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root/radiance/ray/src/rt/data.c
Revision: 1.6
Committed: Fri Apr 6 14:12:21 1990 UTC (34 years ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.5: +25 -21 lines
Log Message:
Changed format for uneven point data and used binary search

File Contents

# User Rev Content
1 greg 1.1 /* Copyright (c) 1986 Regents of the University of California */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6    
7     /*
8     * data.c - routines dealing with interpolated data.
9     *
10     * 6/4/86
11     */
12    
13     #include "standard.h"
14    
15     #include "color.h"
16    
17     #include "data.h"
18    
19    
20     extern char *libpath; /* library search path */
21    
22     static DATARRAY *dlist = NULL; /* data array list */
23    
24     static DATARRAY *plist = NULL; /* picture list */
25    
26    
27     DATARRAY *
28     getdata(dname) /* get data array dname */
29     char *dname;
30     {
31     char *dfname;
32     FILE *fp;
33     int asize;
34 greg 1.4 register int i, j;
35 greg 1.1 register DATARRAY *dp;
36     /* look for array in list */
37     for (dp = dlist; dp != NULL; dp = dp->next)
38     if (!strcmp(dname, dp->name))
39     return(dp); /* found! */
40    
41     /*
42     * If we haven't loaded the data already, we will look
43     * for it in the directorys specified by the library path.
44     *
45     * The file has the following format:
46     *
47 greg 1.4 * N
48 greg 1.1 * beg0 end0 n0
49     * beg1 end1 n1
50     * . . .
51 greg 1.4 * begN endN nN
52 greg 1.1 * data, later dimensions changing faster
53     * . . .
54     *
55 greg 1.4 * For irregularly spaced points, the following can be
56     * substituted for begi endi ni:
57     *
58 greg 1.6 * 0 0 ni p0i p1i .. pni
59 greg 1.1 */
60    
61 greg 1.2 if ((dfname = getpath(dname, libpath, R_OK)) == NULL) {
62 greg 1.1 sprintf(errmsg, "cannot find data file \"%s\"", dname);
63     error(USER, errmsg);
64     }
65     if ((dp = (DATARRAY *)malloc(sizeof(DATARRAY))) == NULL)
66     goto memerr;
67    
68     dp->name = savestr(dname);
69    
70     if ((fp = fopen(dfname, "r")) == NULL) {
71     sprintf(errmsg, "cannot open data file \"%s\"", dfname);
72     error(SYSTEM, errmsg);
73     }
74     /* get dimensions */
75     if (fscanf(fp, "%d", &dp->nd) != 1)
76     goto scanerr;
77     if (dp->nd <= 0 || dp->nd > MAXDIM) {
78     sprintf(errmsg, "bad number of dimensions for \"%s\"", dname);
79     error(USER, errmsg);
80     }
81     asize = 1;
82     for (i = 0; i < dp->nd; i++) {
83     if (fscanf(fp, "%lf %lf %d",
84     &dp->dim[i].org, &dp->dim[i].siz,
85 greg 1.6 &dp->dim[i].ne) != 3)
86     goto scanerr;
87     if (dp->dim[i].ne < 2)
88     goto scanerr;
89     asize *= dp->dim[i].ne;
90     if ((dp->dim[i].siz -= dp->dim[i].org) == 0) {
91 greg 1.4 dp->dim[i].p = (double *)malloc(dp->dim[i].ne*sizeof(double));
92     if (dp->dim[i].p == NULL)
93     goto memerr;
94     for (j = 0; j < dp->dim[i].ne; j++)
95     if (fscanf(fp, "%lf", &dp->dim[i].p[j]) != 1)
96     goto scanerr;
97     for (j = 1; j < dp->dim[i].ne-1; j++)
98     if ((dp->dim[i].p[j-1] < dp->dim[i].p[j]) !=
99     (dp->dim[i].p[j] < dp->dim[i].p[j+1]))
100     goto scanerr;
101     dp->dim[i].org = dp->dim[i].p[0];
102     dp->dim[i].siz = dp->dim[i].p[dp->dim[i].ne-1]
103     - dp->dim[i].p[0];
104     } else
105 greg 1.6 dp->dim[i].p = NULL;
106 greg 1.1 }
107     if ((dp->arr = (DATATYPE *)malloc(asize*sizeof(DATATYPE))) == NULL)
108     goto memerr;
109    
110     for (i = 0; i < asize; i++)
111     if (fscanf(fp, DSCANF, &dp->arr[i]) != 1)
112     goto scanerr;
113    
114     fclose(fp);
115     dp->next = dlist;
116     return(dlist = dp);
117    
118     memerr:
119     error(SYSTEM, "out of memory in getdata");
120     scanerr:
121     sprintf(errmsg, "%s in data file \"%s\"",
122     feof(fp) ? "unexpected EOF" : "bad format", dfname);
123     error(USER, errmsg);
124     }
125    
126    
127 greg 1.5 static double inpaspect; /* aspect ratio of input picture */
128    
129     static
130     headaspect(s) /* check string for aspect ratio */
131     char *s;
132     {
133     if (isaspect(s))
134     inpaspect *= aspectval(s);
135     }
136    
137    
138 greg 1.1 DATARRAY *
139     getpict(pname) /* get picture pname */
140     char *pname;
141     {
142     extern char *libpath;
143     char *pfname;
144     FILE *fp;
145     COLOR *scanin;
146     int width, height;
147     int x, y;
148     register int i;
149     register DATARRAY *pp;
150     /* look for array in list */
151     for (pp = plist; pp != NULL; pp = pp->next)
152     if (!strcmp(pname, pp->name))
153     return(pp); /* found! */
154    
155 greg 1.2 if ((pfname = getpath(pname, libpath, R_OK)) == NULL) {
156 greg 1.1 sprintf(errmsg, "cannot find picture file \"%s\"", pname);
157     error(USER, errmsg);
158     }
159     if ((pp = (DATARRAY *)calloc(3, sizeof(DATARRAY))) == NULL)
160     goto memerr;
161    
162     pp[0].name =
163     pp[1].name =
164     pp[2].name = savestr(pname);
165    
166     if ((fp = fopen(pfname, "r")) == NULL) {
167     sprintf(errmsg, "cannot open picture file \"%s\"", pfname);
168     error(SYSTEM, errmsg);
169     }
170     /* get dimensions */
171 greg 1.5 inpaspect = 1.0;
172     getheader(fp, headaspect);
173 greg 1.3 if (fgetresolu(&width, &height, fp) != (YMAJOR|YDECR))
174 greg 1.1 goto readerr;
175     for (i = 0; i < 3; i++) {
176     pp[i].nd = 2;
177     pp[i].dim[0].ne = width;
178     pp[i].dim[1].ne = height;
179     pp[i].dim[0].org =
180     pp[i].dim[1].org = 0.0;
181 greg 1.5 if (width <= height*inpaspect) {
182 greg 1.1 pp[i].dim[0].siz = 1.0;
183 greg 1.5 pp[i].dim[1].siz = inpaspect*(double)height/width;
184 greg 1.1 } else {
185 greg 1.5 pp[i].dim[0].siz = (double)width/height/inpaspect;
186 greg 1.1 pp[i].dim[1].siz = 1.0;
187     }
188     pp[i].arr = (DATATYPE *)malloc(width*height*sizeof(DATATYPE));
189     if (pp[i].arr == NULL)
190     goto memerr;
191     }
192     /* load picture */
193     if ((scanin = (COLOR *)malloc(width*sizeof(COLOR))) == NULL)
194     goto memerr;
195     for (y = height-1; y >= 0; y--) {
196     if (freadscan(scanin, width, fp) < 0)
197     goto readerr;
198     for (x = 0; x < width; x++)
199     for (i = 0; i < 3; i++)
200     pp[i].arr[x*height+y] = colval(scanin[x],i);
201     }
202     free((char *)scanin);
203     fclose(fp);
204     pp[0].next =
205     pp[1].next =
206     pp[2].next = plist;
207     return(plist = pp);
208    
209     memerr:
210     error(SYSTEM, "out of memory in getpict");
211     readerr:
212     sprintf(errmsg, "bad picture file \"%s\"", pfname);
213     error(USER, errmsg);
214     }
215    
216    
217     freedata(dname) /* free memory associated with dname */
218     char *dname;
219     {
220     register DATARRAY *dp, *dpl;
221 greg 1.4 register int i;
222 greg 1.1
223     for (dpl = NULL, dp = dlist; dp != NULL; dpl = dp, dp = dp->next)
224     if (!strcmp(dname, dp->name)) {
225     if (dpl == NULL)
226     dlist = dp->next;
227     else
228     dpl->next = dp->next;
229     free((char *)dp->arr);
230 greg 1.4 for (i = 0; i < dp->nd; i++)
231     if (dp->dim[i].p != NULL)
232     free((char *)dp->dim[i].p);
233 greg 1.1 freestr(dp->name);
234     free((char *)dp);
235     return;
236     }
237     }
238    
239    
240     freepict(pname) /* free memory associated with pname */
241     char *pname;
242     {
243     register DATARRAY *pp, *ppl;
244    
245     for (ppl = NULL, pp = plist; pp != NULL; ppl = pp, pp = pp->next)
246     if (!strcmp(pname, pp->name)) {
247     if (ppl == NULL)
248     plist = pp->next;
249     else
250     ppl->next = pp->next;
251     free((char *)pp[0].arr);
252     free((char *)pp[1].arr);
253     free((char *)pp[2].arr);
254     freestr(pp[0].name);
255     free((char *)pp);
256     return;
257     }
258     }
259    
260    
261     double
262     datavalue(dp, pt) /* interpolate data value at a point */
263     register DATARRAY *dp;
264     double *pt;
265     {
266     DATARRAY sd;
267     int asize;
268 greg 1.6 int lower, upper;
269 greg 1.1 register int i;
270     double x, y, y0, y1;
271 greg 1.4 /* set up dimensions for recursion */
272 greg 1.1 sd.nd = dp->nd - 1;
273     asize = 1;
274     for (i = 0; i < sd.nd; i++) {
275     sd.dim[i].org = dp->dim[i+1].org;
276     sd.dim[i].siz = dp->dim[i+1].siz;
277 greg 1.4 sd.dim[i].p = dp->dim[i+1].p;
278 greg 1.1 asize *= sd.dim[i].ne = dp->dim[i+1].ne;
279     }
280 greg 1.4 /* get independent variable */
281     if (dp->dim[0].p == NULL) { /* evenly spaced points */
282     x = (pt[0] - dp->dim[0].org)/dp->dim[0].siz;
283     x = x * (dp->dim[0].ne - 1);
284     i = x;
285     if (i < 0)
286     i = 0;
287     else if (i > dp->dim[0].ne - 2)
288     i = dp->dim[0].ne - 2;
289     } else { /* unevenly spaced points */
290 greg 1.6 if (dp->dim[0].siz > 0.0) {
291     lower = 0;
292     upper = dp->dim[0].ne;
293     } else {
294     lower = dp->dim[0].ne;
295     upper = 0;
296     }
297     do {
298     i = (lower + upper) >> 1;
299     if (pt[0] >= dp->dim[0].p[i])
300     lower = i;
301     else if (pt[0] < dp->dim[0].p[i])
302     upper = i;
303     } while (i != (lower + upper) >> 1);
304     if (i < 0)
305 greg 1.4 i = 0;
306 greg 1.6 else if (i > dp->dim[0].ne - 2)
307 greg 1.4 i = dp->dim[0].ne - 2;
308     x = i + (pt[0] - dp->dim[0].p[i]) /
309     (dp->dim[0].p[i+1] - dp->dim[0].p[i]);
310     }
311     /* get dependent variable */
312 greg 1.1 if (dp->nd == 1) {
313     y0 = dp->arr[i];
314     y1 = dp->arr[i+1];
315     } else {
316     sd.arr = &dp->arr[i*asize];
317     y0 = datavalue(&sd, pt+1);
318     sd.arr = &dp->arr[(i+1)*asize];
319     y1 = datavalue(&sd, pt+1);
320     }
321     /*
322     * Extrapolate as far as one division, then
323     * taper off harmonically to zero.
324     */
325     if (x > i+2)
326     y = (2*y1-y0)/(x-i-1);
327     else if (x < i-1)
328     y = (2*y0-y1)/(i-x);
329     else
330     y = y0*((i+1)-x) + y1*(x-i);
331    
332     return(y);
333     }