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root/radiance/ray/src/gen/genrev.c
Revision: 1.4
Committed: Fri Mar 2 17:24:07 1990 UTC (34 years, 1 month ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.3: +15 -1 lines
Log Message:
Added Bezier cubic function

File Contents

# User Rev Content
1 greg 1.2 /* Copyright (c) 1989 Regents of the University of California */
2 greg 1.1
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6 greg 1.2
7     /*
8 greg 1.1 * genrev.c - program to generate functions of rotation about z
9     *
10     * The program takes as input the functions of t for z and r
11     * (the radius). If z is increasing, the normal points
12     * outward, inward for decreasing z. Negative radii are forbidden.
13     *
14     * 8/6/86
15     */
16    
17     #include <stdio.h>
18    
19     #define ZNAME "Z_" /* z function name */
20     #define RNAME "R_" /* r function name */
21    
22     #define PI 3.14159265358979323846
23    
24     #define FTINY 1e-9
25     /* orientation */
26     #define OUT 01
27     #define IN 02
28     #define UP 04
29     #define DOWN 010
30    
31 greg 1.4 double funvalue(), l_hermite(), l_bezier(), argument();
32 greg 1.1
33    
34     main(argc, argv)
35     int argc;
36     char *argv[];
37     {
38     char stmp[256];
39     char *modname;
40     int smooth = 0;
41     double t, lastz, z, nextz, lastr, r, nextr;
42     double lastnz, lastnr, nz, nr, nextnz, nextnr;
43     int i, nseg;
44     int orient;
45    
46     varset("PI", PI);
47     funset("hermite", 5, l_hermite);
48 greg 1.4 funset("bezier", 5, l_bezier);
49 greg 1.1
50     if (argc < 6)
51     goto userror;
52    
53     for (i = 6; i < argc; i++)
54     if (!strcmp(argv[i], "-e"))
55     scompile(NULL, argv[++i]);
56     else if (!strcmp(argv[i], "-f"))
57     fcompile(argv[++i]);
58     else if (!strcmp(argv[i], "-s"))
59     smooth = 1;
60     else
61     goto userror;
62    
63     sprintf(stmp, "%s(t)=%s;", ZNAME, argv[3]);
64     scompile(NULL, stmp);
65     sprintf(stmp, "%s(t)=%s;", RNAME, argv[4]);
66     scompile(NULL, stmp);
67     nseg = atoi(argv[5]);
68     if (nseg <= 0)
69     goto userror;
70 greg 1.3 modname = smooth ? "Phong" : argv[1];
71 greg 1.1
72     printhead(argc, argv);
73    
74     lastnz = lastnr = 0.0;
75     t = 0.0;
76     lastz = funvalue(ZNAME, 1, &t);
77     lastr = funvalue(RNAME, 1, &t);
78     t = 1.0/nseg;
79     z = funvalue(ZNAME, 1, &t);
80     r = funvalue(RNAME, 1, &t);
81     computen(&nz, &nr, lastz, lastr, z, r);
82     for (i = 1; i <= nseg; i++) {
83     if (i < nseg) {
84     t = (double)(i+1)/nseg;
85     nextz = funvalue(ZNAME, 1, &t);
86     nextr = funvalue(RNAME, 1, &t);
87     computen(&nextnz, &nextnr, z, r, nextz, nextr);
88     } else
89     nextnz = nextnr = 0.0;
90     orient = 0;
91     if (z < lastz-FTINY)
92     orient |= DOWN;
93     else if (z > lastz+FTINY)
94     orient |= UP;
95     if (r < lastr-FTINY)
96     orient |= IN;
97     else if (r > lastr+FTINY)
98     orient |= OUT;
99     if (!orient)
100     goto endfor;
101     if (smooth) {
102 greg 1.3 printf("\n%s texfunc Phong\n", argv[1]);
103 greg 1.1 printf("4 rev_dx rev_dy rev_dz rev.cal\n");
104     printf("0\n4\n");
105     if (orient&(UP|DOWN)) {
106     t = (nextnz - lastnz)/(z - lastz);
107     printf("\t%15.9g\t%15.9g\n",
108     t, lastnz - t*lastz);
109     } else
110     printf("\t0\t%d\n", orient&IN ? 1 : -1);
111     if (orient&(OUT|IN)) {
112     t = (nextnr - lastnr)/(r - lastr);
113     printf("\t%15.9g\t%15.9g\n",
114     t, lastnr - t*lastr);
115     } else
116     printf("\t0\t%d\n", orient&UP ? 1 : -1);
117     }
118     if (!(orient&(IN|OUT))) {
119     printf("\n%s %s %s.%d\n", modname,
120     orient&DOWN ? "tube" : "cylinder",
121     argv[2], i);
122     printf("0\n0\n7\n");
123     printf("\t0\t0\t%15.9g\n", lastz);
124     printf("\t0\t0\t%15.9g\n", z);
125     printf("\t%15.9g\n", r);
126     } else if (!(orient&(UP|DOWN))) {
127     printf("\n%s ring %s.%d\n", modname, argv[2], i);
128     printf("0\n0\n8\n");
129     printf("\t0\t0\t%15.9g\n", z);
130     printf("\t0\t0\t%15.9g\n", orient&IN ? 1.0 : -1.0);
131     printf("\t%15.9g\t%15.9g\n", lastr, r);
132     } else {
133     printf("\n%s %s %s.%d\n", modname,
134     orient&DOWN ? "cup" : "cone",
135     argv[2], i);
136     printf("0\n0\n8\n");
137     printf("\t0\t0\t%15.9g\n", lastz);
138     printf("\t0\t0\t%15.9g\n", z);
139     printf("\t%15.9g\t%15.9g\n", lastr, r);
140     }
141     endfor:
142     lastz = z; lastr = r;
143     z = nextz; r = nextr;
144     lastnz = nz; lastnr = nr;
145     nz = nextnz; nr = nextnr;
146     }
147     quit(0);
148    
149     userror:
150     fprintf(stderr,
151     "Usage: %s material name z(t) r(t) nseg [-e expr] [-f file] [-s]\n",
152     argv[0]);
153     quit(1);
154     }
155    
156    
157     computen(nzp, nrp, z0, r0, z1, r1) /* compute normal */
158     double *nzp, *nrp, z0, r0, z1, r1;
159     {
160     extern double sqrt();
161     double dr, dz, len;
162    
163     dz = r0 - r1; /* right angle vector */
164     dr = z1 - z0;
165     len = sqrt(dr*dr + dz*dz);
166     *nzp = dz/len;
167     *nrp = dr/len;
168     }
169    
170    
171     eputs(msg)
172     char *msg;
173     {
174     fputs(msg, stderr);
175     }
176    
177    
178     wputs(msg)
179     char *msg;
180     {
181     eputs(msg);
182     }
183    
184    
185     quit(code)
186     {
187     exit(code);
188     }
189    
190    
191     printhead(ac, av) /* print command header */
192     register int ac;
193     register char **av;
194     {
195     putchar('#');
196     while (ac--) {
197     putchar(' ');
198     fputs(*av++, stdout);
199     }
200     putchar('\n');
201     }
202    
203    
204     double
205     l_hermite()
206     {
207     double t;
208    
209     t = argument(5);
210     return( argument(1)*((2.0*t-3.0)*t*t+1.0) +
211     argument(2)*(-2.0*t+3.0)*t*t +
212     argument(3)*((t-2.0)*t+1.0)*t +
213     argument(4)*(t-1.0)*t*t );
214 greg 1.4 }
215    
216    
217     double
218     l_bezier()
219     {
220     double t;
221    
222     t = argument(5);
223     return( argument(1) * (1.+t*(-3.+t*(3.-t))) +
224     argument(2) * 3.*t*(1.+t*(-2.+t)) +
225     argument(3) * 3.*t*t*(1.-t) +
226     argument(4) * t*t*t );
227 greg 1.1 }