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root/radiance/ray/src/cv/bsdfinterp.c
Revision: 2.2
Committed: Sat Oct 20 07:02:00 2012 UTC (11 years, 6 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.1: +9 -9 lines
Log Message:
Bug fixes and minor improvements

File Contents

# User Rev Content
1 greg 2.1 #ifndef lint
2 greg 2.2 static const char RCSid[] = "$Id: bsdfinterp.c,v 2.1 2012/10/19 04:14:29 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     /* migration edges drawn in raster fashion */
17     MIGRATION *mig_grid[GRIDRES][GRIDRES];
18    
19     #ifdef DEBUG
20     #include "random.h"
21     #include "bmpfile.h"
22     /* Hash pointer to byte value (must return 0 for NULL) */
23     static int
24     byte_hash(const void *p)
25     {
26     size_t h = (size_t)p;
27     h ^= (size_t)p >> 8;
28     h ^= (size_t)p >> 16;
29     h ^= (size_t)p >> 24;
30     return(h & 0xff);
31     }
32     /* Write out BMP image showing edges */
33     static void
34     write_edge_image(const char *fname)
35     {
36     BMPHeader *hdr = BMPmappedHeader(GRIDRES, GRIDRES, 0, 256);
37     BMPWriter *wtr;
38     int i, j;
39    
40     fprintf(stderr, "Writing incident mesh drawing to '%s'\n", fname);
41     hdr->compr = BI_RLE8;
42     for (i = 256; --i; ) { /* assign random color map */
43     hdr->palette[i].r = random() & 0xff;
44     hdr->palette[i].g = random() & 0xff;
45     hdr->palette[i].b = random() & 0xff;
46     /* reject dark colors */
47     i += (hdr->palette[i].r + hdr->palette[i].g +
48     hdr->palette[i].b < 128);
49     }
50     hdr->palette[0].r = hdr->palette[0].g = hdr->palette[0].b = 0;
51     /* open output */
52     wtr = BMPopenOutputFile(fname, hdr);
53     if (wtr == NULL) {
54     free(hdr);
55     return;
56     }
57     for (i = 0; i < GRIDRES; i++) { /* write scanlines */
58     for (j = 0; j < GRIDRES; j++)
59     wtr->scanline[j] = byte_hash(mig_grid[i][j]);
60     if (BMPwriteScanline(wtr) != BIR_OK)
61     break;
62     }
63     BMPcloseOutput(wtr); /* close & clean up */
64     }
65     #endif
66    
67     /* Draw edge list into mig_grid array */
68     void
69     draw_edges(void)
70     {
71     int nnull = 0, ntot = 0;
72     MIGRATION *ej;
73     int p0[2], p1[2];
74    
75     memset(mig_grid, 0, sizeof(mig_grid));
76     for (ej = mig_list; ej != NULL; ej = ej->next) {
77     ++ntot;
78     pos_from_vec(p0, ej->rbfv[0]->invec);
79     pos_from_vec(p1, ej->rbfv[1]->invec);
80     if ((p0[0] == p1[0]) & (p0[1] == p1[1])) {
81     ++nnull;
82     mig_grid[p0[0]][p0[1]] = ej;
83     continue;
84     }
85     if (abs(p1[0]-p0[0]) > abs(p1[1]-p0[1])) {
86     const int xstep = 2*(p1[0] > p0[0]) - 1;
87     const double ystep = (double)((p1[1]-p0[1])*xstep) /
88     (double)(p1[0]-p0[0]);
89     int x;
90     double y;
91     for (x = p0[0], y = p0[1]+.5; x != p1[0];
92     x += xstep, y += ystep)
93     mig_grid[x][(int)y] = ej;
94     mig_grid[x][(int)y] = ej;
95     } else {
96     const int ystep = 2*(p1[1] > p0[1]) - 1;
97     const double xstep = (double)((p1[0]-p0[0])*ystep) /
98     (double)(p1[1]-p0[1]);
99     int y;
100     double x;
101     for (y = p0[1], x = p0[0]+.5; y != p1[1];
102     y += ystep, x += xstep)
103     mig_grid[(int)x][y] = ej;
104     mig_grid[(int)x][y] = ej;
105     }
106     }
107     if (nnull)
108     fprintf(stderr, "Warning: %d of %d edges are null\n",
109     nnull, ntot);
110     #ifdef DEBUG
111     write_edge_image("bsdf_edges.bmp");
112     #endif
113     }
114    
115     /* Identify enclosing triangle for this position (flood fill raster check) */
116     static int
117     identify_tri(MIGRATION *miga[3], unsigned char vmap[GRIDRES][(GRIDRES+7)/8],
118     int px, int py)
119     {
120     const int btest = 1<<(py&07);
121    
122     if (vmap[px][py>>3] & btest) /* already visited here? */
123     return(1);
124     /* else mark it */
125     vmap[px][py>>3] |= btest;
126    
127     if (mig_grid[px][py] != NULL) { /* are we on an edge? */
128     int i;
129     for (i = 0; i < 3; i++) {
130     if (miga[i] == mig_grid[px][py])
131     return(1);
132     if (miga[i] != NULL)
133     continue;
134     miga[i] = mig_grid[px][py];
135     return(1);
136     }
137     return(0); /* outside triangle! */
138     }
139     /* check neighbors (flood) */
140     if (px > 0 && !identify_tri(miga, vmap, px-1, py))
141     return(0);
142     if (px < GRIDRES-1 && !identify_tri(miga, vmap, px+1, py))
143     return(0);
144     if (py > 0 && !identify_tri(miga, vmap, px, py-1))
145     return(0);
146     if (py < GRIDRES-1 && !identify_tri(miga, vmap, px, py+1))
147     return(0);
148     return(1); /* this neighborhood done */
149     }
150    
151     /* Insert vertex in ordered list */
152     static void
153     insert_vert(RBFNODE **vlist, RBFNODE *v)
154     {
155     int i, j;
156    
157     for (i = 0; vlist[i] != NULL; i++) {
158     if (v == vlist[i])
159     return;
160     if (v->ord < vlist[i]->ord)
161     break;
162     }
163     for (j = i; vlist[j] != NULL; j++)
164     ;
165     while (j > i) {
166     vlist[j] = vlist[j-1];
167     --j;
168     }
169     vlist[i] = v;
170     }
171    
172     /* Sort triangle edges in standard order */
173     static int
174     order_triangle(MIGRATION *miga[3])
175     {
176     RBFNODE *vert[7];
177     MIGRATION *ord[3];
178     int i;
179     /* order vertices, first */
180     memset(vert, 0, sizeof(vert));
181     for (i = 3; i--; ) {
182     if (miga[i] == NULL)
183     return(0);
184     insert_vert(vert, miga[i]->rbfv[0]);
185     insert_vert(vert, miga[i]->rbfv[1]);
186     }
187     /* should be just 3 vertices */
188     if ((vert[3] == NULL) | (vert[4] != NULL))
189     return(0);
190     /* identify edge 0 */
191     for (i = 3; i--; )
192     if (miga[i]->rbfv[0] == vert[0] &&
193     miga[i]->rbfv[1] == vert[1]) {
194     ord[0] = miga[i];
195     break;
196     }
197     if (i < 0)
198     return(0);
199     /* identify edge 1 */
200     for (i = 3; i--; )
201     if (miga[i]->rbfv[0] == vert[1] &&
202     miga[i]->rbfv[1] == vert[2]) {
203     ord[1] = miga[i];
204     break;
205     }
206     if (i < 0)
207     return(0);
208     /* identify edge 2 */
209     for (i = 3; i--; )
210     if (miga[i]->rbfv[0] == vert[0] &&
211     miga[i]->rbfv[1] == vert[2]) {
212     ord[2] = miga[i];
213     break;
214     }
215     if (i < 0)
216     return(0);
217     /* reassign order */
218     miga[0] = ord[0]; miga[1] = ord[1]; miga[2] = ord[2];
219     return(1);
220     }
221    
222     /* Find edge(s) for interpolating the given vector, applying symmetry */
223     int
224     get_interp(MIGRATION *miga[3], FVECT invec)
225     {
226     miga[0] = miga[1] = miga[2] = NULL;
227     if (single_plane_incident) { /* isotropic BSDF? */
228     RBFNODE *rbf; /* find edge we're on */
229     for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
230     if (input_orient*rbf->invec[2] < input_orient*invec[2])
231     break;
232     if (rbf->next != NULL &&
233     input_orient*rbf->next->invec[2] <
234     input_orient*invec[2]) {
235     for (miga[0] = rbf->ejl; miga[0] != NULL;
236     miga[0] = nextedge(rbf,miga[0]))
237     if (opp_rbf(rbf,miga[0]) == rbf->next)
238     return(0);
239     break;
240     }
241     }
242     return(-1); /* outside range! */
243     }
244     { /* else use triangle mesh */
245     const int sym = use_symmetry(invec);
246     unsigned char floodmap[GRIDRES][(GRIDRES+7)/8];
247     int pstart[2];
248     RBFNODE *vother;
249     MIGRATION *ej;
250     int i;
251    
252     pos_from_vec(pstart, invec);
253     memset(floodmap, 0, sizeof(floodmap));
254     /* call flooding function */
255     if (!identify_tri(miga, floodmap, pstart[0], pstart[1]))
256     return(-1); /* outside mesh */
257     if ((miga[0] == NULL) | (miga[2] == NULL))
258     return(-1); /* should never happen */
259     if (miga[1] == NULL)
260     return(sym); /* on edge */
261     /* verify triangle */
262     if (!order_triangle(miga)) {
263     #ifdef DEBUG
264     fputs("Munged triangle in get_interp()\n", stderr);
265     #endif
266     vother = NULL; /* find triangle from edge */
267     for (i = 3; i--; ) {
268     RBFNODE *tpair[2];
269     if (get_triangles(tpair, miga[i]) &&
270     (vother = tpair[ is_rev_tri(
271     miga[i]->rbfv[0]->invec,
272     miga[i]->rbfv[1]->invec,
273     invec) ]) != NULL)
274     break;
275     }
276     if (vother == NULL) { /* couldn't find 3rd vertex */
277     #ifdef DEBUG
278     fputs("No triangle in get_interp()\n", stderr);
279     #endif
280     return(-1);
281     }
282     /* reassign other two edges */
283     for (ej = vother->ejl; ej != NULL;
284     ej = nextedge(vother,ej)) {
285     RBFNODE *vorig = opp_rbf(vother,ej);
286     if (vorig == miga[i]->rbfv[0])
287     miga[(i+1)%3] = ej;
288     else if (vorig == miga[i]->rbfv[1])
289     miga[(i+2)%3] = ej;
290     }
291     if (!order_triangle(miga)) {
292     #ifdef DEBUG
293     fputs("Bad triangle in get_interp()\n", stderr);
294     #endif
295     return(-1);
296     }
297     }
298     return(sym); /* return in standard order */
299     }
300     }
301    
302     /* Advect and allocate new RBF along edge */
303     static RBFNODE *
304     e_advect_rbf(const MIGRATION *mig, const FVECT invec)
305     {
306     RBFNODE *rbf;
307     int n, i, j;
308     double t, full_dist;
309     /* get relative position */
310     t = acos(DOT(invec, mig->rbfv[0]->invec));
311     if (t < M_PI/GRIDRES) { /* near first DSF */
312     n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
313     rbf = (RBFNODE *)malloc(n);
314     if (rbf == NULL)
315     goto memerr;
316     memcpy(rbf, mig->rbfv[0], n); /* just duplicate */
317     return(rbf);
318     }
319     full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
320     if (t > full_dist-M_PI/GRIDRES) { /* near second DSF */
321     n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
322     rbf = (RBFNODE *)malloc(n);
323     if (rbf == NULL)
324     goto memerr;
325     memcpy(rbf, mig->rbfv[1], n); /* just duplicate */
326     return(rbf);
327     }
328     t /= full_dist;
329     n = 0; /* count migrating particles */
330     for (i = 0; i < mtx_nrows(mig); i++)
331     for (j = 0; j < mtx_ncols(mig); j++)
332 greg 2.2 n += (mtx_coef(mig,i,j) > FTINY);
333 greg 2.1 #ifdef DEBUG
334     fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
335     mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
336     #endif
337     rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
338     if (rbf == NULL)
339     goto memerr;
340     rbf->next = NULL; rbf->ejl = NULL;
341     VCOPY(rbf->invec, invec);
342     rbf->nrbf = n;
343     rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
344     n = 0; /* advect RBF lobes */
345     for (i = 0; i < mtx_nrows(mig); i++) {
346     const RBFVAL *rbf0i = &mig->rbfv[0]->rbfa[i];
347     const float peak0 = rbf0i->peak;
348     const double rad0 = R2ANG(rbf0i->crad);
349     FVECT v0;
350     float mv;
351     ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
352     for (j = 0; j < mtx_ncols(mig); j++)
353 greg 2.2 if ((mv = mtx_coef(mig,i,j)) > FTINY) {
354 greg 2.1 const RBFVAL *rbf1j = &mig->rbfv[1]->rbfa[j];
355     double rad1 = R2ANG(rbf1j->crad);
356     FVECT v;
357     int pos[2];
358     rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal;
359     rbf->rbfa[n].crad = ANG2R(sqrt(rad0*rad0*(1.-t) +
360     rad1*rad1*t));
361     ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
362     geodesic(v, v0, v, t, GEOD_REL);
363     pos_from_vec(pos, v);
364     rbf->rbfa[n].gx = pos[0];
365     rbf->rbfa[n].gy = pos[1];
366     ++n;
367     }
368     }
369     rbf->vtotal *= mig->rbfv[0]->vtotal; /* turn ratio into actual */
370     return(rbf);
371     memerr:
372     fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
373     exit(1);
374     return(NULL); /* pro forma return */
375     }
376    
377     /* Partially advect between recorded incident angles and allocate new RBF */
378     RBFNODE *
379     advect_rbf(const FVECT invec)
380     {
381     FVECT sivec;
382     MIGRATION *miga[3];
383     RBFNODE *rbf;
384     int sym;
385     float mbfact, mcfact;
386     int n, i, j, k;
387     FVECT v0, v1, v2;
388     double s, t;
389    
390     VCOPY(sivec, invec); /* find triangle/edge */
391     sym = get_interp(miga, sivec);
392     if (sym < 0) /* can't interpolate? */
393     return(NULL);
394     if (miga[1] == NULL) { /* advect along edge? */
395     rbf = e_advect_rbf(miga[0], sivec);
396     rev_rbf_symmetry(rbf, sym);
397     return(rbf);
398     }
399     #ifdef DEBUG
400     if (miga[0]->rbfv[0] != miga[2]->rbfv[0] |
401     miga[0]->rbfv[1] != miga[1]->rbfv[0] |
402     miga[1]->rbfv[1] != miga[2]->rbfv[1]) {
403     fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
404     exit(1);
405     }
406     #endif
407     /* figure out position */
408     fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
409     normalize(v0);
410     fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
411     normalize(v2);
412     fcross(v1, sivec, miga[1]->rbfv[1]->invec);
413     normalize(v1);
414     s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
415     geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
416     s, GEOD_REL);
417     t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
418     n = 0; /* count migrating particles */
419     for (i = 0; i < mtx_nrows(miga[0]); i++)
420     for (j = 0; j < mtx_ncols(miga[0]); j++)
421 greg 2.2 for (k = (mtx_coef(miga[0],i,j) > FTINY) *
422 greg 2.1 mtx_ncols(miga[2]); k--; )
423 greg 2.2 n += (mtx_coef(miga[2],i,k) > FTINY &&
424     mtx_coef(miga[1],j,k) > FTINY);
425 greg 2.1 #ifdef DEBUG
426     fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
427     miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
428     miga[2]->rbfv[1]->nrbf, n);
429     #endif
430     rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
431     if (rbf == NULL) {
432     fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
433     exit(1);
434     }
435     rbf->next = NULL; rbf->ejl = NULL;
436     VCOPY(rbf->invec, sivec);
437     rbf->nrbf = n;
438     n = 0; /* compute RBF lobes */
439     mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
440     (1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
441     mcfact = (1.-s) *
442     (1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
443     for (i = 0; i < mtx_nrows(miga[0]); i++) {
444     const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
445     const float w0i = rbf0i->peak;
446     const double rad0i = R2ANG(rbf0i->crad);
447     ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
448     for (j = 0; j < mtx_ncols(miga[0]); j++) {
449 greg 2.2 const float ma = mtx_coef(miga[0],i,j);
450 greg 2.1 const RBFVAL *rbf1j;
451     double rad1j, srad2;
452     if (ma <= FTINY)
453     continue;
454     rbf1j = &miga[0]->rbfv[1]->rbfa[j];
455     rad1j = R2ANG(rbf1j->crad);
456     srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*rad1j*rad1j;
457     ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
458     geodesic(v1, v0, v1, s, GEOD_REL);
459     for (k = 0; k < mtx_ncols(miga[2]); k++) {
460 greg 2.2 float mb = mtx_coef(miga[1],j,k);
461     float mc = mtx_coef(miga[2],i,k);
462 greg 2.1 const RBFVAL *rbf2k;
463     double rad2k;
464     FVECT vout;
465     int pos[2];
466     if ((mb <= FTINY) | (mc <= FTINY))
467     continue;
468     rbf2k = &miga[2]->rbfv[1]->rbfa[k];
469     rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact);
470     rad2k = R2ANG(rbf2k->crad);
471     rbf->rbfa[n].crad = ANG2R(sqrt(srad2 + t*rad2k*rad2k));
472     ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
473     geodesic(vout, v1, v2, t, GEOD_REL);
474     pos_from_vec(pos, vout);
475     rbf->rbfa[n].gx = pos[0];
476     rbf->rbfa[n].gy = pos[1];
477     ++n;
478     }
479     }
480     }
481     rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
482     rev_rbf_symmetry(rbf, sym);
483     return(rbf);
484     }