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root/Development/ray/src/rt/noise3.c

Comparing ray/src/rt/noise3.c (file contents):
Revision 1.3 by greg, Tue Oct 30 21:03:49 1990 UTC vs.
Revision 1.6 by greg, Fri Aug 2 13:57:09 1991 UTC

#	Line 30 | Line 30 | static char SCCSid[] = "$SunId$ LBL";
30		r0*((t-2.0)*t+1.0)*t + \
31		r1*(t-1.0)*t*t )
32
33	<	double  *noise3(), noise3coef(), argument(), frand();
33	>	static char  noise_name[4][8] = {"noise3a", "noise3b", "noise3c", "noise3"};
34	>	static char  fnoise_name[] = "fnoise3";
35	>	static char  hermite_name[] = "hermite";
36
37	+	double  *noise3(), fnoise3(), argument(), frand();
38	+
39		static long  xlim[3][2];
40		static double  xarg[3];
41
#	Line 39 | Line 43 | static double  xarg[3];
43
44		#define  frand3(x,y,z)  frand(17*(x)+23*(y)+29*(z))
45
42	–	double  fnoise3();
46
47	<
48	<	double
49	<	l_noise3()                      /* compute 3-dimensional noise function */
47	>	static double
48	>	l_noise3(nam)                   /* compute a noise function */
49	>	register char  *nam;
50		{
51	<	return(noise3coef(D));
51	>	register int  i;
52	>	double  x[3];
53	>	/* get point */
54	>	x[0] = argument(1);
55	>	x[1] = argument(2);
56	>	x[2] = argument(3);
57	>	/* make appropriate call */
58	>	if (nam == fnoise_name)
59	>	return(fnoise3(x));
60	>	i = 4;
61	>	while (i--)
62	>	if (nam == noise_name[i])
63	>	return(noise3(x)[i]);
64	>	eputs(nam);
65	>	eputs(": called l_noise3!\n");
66	>	quit(1);
67		}
68
69
70		double
71	<	l_noise3a()                     /* compute x slope of noise function */
71	>	l_hermite()                     /* library call for hermite interpolation */
72		{
73	<	return(noise3coef(A));
73	>	double  t;
74	>
75	>	t = argument(5);
76	>	return( hermite(argument(1), argument(2),
77	>	argument(3), argument(4), t) );
78		}
79
80
81	<	double
60	<	l_noise3b()                     /* compute y slope of noise function */
81	>	setnoisefuncs()                 /* add noise functions to library */
82		{
83	<	return(noise3coef(B));
63	<	}
83	>	register int  i;
84
85	<
86	<	double
87	<	l_noise3c()                     /* compute z slope of noise function */
88	<	{
89	<	return(noise3coef(C));
85	>	funset(hermite_name, 5, ':', l_hermite);
86	>	funset(fnoise_name, 3, ':', l_noise3);
87	>	i = 4;
88	>	while (i--)
89	>	funset(noise_name[i], 3, ':', l_noise3);
90		}
91
92
73	–	double
74	–	l_fnoise3()                     /* compute fractal noise function */
75	–	{
76	–	double  x[3];
77	–
78	–	x[0] = argument(1);
79	–	x[1] = argument(2);
80	–	x[2] = argument(3);
81	–
82	–	return(fnoise3(x));
83	–	}
84	–
85	–
86	–	static double
87	–	noise3coef(coef)                /* return coefficient of noise function */
88	–	int  coef;
89	–	{
90	–	double  x[3];
91	–
92	–	x[0] = argument(1);
93	–	x[1] = argument(2);
94	–	x[2] = argument(3);
95	–
96	–	return(noise3(x)[coef]);
97	–	}
98	–
99	–
93		double *
94		noise3(xnew)                    /* compute the noise function */
95		register double  xnew[3];
#	Line 153 | Line 146 | register long  s;
146
147
148		double
156	–	l_hermite()                     /* library call for hermite interpolation */
157	–	{
158	–	double  t;
159	–
160	–	t = argument(5);
161	–	return( hermite(argument(1), argument(2),
162	–	argument(3), argument(4), t) );
163	–	}
164	–
165	–
166	–	double
149		fnoise3(p)                      /* compute fractal noise function */
150		double  p[3];
151		{
152		double  floor();
153	<	long  t[3], v[3], beg[3], s;
153	>	long  t[3], v[3], beg[3];
154		double  fval[8], fc;
155		int  branch;
156	+	register long  s;
157		register int  i, j;
158		/* get starting cube */
159		s = (long)(1.0/EPSILON);
#	Line 188 | Line 171 | double  p[3];
171		}
172		/* compute fractal */
173		for ( ; ; ) {
174	<	s >>= 1;
174	>	fc = 0.0;
175	>	for (j = 0; j < 8; j++)
176	>	fc += fval[j];
177	>	fc *= 0.125;
178	>	if ((s >>= 1) == 0)
179	>	return(fc);             /* close enough */
180		branch = 0;
181		for (i = 0; i < 3; i++) {       /* do center */
182		v[i] = beg[i] + s;
#	Line 196 | Line 184 | double  p[3];
184		branch |= 1<<i;
185		}
186		}
199	–	fc = 0.0;
200	–	for (j = 0; j < 8; j++)
201	–	fc += fval[j];
202	–	fc *= 0.125;
203	–	if (s < 1)
204	–	return(fc);             /* close enough */
187		fc += s*EPSILON*frand3(v[0],v[1],v[2]);
188		fval[~branch & 7] = fc;
189		for (i = 0; i < 3; i++) {       /* do faces */

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