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root/radiance/ray/src/cv/bsdfmesh.c
Revision: 2.6
Committed: Fri Nov 9 02:16:29 2012 UTC (11 years, 5 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.5: +15 -34 lines
Log Message:
Added data to complete XML file output

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: bsdfmesh.c,v 2.5 2012/11/08 23:32:30 greg Exp $";
3 #endif
4 /*
5 * Create BSDF advection mesh from radial basis functions.
6 *
7 * G. Ward
8 */
9
10 #ifndef _WIN32
11 #include <unistd.h>
12 #include <sys/wait.h>
13 #include <sys/mman.h>
14 #endif
15 #define _USE_MATH_DEFINES
16 #include <stdio.h>
17 #include <stdlib.h>
18 #include <string.h>
19 #include <math.h>
20 #include "bsdfrep.h"
21 /* number of processes to run */
22 int nprocs = 1;
23 /* number of children (-1 in child) */
24 static int nchild = 0;
25
26 typedef struct {
27 int nrows, ncols; /* array size (matches migration) */
28 float *price; /* migration prices */
29 short *sord; /* sort for each row, low to high */
30 } PRICEMAT; /* sorted pricing matrix */
31
32 #define pricerow(p,i) ((p)->price + (i)*(p)->ncols)
33 #define psortrow(p,i) ((p)->sord + (i)*(p)->ncols)
34
35 /* Create a new migration holder (sharing memory for multiprocessing) */
36 static MIGRATION *
37 new_migration(RBFNODE *from_rbf, RBFNODE *to_rbf)
38 {
39 size_t memlen = sizeof(MIGRATION) +
40 sizeof(float)*(from_rbf->nrbf*to_rbf->nrbf - 1);
41 MIGRATION *newmig;
42 #ifdef _WIN32
43 if (nprocs > 1)
44 fprintf(stderr, "%s: warning - multiprocessing not supported\n",
45 progname);
46 nprocs = 1;
47 newmig = (MIGRATION *)malloc(memlen);
48 #else
49 if (nprocs <= 1) { /* single process? */
50 newmig = (MIGRATION *)malloc(memlen);
51 } else { /* else need to share memory */
52 newmig = (MIGRATION *)mmap(NULL, memlen, PROT_READ|PROT_WRITE,
53 MAP_ANON|MAP_SHARED, -1, 0);
54 if ((void *)newmig == MAP_FAILED)
55 newmig = NULL;
56 }
57 #endif
58 if (newmig == NULL) {
59 fprintf(stderr, "%s: cannot allocate new migration\n", progname);
60 exit(1);
61 }
62 newmig->rbfv[0] = from_rbf;
63 newmig->rbfv[1] = to_rbf;
64 /* insert in edge lists */
65 newmig->enxt[0] = from_rbf->ejl;
66 from_rbf->ejl = newmig;
67 newmig->enxt[1] = to_rbf->ejl;
68 to_rbf->ejl = newmig;
69 newmig->next = mig_list; /* push onto global list */
70 return(mig_list = newmig);
71 }
72
73 #ifdef _WIN32
74 #define await_children(n) (void)(n)
75 #define run_subprocess() 0
76 #define end_subprocess() (void)0
77 #else
78
79 /* Wait for the specified number of child processes to complete */
80 static void
81 await_children(int n)
82 {
83 int exit_status = 0;
84
85 if (n > nchild)
86 n = nchild;
87 while (n-- > 0) {
88 int status;
89 if (wait(&status) < 0) {
90 fprintf(stderr, "%s: missing child(ren)!\n", progname);
91 nchild = 0;
92 break;
93 }
94 --nchild;
95 if (status) { /* something wrong */
96 if ((status = WEXITSTATUS(status)))
97 exit_status = status;
98 else
99 exit_status += !exit_status;
100 fprintf(stderr, "%s: subprocess died\n", progname);
101 n = nchild; /* wait for the rest */
102 }
103 }
104 if (exit_status)
105 exit(exit_status);
106 }
107
108 /* Start child process if multiprocessing selected */
109 static pid_t
110 run_subprocess(void)
111 {
112 int status;
113 pid_t pid;
114
115 if (nprocs <= 1) /* any children requested? */
116 return(0);
117 await_children(nchild + 1 - nprocs); /* free up child process */
118 if ((pid = fork())) {
119 if (pid < 0) {
120 fprintf(stderr, "%s: cannot fork subprocess\n",
121 progname);
122 await_children(nchild);
123 exit(1);
124 }
125 ++nchild; /* subprocess started */
126 return(pid);
127 }
128 nchild = -1;
129 return(0); /* put child to work */
130 }
131
132 /* If we are in subprocess, call exit */
133 #define end_subprocess() if (nchild < 0) _exit(0); else
134
135 #endif /* ! _WIN32 */
136
137 /* Comparison routine needed for sorting price row */
138 static int
139 msrt_cmp(void *b, const void *p1, const void *p2)
140 {
141 PRICEMAT *pm = (PRICEMAT *)b;
142 int ri = ((const short *)p1 - pm->sord) / pm->ncols;
143 float c1 = pricerow(pm,ri)[*(const short *)p1];
144 float c2 = pricerow(pm,ri)[*(const short *)p2];
145
146 if (c1 > c2) return(1);
147 if (c1 < c2) return(-1);
148 return(0);
149 }
150
151 /* Compute (and allocate) migration price matrix for optimization */
152 static void
153 price_routes(PRICEMAT *pm, const RBFNODE *from_rbf, const RBFNODE *to_rbf)
154 {
155 FVECT *vto = (FVECT *)malloc(sizeof(FVECT) * to_rbf->nrbf);
156 int i, j;
157
158 pm->nrows = from_rbf->nrbf;
159 pm->ncols = to_rbf->nrbf;
160 pm->price = (float *)malloc(sizeof(float) * pm->nrows*pm->ncols);
161 pm->sord = (short *)malloc(sizeof(short) * pm->nrows*pm->ncols);
162
163 if ((pm->price == NULL) | (pm->sord == NULL) | (vto == NULL)) {
164 fprintf(stderr, "%s: Out of memory in migration_costs()\n",
165 progname);
166 exit(1);
167 }
168 for (j = to_rbf->nrbf; j--; ) /* save repetitive ops. */
169 ovec_from_pos(vto[j], to_rbf->rbfa[j].gx, to_rbf->rbfa[j].gy);
170
171 for (i = from_rbf->nrbf; i--; ) {
172 const double from_ang = R2ANG(from_rbf->rbfa[i].crad);
173 FVECT vfrom;
174 ovec_from_pos(vfrom, from_rbf->rbfa[i].gx, from_rbf->rbfa[i].gy);
175 for (j = to_rbf->nrbf; j--; ) {
176 pricerow(pm,i)[j] = acos(DOT(vfrom, vto[j])) +
177 fabs(R2ANG(to_rbf->rbfa[j].crad) - from_ang);
178 psortrow(pm,i)[j] = j;
179 }
180 qsort_r(psortrow(pm,i), pm->ncols, sizeof(short), pm, &msrt_cmp);
181 }
182 free(vto);
183 }
184
185 /* Free price matrix */
186 static void
187 free_routes(PRICEMAT *pm)
188 {
189 free(pm->price); pm->price = NULL;
190 free(pm->sord); pm->sord = NULL;
191 }
192
193 /* Compute minimum (optimistic) cost for moving the given source material */
194 static double
195 min_cost(double amt2move, const double *avail, const PRICEMAT *pm, int s)
196 {
197 double total_cost = 0;
198 int j;
199
200 if (amt2move <= FTINY) /* pre-emptive check */
201 return(.0);
202 /* move cheapest first */
203 for (j = 0; j < pm->ncols && amt2move > FTINY; j++) {
204 int d = psortrow(pm,s)[j];
205 double amt = (amt2move < avail[d]) ? amt2move : avail[d];
206
207 total_cost += amt * pricerow(pm,s)[d];
208 amt2move -= amt;
209 }
210 return(total_cost);
211 }
212
213 /* Take a step in migration by choosing optimal bucket to transfer */
214 static double
215 migration_step(MIGRATION *mig, double *src_rem, double *dst_rem, const PRICEMAT *pm)
216 {
217 const double maxamt = 1./(double)pm->ncols;
218 const double minamt = maxamt*5e-6;
219 double *src_cost;
220 struct {
221 int s, d; /* source and destination */
222 double price; /* price estimate per amount moved */
223 double amt; /* amount we can move */
224 } cur, best;
225 int i;
226 /* allocate cost array */
227 src_cost = (double *)malloc(sizeof(double)*pm->nrows);
228 if (src_cost == NULL) {
229 fprintf(stderr, "%s: Out of memory in migration_step()\n",
230 progname);
231 exit(1);
232 }
233 for (i = pm->nrows; i--; ) /* starting costs for diff. */
234 src_cost[i] = min_cost(src_rem[i], dst_rem, pm, i);
235
236 /* find best source & dest. */
237 best.s = best.d = -1; best.price = FHUGE; best.amt = 0;
238 for (cur.s = pm->nrows; cur.s--; ) {
239 double cost_others = 0;
240
241 if (src_rem[cur.s] <= minamt)
242 continue;
243 /* examine cheapest dest. */
244 for (i = 0; i < pm->ncols; i++)
245 if (dst_rem[ cur.d = psortrow(pm,cur.s)[i] ] > minamt)
246 break;
247 if (i >= pm->ncols)
248 break;
249 if ((cur.price = pricerow(pm,cur.s)[cur.d]) >= best.price)
250 continue; /* no point checking further */
251 cur.amt = (src_rem[cur.s] < dst_rem[cur.d]) ?
252 src_rem[cur.s] : dst_rem[cur.d];
253 if (cur.amt > maxamt) cur.amt = maxamt;
254 dst_rem[cur.d] -= cur.amt; /* add up differential costs */
255 for (i = pm->nrows; i--; )
256 if (i != cur.s)
257 cost_others += min_cost(src_rem[i], dst_rem, pm, i)
258 - src_cost[i];
259 dst_rem[cur.d] += cur.amt; /* undo trial move */
260 cur.price += cost_others/cur.amt; /* adjust effective price */
261 if (cur.price < best.price) /* are we better than best? */
262 best = cur;
263 }
264 free(src_cost); /* finish up */
265
266 if ((best.s < 0) | (best.d < 0)) /* nothing left to move? */
267 return(.0);
268 /* else make the actual move */
269 mtx_coef(mig,best.s,best.d) += best.amt;
270 src_rem[best.s] -= best.amt;
271 dst_rem[best.d] -= best.amt;
272 return(best.amt);
273 }
274
275 /* Compute and insert migration along directed edge (may fork child) */
276 static MIGRATION *
277 create_migration(RBFNODE *from_rbf, RBFNODE *to_rbf)
278 {
279 const double end_thresh = 5e-6;
280 PRICEMAT pmtx;
281 MIGRATION *newmig;
282 double *src_rem, *dst_rem;
283 double total_rem = 1., move_amt;
284 int i, j;
285 /* check if exists already */
286 for (newmig = from_rbf->ejl; newmig != NULL;
287 newmig = nextedge(from_rbf,newmig))
288 if (newmig->rbfv[1] == to_rbf)
289 return(NULL);
290 /* else allocate */
291 newmig = new_migration(from_rbf, to_rbf);
292 if (run_subprocess())
293 return(newmig); /* child continues */
294 price_routes(&pmtx, from_rbf, to_rbf);
295 src_rem = (double *)malloc(sizeof(double)*from_rbf->nrbf);
296 dst_rem = (double *)malloc(sizeof(double)*to_rbf->nrbf);
297 if ((src_rem == NULL) | (dst_rem == NULL)) {
298 fprintf(stderr, "%s: Out of memory in create_migration()\n",
299 progname);
300 exit(1);
301 }
302 #ifdef DEBUG
303 fprintf(stderr, "Building path from (theta,phi) (%.0f,%.0f) ",
304 get_theta180(from_rbf->invec),
305 get_phi360(from_rbf->invec));
306 fprintf(stderr, "to (%.0f,%.0f) with %d x %d matrix\n",
307 get_theta180(to_rbf->invec),
308 get_phi360(to_rbf->invec),
309 from_rbf->nrbf, to_rbf->nrbf);
310 #endif
311 /* starting quantities */
312 memset(newmig->mtx, 0, sizeof(float)*from_rbf->nrbf*to_rbf->nrbf);
313 for (i = from_rbf->nrbf; i--; )
314 src_rem[i] = rbf_volume(&from_rbf->rbfa[i]) / from_rbf->vtotal;
315 for (j = to_rbf->nrbf; j--; )
316 dst_rem[j] = rbf_volume(&to_rbf->rbfa[j]) / to_rbf->vtotal;
317
318 do { /* move a bit at a time */
319 move_amt = migration_step(newmig, src_rem, dst_rem, &pmtx);
320 total_rem -= move_amt;
321 } while ((total_rem > end_thresh) & (move_amt > 0));
322
323 for (i = from_rbf->nrbf; i--; ) { /* normalize final matrix */
324 double nf = rbf_volume(&from_rbf->rbfa[i]);
325 if (nf <= FTINY) continue;
326 nf = from_rbf->vtotal / nf;
327 for (j = to_rbf->nrbf; j--; )
328 mtx_coef(newmig,i,j) *= nf; /* row now sums to 1.0 */
329 }
330 end_subprocess(); /* exit here if subprocess */
331 free_routes(&pmtx); /* free working arrays */
332 free(src_rem);
333 free(dst_rem);
334 return(newmig);
335 }
336
337 /* Check if prospective vertex would create overlapping triangle */
338 static int
339 overlaps_tri(const RBFNODE *bv0, const RBFNODE *bv1, const RBFNODE *pv)
340 {
341 const MIGRATION *ej;
342 RBFNODE *vother[2];
343 int im_rev;
344 /* find shared edge in mesh */
345 for (ej = pv->ejl; ej != NULL; ej = nextedge(pv,ej)) {
346 const RBFNODE *tv = opp_rbf(pv,ej);
347 if (tv == bv0) {
348 im_rev = is_rev_tri(ej->rbfv[0]->invec,
349 ej->rbfv[1]->invec, bv1->invec);
350 break;
351 }
352 if (tv == bv1) {
353 im_rev = is_rev_tri(ej->rbfv[0]->invec,
354 ej->rbfv[1]->invec, bv0->invec);
355 break;
356 }
357 }
358 if (!get_triangles(vother, ej)) /* triangle on same side? */
359 return(0);
360 return(vother[im_rev] != NULL);
361 }
362
363 /* Find context hull vertex to complete triangle (oriented call) */
364 static RBFNODE *
365 find_chull_vert(const RBFNODE *rbf0, const RBFNODE *rbf1)
366 {
367 FVECT vmid, vejn, vp;
368 RBFNODE *rbf, *rbfbest = NULL;
369 double dprod, area2, bestarea2 = FHUGE, bestdprod = -.5;
370
371 VSUB(vejn, rbf1->invec, rbf0->invec);
372 VADD(vmid, rbf0->invec, rbf1->invec);
373 if (normalize(vejn) == 0 || normalize(vmid) == 0)
374 return(NULL);
375 /* XXX exhaustive search */
376 /* Find triangle with minimum rotation from perpendicular */
377 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
378 if ((rbf == rbf0) | (rbf == rbf1))
379 continue;
380 tri_orient(vp, rbf0->invec, rbf1->invec, rbf->invec);
381 if (DOT(vp, vmid) <= FTINY)
382 continue; /* wrong orientation */
383 area2 = .25*DOT(vp,vp);
384 VSUB(vp, rbf->invec, rbf0->invec);
385 dprod = -DOT(vp, vejn);
386 VSUM(vp, vp, vejn, dprod); /* above guarantees non-zero */
387 dprod = DOT(vp, vmid) / VLEN(vp);
388 if (dprod <= bestdprod + FTINY*(1 - 2*(area2 < bestarea2)))
389 continue; /* found better already */
390 if (overlaps_tri(rbf0, rbf1, rbf))
391 continue; /* overlaps another triangle */
392 rbfbest = rbf;
393 bestdprod = dprod; /* new one to beat */
394 bestarea2 = area2;
395 }
396 return(rbfbest);
397 }
398
399 /* Create new migration edge and grow mesh recursively around it */
400 static void
401 mesh_from_edge(MIGRATION *edge)
402 {
403 MIGRATION *ej0, *ej1;
404 RBFNODE *tvert[2];
405
406 if (edge == NULL)
407 return;
408 /* triangle on either side? */
409 get_triangles(tvert, edge);
410 if (tvert[0] == NULL) { /* grow mesh on right */
411 tvert[0] = find_chull_vert(edge->rbfv[0], edge->rbfv[1]);
412 if (tvert[0] != NULL) {
413 if (tvert[0]->ord > edge->rbfv[0]->ord)
414 ej0 = create_migration(edge->rbfv[0], tvert[0]);
415 else
416 ej0 = create_migration(tvert[0], edge->rbfv[0]);
417 if (tvert[0]->ord > edge->rbfv[1]->ord)
418 ej1 = create_migration(edge->rbfv[1], tvert[0]);
419 else
420 ej1 = create_migration(tvert[0], edge->rbfv[1]);
421 mesh_from_edge(ej0);
422 mesh_from_edge(ej1);
423 }
424 } else if (tvert[1] == NULL) { /* grow mesh on left */
425 tvert[1] = find_chull_vert(edge->rbfv[1], edge->rbfv[0]);
426 if (tvert[1] != NULL) {
427 if (tvert[1]->ord > edge->rbfv[0]->ord)
428 ej0 = create_migration(edge->rbfv[0], tvert[1]);
429 else
430 ej0 = create_migration(tvert[1], edge->rbfv[0]);
431 if (tvert[1]->ord > edge->rbfv[1]->ord)
432 ej1 = create_migration(edge->rbfv[1], tvert[1]);
433 else
434 ej1 = create_migration(tvert[1], edge->rbfv[1]);
435 mesh_from_edge(ej0);
436 mesh_from_edge(ej1);
437 }
438 }
439 }
440
441 /* Build our triangle mesh from recorded RBFs */
442 void
443 build_mesh(void)
444 {
445 double best2 = M_PI*M_PI;
446 RBFNODE *shrt_edj[2];
447 RBFNODE *rbf0, *rbf1;
448 /* check if isotropic */
449 if (single_plane_incident) {
450 for (rbf0 = dsf_list; rbf0 != NULL; rbf0 = rbf0->next)
451 if (rbf0->next != NULL)
452 create_migration(rbf0, rbf0->next);
453 await_children(nchild);
454 return;
455 }
456 shrt_edj[0] = shrt_edj[1] = NULL; /* start w/ shortest edge */
457 for (rbf0 = dsf_list; rbf0 != NULL; rbf0 = rbf0->next)
458 for (rbf1 = rbf0->next; rbf1 != NULL; rbf1 = rbf1->next) {
459 double dist2 = 2. - 2.*DOT(rbf0->invec,rbf1->invec);
460 if (dist2 < best2) {
461 shrt_edj[0] = rbf0;
462 shrt_edj[1] = rbf1;
463 best2 = dist2;
464 }
465 }
466 if (shrt_edj[0] == NULL) {
467 fprintf(stderr, "%s: Cannot find shortest edge\n", progname);
468 exit(1);
469 }
470 /* build mesh from this edge */
471 if (shrt_edj[0]->ord < shrt_edj[1]->ord)
472 mesh_from_edge(create_migration(shrt_edj[0], shrt_edj[1]));
473 else
474 mesh_from_edge(create_migration(shrt_edj[1], shrt_edj[0]));
475 /* complete migrations */
476 await_children(nchild);
477 }