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root/radiance/ray/src/cv/pabopto2xml.c
Revision: 2.2
Committed: Fri Aug 24 20:55:28 2012 UTC (11 years, 9 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.1: +64 -63 lines
Log Message:
Getting closer on initial estimate -- need to add optimization

File Contents

# User Rev Content
1 greg 2.1 #ifndef lint
2 greg 2.2 static const char RCSid[] = "$Id: pabopto2xml.c,v 2.1 2012/08/24 15:20:18 greg Exp $";
3 greg 2.1 #endif
4     /*
5     * Convert PAB-Opto measurements to XML format using tensor tree representation
6     * Employs Bonneel et al. Earth Mover's Distance interpolant.
7     *
8     * G.Ward
9     */
10    
11     #define _USE_MATH_DEFINES
12     #include <stdio.h>
13     #include <stdlib.h>
14     #include <string.h>
15     #include <ctype.h>
16     #include <math.h>
17     #include "bsdf.h"
18    
19     #ifndef GRIDRES
20     #define GRIDRES 200 /* max. grid resolution per side */
21     #endif
22    
23 greg 2.2 #define RSCA 3. /* radius scaling factor (empirical) */
24     #define MSCA .2 /* magnitude scaling (empirical) */
25    
26     #define R2ANG(c) (((c)+.5)*(M_PI/(1<<16)))
27     #define ANG2R(r) (int)((r)*((1<<16)/M_PI))
28 greg 2.1
29     typedef struct {
30     float vsum; /* BSDF sum */
31     unsigned short nval; /* number of values in sum */
32 greg 2.2 unsigned short crad; /* radius (coded angle) */
33 greg 2.1 } GRIDVAL; /* grid value */
34    
35     typedef struct {
36 greg 2.2 float bsdf; /* lobe value at peak */
37     unsigned short crad; /* radius (coded angle) */
38 greg 2.1 unsigned char gx, gy; /* grid position */
39     } RBFVAL; /* radial basis function value */
40    
41     typedef struct s_rbflist {
42     struct s_rbflist *next; /* next in our RBF list */
43     FVECT invec; /* incident vector direction */
44     int nrbf; /* number of RBFs */
45     RBFVAL rbfa[1]; /* RBF array (extends struct) */
46     } RBFLIST; /* RBF representation of BSDF @ 1 incidence */
47    
48     /* our loaded grid for this incident angle */
49     static double theta_in_deg, phi_in_deg;
50     static GRIDVAL bsdf_grid[GRIDRES][GRIDRES];
51    
52     /* processed incident BSDF measurements */
53     static RBFLIST *bsdf_list = NULL;
54    
55     /* Count up non-empty nodes and build RBF representation from current grid */
56     static RBFLIST *
57     make_rbfrep(void)
58     {
59     int nn = 0;
60     RBFLIST *newnode;
61     int i, j;
62     /* count non-empty bins */
63     for (i = 0; i < GRIDRES; i++)
64     for (j = 0; j < GRIDRES; j++)
65     nn += (bsdf_grid[i][j].nval > 0);
66     /* allocate RBF array */
67     newnode = (RBFLIST *)malloc(sizeof(RBFLIST) + sizeof(RBFVAL)*(nn-1));
68     if (newnode == NULL) {
69     fputs("Out of memory in make_rbfrep\n", stderr);
70     exit(1);
71     }
72     newnode->invec[2] = sin(M_PI/180.*theta_in_deg);
73     newnode->invec[0] = cos(M_PI/180.*phi_in_deg)*newnode->invec[2];
74     newnode->invec[1] = sin(M_PI/180.*phi_in_deg)*newnode->invec[2];
75     newnode->invec[2] = sqrt(1. - newnode->invec[2]*newnode->invec[2]);
76     newnode->nrbf = nn;
77     nn = 0; /* fill RBF array */
78     for (i = 0; i < GRIDRES; i++)
79     for (j = 0; j < GRIDRES; j++)
80     if (bsdf_grid[i][j].nval) {
81     newnode->rbfa[nn].bsdf = MSCA*bsdf_grid[i][j].vsum /
82     (double)bsdf_grid[i][j].nval;
83 greg 2.2 newnode->rbfa[nn].crad = RSCA*bsdf_grid[i][j].crad + .5;
84 greg 2.1 newnode->rbfa[nn].gx = i;
85     newnode->rbfa[nn].gy = j;
86     ++nn;
87     }
88     newnode->next = bsdf_list;
89     return(bsdf_list = newnode);
90     }
91    
92     /* Compute grid position from normalized outgoing vector */
93     static void
94     pos_from_vec(int pos[2], const FVECT vec)
95     {
96     double sq[2]; /* uniform hemispherical projection */
97     double norm = 1./sqrt(1. + vec[2]);
98    
99     SDdisk2square(sq, vec[0]*norm, vec[1]*norm);
100    
101     pos[0] = (int)(sq[0]*GRIDRES);
102     pos[1] = (int)(sq[1]*GRIDRES);
103     }
104    
105     /* Compute outgoing vector from grid position */
106     static void
107     vec_from_pos(FVECT vec, int xpos, int ypos)
108     {
109     double uv[2];
110     double r2;
111    
112     SDsquare2disk(uv, (1./GRIDRES)*(xpos+.5), (1./GRIDRES)*(ypos+.5));
113     /* uniform hemispherical projection */
114     r2 = uv[0]*uv[0] + uv[1]*uv[1];
115     vec[0] = vec[1] = sqrt(2. - r2);
116     vec[0] *= uv[0];
117     vec[1] *= uv[1];
118     vec[2] = 1. - r2;
119     }
120    
121     /* Evaluate RBF for BSDF at the given normalized outgoing direction */
122     static double
123     eval_rbfrep(const RBFLIST *rp, const FVECT outvec)
124     {
125     double res = .0;
126     const RBFVAL *rbfp;
127     FVECT odir;
128     double sig2;
129     int n;
130    
131     rbfp = rp->rbfa;
132     for (n = rp->nrbf; n--; rbfp++) {
133     vec_from_pos(odir, rbfp->gx, rbfp->gy);
134 greg 2.2 sig2 = R2ANG(rbfp->crad);
135     sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2);
136 greg 2.1 if (sig2 > -19.)
137     res += rbfp->bsdf * exp(sig2);
138     }
139     return(res);
140     }
141    
142     /* Load a set of measurements corresponding to a particular incident angle */
143     static int
144     load_bsdf_meas(const char *fname)
145     {
146     FILE *fp = fopen(fname, "r");
147     int inp_is_DSF = -1;
148     double theta_out, phi_out, val;
149     char buf[2048];
150     int n, c;
151    
152     if (fp == NULL) {
153     fputs(fname, stderr);
154     fputs(": cannot open\n", stderr);
155     return(0);
156     }
157     memset(bsdf_grid, 0, sizeof(bsdf_grid));
158     /* read header information */
159     while ((c = getc(fp)) == '#' || c == EOF) {
160     if (fgets(buf, sizeof(buf), fp) == NULL) {
161     fputs(fname, stderr);
162     fputs(": unexpected EOF\n", stderr);
163     fclose(fp);
164     return(0);
165     }
166     if (!strcmp(buf, "format: theta phi DSF\n")) {
167     inp_is_DSF = 1;
168     continue;
169     }
170     if (!strcmp(buf, "format: theta phi BSDF\n")) {
171     inp_is_DSF = 0;
172     continue;
173     }
174     if (sscanf(buf, "intheta %lf", &theta_in_deg) == 1)
175     continue;
176     if (sscanf(buf, "inphi %lf", &phi_in_deg) == 1)
177     continue;
178     if (sscanf(buf, "incident_angle %lf %lf",
179     &theta_in_deg, &phi_in_deg) == 2)
180     continue;
181     }
182     if (inp_is_DSF < 0) {
183     fputs(fname, stderr);
184     fputs(": unknown format\n", stderr);
185     fclose(fp);
186     return(0);
187     }
188     ungetc(c, fp); /* read actual data */
189     while (fscanf(fp, "%lf %lf %lf\n", &theta_out, &phi_out, &val) == 3) {
190     FVECT ovec;
191     int pos[2];
192    
193     ovec[2] = sin(M_PI/180.*theta_out);
194     ovec[0] = cos(M_PI/180.*phi_out) * ovec[2];
195     ovec[1] = sin(M_PI/180.*phi_out) * ovec[2];
196     ovec[2] = sqrt(1. - ovec[2]*ovec[2]);
197    
198     if (inp_is_DSF)
199     val /= ovec[2]; /* convert from DSF to BSDF */
200    
201     pos_from_vec(pos, ovec);
202    
203     bsdf_grid[pos[0]][pos[1]].vsum += val;
204     bsdf_grid[pos[0]][pos[1]].nval++;
205     }
206     n = 0;
207     while ((c = getc(fp)) != EOF)
208     n += !isspace(c);
209     if (n)
210     fprintf(stderr,
211     "%s: warning: %d unexpected characters past EOD\n",
212     fname, n);
213     fclose(fp);
214     return(1);
215     }
216    
217     /* Compute radii for non-empty bins */
218     /* (distance to furthest empty bin for which non-empty bin is the closest) */
219     static void
220     compute_radii(void)
221     {
222 greg 2.2 unsigned short fill_grid[GRIDRES][GRIDRES];
223     FVECT ovec0, ovec1;
224     double ang2, lastang2;
225     int r2, lastr2;
226     int r, i, j, jn, ii, jj, inear, jnear;
227    
228     r = GRIDRES/2; /* proceed in zig-zag */
229 greg 2.1 for (i = 0; i < GRIDRES; i++)
230     for (jn = 0; jn < GRIDRES; jn++) {
231     j = (i&1) ? jn : GRIDRES-1-jn;
232     if (bsdf_grid[i][j].nval) /* find empty grid pos. */
233     continue;
234 greg 2.2 vec_from_pos(ovec0, i, j);
235 greg 2.1 inear = jnear = -1; /* find nearest non-empty */
236 greg 2.2 lastang2 = M_PI*M_PI;
237 greg 2.1 for (ii = i-r; ii <= i+r; ii++) {
238     if (ii < 0) continue;
239     if (ii >= GRIDRES) break;
240     for (jj = j-r; jj <= j+r; jj++) {
241     if (jj < 0) continue;
242     if (jj >= GRIDRES) break;
243     if (!bsdf_grid[ii][jj].nval)
244     continue;
245 greg 2.2 vec_from_pos(ovec1, ii, jj);
246     ang2 = 2. - 2.*DOT(ovec0,ovec1);
247     if (ang2 >= lastang2)
248 greg 2.1 continue;
249 greg 2.2 lastang2 = ang2;
250 greg 2.1 inear = ii; jnear = jj;
251     }
252     }
253 greg 2.2 if (inear < 0) {
254     fputs("Could not find non-empty neighbor!\n", stderr);
255     exit(1);
256     }
257     ang2 = sqrt(lastang2);
258     r = ANG2R(ang2); /* record if > previous */
259     if (r > bsdf_grid[inear][jnear].crad)
260     bsdf_grid[inear][jnear].crad = r;
261     /* next search radius */
262     r = ang2*(2.*GRIDRES/M_PI) + 1;
263 greg 2.1 }
264 greg 2.2 /* fill in neighbors */
265 greg 2.1 memset(fill_grid, 0, sizeof(fill_grid));
266     for (i = 0; i < GRIDRES; i++)
267     for (j = 0; j < GRIDRES; j++) {
268     if (!bsdf_grid[i][j].nval)
269 greg 2.2 continue; /* no value -- skip */
270     if (bsdf_grid[i][j].crad)
271     continue; /* has distance already */
272 greg 2.1 r = GRIDRES/20;
273 greg 2.2 lastr2 = 2*r*r + 1;
274 greg 2.1 for (ii = i-r; ii <= i+r; ii++) {
275     if (ii < 0) continue;
276     if (ii >= GRIDRES) break;
277     for (jj = j-r; jj <= j+r; jj++) {
278     if (jj < 0) continue;
279     if (jj >= GRIDRES) break;
280 greg 2.2 if (!bsdf_grid[ii][jj].crad)
281 greg 2.1 continue;
282 greg 2.2 /* OK to use approx. closest */
283 greg 2.1 r2 = (ii-i)*(ii-i) + (jj-j)*(jj-j);
284     if (r2 >= lastr2)
285     continue;
286 greg 2.2 fill_grid[i][j] = bsdf_grid[ii][jj].crad;
287 greg 2.1 lastr2 = r2;
288     }
289     }
290     }
291 greg 2.2 /* copy back filled entries */
292 greg 2.1 for (i = 0; i < GRIDRES; i++)
293     for (j = 0; j < GRIDRES; j++)
294     if (fill_grid[i][j])
295 greg 2.2 bsdf_grid[i][j].crad = fill_grid[i][j];
296 greg 2.1 }
297    
298     /* Cull points for more uniform distribution */
299     static void
300     cull_values(void)
301     {
302 greg 2.2 FVECT ovec0, ovec1;
303     double maxang, maxang2;
304     int i, j, ii, jj, r;
305 greg 2.1 /* simple greedy algorithm */
306     for (i = 0; i < GRIDRES; i++)
307     for (j = 0; j < GRIDRES; j++) {
308     if (!bsdf_grid[i][j].nval)
309     continue;
310 greg 2.2 if (!bsdf_grid[i][j].crad)
311     continue; /* shouldn't happen */
312     vec_from_pos(ovec0, i, j);
313     maxang = 2.*R2ANG(bsdf_grid[i][j].crad);
314     if (maxang > ovec0[2]) /* clamp near horizon */
315     maxang = ovec0[2];
316     r = maxang*(2.*GRIDRES/M_PI) + 1;
317     maxang2 = maxang*maxang;
318 greg 2.1 for (ii = i-r; ii <= i+r; ii++) {
319     if (ii < 0) continue;
320     if (ii >= GRIDRES) break;
321     for (jj = j-r; jj <= j+r; jj++) {
322     if (jj < 0) continue;
323     if (jj >= GRIDRES) break;
324     if (!bsdf_grid[ii][jj].nval)
325     continue;
326 greg 2.2 if ((ii == i) & (jj == j))
327     continue; /* don't get self-absorbed */
328     vec_from_pos(ovec1, ii, jj);
329     if (2. - 2.*DOT(ovec0,ovec1) >= maxang2)
330 greg 2.1 continue;
331 greg 2.2 /* absorb sum */
332 greg 2.1 bsdf_grid[i][j].vsum += bsdf_grid[ii][jj].vsum;
333     bsdf_grid[i][j].nval += bsdf_grid[ii][jj].nval;
334 greg 2.2 /* keep value, though */
335     bsdf_grid[ii][jj].vsum /= (double)bsdf_grid[ii][jj].nval;
336     bsdf_grid[ii][jj].nval = 0;
337 greg 2.1 }
338     }
339     }
340     }
341    
342    
343     #if 1
344     /* Test main produces a Radiance model from the given input file */
345     int
346     main(int argc, char *argv[])
347     {
348     char buf[128];
349     FILE *pfp;
350     double bsdf;
351     FVECT dir;
352     int i, j, n;
353    
354     if (argc != 2) {
355     fprintf(stderr, "Usage: %s input.dat > output.rad\n", argv[0]);
356     return(1);
357     }
358     if (!load_bsdf_meas(argv[1]))
359     return(1);
360     /* produce spheres at meas. */
361     puts("void plastic orange\n0\n0\n5 .6 .4 .01 .04 .08\n");
362     n = 0;
363     for (i = 0; i < GRIDRES; i++)
364     for (j = 0; j < GRIDRES; j++)
365     if (bsdf_grid[i][j].nval) {
366     double bsdf = bsdf_grid[i][j].vsum /
367     (double)bsdf_grid[i][j].nval;
368     FVECT dir;
369    
370     vec_from_pos(dir, i, j);
371     printf("orange sphere s%04d\n0\n0\n", ++n);
372     printf("4 %.6g %.6g %.6g .0015\n\n",
373     dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf);
374     }
375     compute_radii();
376     cull_values();
377     /* highlight chosen values */
378     puts("void plastic pink\n0\n0\n5 .5 .05 .9 .04 .08\n");
379     n = 0;
380     for (i = 0; i < GRIDRES; i++)
381     for (j = 0; j < GRIDRES; j++)
382     if (bsdf_grid[i][j].nval) {
383     bsdf = bsdf_grid[i][j].vsum /
384     (double)bsdf_grid[i][j].nval;
385     vec_from_pos(dir, i, j);
386     printf("pink cone c%04d\n0\n0\n8\n", ++n);
387     printf("\t%.6g %.6g %.6g\n",
388     dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf);
389     printf("\t%.6g %.6g %.6g\n",
390     dir[0]*(bsdf+.005), dir[1]*(bsdf+.005),
391     dir[2]*(bsdf+.005));
392     puts("\t.003\t0\n");
393     }
394     /* output continuous surface */
395     make_rbfrep();
396     puts("void trans tgreen\n0\n0\n7 .7 1 .7 .04 .04 .9 .9\n");
397     fflush(stdout);
398     sprintf(buf, "gensurf tgreen bsdf - - - %d %d", GRIDRES, GRIDRES);
399     pfp = popen(buf, "w");
400     if (pfp == NULL) {
401     fputs(buf, stderr);
402     fputs(": cannot start command\n", stderr);
403     return(1);
404     }
405     for (i = 0; i < GRIDRES; i++)
406     for (j = 0; j < GRIDRES; j++) {
407     vec_from_pos(dir, i, j);
408     bsdf = eval_rbfrep(bsdf_list, dir);
409     fprintf(pfp, "%.8e %.8e %.8e\n",
410     dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf);
411     }
412     return(pclose(pfp)==0 ? 0 : 1);
413     }
414     #endif