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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

# User Rev Content
1 greg 2.1 #ifndef lint
2 greg 2.34 static const char RCSid[] = "$Id: bsdfmesh.c,v 2.33 2014/08/22 05:38:44 greg Exp $";
3 greg 2.1 #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 greg 2.19
22     #ifndef NEIGH_FACT2
23 greg 2.21 #define NEIGH_FACT2 0.1 /* empirical neighborhood distance weight */
24 greg 2.19 #endif
25 greg 2.1 /* number of processes to run */
26     int nprocs = 1;
27     /* number of children (-1 in child) */
28     static int nchild = 0;
29    
30 greg 2.30 /* 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 greg 2.33 sum += eval_rbfrep(rbf, tvec) * COSF(tvec[2]);
55 greg 2.30 ++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 greg 2.33 const double DSFtarget = 0.60653066 * eval_rbfrep(rbf,outvec) *
68     COSF(outvec[2]);
69 greg 2.30 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 greg 2.32 /* Newton's method (sort of) */
76     do {
77 greg 2.30 double test_rad = interp_rad;
78 greg 2.32 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 greg 2.30 inside_rad = test_rad;
86     DSFinside = DSFtest;
87     } else {
88     outside_rad = test_rad;
89     DSFoutside = DSFtest;
90     }
91 greg 2.32 if (DSFoutside >= DSFinside)
92     return(test_rad);
93     } while (outside_rad-inside_rad > rad_epsilon);
94 greg 2.30 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 greg 2.34 const double max_hemi = 0.9;
103 greg 2.30 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 greg 2.31 bsdf_spec_rad = 0;
112 greg 2.30 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 greg 2.31 bsdf_spec_rad = rad_sum/(double)n;
124 greg 2.34 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 greg 2.30 }
127    
128 greg 2.2 /* 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 greg 2.6 await_children(nchild);
216 greg 2.2 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 greg 2.19 /* 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 greg 2.20 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 greg 2.19 }
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 greg 2.27 /* 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 greg 2.1 }
289    
290 greg 2.26
291 greg 2.1 /* 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 greg 2.6 int i, j;
297 greg 2.1 /* 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 greg 2.7 #ifdef DEBUG
304 greg 2.14 fprintf(stderr, "Building path from (theta,phi) (%.1f,%.1f) ",
305 greg 2.7 get_theta180(from_rbf->invec),
306     get_phi360(from_rbf->invec));
307 greg 2.14 fprintf(stderr, "to (%.1f,%.1f) with %d x %d matrix\n",
308 greg 2.7 get_theta180(to_rbf->invec),
309     get_phi360(to_rbf->invec),
310     from_rbf->nrbf, to_rbf->nrbf);
311     #endif
312 greg 2.1 newmig = new_migration(from_rbf, to_rbf);
313     if (run_subprocess())
314     return(newmig); /* child continues */
315 greg 2.27
316     /* compute transport plan */
317     compute_nDSFs(from_rbf, to_rbf);
318     plan_transport(newmig);
319 greg 2.6
320 greg 2.1 for (i = from_rbf->nrbf; i--; ) { /* normalize final matrix */
321 greg 2.6 double nf = rbf_volume(&from_rbf->rbfa[i]);
322 greg 2.1 if (nf <= FTINY) continue;
323     nf = from_rbf->vtotal / nf;
324     for (j = to_rbf->nrbf; j--; )
325 greg 2.6 mtx_coef(newmig,i,j) *= nf; /* row now sums to 1.0 */
326 greg 2.1 }
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 greg 2.14 /* Find convex hull vertex to complete triangle (oriented call) */
358 greg 2.1 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 greg 2.14 VSUB(vp, rbf->invec, vmid);
379 greg 2.1 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 greg 2.28 return;
418 greg 2.1 }
419 greg 2.28 }
420     if (tvert[1] == NULL) { /* grow mesh on left */
421 greg 2.1 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 greg 2.15
437     /* Add normal direction if missing */
438     static void
439     check_normal_incidence(void)
440     {
441 greg 2.25 static FVECT norm_vec = {.0, .0, 1.};
442 greg 2.16 const int saved_nprocs = nprocs;
443     RBFNODE *near_rbf, *mir_rbf, *rbf;
444     double bestd;
445     int n;
446 greg 2.15
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 greg 2.22 mir_rbf->ejl = NULL;
492 greg 2.15 rev_rbf_symmetry(mir_rbf, MIRROR_X|MIRROR_Y);
493     nprocs = 1; /* compute migration matrix */
494 greg 2.22 if (create_migration(mir_rbf, near_rbf) == NULL)
495 greg 2.15 exit(1); /* XXX should never happen! */
496 greg 2.25 norm_vec[2] = input_orient; /* interpolate normal dist. */
497 greg 2.29 rbf = e_advect_rbf(mig_list, norm_vec, 0);
498 greg 2.15 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 greg 2.1
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 greg 2.30 /* average specular peak */
518     comp_bsdf_spec();
519 greg 2.15 /* add normal if needed */
520     check_normal_incidence();
521 greg 2.1 /* 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     }