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root/radiance/ray/src/cv/bsdfmesh.c
Revision: 2.34
Committed: Fri Jan 29 16:21:55 2016 UTC (8 years, 3 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.33: +4 -1 lines
Log Message:
Updated pabopto2bsdf to handle tristimulus color -- change in .sir format

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: bsdfmesh.c,v 2.33 2014/08/22 05:38:44 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
22 #ifndef NEIGH_FACT2
23 #define NEIGH_FACT2 0.1 /* empirical neighborhood distance weight */
24 #endif
25 /* number of processes to run */
26 int nprocs = 1;
27 /* number of children (-1 in child) */
28 static int nchild = 0;
29
30 /* Compute average DSF value at the given radius from central vector */
31 static double
32 eval_DSFsurround(const RBFNODE *rbf, const FVECT outvec, const double rad)
33 {
34 const int ninc = 12;
35 const double phinc = 2.*M_PI/ninc;
36 double sum = 0;
37 int n = 0;
38 FVECT tvec;
39 int i;
40 /* compute initial vector */
41 if (output_orient*outvec[2] >= 1.-FTINY) {
42 tvec[0] = tvec[2] = 0;
43 tvec[1] = 1;
44 } else {
45 tvec[0] = tvec[1] = 0;
46 tvec[2] = 1;
47 }
48 geodesic(tvec, outvec, tvec, rad, GEOD_RAD);
49 /* average surrounding DSF */
50 for (i = 0; i < ninc; i++) {
51 if (i) spinvector(tvec, tvec, outvec, phinc);
52 if (tvec[2] > 0 ^ output_orient > 0)
53 continue;
54 sum += eval_rbfrep(rbf, tvec) * COSF(tvec[2]);
55 ++n;
56 }
57 if (n < 2) /* should never happen! */
58 return(sum);
59 return(sum/(double)n);
60 }
61
62 /* Estimate single-lobe radius for DSF at the given outgoing angle */
63 static double
64 est_DSFrad(const RBFNODE *rbf, const FVECT outvec)
65 {
66 const double rad_epsilon = 0.03;
67 const double DSFtarget = 0.60653066 * eval_rbfrep(rbf,outvec) *
68 COSF(outvec[2]);
69 double inside_rad = rad_epsilon;
70 double outside_rad = 0.5;
71 double DSFinside = eval_DSFsurround(rbf, outvec, inside_rad);
72 double DSFoutside = eval_DSFsurround(rbf, outvec, outside_rad);
73 #define interp_rad inside_rad + (outside_rad-inside_rad) * \
74 (DSFtarget-DSFinside) / (DSFoutside-DSFinside)
75 /* Newton's method (sort of) */
76 do {
77 double test_rad = interp_rad;
78 double DSFtest;
79 if (test_rad >= outside_rad)
80 return(test_rad);
81 if (test_rad <= inside_rad)
82 return(test_rad*(test_rad>0));
83 DSFtest = eval_DSFsurround(rbf, outvec, test_rad);
84 if (DSFtest > DSFtarget) {
85 inside_rad = test_rad;
86 DSFinside = DSFtest;
87 } else {
88 outside_rad = test_rad;
89 DSFoutside = DSFtest;
90 }
91 if (DSFoutside >= DSFinside)
92 return(test_rad);
93 } while (outside_rad-inside_rad > rad_epsilon);
94 return(interp_rad);
95 #undef interp_rad
96 }
97
98 /* Compute average BSDF peak from current DSF's */
99 static void
100 comp_bsdf_spec(void)
101 {
102 const double max_hemi = 0.9;
103 double peak_sum = 0;
104 double rad_sum = 0;
105 int n = 0;
106 RBFNODE *rbf;
107 FVECT sdv;
108
109 if (dsf_list == NULL) {
110 bsdf_spec_peak = 0;
111 bsdf_spec_rad = 0;
112 return;
113 }
114 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
115 sdv[0] = -rbf->invec[0];
116 sdv[1] = -rbf->invec[1];
117 sdv[2] = rbf->invec[2]*(2*(input_orient==output_orient) - 1);
118 peak_sum += eval_rbfrep(rbf, sdv);
119 rad_sum += est_DSFrad(rbf, sdv);
120 ++n;
121 }
122 bsdf_spec_peak = peak_sum/(double)n;
123 bsdf_spec_rad = rad_sum/(double)n;
124 if ((2.*M_PI)*bsdf_spec_peak*bsdf_spec_rad*bsdf_spec_rad > max_hemi)
125 bsdf_spec_peak = max_hemi/((2.*M_PI)*bsdf_spec_rad*bsdf_spec_rad);
126 }
127
128 /* Create a new migration holder (sharing memory for multiprocessing) */
129 static MIGRATION *
130 new_migration(RBFNODE *from_rbf, RBFNODE *to_rbf)
131 {
132 size_t memlen = sizeof(MIGRATION) +
133 sizeof(float)*(from_rbf->nrbf*to_rbf->nrbf - 1);
134 MIGRATION *newmig;
135 #ifdef _WIN32
136 if (nprocs > 1)
137 fprintf(stderr, "%s: warning - multiprocessing not supported\n",
138 progname);
139 nprocs = 1;
140 newmig = (MIGRATION *)malloc(memlen);
141 #else
142 if (nprocs <= 1) { /* single process? */
143 newmig = (MIGRATION *)malloc(memlen);
144 } else { /* else need to share memory */
145 newmig = (MIGRATION *)mmap(NULL, memlen, PROT_READ|PROT_WRITE,
146 MAP_ANON|MAP_SHARED, -1, 0);
147 if ((void *)newmig == MAP_FAILED)
148 newmig = NULL;
149 }
150 #endif
151 if (newmig == NULL) {
152 fprintf(stderr, "%s: cannot allocate new migration\n", progname);
153 exit(1);
154 }
155 newmig->rbfv[0] = from_rbf;
156 newmig->rbfv[1] = to_rbf;
157 /* insert in edge lists */
158 newmig->enxt[0] = from_rbf->ejl;
159 from_rbf->ejl = newmig;
160 newmig->enxt[1] = to_rbf->ejl;
161 to_rbf->ejl = newmig;
162 newmig->next = mig_list; /* push onto global list */
163 return(mig_list = newmig);
164 }
165
166 #ifdef _WIN32
167 #define await_children(n) (void)(n)
168 #define run_subprocess() 0
169 #define end_subprocess() (void)0
170 #else
171
172 /* Wait for the specified number of child processes to complete */
173 static void
174 await_children(int n)
175 {
176 int exit_status = 0;
177
178 if (n > nchild)
179 n = nchild;
180 while (n-- > 0) {
181 int status;
182 if (wait(&status) < 0) {
183 fprintf(stderr, "%s: missing child(ren)!\n", progname);
184 nchild = 0;
185 break;
186 }
187 --nchild;
188 if (status) { /* something wrong */
189 if ((status = WEXITSTATUS(status)))
190 exit_status = status;
191 else
192 exit_status += !exit_status;
193 fprintf(stderr, "%s: subprocess died\n", progname);
194 n = nchild; /* wait for the rest */
195 }
196 }
197 if (exit_status)
198 exit(exit_status);
199 }
200
201 /* Start child process if multiprocessing selected */
202 static pid_t
203 run_subprocess(void)
204 {
205 int status;
206 pid_t pid;
207
208 if (nprocs <= 1) /* any children requested? */
209 return(0);
210 await_children(nchild + 1 - nprocs); /* free up child process */
211 if ((pid = fork())) {
212 if (pid < 0) {
213 fprintf(stderr, "%s: cannot fork subprocess\n",
214 progname);
215 await_children(nchild);
216 exit(1);
217 }
218 ++nchild; /* subprocess started */
219 return(pid);
220 }
221 nchild = -1;
222 return(0); /* put child to work */
223 }
224
225 /* If we are in subprocess, call exit */
226 #define end_subprocess() if (nchild < 0) _exit(0); else
227
228 #endif /* ! _WIN32 */
229
230 /* Compute normalized distribution scattering functions for comparison */
231 static void
232 compute_nDSFs(const RBFNODE *rbf0, const RBFNODE *rbf1)
233 {
234 const double nf0 = (GRIDRES*GRIDRES) / rbf0->vtotal;
235 const double nf1 = (GRIDRES*GRIDRES) / rbf1->vtotal;
236 int x, y;
237 FVECT dv;
238
239 for (x = GRIDRES; x--; )
240 for (y = GRIDRES; y--; ) {
241 ovec_from_pos(dv, x, y); /* cube root (brightness) */
242 dsf_grid[x][y].val[0] = pow(nf0*eval_rbfrep(rbf0, dv), .3333);
243 dsf_grid[x][y].val[1] = pow(nf1*eval_rbfrep(rbf1, dv), .3333);
244 }
245 }
246
247 /* Compute neighborhood distance-squared (dissimilarity) */
248 static double
249 neighborhood_dist2(int x0, int y0, int x1, int y1)
250 {
251 int rad = GRIDRES>>5;
252 double sum2 = 0.;
253 double d;
254 int p[4];
255 int i, j;
256 /* check radius */
257 p[0] = x0; p[1] = y0; p[2] = x1; p[3] = y1;
258 for (i = 4; i--; ) {
259 if (p[i] < rad) rad = p[i];
260 if (GRIDRES-1-p[i] < rad) rad = GRIDRES-1-p[i];
261 }
262 for (i = -rad; i <= rad; i++)
263 for (j = -rad; j <= rad; j++) {
264 d = dsf_grid[x0+i][y0+j].val[0] -
265 dsf_grid[x1+i][y1+j].val[1];
266 sum2 += d*d;
267 }
268 return(sum2 / (4*rad*(rad+1) + 1));
269 }
270
271 /* Compute distance between two RBF lobes */
272 double
273 lobe_distance(RBFVAL *rbf1, RBFVAL *rbf2)
274 {
275 FVECT vfrom, vto;
276 double d, res;
277 /* quadratic cost function */
278 ovec_from_pos(vfrom, rbf1->gx, rbf1->gy);
279 ovec_from_pos(vto, rbf2->gx, rbf2->gy);
280 d = Acos(DOT(vfrom, vto));
281 res = d*d;
282 d = R2ANG(rbf2->crad) - R2ANG(rbf1->crad);
283 res += d*d;
284 /* neighborhood difference */
285 res += NEIGH_FACT2 * neighborhood_dist2( rbf1->gx, rbf1->gy,
286 rbf2->gx, rbf2->gy );
287 return(res);
288 }
289
290
291 /* Compute and insert migration along directed edge (may fork child) */
292 static MIGRATION *
293 create_migration(RBFNODE *from_rbf, RBFNODE *to_rbf)
294 {
295 MIGRATION *newmig;
296 int i, j;
297 /* check if exists already */
298 for (newmig = from_rbf->ejl; newmig != NULL;
299 newmig = nextedge(from_rbf,newmig))
300 if (newmig->rbfv[1] == to_rbf)
301 return(NULL);
302 /* else allocate */
303 #ifdef DEBUG
304 fprintf(stderr, "Building path from (theta,phi) (%.1f,%.1f) ",
305 get_theta180(from_rbf->invec),
306 get_phi360(from_rbf->invec));
307 fprintf(stderr, "to (%.1f,%.1f) with %d x %d matrix\n",
308 get_theta180(to_rbf->invec),
309 get_phi360(to_rbf->invec),
310 from_rbf->nrbf, to_rbf->nrbf);
311 #endif
312 newmig = new_migration(from_rbf, to_rbf);
313 if (run_subprocess())
314 return(newmig); /* child continues */
315
316 /* compute transport plan */
317 compute_nDSFs(from_rbf, to_rbf);
318 plan_transport(newmig);
319
320 for (i = from_rbf->nrbf; i--; ) { /* normalize final matrix */
321 double nf = rbf_volume(&from_rbf->rbfa[i]);
322 if (nf <= FTINY) continue;
323 nf = from_rbf->vtotal / nf;
324 for (j = to_rbf->nrbf; j--; )
325 mtx_coef(newmig,i,j) *= nf; /* row now sums to 1.0 */
326 }
327 end_subprocess(); /* exit here if subprocess */
328 return(newmig);
329 }
330
331 /* Check if prospective vertex would create overlapping triangle */
332 static int
333 overlaps_tri(const RBFNODE *bv0, const RBFNODE *bv1, const RBFNODE *pv)
334 {
335 const MIGRATION *ej;
336 RBFNODE *vother[2];
337 int im_rev;
338 /* find shared edge in mesh */
339 for (ej = pv->ejl; ej != NULL; ej = nextedge(pv,ej)) {
340 const RBFNODE *tv = opp_rbf(pv,ej);
341 if (tv == bv0) {
342 im_rev = is_rev_tri(ej->rbfv[0]->invec,
343 ej->rbfv[1]->invec, bv1->invec);
344 break;
345 }
346 if (tv == bv1) {
347 im_rev = is_rev_tri(ej->rbfv[0]->invec,
348 ej->rbfv[1]->invec, bv0->invec);
349 break;
350 }
351 }
352 if (!get_triangles(vother, ej)) /* triangle on same side? */
353 return(0);
354 return(vother[im_rev] != NULL);
355 }
356
357 /* Find convex hull vertex to complete triangle (oriented call) */
358 static RBFNODE *
359 find_chull_vert(const RBFNODE *rbf0, const RBFNODE *rbf1)
360 {
361 FVECT vmid, vejn, vp;
362 RBFNODE *rbf, *rbfbest = NULL;
363 double dprod, area2, bestarea2 = FHUGE, bestdprod = -.5;
364
365 VSUB(vejn, rbf1->invec, rbf0->invec);
366 VADD(vmid, rbf0->invec, rbf1->invec);
367 if (normalize(vejn) == 0 || normalize(vmid) == 0)
368 return(NULL);
369 /* XXX exhaustive search */
370 /* Find triangle with minimum rotation from perpendicular */
371 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
372 if ((rbf == rbf0) | (rbf == rbf1))
373 continue;
374 tri_orient(vp, rbf0->invec, rbf1->invec, rbf->invec);
375 if (DOT(vp, vmid) <= FTINY)
376 continue; /* wrong orientation */
377 area2 = .25*DOT(vp,vp);
378 VSUB(vp, rbf->invec, vmid);
379 dprod = -DOT(vp, vejn);
380 VSUM(vp, vp, vejn, dprod); /* above guarantees non-zero */
381 dprod = DOT(vp, vmid) / VLEN(vp);
382 if (dprod <= bestdprod + FTINY*(1 - 2*(area2 < bestarea2)))
383 continue; /* found better already */
384 if (overlaps_tri(rbf0, rbf1, rbf))
385 continue; /* overlaps another triangle */
386 rbfbest = rbf;
387 bestdprod = dprod; /* new one to beat */
388 bestarea2 = area2;
389 }
390 return(rbfbest);
391 }
392
393 /* Create new migration edge and grow mesh recursively around it */
394 static void
395 mesh_from_edge(MIGRATION *edge)
396 {
397 MIGRATION *ej0, *ej1;
398 RBFNODE *tvert[2];
399
400 if (edge == NULL)
401 return;
402 /* triangle on either side? */
403 get_triangles(tvert, edge);
404 if (tvert[0] == NULL) { /* grow mesh on right */
405 tvert[0] = find_chull_vert(edge->rbfv[0], edge->rbfv[1]);
406 if (tvert[0] != NULL) {
407 if (tvert[0]->ord > edge->rbfv[0]->ord)
408 ej0 = create_migration(edge->rbfv[0], tvert[0]);
409 else
410 ej0 = create_migration(tvert[0], edge->rbfv[0]);
411 if (tvert[0]->ord > edge->rbfv[1]->ord)
412 ej1 = create_migration(edge->rbfv[1], tvert[0]);
413 else
414 ej1 = create_migration(tvert[0], edge->rbfv[1]);
415 mesh_from_edge(ej0);
416 mesh_from_edge(ej1);
417 return;
418 }
419 }
420 if (tvert[1] == NULL) { /* grow mesh on left */
421 tvert[1] = find_chull_vert(edge->rbfv[1], edge->rbfv[0]);
422 if (tvert[1] != NULL) {
423 if (tvert[1]->ord > edge->rbfv[0]->ord)
424 ej0 = create_migration(edge->rbfv[0], tvert[1]);
425 else
426 ej0 = create_migration(tvert[1], edge->rbfv[0]);
427 if (tvert[1]->ord > edge->rbfv[1]->ord)
428 ej1 = create_migration(edge->rbfv[1], tvert[1]);
429 else
430 ej1 = create_migration(tvert[1], edge->rbfv[1]);
431 mesh_from_edge(ej0);
432 mesh_from_edge(ej1);
433 }
434 }
435 }
436
437 /* Add normal direction if missing */
438 static void
439 check_normal_incidence(void)
440 {
441 static FVECT norm_vec = {.0, .0, 1.};
442 const int saved_nprocs = nprocs;
443 RBFNODE *near_rbf, *mir_rbf, *rbf;
444 double bestd;
445 int n;
446
447 if (dsf_list == NULL)
448 return; /* XXX should be error? */
449 near_rbf = dsf_list;
450 bestd = input_orient*near_rbf->invec[2];
451 if (single_plane_incident) { /* ordered plane incidence? */
452 if (bestd >= 1.-2.*FTINY)
453 return; /* already have normal */
454 } else {
455 switch (inp_coverage) {
456 case INP_QUAD1:
457 case INP_QUAD2:
458 case INP_QUAD3:
459 case INP_QUAD4:
460 break; /* quadrilateral symmetry? */
461 default:
462 return; /* else we can interpolate */
463 }
464 for (rbf = near_rbf->next; rbf != NULL; rbf = rbf->next) {
465 const double d = input_orient*rbf->invec[2];
466 if (d >= 1.-2.*FTINY)
467 return; /* seems we have normal */
468 if (d > bestd) {
469 near_rbf = rbf;
470 bestd = d;
471 }
472 }
473 }
474 if (mig_list != NULL) { /* need to be called first */
475 fprintf(stderr, "%s: Late call to check_normal_incidence()\n",
476 progname);
477 exit(1);
478 }
479 #ifdef DEBUG
480 fprintf(stderr, "Interpolating normal incidence by mirroring (%.1f,%.1f)\n",
481 get_theta180(near_rbf->invec), get_phi360(near_rbf->invec));
482 #endif
483 /* mirror nearest incidence */
484 n = sizeof(RBFNODE) + sizeof(RBFVAL)*(near_rbf->nrbf-1);
485 mir_rbf = (RBFNODE *)malloc(n);
486 if (mir_rbf == NULL)
487 goto memerr;
488 memcpy(mir_rbf, near_rbf, n);
489 mir_rbf->ord = near_rbf->ord - 1; /* not used, I think */
490 mir_rbf->next = NULL;
491 mir_rbf->ejl = NULL;
492 rev_rbf_symmetry(mir_rbf, MIRROR_X|MIRROR_Y);
493 nprocs = 1; /* compute migration matrix */
494 if (create_migration(mir_rbf, near_rbf) == NULL)
495 exit(1); /* XXX should never happen! */
496 norm_vec[2] = input_orient; /* interpolate normal dist. */
497 rbf = e_advect_rbf(mig_list, norm_vec, 0);
498 nprocs = saved_nprocs; /* final clean-up */
499 free(mir_rbf);
500 free(mig_list);
501 mig_list = near_rbf->ejl = NULL;
502 insert_dsf(rbf); /* insert interpolated normal */
503 return;
504 memerr:
505 fprintf(stderr, "%s: Out of memory in check_normal_incidence()\n",
506 progname);
507 exit(1);
508 }
509
510 /* Build our triangle mesh from recorded RBFs */
511 void
512 build_mesh(void)
513 {
514 double best2 = M_PI*M_PI;
515 RBFNODE *shrt_edj[2];
516 RBFNODE *rbf0, *rbf1;
517 /* average specular peak */
518 comp_bsdf_spec();
519 /* add normal if needed */
520 check_normal_incidence();
521 /* check if isotropic */
522 if (single_plane_incident) {
523 for (rbf0 = dsf_list; rbf0 != NULL; rbf0 = rbf0->next)
524 if (rbf0->next != NULL)
525 create_migration(rbf0, rbf0->next);
526 await_children(nchild);
527 return;
528 }
529 shrt_edj[0] = shrt_edj[1] = NULL; /* start w/ shortest edge */
530 for (rbf0 = dsf_list; rbf0 != NULL; rbf0 = rbf0->next)
531 for (rbf1 = rbf0->next; rbf1 != NULL; rbf1 = rbf1->next) {
532 double dist2 = 2. - 2.*DOT(rbf0->invec,rbf1->invec);
533 if (dist2 < best2) {
534 shrt_edj[0] = rbf0;
535 shrt_edj[1] = rbf1;
536 best2 = dist2;
537 }
538 }
539 if (shrt_edj[0] == NULL) {
540 fprintf(stderr, "%s: Cannot find shortest edge\n", progname);
541 exit(1);
542 }
543 /* build mesh from this edge */
544 if (shrt_edj[0]->ord < shrt_edj[1]->ord)
545 mesh_from_edge(create_migration(shrt_edj[0], shrt_edj[1]));
546 else
547 mesh_from_edge(create_migration(shrt_edj[1], shrt_edj[0]));
548 /* complete migrations */
549 await_children(nchild);
550 }