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root/radiance/ray/src/cv/bsdfinterp.c
Revision: 2.4
Committed: Tue Oct 23 21:09:29 2012 UTC (11 years, 5 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.3: +62 -35 lines
Log Message:
First semi-working version

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: bsdfinterp.c,v 2.3 2012/10/23 05:10:42 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 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 MIGRATION *ej1, *ej2;
155 RBFNODE *tv;
156 /* check visitation record */
157 if (!check_edge(emap, nedges, mig, 1))
158 return(0);
159 if (on_edge(mig, ivec)) {
160 miga[0] = mig; /* close enough to edge */
161 return(1);
162 }
163 /* do triangles either side */
164 for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
165 ej1 = nextedge(mig->rbfv[0],ej1)) {
166 if (ej1 == mig)
167 continue;
168 tv = opp_rbf(mig->rbfv[0],ej1);
169 for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
170 if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
171 int do_ej1 = check_edge(emap, nedges, ej1, 0);
172 int do_ej2 = check_edge(emap, nedges, ej2, 0);
173 if (do_ej1 && in_mesh(miga, emap, nedges, ivec, ej1))
174 return(1);
175 if (do_ej2 && in_mesh(miga, emap, nedges, ivec, ej2))
176 return(1);
177 /* check just once */
178 if (do_ej1 & do_ej2 && in_tri(mig->rbfv[0],
179 mig->rbfv[1], tv, ivec)) {
180 miga[0] = mig;
181 miga[1] = ej1;
182 miga[2] = ej2;
183 return(1);
184 }
185 }
186 }
187 return(0); /* not near this edge */
188 }
189
190 /* Find edge(s) for interpolating the given vector, applying symmetry */
191 int
192 get_interp(MIGRATION *miga[3], FVECT invec)
193 {
194 miga[0] = miga[1] = miga[2] = NULL;
195 if (single_plane_incident) { /* isotropic BSDF? */
196 RBFNODE *rbf; /* find edge we're on */
197 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
198 if (input_orient*rbf->invec[2] < input_orient*invec[2])
199 break;
200 if (rbf->next != NULL &&
201 input_orient*rbf->next->invec[2] <
202 input_orient*invec[2]) {
203 for (miga[0] = rbf->ejl; miga[0] != NULL;
204 miga[0] = nextedge(rbf,miga[0]))
205 if (opp_rbf(rbf,miga[0]) == rbf->next)
206 return(0);
207 break;
208 }
209 }
210 return(-1); /* outside range! */
211 }
212 { /* else use triangle mesh */
213 int sym = use_symmetry(invec);
214 int nedges = 0;
215 MIGRATION *mep;
216 unsigned char *emap;
217 /* clear visitation map */
218 for (mep = mig_list; mep != NULL; mep = mep->next)
219 ++nedges;
220 emap = (unsigned char *)calloc((nedges*(nedges-1) + 7)>>3, 1);
221 if (emap == NULL) {
222 fprintf(stderr, "%s: Out of memory in get_interp()\n",
223 progname);
224 exit(1);
225 }
226 /* identify intersection */
227 if (!in_mesh(miga, emap, nedges, invec, mig_list))
228 sym = -1; /* outside mesh */
229 else if (miga[1] != NULL &&
230 (miga[2] == NULL || !order_triangle(miga))) {
231 #ifdef DEBUG
232 fputs("Munged triangle in get_interp()\n", stderr);
233 #endif
234 sym = -1;
235 }
236 free(emap);
237 return(sym); /* return in standard order */
238 }
239 }
240
241 /* Advect and allocate new RBF along edge */
242 static RBFNODE *
243 e_advect_rbf(const MIGRATION *mig, const FVECT invec)
244 {
245 RBFNODE *rbf;
246 int n, i, j;
247 double t, full_dist;
248 /* get relative position */
249 t = acos(DOT(invec, mig->rbfv[0]->invec));
250 if (t < M_PI/GRIDRES) { /* near first DSF */
251 n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
252 rbf = (RBFNODE *)malloc(n);
253 if (rbf == NULL)
254 goto memerr;
255 memcpy(rbf, mig->rbfv[0], n); /* just duplicate */
256 return(rbf);
257 }
258 full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
259 if (t > full_dist-M_PI/GRIDRES) { /* near second DSF */
260 n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
261 rbf = (RBFNODE *)malloc(n);
262 if (rbf == NULL)
263 goto memerr;
264 memcpy(rbf, mig->rbfv[1], n); /* just duplicate */
265 return(rbf);
266 }
267 t /= full_dist;
268 n = 0; /* count migrating particles */
269 for (i = 0; i < mtx_nrows(mig); i++)
270 for (j = 0; j < mtx_ncols(mig); j++)
271 n += (mtx_coef(mig,i,j) > FTINY);
272 #ifdef DEBUG
273 fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
274 mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
275 #endif
276 rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
277 if (rbf == NULL)
278 goto memerr;
279 rbf->next = NULL; rbf->ejl = NULL;
280 VCOPY(rbf->invec, invec);
281 rbf->nrbf = n;
282 rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
283 n = 0; /* advect RBF lobes */
284 for (i = 0; i < mtx_nrows(mig); i++) {
285 const RBFVAL *rbf0i = &mig->rbfv[0]->rbfa[i];
286 const float peak0 = rbf0i->peak;
287 const double rad0 = R2ANG(rbf0i->crad);
288 FVECT v0;
289 float mv;
290 ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
291 for (j = 0; j < mtx_ncols(mig); j++)
292 if ((mv = mtx_coef(mig,i,j)) > FTINY) {
293 const RBFVAL *rbf1j = &mig->rbfv[1]->rbfa[j];
294 double rad1 = R2ANG(rbf1j->crad);
295 FVECT v;
296 int pos[2];
297 rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal;
298 rbf->rbfa[n].crad = ANG2R(sqrt(rad0*rad0*(1.-t) +
299 rad1*rad1*t));
300 ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
301 geodesic(v, v0, v, t, GEOD_REL);
302 pos_from_vec(pos, v);
303 rbf->rbfa[n].gx = pos[0];
304 rbf->rbfa[n].gy = pos[1];
305 ++n;
306 }
307 }
308 rbf->vtotal *= mig->rbfv[0]->vtotal; /* turn ratio into actual */
309 return(rbf);
310 memerr:
311 fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
312 exit(1);
313 return(NULL); /* pro forma return */
314 }
315
316 /* Partially advect between recorded incident angles and allocate new RBF */
317 RBFNODE *
318 advect_rbf(const FVECT invec)
319 {
320 FVECT sivec;
321 MIGRATION *miga[3];
322 RBFNODE *rbf;
323 int sym;
324 float mbfact, mcfact;
325 int n, i, j, k;
326 FVECT v0, v1, v2;
327 double s, t;
328
329 VCOPY(sivec, invec); /* find triangle/edge */
330 sym = get_interp(miga, sivec);
331 if (sym < 0) /* can't interpolate? */
332 return(NULL);
333 if (miga[1] == NULL) { /* advect along edge? */
334 rbf = e_advect_rbf(miga[0], sivec);
335 rev_rbf_symmetry(rbf, sym);
336 return(rbf);
337 }
338 #ifdef DEBUG
339 if (miga[0]->rbfv[0] != miga[2]->rbfv[0] |
340 miga[0]->rbfv[1] != miga[1]->rbfv[0] |
341 miga[1]->rbfv[1] != miga[2]->rbfv[1]) {
342 fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
343 exit(1);
344 }
345 #endif
346 /* figure out position */
347 fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
348 normalize(v0);
349 fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
350 normalize(v2);
351 fcross(v1, sivec, miga[1]->rbfv[1]->invec);
352 normalize(v1);
353 s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
354 geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
355 s, GEOD_REL);
356 t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
357 n = 0; /* count migrating particles */
358 for (i = 0; i < mtx_nrows(miga[0]); i++)
359 for (j = 0; j < mtx_ncols(miga[0]); j++)
360 for (k = (mtx_coef(miga[0],i,j) > FTINY) *
361 mtx_ncols(miga[2]); k--; )
362 n += (mtx_coef(miga[2],i,k) > FTINY ||
363 mtx_coef(miga[1],j,k) > FTINY);
364 #ifdef DEBUG
365 fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
366 miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
367 miga[2]->rbfv[1]->nrbf, n);
368 #endif
369 rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
370 if (rbf == NULL) {
371 fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
372 exit(1);
373 }
374 rbf->next = NULL; rbf->ejl = NULL;
375 VCOPY(rbf->invec, sivec);
376 rbf->nrbf = n;
377 n = 0; /* compute RBF lobes */
378 mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
379 (1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
380 mcfact = (1.-s) *
381 (1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
382 for (i = 0; i < mtx_nrows(miga[0]); i++) {
383 const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
384 const float w0i = rbf0i->peak;
385 const double rad0i = R2ANG(rbf0i->crad);
386 ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
387 for (j = 0; j < mtx_ncols(miga[0]); j++) {
388 const float ma = mtx_coef(miga[0],i,j);
389 const RBFVAL *rbf1j;
390 double rad1j, srad2;
391 if (ma <= FTINY)
392 continue;
393 rbf1j = &miga[0]->rbfv[1]->rbfa[j];
394 rad1j = R2ANG(rbf1j->crad);
395 srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*rad1j*rad1j;
396 ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
397 geodesic(v1, v0, v1, s, GEOD_REL);
398 for (k = 0; k < mtx_ncols(miga[2]); k++) {
399 float mb = mtx_coef(miga[1],j,k);
400 float mc = mtx_coef(miga[2],i,k);
401 const RBFVAL *rbf2k;
402 double rad2k;
403 FVECT vout;
404 int pos[2];
405 if ((mb <= FTINY) & (mc <= FTINY))
406 continue;
407 rbf2k = &miga[2]->rbfv[1]->rbfa[k];
408 rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact);
409 rad2k = R2ANG(rbf2k->crad);
410 rbf->rbfa[n].crad = ANG2R(sqrt(srad2 + t*rad2k*rad2k));
411 ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
412 geodesic(vout, v1, v2, t, GEOD_REL);
413 pos_from_vec(pos, vout);
414 rbf->rbfa[n].gx = pos[0];
415 rbf->rbfa[n].gy = pos[1];
416 ++n;
417 }
418 }
419 }
420 rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
421 rev_rbf_symmetry(rbf, sym);
422 return(rbf);
423 }