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root/radiance/ray/src/util/glaresrc.c
Revision: 1.12
Committed: Fri Apr 12 10:28:36 1991 UTC (32 years, 11 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.11: +9 -6 lines
Log Message:
minor changes and bug fixes

File Contents

# Content
1 /* Copyright (c) 1991 Regents of the University of California */
2
3 #ifndef lint
4 static char SCCSid[] = "$SunId$ LBL";
5 #endif
6
7 /*
8 * Gather samples and compute glare sources.
9 */
10
11 #include "glare.h"
12
13 #define vcont(vd,vu) ((vu)-(vd)<=SEPS)
14 #define hcont(s1,s2) ((s1)->r-(s2)->l>=-SEPS&&(s2)->r-(s1)->l>=-SEPS)
15
16 struct source *curlist = NULL; /* current source list */
17 struct source *donelist = NULL; /* finished sources */
18
19
20 struct srcspan *
21 newspan(l, r, v, sb) /* allocate a new source span */
22 int l, r, v;
23 float *sb;
24 {
25 register struct srcspan *ss;
26 register int i;
27
28 ss = (struct srcspan *)malloc(sizeof(struct srcspan));
29 if (ss == NULL)
30 memerr("source spans");
31 ss->l = l;
32 ss->r = r;
33 ss->v = v;
34 ss->brsum = 0.0;
35 for (i = l; i < r; i++)
36 ss->brsum += sb[i+hsize];
37 return(ss);
38 }
39
40
41 analyze() /* analyze our scene */
42 {
43 int h, v;
44 int left;
45 float *spanbr;
46
47 spanbr = (float *)malloc((2*hsize+1)*sizeof(float));
48 if (spanbr == NULL)
49 memerr("view span brightness buffer");
50 for (v = vsize; v >= -vsize; v--) {
51 close_sources(v);
52 #ifndef DEBUG
53 if (verbose)
54 fprintf(stderr, "%s: analyzing... %3ld%%\r",
55 progname, 100L*(vsize-v)/(2*vsize));
56 #endif
57 getviewspan(v, spanbr);
58 left = hsize + 1;
59 for (h = -hsize; h <= hsize; h++) {
60 if (spanbr[h+hsize] < 0.0) { /* off view */
61 if (left < h) {
62 addsrcspan(newspan(left,h,v,spanbr));
63 left = hsize + 1;
64 }
65 continue;
66 }
67 if (spanbr[h+hsize] > threshold) { /* in source */
68 if (left > h)
69 left = h;
70 } else { /* out of source */
71 if (left < h) {
72 addsrcspan(newspan(left,h,v,spanbr));
73 left = hsize + 1;
74 }
75 addindirect(h, spanbr[h+hsize]);
76 }
77 }
78 if (left < h)
79 addsrcspan(newspan(left,h,v,spanbr));
80 }
81 free((char *)spanbr);
82 close_allsrcs();
83 }
84
85
86 addindirect(h, br) /* add brightness to indirect illuminances */
87 int h;
88 double br;
89 {
90 double tanb, d;
91 register int i;
92
93 if (h <= -hlim) { /* left region */
94 d = (double)(-h-hlim)/sampdens;
95 if (d >= 1.0-FTINY)
96 return;
97 tanb = d/sqrt(1.0-d*d);
98 for (i = 0; i < nglardirs; i++) {
99 d = indirect[i].lcos - tanb*indirect[i].lsin;
100 if (d > 0.0) {
101 indirect[i].sum += d * br;
102 indirect[i].n += d;
103 }
104 }
105 return;
106 }
107 if (h >= hlim) { /* right region */
108 d = (double)(-h+hlim)/sampdens;
109 if (d <= -1.0+FTINY)
110 return;
111 tanb = d/sqrt(1.0-d*d);
112 for (i = 0; i < nglardirs; i++) {
113 d = indirect[i].rcos - tanb*indirect[i].rsin;
114 if (d > 0.0) {
115 indirect[i].sum += d * br;
116 indirect[i].n += d;
117 }
118 }
119 return;
120 }
121 /* central region */
122 for (i = 0; i < nglardirs; i++) {
123 d = cos(h_theta(h) - indirect[i].theta);
124 if (d > 0.0) {
125 indirect[i].sum += d * br;
126 indirect[i].n += d;
127 }
128 }
129 }
130
131
132 comp_thresh() /* compute glare threshold */
133 {
134 SPANERR sperr;
135 int h, v;
136 int nsamps;
137 double brsum, br;
138
139 if (verbose)
140 fprintf(stderr, "%s: computing glare threshold...\n",
141 progname);
142 brsum = 0.0;
143 nsamps = 0;
144 for (v = vsize; v >= -vsize; v -= TSAMPSTEP) {
145 setspanerr(&sperr, v);
146 for (h = -hsize; h <= hsize; h += TSAMPSTEP) {
147 if ((br = getviewpix(h, v, &sperr)) < 0.0)
148 continue;
149 brsum += br;
150 nsamps++;
151 }
152 }
153 if (nsamps == 0) {
154 fprintf(stderr, "%s: no viewable scene!\n", progname);
155 exit(1);
156 }
157 threshold = GLAREBR * brsum / nsamps;
158 if (threshold <= FTINY) {
159 fprintf(stderr, "%s: threshold zero!\n", progname);
160 exit(1);
161 }
162 if (verbose) {
163 #ifdef DEBUG
164 pict_stats();
165 #endif
166 fprintf(stderr,
167 "%s: threshold set to %f cd/m2 from %d samples\n",
168 progname, threshold, nsamps);
169 }
170 }
171
172
173 addsrcspan(nss) /* add new source span to our list */
174 struct srcspan *nss;
175 {
176 struct source *last, *cs, *this;
177 register struct srcspan *ss;
178
179 cs = NULL;
180 for (this = curlist; this != NULL; this = this->next) {
181 for (ss = this->first; ss != NULL; ss = ss->next) {
182 if (!vcont(nss->v, ss->v))
183 break;
184 if (hcont(ss, nss)) {
185 if (cs == NULL)
186 cs = this;
187 else {
188 last->next = this->next;
189 mergesource(cs, this);
190 this = last;
191 }
192 break;
193 }
194 }
195 last = this;
196 }
197 if (cs == NULL) {
198 cs = (struct source *)malloc(sizeof(struct source));
199 if (cs == NULL)
200 memerr("source records");
201 cs->dom = 0.0;
202 cs->first = NULL;
203 cs->next = curlist;
204 curlist = cs;
205 }
206 nss->next = cs->first;
207 cs->first = nss;
208 }
209
210
211 mergesource(sp, ap) /* merge source ap into source sp */
212 struct source *sp, *ap;
213 {
214 struct srcspan head;
215 register struct srcspan *alp, *prev, *tp;
216
217 head.next = sp->first;
218 prev = &head;
219 alp = ap->first;
220 while (alp != NULL && prev->next != NULL) {
221 if (prev->next->v > alp->v) {
222 tp = alp->next;
223 alp->next = prev->next;
224 prev->next = alp;
225 alp = tp;
226 }
227 prev = prev->next;
228 }
229 if (prev->next == NULL)
230 prev->next = alp;
231 sp->first = head.next;
232 if (ap->dom > 0.0 && sp->dom > 0.0) { /* sources are done */
233 sp->dir[0] *= sp->dom;
234 sp->dir[1] *= sp->dom;
235 sp->dir[2] *= sp->dom;
236 fvsum(sp->dir, sp->dir, ap->dir, ap->dom);
237 normalize(sp->dir);
238 sp->brt = (sp->brt*sp->dom + ap->brt*ap->dom)
239 / (sp->dom + ap->dom);
240 }
241 free((char *)ap);
242 }
243
244
245 close_sources(v) /* close sources above v */
246 int v;
247 {
248 struct source head;
249 register struct source *last, *this;
250
251 head.next = curlist;
252 last = &head;
253 for (this = curlist; this != NULL; this = this->next)
254 if (!vcont(v, this->first->v)) {
255 last->next = this->next;
256 donesource(this);
257 this = last;
258 } else
259 last = this;
260 curlist = head.next;
261 }
262
263
264 close_allsrcs() /* done with everything */
265 {
266 register struct source *this, *next;
267
268 this = curlist;
269 while (this != NULL) {
270 next = this->next;
271 donesource(this);
272 this = next;
273 }
274 curlist = NULL;
275 }
276
277
278 donesource(sp) /* finished with this source */
279 register struct source *sp;
280 {
281 FVECT dthis, dright;
282 register struct srcspan *ss;
283 int h, n;
284 double d;
285
286 sp->dom = 0.0;
287 sp->dir[0] = sp->dir[1] = sp->dir[2] = 0.0;
288 sp->brt = 0.0;
289 n = 0;
290 for (ss = sp->first; ss != NULL; ss = ss->next) {
291 sp->brt += ss->brsum;
292 n += ss->r - ss->l;
293 if (compdir(dright, ss->r, ss->v, NULL) < 0)
294 compdir(dright, ss->r-2, ss->v, NULL);
295 for (h = ss->r-1; h >= ss->l; h--)
296 if (compdir(dthis, h, ss->v, NULL) == 0) {
297 d = dist2(dthis, dright);
298 fvsum(sp->dir, sp->dir, dthis, d);
299 sp->dom += d;
300 VCOPY(dright, dthis);
301 }
302 free((char *)ss);
303 }
304 sp->first = NULL;
305 sp->brt /= (double)n;
306 normalize(sp->dir);
307 sp->next = donelist;
308 donelist = sp;
309 if (verbose)
310 fprintf(stderr,
311 "%s: source at [%.3f,%.3f,%.3f], dw %.5f, br %.1f (%d samps)\n",
312 progname, sp->dir[0], sp->dir[1], sp->dir[2],
313 sp->dom, sp->brt, n);
314 }
315
316
317 struct source *
318 findbuddy(s, l) /* find close enough source to s in l*/
319 register struct source *s, *l;
320 {
321 struct source *bestbuddy = NULL;
322 double d, r, mindist = MAXBUDDY;
323
324 r = sqrt(s->dom/PI);
325 for ( ; l != NULL; l = l->next) {
326 d = sqrt(dist2(l->dir, s->dir)) - sqrt(l->dom/PI) - r;
327 if (d < mindist) {
328 bestbuddy = l;
329 mindist = d;
330 }
331 }
332 return(bestbuddy);
333 }
334
335
336 absorb_specks() /* eliminate too-small sources */
337 {
338 struct source head, *buddy;
339 register struct source *last, *this;
340
341 if (verbose)
342 fprintf(stderr, "%s: absorbing small sources...\n", progname);
343 head.next = donelist;
344 last = &head;
345 for (this = head.next; this != NULL; this = this->next)
346 if (TOOSMALL(this)) {
347 last->next = this->next;
348 buddy = findbuddy(this, head.next);
349 if (buddy != NULL)
350 mergesource(buddy, this);
351 else
352 absorb(this);
353 this = last;
354 } else
355 last = this;
356 donelist = head.next;
357 }
358
359
360 absorb(s) /* absorb a source into indirect */
361 register struct source *s;
362 {
363 FVECT dir;
364 double d;
365 register int i;
366
367 for (i = 0; i < nglardirs; i++) {
368 spinvector(dir, ourview.vdir, ourview.vup, indirect[i].theta);
369 d = DOT(dir,s->dir)*s->dom*(sampdens*sampdens);
370 if (d <= 0.0)
371 continue;
372 indirect[i].sum += d * s->brt;
373 indirect[i].n += d;
374 }
375 for ( ; s->first != NULL; s->first = s->first->next)
376 free((char *)s->first);
377 free((char *)s);
378 }