ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/cv/bsdfinterp.c
Revision: 2.18
Committed: Mon Mar 24 17:22:33 2014 UTC (10 years ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R2
Changes since 2.17: +6 -5 lines
Log Message:
Major bug in isotropic material interpolation near normal

File Contents

# User Rev Content
1 greg 2.1 #ifndef lint
2 greg 2.18 static const char RCSid[] = "$Id: bsdfinterp.c,v 2.17 2014/02/19 05:16:06 greg Exp $";
3 greg 2.1 #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 greg 2.4 if ((vert[2] == NULL) | (vert[3] != NULL))
55 greg 2.1 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 greg 2.4 /* Determine if we are close enough to an edge */
89 greg 2.3 static int
90     on_edge(const MIGRATION *ej, const FVECT ivec)
91     {
92 greg 2.4 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 greg 2.15 if (cos_a >= 1.) /* handles rounding error */
98     return(1);
99 greg 2.4
100     cos_b = DOT(ej->rbfv[1]->invec, ivec);
101     if (cos_b <= 0)
102     return(0);
103 greg 2.15 if (cos_b >= 1.)
104     return(1);
105 greg 2.3
106 greg 2.4 cos_aplusb = cos_a*cos_b - sqrt((1.-cos_a*cos_a)*(1.-cos_b*cos_b));
107     if (cos_aplusb <= 0)
108     return(0);
109    
110     cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);
111    
112     return(cos_c - cos_aplusb < .001);
113 greg 2.3 }
114    
115     /* Determine if we are inside the given triangle */
116     static int
117     in_tri(const RBFNODE *v1, const RBFNODE *v2, const RBFNODE *v3, const FVECT p)
118     {
119     FVECT vc;
120     int sgn1, sgn2, sgn3;
121     /* signed volume test */
122     VCROSS(vc, v1->invec, v2->invec);
123     sgn1 = (DOT(p, vc) > 0);
124     VCROSS(vc, v2->invec, v3->invec);
125     sgn2 = (DOT(p, vc) > 0);
126     if (sgn1 != sgn2)
127     return(0);
128     VCROSS(vc, v3->invec, v1->invec);
129     sgn3 = (DOT(p, vc) > 0);
130     return(sgn2 == sgn3);
131     }
132    
133 greg 2.6 /* Test (and set) bitmap for edge */
134 greg 2.4 static int
135     check_edge(unsigned char *emap, int nedges, const MIGRATION *mig, int mark)
136     {
137     int ejndx, bit2check;
138    
139     if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
140     ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
141     else
142     ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;
143    
144     bit2check = 1<<(ejndx&07);
145    
146     if (emap[ejndx>>3] & bit2check)
147     return(0);
148     if (mark)
149     emap[ejndx>>3] |= bit2check;
150     return(1);
151     }
152    
153 greg 2.3 /* Compute intersection with the given position over remaining mesh */
154     static int
155     in_mesh(MIGRATION *miga[3], unsigned char *emap, int nedges,
156     const FVECT ivec, MIGRATION *mig)
157     {
158 greg 2.9 RBFNODE *tv[2];
159     MIGRATION *sej[2], *dej[2];
160     int i;
161 greg 2.3 /* check visitation record */
162 greg 2.4 if (!check_edge(emap, nedges, mig, 1))
163 greg 2.3 return(0);
164     if (on_edge(mig, ivec)) {
165     miga[0] = mig; /* close enough to edge */
166     return(1);
167     }
168 greg 2.9 if (!get_triangles(tv, mig)) /* do triangles either side? */
169     return(0);
170     for (i = 2; i--; ) { /* identify edges to check */
171     MIGRATION *ej;
172     sej[i] = dej[i] = NULL;
173     if (tv[i] == NULL)
174     continue;
175     for (ej = tv[i]->ejl; ej != NULL; ej = nextedge(tv[i],ej)) {
176     RBFNODE *rbfop = opp_rbf(tv[i],ej);
177     if (rbfop == mig->rbfv[0]) {
178     if (check_edge(emap, nedges, ej, 0))
179     sej[i] = ej;
180     } else if (rbfop == mig->rbfv[1]) {
181     if (check_edge(emap, nedges, ej, 0))
182     dej[i] = ej;
183 greg 2.3 }
184 greg 2.4 }
185 greg 2.3 }
186 greg 2.9 for (i = 2; i--; ) { /* check triangles just once */
187     if (sej[i] != NULL && in_mesh(miga, emap, nedges, ivec, sej[i]))
188     return(1);
189     if (dej[i] != NULL && in_mesh(miga, emap, nedges, ivec, dej[i]))
190     return(1);
191     if ((sej[i] == NULL) | (dej[i] == NULL))
192     continue;
193     if (in_tri(mig->rbfv[0], mig->rbfv[1], tv[i], ivec)) {
194     miga[0] = mig;
195     miga[1] = sej[i];
196     miga[2] = dej[i];
197     return(1);
198     }
199     }
200 greg 2.4 return(0); /* not near this edge */
201 greg 2.3 }
202    
203 greg 2.1 /* Find edge(s) for interpolating the given vector, applying symmetry */
204     int
205     get_interp(MIGRATION *miga[3], FVECT invec)
206     {
207     miga[0] = miga[1] = miga[2] = NULL;
208     if (single_plane_incident) { /* isotropic BSDF? */
209 greg 2.10 RBFNODE *rbf; /* find edge we're on */
210     for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
211 greg 2.16 if (input_orient*rbf->invec[2] < input_orient*invec[2]-FTINY)
212 greg 2.10 break;
213     if (rbf->next != NULL && input_orient*rbf->next->invec[2] <
214 greg 2.16 input_orient*invec[2]+FTINY) {
215 greg 2.10 for (miga[0] = rbf->ejl; miga[0] != NULL;
216     miga[0] = nextedge(rbf,miga[0]))
217     if (opp_rbf(rbf,miga[0]) == rbf->next) {
218 greg 2.18 double nf = 1. -
219     rbf->next->invec[2]*rbf->next->invec[2];
220 greg 2.10 if (nf > FTINY) { /* rotate to match */
221     nf = sqrt((1.-invec[2]*invec[2])/nf);
222 greg 2.18 invec[0] = nf*rbf->next->invec[0];
223     invec[1] = nf*rbf->next->invec[1];
224 greg 2.10 }
225 greg 2.18 return(0); /* rotational symmetry */
226 greg 2.1 }
227 greg 2.10 break;
228 greg 2.1 }
229 greg 2.10 }
230     return(-1); /* outside range! */
231 greg 2.1 }
232     { /* else use triangle mesh */
233 greg 2.3 int sym = use_symmetry(invec);
234     int nedges = 0;
235     MIGRATION *mep;
236     unsigned char *emap;
237     /* clear visitation map */
238     for (mep = mig_list; mep != NULL; mep = mep->next)
239     ++nedges;
240     emap = (unsigned char *)calloc((nedges*(nedges-1) + 7)>>3, 1);
241     if (emap == NULL) {
242     fprintf(stderr, "%s: Out of memory in get_interp()\n",
243     progname);
244     exit(1);
245     }
246     /* identify intersection */
247 greg 2.9 if (!in_mesh(miga, emap, nedges, invec, mig_list)) {
248     #ifdef DEBUG
249     fprintf(stderr,
250     "Incident angle (%.1f,%.1f) deg. outside mesh\n",
251     get_theta180(invec), get_phi360(invec));
252     #endif
253 greg 2.3 sym = -1; /* outside mesh */
254 greg 2.9 } else if (miga[1] != NULL &&
255 greg 2.3 (miga[2] == NULL || !order_triangle(miga))) {
256 greg 2.1 #ifdef DEBUG
257     fputs("Munged triangle in get_interp()\n", stderr);
258     #endif
259 greg 2.3 sym = -1;
260 greg 2.1 }
261 greg 2.3 free(emap);
262 greg 2.1 return(sym); /* return in standard order */
263     }
264     }
265    
266 greg 2.16 /* Advect between recorded incident angles and allocate new RBF */
267 greg 2.1 RBFNODE *
268 greg 2.12 advect_rbf(const FVECT invec, int lobe_lim)
269 greg 2.1 {
270 greg 2.12 double cthresh = FTINY;
271 greg 2.1 FVECT sivec;
272     MIGRATION *miga[3];
273     RBFNODE *rbf;
274     int sym;
275     float mbfact, mcfact;
276     int n, i, j, k;
277     FVECT v0, v1, v2;
278 greg 2.8 double s, t;
279 greg 2.1
280     VCOPY(sivec, invec); /* find triangle/edge */
281     sym = get_interp(miga, sivec);
282     if (sym < 0) /* can't interpolate? */
283     return(NULL);
284     if (miga[1] == NULL) { /* advect along edge? */
285 greg 2.13 rbf = e_advect_rbf(miga[0], sivec, lobe_lim);
286 greg 2.5 if (single_plane_incident)
287     rotate_rbf(rbf, invec);
288     else
289     rev_rbf_symmetry(rbf, sym);
290 greg 2.1 return(rbf);
291     }
292     #ifdef DEBUG
293 greg 2.16 if ((miga[0]->rbfv[0] != miga[2]->rbfv[0]) |
294     (miga[0]->rbfv[1] != miga[1]->rbfv[0]) |
295     (miga[1]->rbfv[1] != miga[2]->rbfv[1])) {
296 greg 2.1 fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
297     exit(1);
298     }
299     #endif
300     /* figure out position */
301     fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
302     normalize(v0);
303     fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
304     normalize(v2);
305     fcross(v1, sivec, miga[1]->rbfv[1]->invec);
306     normalize(v1);
307 greg 2.7 s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
308 greg 2.1 geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
309 greg 2.7 s, GEOD_REL);
310 greg 2.8 t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
311 greg 2.12 tryagain:
312 greg 2.1 n = 0; /* count migrating particles */
313     for (i = 0; i < mtx_nrows(miga[0]); i++)
314     for (j = 0; j < mtx_ncols(miga[0]); j++)
315 greg 2.12 for (k = (mtx_coef(miga[0],i,j) > cthresh) *
316 greg 2.1 mtx_ncols(miga[2]); k--; )
317 greg 2.12 n += (mtx_coef(miga[2],i,k) > cthresh ||
318     mtx_coef(miga[1],j,k) > cthresh);
319 greg 2.13 /* are we over our limit? */
320 greg 2.12 if ((lobe_lim > 0) & (n > lobe_lim)) {
321     cthresh = cthresh*2. + 10.*FTINY;
322     goto tryagain;
323     }
324 greg 2.1 #ifdef DEBUG
325     fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
326     miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
327     miga[2]->rbfv[1]->nrbf, n);
328     #endif
329     rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
330     if (rbf == NULL) {
331     fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
332     exit(1);
333     }
334     rbf->next = NULL; rbf->ejl = NULL;
335     VCOPY(rbf->invec, sivec);
336     rbf->nrbf = n;
337     n = 0; /* compute RBF lobes */
338     mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
339     (1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
340     mcfact = (1.-s) *
341     (1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
342     for (i = 0; i < mtx_nrows(miga[0]); i++) {
343     const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
344     const float w0i = rbf0i->peak;
345     const double rad0i = R2ANG(rbf0i->crad);
346     ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
347     for (j = 0; j < mtx_ncols(miga[0]); j++) {
348 greg 2.2 const float ma = mtx_coef(miga[0],i,j);
349 greg 2.1 const RBFVAL *rbf1j;
350 greg 2.14 double srad2;
351 greg 2.12 if (ma <= cthresh)
352 greg 2.1 continue;
353     rbf1j = &miga[0]->rbfv[1]->rbfa[j];
354 greg 2.14 srad2 = R2ANG(rbf1j->crad);
355     srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*srad2*srad2;
356 greg 2.1 ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
357 greg 2.7 geodesic(v1, v0, v1, s, GEOD_REL);
358 greg 2.1 for (k = 0; k < mtx_ncols(miga[2]); k++) {
359 greg 2.2 float mb = mtx_coef(miga[1],j,k);
360     float mc = mtx_coef(miga[2],i,k);
361 greg 2.1 const RBFVAL *rbf2k;
362 greg 2.14 double rad2;
363 greg 2.1 int pos[2];
364 greg 2.12 if ((mb <= cthresh) & (mc <= cthresh))
365 greg 2.1 continue;
366     rbf2k = &miga[2]->rbfv[1]->rbfa[k];
367 greg 2.14 rad2 = R2ANG(rbf2k->crad);
368     rad2 = srad2 + t*rad2*rad2;
369     rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact) *
370     rad0i*rad0i/rad2;
371     rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
372 greg 2.1 ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
373 greg 2.8 geodesic(v2, v1, v2, t, GEOD_REL);
374     pos_from_vec(pos, v2);
375 greg 2.1 rbf->rbfa[n].gx = pos[0];
376     rbf->rbfa[n].gy = pos[1];
377     ++n;
378     }
379     }
380     }
381     rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
382     rev_rbf_symmetry(rbf, sym);
383     return(rbf);
384     }