rand3d(x,y,z) frand(103(x)+107(y)+109*(z))
24
25	greg	1.7	#define hpoly1(t) ((2.0t-3.0)t*t+1.0)
26			#define hpoly2(t) (-2.0t+3.0)t*t
27			#define hpoly3(t) ((t-2.0)t+1.0)t
28			#define hpoly4(t) (t-1.0)tt
29	greg	1.1
30	greg	1.7	#define hermite(p0,p1,r0,r1,t) ( p0*hpoly1(t) + \
31			p1*hpoly2(t) + \
32			r0*hpoly3(t) + \
33			r1*hpoly4(t) )
34
35	greg	2.5	static char noise_name[4][8] = {"noise3x", "noise3y", "noise3z", "noise3"};
36	greg	1.5	static char fnoise_name[] = "fnoise3";
37			static char hermite_name[] = "hermite";
38	greg	1.1
39	greg	1.5	double *noise3(), fnoise3(), argument(), frand();
40	greg	2.3	static interpolate();
41	greg	1.5
42	greg	1.1	static long xlim[3][2];
43			static double xarg[3];
44
45	greg	2.4	#define EPSILON .001 /* error allowed in fractal */
46	greg	1.1
47	greg	1.3	#define frand3(x,y,z) frand(17(x)+23(y)+29*(z))
48	greg	1.1
49
50	greg	1.5	static double
51			l_noise3(nam) /* compute a noise function */
52			register char *nam;
53	greg	1.1	{
54	greg	1.5	register int i;
55			double x[3];
56			/* get point */
57			x[0] = argument(1);
58			x[1] = argument(2);
59			x[2] = argument(3);
60			/* make appropriate call */
61			if (nam == fnoise_name)
62			return(fnoise3(x));
63			i = 4;
64			while (i--)
65			if (nam == noise_name[i])
66			return(noise3(x)[i]);
67	greg	1.6	eputs(nam);
68			eputs(": called l_noise3!\n");
69	greg	1.5	quit(1);
70	greg	1.1	}
71
72
73			double
74	greg	1.5	l_hermite() /* library call for hermite interpolation */
75	greg	1.1	{
76	greg	1.5	double t;
77
78			t = argument(5);
79			return( hermite(argument(1), argument(2),
80			argument(3), argument(4), t) );
81	greg	1.1	}
82
83
84	greg	1.5	setnoisefuncs() /* add noise functions to library */
85	greg	1.1	{
86	greg	1.5	register int i;
87	greg	1.1
88	greg	1.5	funset(hermite_name, 5, ':', l_hermite);
89			funset(fnoise_name, 3, ':', l_noise3);
90			i = 4;
91			while (i--)
92			funset(noise_name[i], 3, ':', l_noise3);
93	greg	1.1	}
94
95
96			double *
97			noise3(xnew) /* compute the noise function */
98			register double xnew[3];
99			{
100			static double x[3] = {-100000.0, -100000.0, -100000.0};
101			static double f[4];
102
103			if (x[0]==xnew[0] && x[1]==xnew[1] && x[2]==xnew[2])
104			return(f);
105			x[0] = xnew[0]; x[1] = xnew[1]; x[2] = xnew[2];
106			xlim[0][0] = floor(x[0]); xlim[0][1] = xlim[0][0] + 1;
107			xlim[1][0] = floor(x[1]); xlim[1][1] = xlim[1][0] + 1;
108			xlim[2][0] = floor(x[2]); xlim[2][1] = xlim[2][0] + 1;
109			xarg[0] = x[0] - xlim[0][0];
110			xarg[1] = x[1] - xlim[1][0];
111			xarg[2] = x[2] - xlim[2][0];
112			interpolate(f, 0, 3);
113			return(f);
114			}
115
116
117			static
118			interpolate(f, i, n)
119			double f[4];
120			register int i, n;
121			{
122	greg	1.7	double f0[4], f1[4], hp1, hp2;
123	greg	1.1
124			if (n == 0) {
125			f[A] = rand3a(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
126			f[B] = rand3b(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
127			f[C] = rand3c(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
128			f[D] = rand3d(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]);
129			} else {
130			n--;
131			interpolate(f0, i, n);
132			interpolate(f1, i \| 1<<n, n);
133	greg	1.7	hp1 = hpoly1(xarg[n]); hp2 = hpoly2(xarg[n]);
134			f[A] = f0[A]hp1 + f1[A]hp2;
135			f[B] = f0[B]hp1 + f1[B]hp2;
136			f[C] = f0[C]hp1 + f1[C]hp2;
137			f[D] = f0[D]hp1 + f1[D]hp2 +
138			f0[n]hpoly3(xarg[n]) + f1[n]hpoly4(xarg[n]);
139	greg	1.1	}
140			}
141
142
143			double
144			frand(s) /* get random number from seed */
145			register long s;
146			{
147			s = s<<13 ^ s;
148			return(1.0-((s(ss*15731+789221)+1376312589)&0x7fffffff)/1073741824.0);
149			}
150
151
152			double
153			fnoise3(p) /* compute fractal noise function */
154	greg	1.3	double p[3];
155	greg	1.1	{
156	greg	1.4	long t[3], v[3], beg[3];
157	greg	1.3	double fval[8], fc;
158			int branch;
159	greg	1.4	register long s;
160	greg	1.1	register int i, j;
161			/* get starting cube */
162	greg	1.3	s = (long)(1.0/EPSILON);
163			for (i = 0; i < 3; i++) {
164			t[i] = s*p[i];
165			beg[i] = s*floor(p[i]);
166			}
167	greg	1.1	for (j = 0; j < 8; j++) {
168			for (i = 0; i < 3; i++) {
169			v[i] = beg[i];
170			if (j & 1<<i)
171	greg	1.3	v[i] += s;
172	greg	1.1	}
173			fval[j] = frand3(v[0],v[1],v[2]);
174			}
175			/* compute fractal */
176			for ( ; ; ) {
177	greg	1.4	fc = 0.0;
178			for (j = 0; j < 8; j++)
179			fc += fval[j];
180			fc *= 0.125;
181			if ((s >>= 1) == 0)
182			return(fc); /* close enough */
183	greg	1.1	branch = 0;
184			for (i = 0; i < 3; i++) { /* do center */
185			v[i] = beg[i] + s;
186	greg	1.3	if (t[i] > v[i]) {
187	greg	1.1	branch \|= 1<<i;
188	greg	1.3	}
189	greg	1.1	}
190	greg	1.3	fc += sEPSILONfrand3(v[0],v[1],v[2]);
191	greg	1.1	fval[~branch & 7] = fc;
192			for (i = 0; i < 3; i++) { /* do faces */
193			if (branch & 1<<i)
194			v[i] += s;
195			else
196			v[i] -= s;
197			fc = 0.0;
198			for (j = 0; j < 8; j++)
199			if (~(j^branch) & 1<<i)
200			fc += fval[j];
201	greg	1.3	fc = 0.25fc + sEPSILON*frand3(v[0],v[1],v[2]);
202	greg	1.1	fval[~(branch^1<<i) & 7] = fc;
203			v[i] = beg[i] + s;
204			}
205			for (i = 0; i < 3; i++) { /* do edges */
206			j = (i+1)%3;
207			if (branch & 1<<j)
208			v[j] += s;
209			else
210			v[j] -= s;
211			j = (i+2)%3;
212			if (branch & 1<<j)
213			v[j] += s;
214			else
215			v[j] -= s;
216			fc = fval[branch & ~(1<<i)];
217			fc += fval[branch \| 1<<i];
218	greg	1.3	fc = 0.5fc + sEPSILON*frand3(v[0],v[1],v[2]);
219	greg	1.1	fval[branch^1<<i] = fc;
220			j = (i+1)%3;
221			v[j] = beg[j] + s;
222			j = (i+2)%3;
223			v[j] = beg[j] + s;
224			}
225			for (i = 0; i < 3; i++) /* new cube */
226			if (branch & 1<<i)
227			beg[i] += s;
228			}
229			}