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root/radiance/ray/src/cv/bsdfinterp.c
Revision: 2.3
Committed: Tue Oct 23 05:10:42 2012 UTC (11 years, 6 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.2: +96 -184 lines
Log Message:
Hopeful bug fix in BSDF interpolation code

File Contents

# User Rev Content
1 greg 2.1 #ifndef lint
2 greg 2.3 static const char RCSid[] = "$Id: bsdfinterp.c,v 2.2 2012/10/20 07:02:00 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     if ((vert[3] == NULL) | (vert[4] != 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 greg 2.3 /* Determine if we are close enough to the given edge */
89     static int
90     on_edge(const MIGRATION *ej, const FVECT ivec)
91     {
92     double cos_a = DOT(ej->rbfv[0]->invec, ivec);
93     double cos_b = DOT(ej->rbfv[1]->invec, ivec);
94     double cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);
95     double cos_aplusb = cos_a*cos_b -
96     sqrt((1.-cos_a*cos_a)*(1.-cos_b*cos_b));
97    
98     return(cos_aplusb - cos_c < .01);
99     }
100    
101     /* Determine if we are inside the given triangle */
102     static int
103     in_tri(const RBFNODE *v1, const RBFNODE *v2, const RBFNODE *v3, const FVECT p)
104     {
105     FVECT vc;
106     int sgn1, sgn2, sgn3;
107     /* signed volume test */
108     VCROSS(vc, v1->invec, v2->invec);
109     sgn1 = (DOT(p, vc) > 0);
110     VCROSS(vc, v2->invec, v3->invec);
111     sgn2 = (DOT(p, vc) > 0);
112     if (sgn1 != sgn2)
113     return(0);
114     VCROSS(vc, v3->invec, v1->invec);
115     sgn3 = (DOT(p, vc) > 0);
116     return(sgn2 == sgn3);
117     }
118    
119     /* Compute intersection with the given position over remaining mesh */
120     static int
121     in_mesh(MIGRATION *miga[3], unsigned char *emap, int nedges,
122     const FVECT ivec, MIGRATION *mig)
123     {
124     MIGRATION *ej1, *ej2;
125     RBFNODE *tv;
126     int ejndx;
127     /* check visitation record */
128     if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
129     ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
130     else
131     ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;
132     if (emap[ejndx>>3] & 1<<(ejndx&07)) /* tested already? */
133     return(0);
134     emap[ejndx>>3] |= 1<<(ejndx&07); /* else mark & test it */
135     if (on_edge(mig, ivec)) {
136     miga[0] = mig; /* close enough to edge */
137     return(1);
138     }
139     /* do triangles either side */
140     for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
141     ej1 = nextedge(mig->rbfv[0],ej1)) {
142     if (ej1 == mig)
143     continue;
144     tv = opp_rbf(mig->rbfv[0],ej1);
145     for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
146     if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
147     if (in_mesh(miga, emap, nedges, ivec, ej1))
148     return(1);
149     if (in_mesh(miga, emap, nedges, ivec, ej2))
150     return(1);
151     if (in_tri(mig->rbfv[0], mig->rbfv[1],
152     tv, ivec)) {
153     miga[0] = mig;
154     miga[1] = ej1;
155     miga[2] = ej2;
156     return(1);
157     }
158     }
159     }
160     return(0);
161     }
162    
163 greg 2.1 /* Find edge(s) for interpolating the given vector, applying symmetry */
164     int
165     get_interp(MIGRATION *miga[3], FVECT invec)
166     {
167     miga[0] = miga[1] = miga[2] = NULL;
168     if (single_plane_incident) { /* isotropic BSDF? */
169     RBFNODE *rbf; /* find edge we're on */
170     for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
171     if (input_orient*rbf->invec[2] < input_orient*invec[2])
172     break;
173     if (rbf->next != NULL &&
174     input_orient*rbf->next->invec[2] <
175     input_orient*invec[2]) {
176     for (miga[0] = rbf->ejl; miga[0] != NULL;
177     miga[0] = nextedge(rbf,miga[0]))
178     if (opp_rbf(rbf,miga[0]) == rbf->next)
179     return(0);
180     break;
181     }
182     }
183     return(-1); /* outside range! */
184     }
185     { /* else use triangle mesh */
186 greg 2.3 int sym = use_symmetry(invec);
187     int nedges = 0;
188     MIGRATION *mep;
189     unsigned char *emap;
190     /* clear visitation map */
191     for (mep = mig_list; mep != NULL; mep = mep->next)
192     ++nedges;
193     emap = (unsigned char *)calloc((nedges*(nedges-1) + 7)>>3, 1);
194     if (emap == NULL) {
195     fprintf(stderr, "%s: Out of memory in get_interp()\n",
196     progname);
197     exit(1);
198     }
199     /* identify intersection */
200     if (!in_mesh(miga, emap, nedges, invec, mig_list))
201     sym = -1; /* outside mesh */
202     else if (miga[1] != NULL &&
203     (miga[2] == NULL || !order_triangle(miga))) {
204 greg 2.1 #ifdef DEBUG
205     fputs("Munged triangle in get_interp()\n", stderr);
206     #endif
207 greg 2.3 sym = -1;
208 greg 2.1 }
209 greg 2.3 free(emap);
210 greg 2.1 return(sym); /* return in standard order */
211     }
212     }
213    
214     /* Advect and allocate new RBF along edge */
215     static RBFNODE *
216     e_advect_rbf(const MIGRATION *mig, const FVECT invec)
217     {
218     RBFNODE *rbf;
219     int n, i, j;
220     double t, full_dist;
221     /* get relative position */
222     t = acos(DOT(invec, mig->rbfv[0]->invec));
223     if (t < M_PI/GRIDRES) { /* near first DSF */
224     n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
225     rbf = (RBFNODE *)malloc(n);
226     if (rbf == NULL)
227     goto memerr;
228     memcpy(rbf, mig->rbfv[0], n); /* just duplicate */
229     return(rbf);
230     }
231     full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
232     if (t > full_dist-M_PI/GRIDRES) { /* near second DSF */
233     n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
234     rbf = (RBFNODE *)malloc(n);
235     if (rbf == NULL)
236     goto memerr;
237     memcpy(rbf, mig->rbfv[1], n); /* just duplicate */
238     return(rbf);
239     }
240     t /= full_dist;
241     n = 0; /* count migrating particles */
242     for (i = 0; i < mtx_nrows(mig); i++)
243     for (j = 0; j < mtx_ncols(mig); j++)
244 greg 2.2 n += (mtx_coef(mig,i,j) > FTINY);
245 greg 2.1 #ifdef DEBUG
246     fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
247     mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
248     #endif
249     rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
250     if (rbf == NULL)
251     goto memerr;
252     rbf->next = NULL; rbf->ejl = NULL;
253     VCOPY(rbf->invec, invec);
254     rbf->nrbf = n;
255     rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
256     n = 0; /* advect RBF lobes */
257     for (i = 0; i < mtx_nrows(mig); i++) {
258     const RBFVAL *rbf0i = &mig->rbfv[0]->rbfa[i];
259     const float peak0 = rbf0i->peak;
260     const double rad0 = R2ANG(rbf0i->crad);
261     FVECT v0;
262     float mv;
263     ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
264     for (j = 0; j < mtx_ncols(mig); j++)
265 greg 2.2 if ((mv = mtx_coef(mig,i,j)) > FTINY) {
266 greg 2.1 const RBFVAL *rbf1j = &mig->rbfv[1]->rbfa[j];
267     double rad1 = R2ANG(rbf1j->crad);
268     FVECT v;
269     int pos[2];
270     rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal;
271     rbf->rbfa[n].crad = ANG2R(sqrt(rad0*rad0*(1.-t) +
272     rad1*rad1*t));
273     ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
274     geodesic(v, v0, v, t, GEOD_REL);
275     pos_from_vec(pos, v);
276     rbf->rbfa[n].gx = pos[0];
277     rbf->rbfa[n].gy = pos[1];
278     ++n;
279     }
280     }
281     rbf->vtotal *= mig->rbfv[0]->vtotal; /* turn ratio into actual */
282     return(rbf);
283     memerr:
284     fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
285     exit(1);
286     return(NULL); /* pro forma return */
287     }
288    
289     /* Partially advect between recorded incident angles and allocate new RBF */
290     RBFNODE *
291     advect_rbf(const FVECT invec)
292     {
293     FVECT sivec;
294     MIGRATION *miga[3];
295     RBFNODE *rbf;
296     int sym;
297     float mbfact, mcfact;
298     int n, i, j, k;
299     FVECT v0, v1, v2;
300     double s, t;
301    
302     VCOPY(sivec, invec); /* find triangle/edge */
303     sym = get_interp(miga, sivec);
304     if (sym < 0) /* can't interpolate? */
305     return(NULL);
306     if (miga[1] == NULL) { /* advect along edge? */
307     rbf = e_advect_rbf(miga[0], sivec);
308     rev_rbf_symmetry(rbf, sym);
309     return(rbf);
310     }
311     #ifdef DEBUG
312     if (miga[0]->rbfv[0] != miga[2]->rbfv[0] |
313     miga[0]->rbfv[1] != miga[1]->rbfv[0] |
314     miga[1]->rbfv[1] != miga[2]->rbfv[1]) {
315     fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
316     exit(1);
317     }
318     #endif
319     /* figure out position */
320     fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
321     normalize(v0);
322     fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
323     normalize(v2);
324     fcross(v1, sivec, miga[1]->rbfv[1]->invec);
325     normalize(v1);
326     s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
327     geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
328     s, GEOD_REL);
329     t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
330     n = 0; /* count migrating particles */
331     for (i = 0; i < mtx_nrows(miga[0]); i++)
332     for (j = 0; j < mtx_ncols(miga[0]); j++)
333 greg 2.2 for (k = (mtx_coef(miga[0],i,j) > FTINY) *
334 greg 2.1 mtx_ncols(miga[2]); k--; )
335 greg 2.2 n += (mtx_coef(miga[2],i,k) > FTINY &&
336     mtx_coef(miga[1],j,k) > FTINY);
337 greg 2.1 #ifdef DEBUG
338     fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
339     miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
340     miga[2]->rbfv[1]->nrbf, n);
341     #endif
342     rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
343     if (rbf == NULL) {
344     fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
345     exit(1);
346     }
347     rbf->next = NULL; rbf->ejl = NULL;
348     VCOPY(rbf->invec, sivec);
349     rbf->nrbf = n;
350     n = 0; /* compute RBF lobes */
351     mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
352     (1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
353     mcfact = (1.-s) *
354     (1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
355     for (i = 0; i < mtx_nrows(miga[0]); i++) {
356     const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
357     const float w0i = rbf0i->peak;
358     const double rad0i = R2ANG(rbf0i->crad);
359     ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
360     for (j = 0; j < mtx_ncols(miga[0]); j++) {
361 greg 2.2 const float ma = mtx_coef(miga[0],i,j);
362 greg 2.1 const RBFVAL *rbf1j;
363     double rad1j, srad2;
364     if (ma <= FTINY)
365     continue;
366     rbf1j = &miga[0]->rbfv[1]->rbfa[j];
367     rad1j = R2ANG(rbf1j->crad);
368     srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*rad1j*rad1j;
369     ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
370     geodesic(v1, v0, v1, s, GEOD_REL);
371     for (k = 0; k < mtx_ncols(miga[2]); k++) {
372 greg 2.2 float mb = mtx_coef(miga[1],j,k);
373     float mc = mtx_coef(miga[2],i,k);
374 greg 2.1 const RBFVAL *rbf2k;
375     double rad2k;
376     FVECT vout;
377     int pos[2];
378     if ((mb <= FTINY) | (mc <= FTINY))
379     continue;
380     rbf2k = &miga[2]->rbfv[1]->rbfa[k];
381     rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact);
382     rad2k = R2ANG(rbf2k->crad);
383     rbf->rbfa[n].crad = ANG2R(sqrt(srad2 + t*rad2k*rad2k));
384     ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
385     geodesic(vout, v1, v2, t, GEOD_REL);
386     pos_from_vec(pos, vout);
387     rbf->rbfa[n].gx = pos[0];
388     rbf->rbfa[n].gy = pos[1];
389     ++n;
390     }
391     }
392     }
393     rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
394     rev_rbf_symmetry(rbf, sym);
395     return(rbf);
396     }