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root/radiance/ray/src/cv/bsdfinterp.c
Revision: 2.14
Committed: Tue Oct 22 04:29:27 2013 UTC (10 years, 5 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.13: +16 -12 lines
Log Message:
Added bsdf2rad test program and fixed bug in normalization for interpolant

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: bsdfinterp.c,v 2.13 2013/09/26 17:15:22 greg Exp $";
3 #endif
4 /*
5 * Interpolate BSDF data from radial basis functions in advection mesh.
6 *
7 * G. Ward
8 */
9
10 #define _USE_MATH_DEFINES
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <string.h>
14 #include <math.h>
15 #include "bsdfrep.h"
16
17 /* Insert vertex in ordered list */
18 static void
19 insert_vert(RBFNODE **vlist, RBFNODE *v)
20 {
21 int i, j;
22
23 for (i = 0; vlist[i] != NULL; i++) {
24 if (v == vlist[i])
25 return;
26 if (v->ord < vlist[i]->ord)
27 break;
28 }
29 for (j = i; vlist[j] != NULL; j++)
30 ;
31 while (j > i) {
32 vlist[j] = vlist[j-1];
33 --j;
34 }
35 vlist[i] = v;
36 }
37
38 /* Sort triangle edges in standard order */
39 static int
40 order_triangle(MIGRATION *miga[3])
41 {
42 RBFNODE *vert[7];
43 MIGRATION *ord[3];
44 int i;
45 /* order vertices, first */
46 memset(vert, 0, sizeof(vert));
47 for (i = 3; i--; ) {
48 if (miga[i] == NULL)
49 return(0);
50 insert_vert(vert, miga[i]->rbfv[0]);
51 insert_vert(vert, miga[i]->rbfv[1]);
52 }
53 /* should be just 3 vertices */
54 if ((vert[2] == NULL) | (vert[3] != NULL))
55 return(0);
56 /* identify edge 0 */
57 for (i = 3; i--; )
58 if (miga[i]->rbfv[0] == vert[0] &&
59 miga[i]->rbfv[1] == vert[1]) {
60 ord[0] = miga[i];
61 break;
62 }
63 if (i < 0)
64 return(0);
65 /* identify edge 1 */
66 for (i = 3; i--; )
67 if (miga[i]->rbfv[0] == vert[1] &&
68 miga[i]->rbfv[1] == vert[2]) {
69 ord[1] = miga[i];
70 break;
71 }
72 if (i < 0)
73 return(0);
74 /* identify edge 2 */
75 for (i = 3; i--; )
76 if (miga[i]->rbfv[0] == vert[0] &&
77 miga[i]->rbfv[1] == vert[2]) {
78 ord[2] = miga[i];
79 break;
80 }
81 if (i < 0)
82 return(0);
83 /* reassign order */
84 miga[0] = ord[0]; miga[1] = ord[1]; miga[2] = ord[2];
85 return(1);
86 }
87
88 /* Determine if we are close enough to an edge */
89 static int
90 on_edge(const MIGRATION *ej, const FVECT ivec)
91 {
92 double cos_a, cos_b, cos_c, cos_aplusb;
93 /* use triangle inequality */
94 cos_a = DOT(ej->rbfv[0]->invec, ivec);
95 if (cos_a <= 0)
96 return(0);
97
98 cos_b = DOT(ej->rbfv[1]->invec, ivec);
99 if (cos_b <= 0)
100 return(0);
101
102 cos_aplusb = cos_a*cos_b - sqrt((1.-cos_a*cos_a)*(1.-cos_b*cos_b));
103 if (cos_aplusb <= 0)
104 return(0);
105
106 cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);
107
108 return(cos_c - cos_aplusb < .001);
109 }
110
111 /* Determine if we are inside the given triangle */
112 static int
113 in_tri(const RBFNODE *v1, const RBFNODE *v2, const RBFNODE *v3, const FVECT p)
114 {
115 FVECT vc;
116 int sgn1, sgn2, sgn3;
117 /* signed volume test */
118 VCROSS(vc, v1->invec, v2->invec);
119 sgn1 = (DOT(p, vc) > 0);
120 VCROSS(vc, v2->invec, v3->invec);
121 sgn2 = (DOT(p, vc) > 0);
122 if (sgn1 != sgn2)
123 return(0);
124 VCROSS(vc, v3->invec, v1->invec);
125 sgn3 = (DOT(p, vc) > 0);
126 return(sgn2 == sgn3);
127 }
128
129 /* Test (and set) bitmap for edge */
130 static int
131 check_edge(unsigned char *emap, int nedges, const MIGRATION *mig, int mark)
132 {
133 int ejndx, bit2check;
134
135 if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
136 ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
137 else
138 ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;
139
140 bit2check = 1<<(ejndx&07);
141
142 if (emap[ejndx>>3] & bit2check)
143 return(0);
144 if (mark)
145 emap[ejndx>>3] |= bit2check;
146 return(1);
147 }
148
149 /* Compute intersection with the given position over remaining mesh */
150 static int
151 in_mesh(MIGRATION *miga[3], unsigned char *emap, int nedges,
152 const FVECT ivec, MIGRATION *mig)
153 {
154 RBFNODE *tv[2];
155 MIGRATION *sej[2], *dej[2];
156 int i;
157 /* check visitation record */
158 if (!check_edge(emap, nedges, mig, 1))
159 return(0);
160 if (on_edge(mig, ivec)) {
161 miga[0] = mig; /* close enough to edge */
162 return(1);
163 }
164 if (!get_triangles(tv, mig)) /* do triangles either side? */
165 return(0);
166 for (i = 2; i--; ) { /* identify edges to check */
167 MIGRATION *ej;
168 sej[i] = dej[i] = NULL;
169 if (tv[i] == NULL)
170 continue;
171 for (ej = tv[i]->ejl; ej != NULL; ej = nextedge(tv[i],ej)) {
172 RBFNODE *rbfop = opp_rbf(tv[i],ej);
173 if (rbfop == mig->rbfv[0]) {
174 if (check_edge(emap, nedges, ej, 0))
175 sej[i] = ej;
176 } else if (rbfop == mig->rbfv[1]) {
177 if (check_edge(emap, nedges, ej, 0))
178 dej[i] = ej;
179 }
180 }
181 }
182 for (i = 2; i--; ) { /* check triangles just once */
183 if (sej[i] != NULL && in_mesh(miga, emap, nedges, ivec, sej[i]))
184 return(1);
185 if (dej[i] != NULL && in_mesh(miga, emap, nedges, ivec, dej[i]))
186 return(1);
187 if ((sej[i] == NULL) | (dej[i] == NULL))
188 continue;
189 if (in_tri(mig->rbfv[0], mig->rbfv[1], tv[i], ivec)) {
190 miga[0] = mig;
191 miga[1] = sej[i];
192 miga[2] = dej[i];
193 return(1);
194 }
195 }
196 return(0); /* not near this edge */
197 }
198
199 /* Find edge(s) for interpolating the given vector, applying symmetry */
200 int
201 get_interp(MIGRATION *miga[3], FVECT invec)
202 {
203 miga[0] = miga[1] = miga[2] = NULL;
204 if (single_plane_incident) { /* isotropic BSDF? */
205 RBFNODE *rbf; /* find edge we're on */
206 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
207 if (input_orient*rbf->invec[2] < input_orient*invec[2])
208 break;
209 if (rbf->next != NULL && input_orient*rbf->next->invec[2] <
210 input_orient*invec[2]) {
211 for (miga[0] = rbf->ejl; miga[0] != NULL;
212 miga[0] = nextedge(rbf,miga[0]))
213 if (opp_rbf(rbf,miga[0]) == rbf->next) {
214 double nf = 1. - rbf->invec[2]*rbf->invec[2];
215 if (nf > FTINY) { /* rotate to match */
216 nf = sqrt((1.-invec[2]*invec[2])/nf);
217 invec[0] = nf*rbf->invec[0];
218 invec[1] = nf*rbf->invec[1];
219 }
220 return(0);
221 }
222 break;
223 }
224 }
225 return(-1); /* outside range! */
226 }
227 { /* else use triangle mesh */
228 int sym = use_symmetry(invec);
229 int nedges = 0;
230 MIGRATION *mep;
231 unsigned char *emap;
232 /* clear visitation map */
233 for (mep = mig_list; mep != NULL; mep = mep->next)
234 ++nedges;
235 emap = (unsigned char *)calloc((nedges*(nedges-1) + 7)>>3, 1);
236 if (emap == NULL) {
237 fprintf(stderr, "%s: Out of memory in get_interp()\n",
238 progname);
239 exit(1);
240 }
241 /* identify intersection */
242 if (!in_mesh(miga, emap, nedges, invec, mig_list)) {
243 #ifdef DEBUG
244 fprintf(stderr,
245 "Incident angle (%.1f,%.1f) deg. outside mesh\n",
246 get_theta180(invec), get_phi360(invec));
247 #endif
248 sym = -1; /* outside mesh */
249 } else if (miga[1] != NULL &&
250 (miga[2] == NULL || !order_triangle(miga))) {
251 #ifdef DEBUG
252 fputs("Munged triangle in get_interp()\n", stderr);
253 #endif
254 sym = -1;
255 }
256 free(emap);
257 return(sym); /* return in standard order */
258 }
259 }
260
261 /* Advect and allocate new RBF along edge */
262 static RBFNODE *
263 e_advect_rbf(const MIGRATION *mig, const FVECT invec, int lobe_lim)
264 {
265 double cthresh = FTINY;
266 RBFNODE *rbf;
267 int n, i, j;
268 double t, full_dist;
269 /* get relative position */
270 t = Acos(DOT(invec, mig->rbfv[0]->invec));
271 if (t < M_PI/grid_res) { /* near first DSF */
272 n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
273 rbf = (RBFNODE *)malloc(n);
274 if (rbf == NULL)
275 goto memerr;
276 memcpy(rbf, mig->rbfv[0], n); /* just duplicate */
277 rbf->next = NULL; rbf->ejl = NULL;
278 return(rbf);
279 }
280 full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
281 if (t > full_dist-M_PI/grid_res) { /* near second DSF */
282 n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
283 rbf = (RBFNODE *)malloc(n);
284 if (rbf == NULL)
285 goto memerr;
286 memcpy(rbf, mig->rbfv[1], n); /* just duplicate */
287 rbf->next = NULL; rbf->ejl = NULL;
288 return(rbf);
289 }
290 t /= full_dist;
291 tryagain:
292 n = 0; /* count migrating particles */
293 for (i = 0; i < mtx_nrows(mig); i++)
294 for (j = 0; j < mtx_ncols(mig); j++)
295 n += (mtx_coef(mig,i,j) > cthresh);
296 /* are we over our limit? */
297 if ((lobe_lim > 0) & (n > lobe_lim)) {
298 cthresh = cthresh*2. + 10.*FTINY;
299 goto tryagain;
300 }
301 #ifdef DEBUG
302 fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
303 mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
304 #endif
305 rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
306 if (rbf == NULL)
307 goto memerr;
308 rbf->next = NULL; rbf->ejl = NULL;
309 VCOPY(rbf->invec, invec);
310 rbf->nrbf = n;
311 rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
312 n = 0; /* advect RBF lobes */
313 for (i = 0; i < mtx_nrows(mig); i++) {
314 const RBFVAL *rbf0i = &mig->rbfv[0]->rbfa[i];
315 const float peak0 = rbf0i->peak;
316 const double rad0 = R2ANG(rbf0i->crad);
317 FVECT v0;
318 float mv;
319 ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
320 for (j = 0; j < mtx_ncols(mig); j++)
321 if ((mv = mtx_coef(mig,i,j)) > cthresh) {
322 const RBFVAL *rbf1j = &mig->rbfv[1]->rbfa[j];
323 double rad2;
324 FVECT v;
325 int pos[2];
326 rad2 = R2ANG(rbf1j->crad);
327 rad2 = rad0*rad0*(1.-t) + rad2*rad2*t;
328 rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal *
329 rad0*rad0/rad2;
330 rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
331 ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
332 geodesic(v, v0, v, t, GEOD_REL);
333 pos_from_vec(pos, v);
334 rbf->rbfa[n].gx = pos[0];
335 rbf->rbfa[n].gy = pos[1];
336 ++n;
337 }
338 }
339 rbf->vtotal *= mig->rbfv[0]->vtotal; /* turn ratio into actual */
340 return(rbf);
341 memerr:
342 fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
343 exit(1);
344 return(NULL); /* pro forma return */
345 }
346
347 /* Partially advect between recorded incident angles and allocate new RBF */
348 RBFNODE *
349 advect_rbf(const FVECT invec, int lobe_lim)
350 {
351 double cthresh = FTINY;
352 FVECT sivec;
353 MIGRATION *miga[3];
354 RBFNODE *rbf;
355 int sym;
356 float mbfact, mcfact;
357 int n, i, j, k;
358 FVECT v0, v1, v2;
359 double s, t;
360
361 VCOPY(sivec, invec); /* find triangle/edge */
362 sym = get_interp(miga, sivec);
363 if (sym < 0) /* can't interpolate? */
364 return(NULL);
365 if (miga[1] == NULL) { /* advect along edge? */
366 rbf = e_advect_rbf(miga[0], sivec, lobe_lim);
367 if (single_plane_incident)
368 rotate_rbf(rbf, invec);
369 else
370 rev_rbf_symmetry(rbf, sym);
371 return(rbf);
372 }
373 #ifdef DEBUG
374 if (miga[0]->rbfv[0] != miga[2]->rbfv[0] |
375 miga[0]->rbfv[1] != miga[1]->rbfv[0] |
376 miga[1]->rbfv[1] != miga[2]->rbfv[1]) {
377 fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
378 exit(1);
379 }
380 #endif
381 /* figure out position */
382 fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
383 normalize(v0);
384 fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
385 normalize(v2);
386 fcross(v1, sivec, miga[1]->rbfv[1]->invec);
387 normalize(v1);
388 s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
389 geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
390 s, GEOD_REL);
391 t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
392 tryagain:
393 n = 0; /* count migrating particles */
394 for (i = 0; i < mtx_nrows(miga[0]); i++)
395 for (j = 0; j < mtx_ncols(miga[0]); j++)
396 for (k = (mtx_coef(miga[0],i,j) > cthresh) *
397 mtx_ncols(miga[2]); k--; )
398 n += (mtx_coef(miga[2],i,k) > cthresh ||
399 mtx_coef(miga[1],j,k) > cthresh);
400 /* are we over our limit? */
401 if ((lobe_lim > 0) & (n > lobe_lim)) {
402 cthresh = cthresh*2. + 10.*FTINY;
403 goto tryagain;
404 }
405 #ifdef DEBUG
406 fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
407 miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
408 miga[2]->rbfv[1]->nrbf, n);
409 #endif
410 rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
411 if (rbf == NULL) {
412 fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
413 exit(1);
414 }
415 rbf->next = NULL; rbf->ejl = NULL;
416 VCOPY(rbf->invec, sivec);
417 rbf->nrbf = n;
418 n = 0; /* compute RBF lobes */
419 mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
420 (1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
421 mcfact = (1.-s) *
422 (1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
423 for (i = 0; i < mtx_nrows(miga[0]); i++) {
424 const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
425 const float w0i = rbf0i->peak;
426 const double rad0i = R2ANG(rbf0i->crad);
427 ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
428 for (j = 0; j < mtx_ncols(miga[0]); j++) {
429 const float ma = mtx_coef(miga[0],i,j);
430 const RBFVAL *rbf1j;
431 double srad2;
432 if (ma <= cthresh)
433 continue;
434 rbf1j = &miga[0]->rbfv[1]->rbfa[j];
435 srad2 = R2ANG(rbf1j->crad);
436 srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*srad2*srad2;
437 ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
438 geodesic(v1, v0, v1, s, GEOD_REL);
439 for (k = 0; k < mtx_ncols(miga[2]); k++) {
440 float mb = mtx_coef(miga[1],j,k);
441 float mc = mtx_coef(miga[2],i,k);
442 const RBFVAL *rbf2k;
443 double rad2;
444 int pos[2];
445 if ((mb <= cthresh) & (mc <= cthresh))
446 continue;
447 rbf2k = &miga[2]->rbfv[1]->rbfa[k];
448 rad2 = R2ANG(rbf2k->crad);
449 rad2 = srad2 + t*rad2*rad2;
450 rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact) *
451 rad0i*rad0i/rad2;
452 rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
453 ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
454 geodesic(v2, v1, v2, t, GEOD_REL);
455 pos_from_vec(pos, v2);
456 rbf->rbfa[n].gx = pos[0];
457 rbf->rbfa[n].gy = pos[1];
458 ++n;
459 }
460 }
461 }
462 rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
463 rev_rbf_symmetry(rbf, sym);
464 return(rbf);
465 }